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Hip internal rotation has been reported to affect patellofemoral joint mechanics and contribute to patellofemoral pain (PFP). The SERF (S tability through E xternal R otation of the F emur) strap was designed to provide hip stability by pulling the thigh into external rotation during weight-bearing activities. What are the effects of the SERF strap on hip internal rotation and pain response in females with PFP who present with hip internal rotation during weight-bearing activities? Nineteen females between the ages of 18 and 45 with a diagnosis of PFP participated. Lower extremity kinematics were obtained during three tasks (drop-jump, unilateral step-down, over-ground running) under strap and no-strap conditions. A 10-cm visual analog scale (VAS) was used to assess pain response during each task and strap condition. Participants who exhibited at least 5 degrees of hip internal rotation during at least one of the 3 tasks were included in the final analysis. Peak hip internal rotation and mean VAS score were compared separately between strap conditions across tasks using 2 ×3 (strap condition x task) repeated-measures ANOVAs. Eighteen of the 19 females with PFP met the criteria for the presence of hip internal rotation. There was a significant reduction in peak hip internal rotation across tasks when wearing the SERF strap (mean ± sd = 7.4 ± 2.3, p<0.001). Additionally, the change in mean VAS pain score was significantly lower across tasks when wearing the SERF strap (1.0 ± 1.0, p=0.03). The SERF strap was effective in reducing hip internal rotation and PFP during dynamic weight-bearing activities in symptomatic females. The SERF strap may be a useful treatment adjunct for persons with PFP who present with poor transverse plane control of the hip. • SERF strap reduced hip internal rotation in females with patellofemoral pain. • SERF strap produced small absolute but large percent decreases in knee pain. • The reduced hip internal rotation suggests meaningful changes in joint loading. • Reduced hip internal rotation and knee pain are not necessarily causally related. [ABSTRACT FROM AUTHOR]

Certain movements patterns have been indicated in knee injuries during cutting while running tasks. Differences in the executed cut angle (ECA) could partially account for group differences in joint kinematics previously observed, including sex differences. Are there relationships between joint angles with entry speed and ECA during side-step cutting in soccer players? This cross-sectional study recruited 21 (10 females) soccer players. Participants completed 45° unanticipated side-step cuts in both directions. Kinematic data were captured with a 12 camera motion capture system with 46 reflective markers placed on the participants. Peak joint angles were determined during the stance phase of the cutting task. Entry speed and ECA were determined from pelvis markers. Hierarchical linear models examined relationships between angles, entry speed, and ECA, after accounting for age, sex, and leg preference. Regression coefficients with 95 % confidence intervals were reported and statistical significance (p<0.05) were examined using the Wald statistic. The mean ECA (24.6°) was lower than the intended 45° angle. Peak joint angles were significantly related to both ECA and entry speed. Specifically, an increase in ECA by 10° (i.e., sharper cuts) would increase hip internal rotation and ankle plantarflexion by 1.8–2.1°, and decrease hip adduction, knee abduction and ankle eversion by 1.3–2.4°. Faster entry speeds by 0.5 m/s would increase hip flexion, hip internal rotation and knee extension angles by 1.8–3.8°, and decrease knee abduction by 2.6°. Studies evaluating cutting while running should consider ECA and entry speed in their design. Potential differences could confound between-group comparisons of joint angles, including when comparing sexes, and impact interpretations of injury risk. • Pre-planned angles during cutting while running are not often reached in studies • The executed cut angle (ECA) is related to joint angles during cutting tasks • Entry speed is related to joint angles during cutting tasks • ECA and speed could partially account for previously shown group differences [ABSTRACT FROM AUTHOR]

Stiff knee gait is characterized by a reduced peak knee flexion during swing. Overactivity of the rectus femoris is often cited as a main cause for stiff knee gait. Little is known about the effect of an isolated rectus femoris transfer treatment on kinematic and functional outcomes in a group of stroke survivors. To perform an experimental study to evaluate the effect of an isolated rectus femoris transfer on knee and hip kinematics and functional outcomes in adult stroke patients walking with a stiff knee gait. In this experimental study, 10 stroke survivors were included. During the surgical procedure, the distal rectus femoris tendon of the affected side was transferred to the medial knee flexors to improve knee flexion during swing. Knee and hip kinematics and a variety of functional outcomes were measured within 3 weeks before surgery and between 6 and 7 months after the surgery. We found a statistically significant improvements in peak knee flexion during swing and knee range of motion of 10.6° (sd 4.7, p=0.000) and 10.5° (sd 6.2, p=0.001) post-surgery, respectively. Hip kinematics showed no significant differences. In addition, we found statistically significant improvements on the 6-minute walk test (42.5, sd 36.7, p=0.008), 10-meter walk test (1.26, sd 1.4, p=0.030), Timed up-and-go test (1.34, sd 1.18, p=0.009), L-test (2.97 sd 2.85, p=0.014) and on a subjective BORG scoring of foot clearance (1.8, sd 0.6, p=0.006). No significant differences were found on other measured functional outcomes. Rectus femoris transfer is a valuable treatment option for stroke patients walking with a stiff knee gait to improve knee kinematics and a selection of functional outcomes. There are no detrimental side effects on hip kinematics. • There is a significant improvement in peak knee flexion during swing (10.6°). • There is a significant improvement in knee range of motion (10.5°). • There is a significant improvement on the 6 MWT, 10 MWT and L-test. • There is a significant improvement on the TUG test, and on foot clearance. • Rectus femoris transfer is a valuable treatment option for stroke patients. [ABSTRACT FROM AUTHOR]

Multi-segment foot models (MFMs) provide a better understanding of the intricate biomechanics of the foot, yet it is unclear if they accurately differentiate foot type function during locomotion. We employed an MFM to detect subtle kinematic differences between foot types, including: pes cavus, neutrally aligned, and asymptomatic and symptomatic pes planus. The study investigates how variable the results of this MFM are and if it can detect kinematic differences between pathologic and non-pathologic foot types during the stance phase of gait. Independently, three raters instrumented three subjects on three days to assess variability. In a separate cohort, each foot type was statically quantified for ten subjects per group. Each subject walked while instrumented with a four-segment foot model to assess static alignment and foot motion during the stance phase of gait. Statistical analysis performed with a linear mixed effects regression. Model variability was highest for between-day and lowest for between–rater, with all variability measures being within the true sample variance. Almost all static measures (radiographic, digital scan, and kinematic markers) differed significantly by foot type. Sagittal hindfoot to leg and forefoot to leg kinematics differed between foot types during late stance, as well as coronal hallux to forefoot range of motion. The MFM had low between-rater variability and may be suitable for multiple raters to apply to a single study sample without introducing significant error. The model, however, only detected a few dynamic differences, with the most dramatic being the hallux to forefoot coronal plane range of motion. Significance: Results only somewhat aligned with previous work. It remains unclear if the MFM is sensitive enough to accurately detect different motion between foot types (pathologic and non-pathologic). A more accurate method of tracking foot bone motion (e.g., biplane fluoroscopy) may be needed to address this question. • The majority of static measures differed significantly by foot type. • Sagittal hind- and forefoot to leg kinematics differed between groups during stance. • Coronal hallux to forefoot range of motion varied by foot type during gait. • All variability measures were within the true sample variance. [ABSTRACT FROM AUTHOR]

The sit-to-stand transfer is a fundamental functional movement during normal activities of daily living. Central nervous system disorders can negatively impact the execution of sit-to-stand transfers, often impeding successful completion. Despite its importance, the neurophysiological basis at muscle (electromyography (EMG)) and brain (electroencephalography (EEG)) level as related to the kinematic movement is not well understood. This review synthesises the published literature addressing central and peripheral neural activity during 3D kinematic capture of sit-to-stand transfers. A pre-registered systematic review was conducted. Electronic databases (PubMed, CINAHL Plus, Web of Science, Scopus and EMBASE) were searched from inception using search operators that included sit-to-stand, kinematics and EMG and/or EEG. The search was not limited by study type but was limited to populations comprising of healthy individuals or individuals with a central neurological pathology. From a total of 28,770 identified papers, 59 were eligible for inclusion. Ten of these 59 studies received a moderate quality rating; with the remainder rated as weak using the Effective Public Health Practice Project tool. Fifty-eight studies captured kinematic data of sit-to-stand with associated EMG activity only and one study captured kinematics with co-registered EMG and EEG data. Fifty-six studies examined sit-to-stand transfer in healthy individuals, reporting four dynamic movement phases and three muscle synergies commonly used by most individuals to stand-up. Pre-movement EEG activity was reported in one study with an absence of data during execution. Eight studies examined participants following stroke and two examined participants with Parkinson's disease, both reporting no statistically significant differences between their kinematics and muscle activity and those of healthy controls. Little is known about the neural basis of the sit-to-stand transfer at brain level with limited focus in central neurological pathology. This poses a barrier to targeted mechanistic-based rehabilitation of the sit-to-stand movement in neurological populations. • Four dynamic movement phases are commonly used by most individuals to stand up. • Three muscle synergies are commonly used by most individuals to stand up. • No EEG data during sit-to-stand execution with 3D motion analysis was found. [ABSTRACT FROM AUTHOR]

Chronic ankle instability (CAI) has been associated with lower limb deficits that can lead to altered biomechanics during dynamic tasks. There have been contradictory findings in terms of ankle and hip joint biomechanics to date, influenced by the variety of movement tasks and varying definitions of the CAI condition. How do biomechanical variables of the lower extremity differ during walking, running, and jump-landing in individuals with CAI compared with those without CAI? Thirty-two individuals (17 CAI and 15 controls) participated in this retrospective case-control study. Sagittal and frontal plane ankle and hip joint angles and moments, and mediolateral foot balance (MLFB) were calculated during the tasks. Statistical parametric mapping (SPM) was used for the whole trajectory analysis to detect group differences. Discrete variables, including initial contact (IC) and peak angles and moments, were additionally compared. No differences were found between groups during walking. During running, the CAI group exhibited a lower plantar flexor moment (p < 0.001) and more laterally deviated MLFB (p = 0.014) during mid-stance when compared to controls. Additionally, participants with CAI had a significantly greater peak plantar flexion angle in early stance (p = 0.022) and a reduced peak plantar flexor moment (p = 0.002). In the jump-landing, the CAI group demonstrated an increased hip extensor moment (p = 0.008), and a greater peak hip adduction angle (p = 0.039) shortly after ground contact compared to the control group. Differences in ankle and hip biomechanics were observed between groups during running and jump landing, but not during walking. These differences may be indicative of impairments in the sensorimotor system or of learnt strategies adopted to try to minimise instability and injury risk and can help to inform future intervention design. • Individuals with CAI display different ankle joint biomechanics than controls during running. • Individuals with CAI display different hip joint biomechanics than controls during jump-landing. • The level of demand for the task may influence the biomechanical strategy adopted. [ABSTRACT FROM AUTHOR]

Obesity is a crucial factor that increases the risk of initiating and advancing knee osteoarthritis. However, it remains unclear how obesity directly impacts the biomechanical experience of the lower limb joints, potentially triggering or exacerbating joint degeneration. This study investigated the interactive effects of BMI augmentation on lower limb kinematics, kinetics, and muscle activations during walking. A group of 60 participants underwent a three-dimensional gait analysis. These individuals were categorized into three groups based on their body mass index (BMI): those with a BMI below 25 were classified as having a healthy weight, those with a BMI between 25 and 30 were categorized as overweight, and those with a BMI exceeding 30 were considered obese. This study analyzed the gait of 60 participants categorized by BMI. During walking trials, they recorded ground reaction forces electromyography of leg muscles like the gastrocnemii, hamstrings, and quadriceps. Lower limb joint angles and net moments were also calculated. Statistical mapping identified variations in kinematic, kinetic, and muscle activation patterns across the stance phase between BMI groups. The results displayed distinct biomechanical patterns in obese individuals. Notably, there was a significant increase in flexion observed in the hip and knee joints (P < 0.001) during the initial stance phase and an increase in hip and knee adduction angles and moments throughout the entire stance phase (P < 0.001). Additionally, muscle activations underwent significant changes (P < 0.01), with a positive correlation noted with the BMI factor. This correlation was most pronounced during the early stance phase for the quadriceps and hamstring muscles and the late stance phase for the gastrocnemius. These findings represent a comprehensive picture that contributes to understanding how excess weight and obesity influence joint biomechanics, highlighting the associated risk of joint osteoarthritis. • The study analyzes how BMI affects gait biomechanics in 60 guys aged 18-30. • Gait analysis, force plates, and motion capture analyze 3D motion, forces, and muscle activation. • Obesity increased hip/knee angles and moments, indicating biomechanical effects. • Research relates BMI to walking quadriceps, hamstring, and calf muscular activation. [ABSTRACT FROM AUTHOR]

Individuals with myelomeningocele (MMC) present with neurological and orthopaedic deficiencies, requiring orthoses during walking. Orthoses for counteracting dorsiflexion may restrict activities such as rising from a chair. How are sit-to-stand (STS) movements performed with ankle joint-restricted ankle-foot orthoses (AFO) and knee-ankle-foot orthoses with a free-articulated knee joint (KAFO-F)? Twenty-eight adults with MMC, mean age 25.5 years (standard deviation: 3.5 years), were divided into an AnkleFree group (no orthosis or a foot orthosis) and an AnkleRestrict group (AFOs or KAFO-Fs). Study participants performed the five times STS test (5STS) while their movements were simultaneously captured with a three-dimensional motion system. Centre of mass (CoM) trajectories and joint kinematics were analysed using statistical parametric mapping. The AnkleRestrict group performed the STS slower than the AnkleFree group, median 8.8 s (min, max: 6.9, 14.61 s) vs 15.0 s (min, max: 7.5, 32.2 s) (p = 0.002), displayed reduced ankle dorsiflexion (mean difference: 6°, p = 0.044) (74–81 % of the STS cycle), reduced knee extension (mean difference: 14°, p = 0.002) (17–41 % of the STS cycle), larger anterior pelvic tilt angle (average difference: 11°, p = 0.024) (12–24 % of the STS cycle), and larger trunk flexion angle (on average 4°, p = 0.029) (6–15 % of the STS cycle). The differences between the AnkleFree and AnkleRestrict groups in performing the STS seem consistent with the participants functional ambulation: community ambulation in the AnkleFree group, and household and nonfunctional ambulation with less hip muscle strength in the majority of the AnkleRestrict group. No differences in the 5STS CoM trajectories or the kinematics were found with respect to the AFO and KAFO-Fs groups. Because orthoses are constructed to enable walking, the environment needs to be adjusted for activities in daily living such as the STS movement. • Orthoses for walking require restricted ankle dorsiflexion in individuals with MMC. • A blocked ankle hampers forward movement altering sit-to-stand (STS) movements. • The effort required to perform STS in everyday activities should be acknowledged. • The findings highlight the importance of adjusting the environment with external support. [ABSTRACT FROM AUTHOR]

Three dimensional (3D) kinematic analysis based on motion capture can study synchronized data from the integrated jaw and neck motor system. Jaw function is commonly estimated on linear outcome variables of motion range. By combining jaw border movements in three planes the functional range of motion could be described by movement area and volume measures. Can we ensure the accuracy, test-retest reliability, and intra-individual variability with 3D kinematic analysis for estimating jaw functional range of motion (ROM), including jaw movement area and volume and jaw and head linear measures? Accuracy was estimated by applying the method to a set of beakers with known volume, based on the percentage deviation and Pearson correlation coefficient between target and estimated values. Test-retest reliability was then analysed on maximum jaw movements performed in a pre-determined movement sequence by 17 pain-free participants (25.4 years ± 2.4) to estimate jaw functional ROM. Intraclass correlation coefficients (ICC) were calculated, and Bland-Altman plots were constructed. Coefficient of variation (CV) tested the within session reliability. The accuracy in volume and area measurements were high with a percentage deviation (0.03±0.59) and (1.2±0.45), respectively, with a strong linear relationship (R2=0.99) between target and estimated values. The test-retest reliability showed moderate to excellent reliability, and Bland-Altman plots showed good agreement. Overall, CVs showed high repeatability, but jaw movements in horizontal directions were less reliable and presented higher variability. The study with 3D kinematic analysis of jaw functional ROM, provides a methodological basis for accurate and reliable measurements. The study presents a new way to estimate jaw functional ROM measures, useful for evaluation in clinical intervention, for instance in pain and jaw dysfunction. Moreover, the natural biological movement variability and the complexity of the interplay of jaw-head movement will be emphasised. • A new kinematic method to estimate jaw functional range of motion. • The accuracy in area and volume measurements were high. • Jaw and head linear movement displacements showed high test-retest reliability. • The method has potential to evaluate dysfunctions in jaw-neck motor system. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament injuries are serious conditions encountered in volleyball players and occur frequently during spike jump landings. During spike jumps, the lower limb kinematics and kinetics during landing may be altered in relation to the ball position. Does the ball position have an effect on lower-limb kinematics and kinetics during spike jumps? We measured the lower limb kinematics and kinetics of 20 healthy female college volleyball athletes during a spike jump using a three-dimensional motion analysis system. The ball positions were set to normal, dominant, and non-dominant positions. A repeated analysis of variance was used to compare the lower limb kinematics and kinetics at the initial contact and the maximum knee flexion during jump landing. Additionally, statistical parametric mapping analysis was used to analyze changes over time during the spike jumps. At the initial contact of the spike jump landing, the knee valgus angle, trunk lateral bending angle, and maximum knee valgus moment when the ball was set at the non-dominant position increased compared to those at the dominant position. Statistical parametric mapping analysis showed no significant change in knee valgus angle and moment of jump landing. Knee valgus angle, trunk lateral bending angle, and maximum knee valgus moment increased with the non-dominant position; furthermore, the risk of ACL injury may also be increased. The posture at ball impact may influence the landing kinematics and kinetics. Therefore, it is necessary to pay close attention to movements during and prior to landing. • Ball positions influenced trunk and lower limb in volleyball. • The knee valgus angle and moment were increased in non-dominant position. • The movement of trunk lateral bend during mid-flight affect the landing movement. [ABSTRACT FROM AUTHOR]

Gait kinematics differ between settings and among young and older adults with and without knee osteoarthritis. Out-of-lab data has a variety of walking bout characteristics compared to controlled in-lab settings. The effect of walking bout duration on gait analysis results is unclear, and there is no standardized procedure for segmenting or selecting out-of-lab data for analysis. Do gait kinematics differ by bout duration or setting in young and older adults with and without knee osteoarthritis? Ten young (28.1±3.5 yrs), ten older adults (60.8±3.3 yrs), and ten older adults with knee osteoarthritis (64.1±3.6 yrs) performed a standard in-lab gait analysis followed by a prescribed walking route outside the lab at a comfortable speed with four IMUs. Walking speed, stride length, and sagittal hip, knee, and ankle angular excursion (ROM) were calculated for each identified stride. Out-of-lab strides included straight-line, level walking divided into strides that occurred during long (>60 s) or short (≤60 s) bouts. Gait kinematics were compared between in-lab and both out-of-lab bout durations among groups. Significant main effects of setting or duration were found for walking speed and stride length, but there were no significant differences in hip, knee, or ankle joint ROM. Walking speed and stride length were greater in-lab followed by long and short bout out-of-lab. No significant interaction was observed between group and setting or bout duration for any spatiotemporal variables or joint ROMs. Out-of-lab gait data can be beneficial in identifying gait characteristics that individuals may not encounter in the traditional lab setting. Setting has an impact on walking kinematics, so comparisons of in-lab and free-living gait may be impacted by the duration of walking bouts. A standardized approach for to analyzing out-of-lab gait data is important for comparing studies and populations. • Setting and the duration of walking bouts have an influence on gait kinematics. • Speed and stride length were greater in vs out of lab and for long vs short bouts. • Adults respond similarly to different settings or bout durations regardless of age. [ABSTRACT FROM AUTHOR]

Gait abnormalities have been described in patients after total knee arthroplasty (TKA), leading to the development of inter-joint coordination abnormalities and increased risk of falling. Such impairments have been reported to persist in the long-term, although the majority of studies assessed gait pattern especially in the first months after TKA. What are the long-term gait impairments in patients after TKA compared to healthy age-matched subjects? A systematic search was conducted on MEDLINE/PubMed, EMBASE, CENTRAL and Scopus databases. Observational studies or randomized controlled trials investigating gait spatial-temporal, kinematic and kinetics parameters in a time-window longer than 6 months in patients with TKA compared to healthy age-matched subjects were included. Methodological quality was assessed using the modified Downs and Black (D&B) checklist and participants' characteristics, surgical procedures details and outcome measures were extracted. Pooled or un-pooled findings were categorized into "6 months - 1 year" and "more than 1 year" timepoint categories. Twenty-eight studies (976 patients) were included. Overall quality was fair with a mean modified D&B score of 63.5 %. Reduced speed, stride length, cadence and longer stance phase were found in patients when compared to healthy individuals at "6 months - 1 year" follow-up. Spatial-temporal parameters deficits were also found at more than 1 year after TKA, where lower single-limb support and longer double-limb support durations were detected. These impairments occurred in concomitance with decreased knee range of motion along the sagittal and frontal planes and altered kinetic parameters. Hip kinematic and kinetic long-term impairments were also detected after TKA. These findings highlighted long-term gait pattern alterations in patients with TKA compared to age-matched healthy subjects. Future studies should identify interventions able to reduce long-term gait pattern alterations and improve function in patients after TKA. • Long-term gait impairments were found in patients after TKA. • Lower speed, stride length, cadence and longer stance phase occurred after TKA. • Hip and knee kinematic and kinetic deficits were detected after TKA. [ABSTRACT FROM AUTHOR]

Multi-segment foot models have been used to quantify foot kinematics during walking. However, walking kinematics is not sufficient to assess hindfoot flexibility (available range of hindfoot varus-valgus motion). The modified Shriners Hospitals for Children – Greenville (mSHCG) foot model has been used to quantify hindfoot flexibility with Coleman block test (peak hindfoot valgus) and Root test (peak hindfoot varus). Sensitivity of mSHCG foot model to detect clinically relevant difference in hindfoot flexibility measures for planovalgus (PV) and cavovarus (CV) feet has not been demonstrated. Can mSHCG foot model detect statistically significant difference in hindfoot flexibility measures between PV, CV and typically developing (TD) feet? Hindfoot flexibility assessment was completed for 32 PV (37 feet), 27 CV (37 feet) and 20 TD (40 feet) individuals. Hindfoot position relative to tibia in coronal plane was measured in three postures: standing, heel raise and Coleman block test. Radiographic measures in standing position were also completed for PV and CV individuals and their correlation with hindfoot flexibility measures were evaluated. Statistically significant (p<0.001) differences were observed between three groups (TD, PV, CV) in all three hindfoot flexibility measures- (i) Hindfoot varus in standing position (ii) Peak hindfoot varus in heel raise and (iii) Peak hindfoot valgus in Coleman block test. There was relatively stronger correlation (R2=0.407–0.854) between three radiographic measures and hindfoot varus in standing position. Correlation between hindfoot range of motion towards valgus from standing to Coleman block test and the three radiographic measures was weaker (R2=0.2329–0.3042). Hindfoot flexibility assessment can detect statistically significant difference between PV, CV and TD feet and provides additional information about available dynamic range of motion of hindfoot in the coronal plane that cannot be predicted from radiographic measures. Therefore, hindfoot flexibility assessment may assist in treatment planning of foot deformities. • mSHCG foot model can be used to quantify hindfoot flexibility. • Significant difference observed in hindfoot flexibility for PV and CV feet compared to TD. • Hindfoot varus in standing position strongly correlated with radiographic measures. • Hindfoot valgus range in Coleman block test weakly correlated with radiographic measures. • Hindfoot flexibility assessment may be critical to treatment planning. [ABSTRACT FROM AUTHOR]

Wearable sensors provide the ability to assess ambulatory activity in the community after hip preservation surgery (HPS). In combination with gait analysis and patient reported outcomes, more perspective on post-operative function is gained. The purpose of this study was to assess the relationship between self-reported function/activity, temporo-spatial parameters and walking kinematics to objectively measured ambulatory activity. Forty-nine participants (38 Females; age range 16–38 years) who were five years or more post-surgery and the following diagnoses were included: Acetabular Dysplasia (n=34), Femoroacetabular Impingement (n=12) and Legg-Calvé Perthes disease (n=3). Participants underwent 3D gait analysis and gait deviations were quantified using the Gait Deviation Index (GDI) and Gait Profile Score (GPS). Temporo-spatial parameters were also calculated. Self-reported pain/function and activity level were assessed via the Harris Hip Score (HHS) and UCLA Activity Scale (UCLA). Participants wore a StepWatch Activity Monitor in their community and the Intensity/Duration of ambulatory bouts were analyzed. Spearman correlation coefficients were run to assess the following relationships: in-lab walking measures, self-reported function/activity vs.community ambulatory activity. There were no statistically significant correlations between HHS, UCLA or temporospatial parameters with ambulatory activity (p>0.05). Worsening gait deviations (GDI/GPS scores) correlated with daily total ambulatory time (ρ=0.284/-0.284, p<0.05), time spent in Short duration ambulatory bouts (ρ=-0.321/0.321, p<0.05) and the amount of time in Long duration ambulatory bouts (ρ=0.366/-0.366, p<0.05). The amount of time spent in Easy intensity/Short duration and Easy intensity/Long duration ambulatory bouts did have a weak correlation with the GDI and GPS (p<0.05). In HPS patients after long-term follow up, ambulatory activity in the community did not correlate with patient reported outcomes but there was a weak correlation with the presence of gait deviations. Incorporating wearable sensors to assess community ambulatory bout intensity/duration, provides additional quantifiable measures into the overall function of patients following HPS • Harris Hip Score did not correlate with community ambulatory activity. • Temporal spatial parameters did not correlate with community ambulatory activity. • Overall walking mechanics weakly correlate with community ambulatory activity. • Wearable sensors provide information on community ambulatory intensity/duration. [ABSTRACT FROM AUTHOR]

An ankle-foot orthosis (AFO) with plantar flexion resistance (PFR) can improve the first rocker function during gait, but the incremental changes in the resistive moment on balance and gait have not been well identified. To investigate the effect of changing the PFR moment of dynamic AFO (DAFO) on measures of the center of pressure (COP) and clinical gait outcomes in individuals with post-stroke hemiparesis. In this randomized repeated measure study of 36 stroke individuals, the customized DAFO using foot drop ankle units set in three PFR situations (low, medium, and high) was evaluated. The balance parameters for COP measures were investigated by HUMAC® Balance & Tilt System. Gait parameters and ankle kinematics were recorded using the 3D motion analysis through force platform and optoelectronic system. The comparison was made using a parametric ANOVA test and the P value was set at 0.05 for statistical significance. Significant differences were observed for COP average velocity (1.30 ± 0.64, 1.10 ± 0.05, and 1.37 ± 0.43), COP path length (43.3 ± 4.6, 33.4 ± 4.3, and 36.3 ± 5.4), walking velocity (11.0 ± 3.1, 13.2 ± 4.4, and 9.9 ± 3.5), and cadence (31.5 ± 2.0, 33.0 ± 3.1, and 29.0 ± 1.6) respectively for low, medium and high PFR settings (P < 0.05). Except for the COP path length and cadence, posthoc multiple comparisons revealed significant differences between low and medium (P < 0.05) and medium and high (P < 0.05) PFR grades. PFR with medium resistance demonstrated near-normal maximal peak ankle dorsiflexion (mean deviation of 8 degrees, P < 0.05). Medium PFR grade should be encouraged since it can enhance balance parameters like path length and average velocity of COP, increase cadence and average velocity during gait, and improve maximal peak ankle dorsiflexion. • Changes in resistive moment of plantar-flexion affects gait and balance in stroke. • The influence of PFR moment on ankle kinematics, gait and balance was examined. • Dynamic AFOs with dorsiflexion assist Klenzak joints allow for adjustable PFR. • Moderate PFR setting may improve the ankle kinematics, gait and balance parameters. • High PFR may increase non-symmetrical ankle dorsiflexion during swing. [ABSTRACT FROM AUTHOR]

The effects of foot orthoses on lower limb biomechanics during walking have been studied extensively. However, the lack of knowledge regarding the effects of various foot orthoses models for the same population complicates model selection in clinical practice and research. Additionally, there is a critical need to enhance our ability to predict the outcomes of foot orthoses using clinical tests, such as the supination resistance test. What are the effects of two commonly prescribed types of FO (thin-flexible and medially wedged) on lower limb biomechanics during gait? Is there a correlation on these effects with the results of the supination resistance test? Twenty-three participants with flat feet were enrolled in this cross-sectional descriptive study. Participants underwent walking trials under three conditions: shod, thin-flexible FOs and medially wedged FOs. Midfoot, ankle, knee and hip angles, moments were calculated. Repeated measure ANOVAs were employed for within-group comparison across conditions. Correlations between the effects of FOs on foot and ankle angles/moments and supination resistance were determined using regression analyses using a statistical parametric mapping approach. Thin-flexible and medially wedged FOs reduced midfoot dorsiflexion angles and ankle inversion moments. Medially wedged FOs also decreased midfoot and ankle abduction angles, midfoot plantarflexion moments compared to thin-flexible FOs and shoes. Moderate to good correlations between the supination resistance test and the medially wedged FOs were observed for the frontal and transverse ankle angles and moments. Medially wedged FOs are more effective in modifying lower limb biomechanics during walking compared to thin-flexible FOs. Greater supination resistance was associated with more pronounced effects for medially wedged FOs on foot and ankle biomechanics. These findings hold promise for refining orthotic prescription strategies, potentially offering advantages to individuals with musculoskeletal disorders. • Medially wedged foot orthoses generated the greater biomechanical effects. • Foot orthoses primarily impacted the distal segments of the lower limb. • Moderate correlations were observed between SRT and the biomechanical effects. • The supination resistance test will help in the foot orthoses selection process. [ABSTRACT FROM AUTHOR]

In daily life tasks of the upper limb, we must make quick corrections with our hands in unstable postural situations. Postural and reaching control mechanisms are involved in the accurate execution of upper-limb tasks. This research aimed to determine the effect of different postural stability conditions on the motor performance of the upper limb in a reaching task with non-static targets. 19 young participants performed a reaching task toward targets that exhibited a change in position (at 200 or 600 ms) in different postural conditions (bipedal-firm, bipedal-foam, and unipedal-foam surface). Performance on the screen (motion time and spatial error), balance (center of pressure displacements, CoP), and index finger movements were recorded during the reaching task. The instability affects the finger kinematic (displacements) and CoP kinematic (displacements, speed, and smoothness) without affecting the performance on the screen (precision and duration). The timing of target change affects the performance on the screen, finger kinematic (speed and smoothness), and CoP kinematic (displacements, speed, and smoothness). Postural and reaching control systems enable accurate hand motions in less stable situations, even in reaching tasks with non-static targets. The postural and reaching control systems can protect the end-effector performance during unstable conditions but not during trials with less time to correct the motion. • Postural instability does not affect the finger performance on the screen of non-static reaching. • Postural instability affects the finger and CoP kinematics during non-static reaching. • The timing of target change affects the performance of reaching and body kinematics. • Postural and reaching control systems can protect finger performance on the screen during unstable conditions. • Postural and reaching control systems cannot protect finger performance on the screen with little time to correct. [ABSTRACT FROM AUTHOR]

Transhumeral (TH) limb loss leads to loss of body mass and reduced shoulder range of motion. Despite most owning a prosthesis, prosthesis abandonment is common. The consequence of TH limb loss and prosthesis use and disuse during gait may be compensation in the upper body, contributing to back pain or injury. Understanding the impact of not wearing a TH prosthesis on upper body asymmetries and spatial-temporal aspects of gait will inform how TH prosthesis use and disuse affects the body. Does TH limb loss alter upper body asymmetries and spatial-temporal parameters during gait when wearing and not wearing a prosthesis compared to able-bodied controls? Eight male TH limb loss participants and eight male control participants completed three gait trials at self-selected speeds. The TH limb loss group performed trials with and without their prosthesis. Arm swing, trunk angular displacement, trunk-pelvis moment, and spatial-temporal aspects were compared using non-parametric statistical analyses. Both TH walking conditions showed greater arm swing in the intact limb compared to the residual (p≤0.001), resulting in increased asymmetry compared to the control group (p≤0.001). Without the prosthesis, there was less trunk flexion and lateral flexion compared to the control group (p≤0.001). Maximum moments between the trunk and pelvis were higher in the TH group than the control group (p≤0.05). Spatial-temporal parameters of gait did not differ between the control group and either TH limb loss condition. Prosthesis use affects upper body kinematics and kinetics, but does not significantly impact spatial-temporal aspects of gait, suggesting these are compensatory actions. Wearing a prosthesis helps achieve more normative upper body kinematics and kinetics than not wearing a prosthesis, which may help limit back pain. These findings emphasize the importance of encouraging at least passive use of prostheses for individuals with TH limb loss. • Transhumeral prosthesis use preserved upper body motion more than disuse during gait. • Significant arm swing asymmetry occurs in transhumeral prosthesis use and disuse. • Transhumeral prosthesis disuse increases joint moments in the upper body during gait. • No differences in gait were observed between prosthesis use/disuse and the control. • Changes in upper body kinematics may be compensatory to preserve gait symmetry. [ABSTRACT FROM AUTHOR]

Prader-Willi syndrome (PWS) is characterized by a complex clinical condition, whose typical features lead to impaired motor and functional skills. To date, limited data is available as regards symmetry of gait in PWS. The aim of this study was to characterize lower-limb asymmetry during gait in a group of Prader-Willi Syndrome (PWS) individuals by using the synchronized cyclograms and to compare it with those of two different control groups, a normal-weight group and an obese group. A total of 18 PWS, 30 normal weight (NW) and 28 obese individuals (OG) matched for age, sex and height were assessed via 3D gait analysis. Gait spatio-temporal parameters were computed together with angle-angle diagrams, characterized in terms of their geometric features (i.e. area, orientation, and trend symmetry index). Individuals with PWS exhibit reduced speed, stride length and cadence and increased duration of both stance and double support phase than the other groups. OG was characterized by the same pattern when compared to NW. With respect to inter-limb symmetry, individuals with PWS exhibited significantly larger cyclogram areas at hip joint with respect to the other two groups (203.32 degrees2 vs. 130.73 degrees2 vs. 111.59 degrees2) and significantly higher orientation angle (4.17° vs. 2.11° vs. 1.22°) and Trend Symmetry (3.72 vs. 2.02 vs. 1.21) with respect to the other two groups at knee joint; no differences were found at ankle joint. Both individuals with PWS and those of OG exhibited reduced ROM at knee and ankle joints with respect with normal weight, but no statistically significant differences were observed between PWS and OG. The obtained results may provide novel and useful insights to understand better the impairments in motor control associated with this pathological state, supporting clinics in the identification of the best rehabilitation program for this rare pathological state, aimed to improve stability and motor control. • limited data is available as regards symmetry of gait in patients with Prader-Willi syndrome. • symmetry can be assessed through the calculation of several geometric properties of the cyclogram. • patients with Prader-Willi syndrome present altered spatio-temporal parameters and poor inter-limb symmetry. [ABSTRACT FROM AUTHOR]

Biplanar radiography displays promising results in the production of subject-specific (S.specific) biomechanical models. However, the focus has predominantly centred on methodological investigations in gait analysis. Exploring the influence of such models on the analysis of high range of motion tasks linked to hip pathologies is warranted. The aim of this study is to investigate the effect of S.Specific modelling techniques on the reliability of deep squats kinematics in comparison to generic modelling. 8 able-bodied male participants attended 5 motion capture sessions conducted by 3 observers and performed 5 deep squats in each. Prior to each session a biplanar scan was acquired with the reflective-markers attached. Inverse kinematics of pelvis and thigh segments were calculated based on S.specific and Generic model definition. Agreement between the two models femoropelvic orientation in standing was assessed with Bland-Altman plots and paired t- tests. Inter-trial, inter-session, inter-observer variability and observer/trial difference and ratio were calculated for squat kinematic data derived from the two modelling approaches. Compared to the Generic model, the S.Specific model produced a calibration trial that is significantly offset into more posterior pelvis tilt (–2.8±2.7), hip extension (–2.2±3.8), hip abduction (–1.2±3.6) and external rotation (–13.8±11.4). The S.specific model produced significantly different squat kinematics in the sagittal plane of the pelvis (entire squat cycle) and hip (between 40 % and 60 % of the squat cycle). Variability analysis indicated that the error magnitude between the two models was comparable (difference<2°). The S.specific model exhibited a lower variability in the observer/trial ratio in the sagittal pelvis and hip, the frontal hip, but showed a higher variability in the transverse hip. S.specific modelling appears to introduce a calibration offset that primarily translates into an effect in the sagittal plane kinematics. However, the clinical added value of S.specific modelling in terms of reducing experimental sources of kinematic variability was limited. • Biplanar radiography was used to produce subject-specific hip and pelvis model. • S.specific model kinematics were compared to generic model kinematics. • S.specific modelling significantly offsets the calibration of the standing trial. • This offset influenced the kinematics of the Sagittal pelvis and hip kinematics. • This offset had minimum impact on the variability of deep squat kinematics. [ABSTRACT FROM AUTHOR]

Developments in vision-based systems and human pose estimation algorithms have the potential to detect, monitor and intervene early on neurodegenerative diseases through gait analysis. However, the gap between the technology available and actual clinical practice is evident as most clinicians still rely on subjective observational gait analysis or objective marker-based analysis that is time-consuming. This paper aims to examine the main developments of vision-based motion capture and how such advances may be integrated into clinical practice. The literature review was conducted in six online databases using Boolean search terms. A commercial system search was also included. A predetermined methodological criterion was then used to assess the quality of the selected articles. A total of seventeen studies were evaluated, with thirteen studies focusing on gait classification systems and four studies on gait measurement systems. Of the gait classification systems, nine studies utilized artificial intelligence-assisted techniques, while four studies employed statistical techniques. The results revealed high correlations of gait features identified by classifier models with existing clinical rating scales. These systems demonstrated generally high classification accuracies and were effective in diagnosing disease severity levels. Gait measurement systems that extract spatiotemporal and kinematic joint information from video data generally found accurate measurements of gait parameters with low mean absolute errors, high intra- and inter-rater reliability. Low cost, portable vision-based systems can provide proof of concept for the quantification of gait, expansion of gait assessment tools, remote gait analysis of neurodegenerative diseases and a point of care system for orthotic evaluation. However, certain challenges, including small sample sizes, occlusion risks, and selection bias in training models, need to be addressed. Nevertheless, these systems can serve as complementary tools, equipping clinicians with essential gait information to objectively assess disease severity and tailor personalized treatment for enhanced patient care. • Low-cost vision-based systems may enable more objective quantification of gait. • Vision-based systems allow early detection and severity monitoring of diseases. • Gait classification systems show high correlations with clinical rating scales. • Gait measurement systems effectively extract spatiotemporal and kinematic data. • A point of care system enabling remote gait analysis and orthotic evaluation. [ABSTRACT FROM AUTHOR]

The complex anatomical structure of the foot-ankle imposes challenges to accurately quantify detailed hindfoot kinematics and estimate musculoskeletal loading parameters. Most systems used to capture or estimate dynamic joint function oversimplify the anatomical structure by reducing its complexity. Can four dimensional computed tomography (4D CT) imaging in combination with an innovative foot manipulator capture in vivo hindfoot kinematics during a simulated stance phase of walking and can talocrural and subtalar articular joint mechanics be estimated based on a detailed in silico musculoskeletal foot-ankle model. A foot manipulator imposed plantar/dorsiflexion and inversion/eversion representing a healthy stance phase of gait in 12 healthy participants while simultaneously acquiring 4D CT images. Participant-specific 3D hindfoot rotations and translations were calculated based on bone-specific anatomical coordinate systems. Articular cartilage contact area and contact pressure of the talocrural and subtalar joints were estimated using an extended foot-ankle model updated with an elastic foundation contact model upon prescribing the participant-specific rotations measured in the 4D CT measurement. Plantar/dorsiflexion predominantly occurred at the talocrural joint (RoM 15.9±3.9°), while inversion/eversion (RoM 5.9±3.9°) occurred mostly at the subtalar joint, with the contact area being larger at the subtalar than at the talocrural joint. Contact pressure was evenly distributed between the talocrural and subtalar joint at the beginning of the simulated stance phase but was then redistributed from the talocrural to the subtalar joint with increasing dorsiflexion. In a clinical case study, the healthy participants were compared with four patients after surgically treaded intra-articular calcaneal fracture. The proposed workflow was able to detect small but meaningful differences in hindfoot kinematics and kinetics, indicative of remaining hindfoot pathomechanics that may influence the onset and progression of degenerative joint diseases. • 4D CT enables in vivo quantification of dynamic gait-like motion of the hindfoot. • Talocrural joint allows plantar/dorsiflexion; subtalar enables inversion/eversion. • Musculoskeletal modelling allows quantification of dynamic hindfoot loading. • Talocrural contact pressure is negatively correlated with talocrural dorsiflexion. • Detection of meaningful differences between healthy and pathological subjects. [ABSTRACT FROM AUTHOR]

The decline in cognitive function in older adults with mild cognitive impairment (MCI) may contribute to a change in movement pattern during sit-to-stand transitions (STS). However, when comparing older adults with MCI to older adults without MCI, there is a lack of evidence of kinematic and kinetic data during STS. Furthermore, while significant cognitive dual-task interference has been demonstrated in older adults with MCI, studies on the effects of dual motor tasks in MCI, particularly during STS, have not been reported. Are there any differences in the movement time, joint angles, and maximum joint moments while performing STS under single- and dual-task conditions in older adults with and without MCI? In a cross-sectional study, 70 participants were divided into two groups: older adults with MCI and without MCI. Motion analysis and a force plate system were used to collect and analyze the STS movement. All participants were asked to do the STS movement alone and the STS with a dual motor task with the self-selected pattern on an adjustable bench. Older adults with MCI had greater maximum trunk flexion during STS with a dual task than older adults without MCI and greater than STS alone. Furthermore, older adults with MCI had a greater ankle plantar flexion moment during STS with a dual task than during STS alone. Even though the STS task is one of the simplest functional activities, different strategies to achieve the STS action with dual tasks were found among older adults with and without MCI in terms of joint angle and joint moments. • The time used for STS showed no difference between older adults with and without MCI. • STS with dual tasks spent more time to complete than STS alone. • Older adults with MCI perform more trunk flexion during STS with dual tasks. • Older adults with MCI rely on the ankle plantar flexor during STS with dual tasks. [ABSTRACT FROM AUTHOR]

As total ankle arthroplasty (TAA) is an increasingly common surgical intervention for patients with end-stage ankle arthritis, there is a need to better understand the dynamic performance of prosthetic implants during activities of daily living. Our purpose was to quantify and compare relative tibiotalar motion during gait in persons with a fixed-bearing (FB) and mobile-bearing (MB) total ankle arthroplasty. We hypothesized a FB prosthesis would have lower tibiotalar range of motion (ROM). Patients at least 12 months postoperative with either a FB (n=5) or MB (n=3) total ankle arthroplasty were tested. We used high-speed biplanar videoradiography to quantify tibiotalar kinematics during self-selected gait. Angular and linear ROM in three axes were compared between the groups. ROM for dorsiflexion-plantarflexion, internal-external rotation, and inversion-eversion angles in FB subjects averaged 7.47±4.05°, 7.39±3.63°, and 4.51±2.13°, respectively. ROM in MB subjects averaged 6.74±2.04°, 6.28±4.51°, and 5.68±2.81°, respectively. Linear ROM along anteroposterior, mediolateral, and superior-inferior axes in FB subjects averaged 1.47±2.07 mm, 1.13±1.49 mm, and 0.28±0.30 mm, respectively. Linear ROM in MB subjects averaged 0.68±1.44 mm, 0.60±1.41 mm, and 0.20±0.13 mm, respectively. We found no significant difference between the two groups for any of these ROM parameters (p>0.05). Total ankle arthroplasty using either FB or MB design appears to confer similar ankle motion during the gait cycle in this biplanar fluoroscopic model. Level IV, case series. • X-ray motion analysis is a useful tool to compare ankle arthroplasty systems. • No differences in angular motion between MB and FB arthroplasty systems. • No significant difference in linear translation along joint axes in both systems. [ABSTRACT FROM AUTHOR]

Clinical gait analysis (CGA) is a systematic approach to comprehensively evaluate gait patterns, quantify impairments, plan targeted interventions, and evaluate the impact of interventions. However, international standards for CGA are currently lacking, resulting in various national initiatives. Standards are important to ensure safe and effective healthcare practices and to enable evidence-based clinical decision-making, facilitating interoperability, and reimbursement under national healthcare policies. Collaborative clinical and research work between European countries would benefit from common standards. This study aimed to review the current laboratory practices for CGA in Europe. A comprehensive survey was conducted by the European Society for Movement Analysis in Adults and Children (ESMAC), in close collaboration with the European national societies. The survey involved 97 gait laboratories across 16 countries. The survey assessed several aspects related to CGA, including equipment used, data collection, processing, and reporting methods. There was a consensus between laboratories concerning the data collected during CGA. The Conventional Gait Model (CGM) was the most used biomechanical model for calculating kinematics and kinetics. Respondents also reported the use of video recording, 3D motion capture systems, force plates, and surface electromyography. While there was a consensus on the reporting of CGA data, variations were reported in training, documentation, data preprocessing and equipment maintenance practices. The findings of this study will serve as a foundation for the development of standardized guidelines for CGA in Europe. • Survey report on current Clinical Gait Analysis (CGA) practices across Europe. • Good agreement on data included in CGA with video, kinematics, kinetics and EMG. • Training, documentation, maintenance, reliability evaluations vary between laboratories. • New gait analysis tools have limited adoption in CGA. • Results set foundation for a Delphi process to define European CGA standards. [ABSTRACT FROM AUTHOR]

The subtalar joint movement between the talus and calcaneus is restricted in patients with talocalcaneal coalition (TCC). When the motion of the subtalar joint is restricted, shock absorption in the foot decreases, leading to pain during walking. Resection methods to maintain subtalar motion by removing abnormal unions have been proposed. The purpose of this study was to analyze the joint kinematics of patients who underwent TCC resection and to quantitatively evaluate the results of the surgery based on the measured kinematics. Joint kinematics of five patients with TCC were obtained using a biplane fluoroscopic imaging system and an intensity-based two-/three-dimensional registration method. The joint kinematics of the tibiotalar and subtalar joints and the tibiocalcaneal motion during the stance phase of walking were obtained. From the kinematics of the hindfoot joints, the inversion/eversion range of motion (ROM) of the patients before and after resection was statistically analyzed using the Wilcoxon signed-rank test to test whether TCC resection improved the ROM. During the loading response period, the eversion ROM of the subtalar joint and tibiocalcaneal motion significantly increased postoperatively. In addition, a significant postoperative increase was observed in the subtalar and tibiocalcaneal inversion ROM during the pre-swing period. TCC resection surgery increased the ROM of the subtalar joint, which in turn contributed to the increase in tibiocalcaneal ROM. Increased subtalar and tibiocalcaneal ROM could result in increased shock attenuation and may be a contributing factor to pain relief during walking. [ABSTRACT FROM AUTHOR]

Individuals with cerebral palsy (CP) often present with altered motor control. This can be assessed selectively during sitting/lying with the Selective Control Assessment of the Lower Extremity (SCALE), or dynamically with the dynamic motor control index during walking (walk-DMC). Both approaches suggest that altered selective motor control relate to larger gait deviations. Does the walk-DMC provide valuable information in addition to the SCALE for estimating gait deviations in individuals with CP. Retrospective, treadmill-based gait analysis data of 157 children with spastic CP (mean 11.4±3.5 years) and Gross Motor Function Classification System levels I (n=45), II (n=88) or III (n=24) were extracted. Gait kinematic deviations were evaluated using the Gait Profile Score (GPS). The SCALE, walk-DMC and GPS were extracted for the more clinically involved leg (unilateral-analysis), and for both legs together (bilateral-analysis). GPS moderately correlated with both SCALE and walk-DMC scores, unilaterally and bilaterally (r≥0.4; p<0.001). Multivariate linear regression analyses were conducted, taking into account potential confounding factors. In the unilateral analysis, 54% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p=0.008, respectively). In the bilateral analysis, 61% of the GPS variance was explained (p<0.001), with both walk-DMC and SCALE significantly contributing to the GPS variance (p=0.006 and p<0.001, respectively). Dimensionless walking speed and use of assistive devices were the only confounding factors included in each analysis. Both SCALE and walk-DMC significantly contribute to GPS variance, suggesting that they likely measure different components of motor control, and both may be useful in understanding the underlying relationship between motor control and deviations in gait kinematics. • Both the SCALE and walk-DMC relate to kinematic gait deviations in CP. • The SCALE and walk-DMC likely measure different components of motor control in CP. • In the absence of EMG, the SCALE can be used to quantify motor control in CP. [ABSTRACT FROM AUTHOR]

Posterior tibialis tendon dysfunction (PTTD) is a chronic degenerative musculoskeletal disorder causing a progressive ankle complex and arch collapse altering lower limb biomechanics. However, biomechanical changes associated with stage 1 and 2 PTTD need to be better characterized during walking to guide clinical recommendations and improve non-operative treatments. What are the lower limb kinematic and kinetic differences between individuals with stage 1 (PTTD1), individuals with stage 2 PTTD (PTTD2) and healthy counterparts during gait? Sixteen PTTD1, 11 PTTD2 and 20 healthy controls were included in this multicentric case-control study to compare their lower limb gait biomechanics. Kinematic and kinetic data were recorded using a three-dimensional motion capture system and a force plate. One-dimensional statistical parametric mapping was used to compare lower limb joint motion and moments between groups during the stance phase. PTTD1 had minimal biomechanical differences compared with the control group. In contrast, PTTD2 presented significant differences compared with controls and PTTD1. At the ankle, PTTD2 exhibited greater plantarflexion and eversion angles and midfoot dorsiflexion and inversion angles throughout stance compared with controls and PTTD1. PTTD2 presented lower midfoot abduction moments compared with controls. These changes led PTTD2 to exhibit knee and hip adaptative biomechanical mechanisms in the frontal and transverse planes in late stance. PTTD2 had greater knee internal rotation angles and smaller knee external rotation moments compared to controls. PTTD2 had smaller hip internal rotation angles compared with PTTD1 and smaller hip adduction moments compared with controls. PTTD1 showed minimal biomechanical differences compared to controls and important differences compared to PTTD2. The lower limb biomechanical deficits accentuate as the pathology advances from stage 1 to stage 2. PTTD is a progressive condition needing early clinical management at stage 1 to avoid successive biomechanical changes associated with stage 2. • PTTD2 presented greater foot and ankle pronation than PTTD1. • Medial longitudinal arch was more collapsed for PTTD2 than PTTD1. • PTTD2 exhibited greater midfoot dorsiflexion/inversion and ankle plantarflexion/eversion. • The lower limbs' biomechanics was similar between PTTD1 and controls. [ABSTRACT FROM AUTHOR]

Trendelenburg gait describes contralateral pelvic drop during single leg stance (SLS) with occasional lateral trunk lean compensation over the stance limb. However, quantitative research on 'uncompensated Trendelenburg' gait (pelvic drop independent of lateral trunk lean) remains sparse among populations that commonly utilize this gait pattern, such as adolescent hip pathology patients. How prevalent is uncompensated Trendelenburg among various adolescent hip pathologies and how is it related to hip load, hip abduction strength, and self-reported hip pain? Gait, strength, and pain data were collected among 152 pre-operative patients clinically diagnosed with acetabular hip dysplasia, femoroacetabular impingement, Legg-Calvé-Perthes, or slipped capital femoral epiphysis (SCFE). Patients with ≥ 5.4° of dynamic pelvic drop in SLS were divided into a 'pelvic drop' group and screened to exclude those with excessive ipsilateral trunk lean. They were then compared to the 'stable pelvis' patients using a Mann-Whitney test. Dysplasia patients represented the highest proportion of the pelvic drop group (46%). The pelvic drop group showed a significant increase in self-reported hip pain (p = 0.011), maximum hip abductor moment (p = 0.002), and peak coronal power absorption at the affected hip during SLS loading response, (p < 0.001) while showing no difference in abduction strength (p = 0.381). Uncompensated Trendelenburg gait may lead to increased loading of the affected hip in adolescent hip pathology patients. Disadvantageous hip biomechanics can create increased abductor muscle demand among these pathological populations, with dysplasia patients showing the highest prevalence. Maximal abduction strength did not correlate with pelvic drop. Future work should aim to identify and quantify causal factors. Increased coronal hip power absorption during weight acceptance warrants clinical attention, as there may be a detrimental, over-reliance on passive hip structures to support load among a population that that is already predisposed to hip osteoarthritis. • Excessive pelvic drop in gait can be exhibited by adolescents with hip disorders. • Without a trunk lean compensation, this gait increases load at the affected hip. • Abnormal hip morphology may create mechanical disadvantages that cannot be overcome. • There may be an over-reliance on passive hip structures to support load. • In populations predisposed to hip osteoarthritis, clinical awareness is warranted. [ABSTRACT FROM AUTHOR]

Hallux Rigidus is the result of degeneration of the 1st metatarsophalangeal joint (1st MTPJ). In end-stage hallux rigidus, treatment is mainly surgical with arthrodesis being a favourable option. Although the biomechanical effects of arthrodesis have been examined, a detailed comparison of pre- and post-operative biomechanics has yet to be conducted. Does 1st MTPJ arthrodesis positively affect foot kinematics and plantar pressure distribution? Twelve 1st MTPJ arthrodesis were performed in patients with a mean age of 53.5 ± 5.4 years and follow up time of 6.9 ± 1.0 months. Pre- and post-operative data were collected at a CMAS (Clinical Movement Analysis Society) accredited gait laboratory using a BTS motion capture system and pedobarographic pressure plates. Patient outcome measures were also assessed using the MOXFQ. Statistical analysis was conducted using a two-way repeated measures ANOVA. Significant changes in stride length, cycle duration, cadence and velocity were identified following 1st MTPJ arthrodesis. A significant reduction in forefoot-hallux dorsiflexion at toe-off was identified for the operated foot from the pre-operative (20.23 ± 5.98°) to post-operative (7.56 ± 2.96°) assessment. Post-operative sagittal and transverse plane changes in the operated foot were also identified. Peak pressure and PTI results indicated significant lateralisation of load for the operated foot, but importantly this was not influenced following arthrodesis. Finally, there was a significant improvement in MOXFQ score. Following 1st MTPJ fusion there is an improvement in overall gait mechanics which accompanied by the improved MOXFQ score indicates a reduction in pain and improved confidence during gait. The lack of post-operative dorsiflexion at forefoot-hallux caused load to remain lateralised and compensatory mechanisms to occur at the more proximal joints within the foot. These results provide valuable information for clinicians and will enable more accurate counselling to be provided to patients with end-stage hallux rigidus. • Stride length, cycle duration and cadence significantly increased. • There was an improvement in the patient reported outcome. • Forefoot-hallux dorsiflexion for the operated foot significantly reduced at toe-off for the operated foot. • Load remains weighed on the lateral aspect of the foot. • Compensatory kinematic mechanics occur at more proximal joints within the foot. [ABSTRACT FROM AUTHOR]

To study the body posture characteristics when walking with trolley case, and to explore the effects of different usage methods and weights of trolley case on body posture characteristics. Fifteen subjects pushed and pulled(Condition 1 and 2) the case with three load weights of 10 %, 20 % and 30 % of their own body weight with 0 % no load as baseline for both conditions. The basic gait parameters, kinematic and kinetic data were collected using the VICON infrared motion capture system and a 3D force platform. Two repeated measures factor (condition×weight) analysis of variance was used for statistical analysis of the gait temporal and spatial parameters, as well as trunk angle, kinetic ground reaction force, shoulder joint force, and trunk moment. Significant condition*weight interactions were detected in DLST (Double Limb Stance Time) (F=5.341，P = 0.006), GRF (Ground Reaction Force) in frontal plane (F=10.507, p < 0.001) and vertical plane (F=3.751, p = 0.021), shoulder joint force in sagittal plane (F=21.129, p < 0.001), and flexion-extension angle of the trunk in the sagittal plane (F=4.888, p < 0.010). Significant main effects were detected in walking speed (F=35.842, p < 0.001), right support time (F=12.156, p < 0.001), left swing time (F=8.506, p < 0.001), left support time (F=1.122, p < 0.001), right step length (F=33.900, p < 0.001), and left step length (F=14.960, p < 0.001) under different weights. A significant main effect was detected in sagittal GRF (F=11.77, p < 0.001), trunk rotation angle (F=4.124, p = 0.016), amplitude of COM (F=2.993, p = 0.046), under different weights. When the weight of the case exceeds 20 % of the body weight, from the perspective of energy efficiency, the push method is more advantageous than the pull method. When walking with luggage, people tend to maintain the stability of their trunk posture by adjusting the force on their arms more often. • To explore the effects of Trolley Case on body posture characteristics. • Adopt two methods and three kinds of weight control trolley. • VICON and three-dimensional dynamometer measure the basic parameters. • Changes in body posture parameters vary across different Trolley Case usage methods. • It is recommended to use the side push mode and 20 % body weight control trolley. [ABSTRACT FROM AUTHOR]

Perinatal running participation has increased recently; however, pregnancy related symptoms can limit activity. Perinatal running biomechanics could inform interventions to help perinatal individuals maintain an active lifestyle. Are perinatal running biomaechanics and muscle activation different compared to nulligravida females? Sixteen pregnant participants completed self-selected velocity running during second trimester (2 T), third trimester (3 T), and postpartum (PP) and 16 matched controls completed these procedures once in this case control study. Kinematic, kinetic, and electromyography (EMG) data were collected using a motion capture system, force plates, and EMG electrodes. Peak trunk, pelvis, hip, knee, and ankle kinematics and hip, knee, and ankle moments during stance phase, and average and peak erector spinae (ES), gluteus maximus (GMax), and gluteus medius (GMed) EMG amplitude and duration of activation during stance and swing phases were calculated. Independent t-tests were used to compare 2 T, 3 T, and PP to control participants (α < 0.05). Running velocity was slower during 3 T compared to control participants. At all pregnancy timepoints compared to the control group, peak trunk contralateral rotation was smaller. During 2 T and 3 T peak hip flexor moments were smaller. At 3 T pelvis contralateral rotation was smaller, ES average amplitude was greater during swing, GMax percent duration during stance and GMed percent duration during swing were smaller. At PP trunk flexion was smaller and knee abduction was greater (all p < 0.05). Decreased running velocity may help offset increased demand during pregnancy. During 3 T, greater ES activation, smaller trunk and pelvis motion, and altered gluteal activation could indicate trunk rigidity combined with modified hip stabilizer muscle utilization. During PP, the rigid trunk combined with greater knee abduction may indicate hip and trunk strength deficits. Altered trunk and hip motion and activation could be relevant to pathologies such as perinatal low back, pelvic girdle, or knee pain. • Decreased trunk rotation was observed during and after pregnancy with running. • Increased trunk activity and decreased gluteal muscle duration were observed during pregnancy. • During third trimester slower running may decrease joint and muscle demand. • Postpartum runners demonstrated an upright trunk and increased knee abduction. [ABSTRACT FROM AUTHOR]

It has been suggested that sitting posture affects clavicular, scapular and spinal kinematics, however its effects in people with neck pain and scapular dysfunction remain unknown. The study aimed to determine the clavicular and scapular kinematics in different sitting postures in patients with neck pain and scapular dysfunction. Thirty-four participants with neck pain and scapular dysfunction were recruited into the study. Kinematics of the clavicle and scapula were recorded using motion analysis at rest and during arm elevation (at 30, 60, 90, and 120 degrees) in a slouched and upright sitting posture. Compared to the upright sitting posture, the slouched sitting posture had increased clavicular protraction and elevation as well as scapular internal rotation and anterior tilt at rest and during the arm raising and lowering phases (at 30, 60, 90, and 120 degrees) (p < 0.05). The slouched sitting also had increased scapular upward rotation in the lowering phase at all angles (p < 0.05). The slouched sitting posture has a significant influence on clavicular and scapular kinematics. Awareness of good sitting posture should be encouraged in patients with neck pain and scapular dysfunction. • Slouched sitting alters the clavicular and scapular orientations and movements. • Patients with neck pain tend to protract shoulder girdle in slouched sitting. • Side of neck pain has no influence on clavicular and scapular positions in sitting. [ABSTRACT FROM AUTHOR]

Exploring the use of minimum marker sets is important for balancing the technical quality of motion capture with challenging data collection environments and protocols. While minimum marker sets have been demonstrated to be appropriate for evaluation of some motion patterns, there is limited evidence to support model choices for abrupt, asymmetrical, non-cyclic motion such as balance disturbance during a bathtub exit task. How effective are six models of reduced complexity for the estimation of centre of mass (COM) displacement and velocity, relative to a full-body model. Eight participants completed a bathtub exit task. Participants received a balance perturbation as they crossed the bathtub rim, stepping from a soapy wet bathtub to a dry floor. Six reduced models were developed from the full, 72-marker, 12 segment 3D kinematic data set. Peak displacement and velocity of the body COM, and RMSE (relative to the full-body model) for displacement and velocity of the body COM were determined for each model. Main effects were observed for peak right, left, anterior, posterior, upwards and downwards motion, and peak left, anterior, posterior, upwards and downwards velocity. Time-varying (RMSE) was smaller for models including the thighs than models not containing the thighs. In contrast, inclusion of upper arm, forearm, and hand segments did not improve model performance. The model containing the sacrum marker only consistently performed the worst across peak and RMSE metrics. Findings suggest a simplified centre of mass model may adequately capture abrupt, asymmetrical, non-cyclic tasks, such as balance disturbance recovery during obstacle crossing. A reduced kinematic model should include the thighs, trunk and pelvis segments, although models that are more complex are recommended, depending on the metrics of interest. • Participants were perturbed as they stepped from a soapy wet bathtub to a dry floor. • Six reduced models were compared against a 12-segment full-body model. • A simplified centre of mass model may capture abrupt, asymmetrical, non-cyclic tasks. • A reduced kinematic model should include the thighs, trunk and pelvis segments. [ABSTRACT FROM AUTHOR]

Prosthetic foot stiffness, which is typically invariable for commercially available prosthetic feet, needs to be considered when prescribing a prosthetic foot. While a biological foot adapts its function according to the movement task, an individual with lower limb amputation may be limited during more functionally demanding gait tasks by their conventional energy storing and return prosthetic foot. How do changes in prosthetic foot stiffness during incline walking affect biomechanical measures as well as perception of participants. Kinetic and kinematic data were collected during incline walking, for five participants with trans-tibial amputation. A mixed model analysis of variance was used to analyse the effects of changing the stiffness during incline walking, using a novel variable-stiffness unit built on a commercially available prosthetic foot. Biomechanical results were also analysed on an individual level alongside the participant feedback, for a better understanding of the various strategies and perceptions exhibited during incline walking. Statistically significant effects were only observed on the biomechanical parameters directly related to prosthetic ankle kinematics and kinetics (i.e., peak prosthetic ankle dorsiflexion, peak prosthetic ankle power, dynamic joint stiffness during controlled dorsiflexion). Participant perception during walking was affected by changes in stiffness. Individual analyses revealed varied perceptions and varied biomechanical responses among participants. While changes in prosthesis mechanical properties influenced the amputee's experience, minimal immediate effects were found with the overall gait pattern. The reported inter-participant variability may be due to the person's physical characteristics or habitual gait pattern, which may influence prosthesis function. The ability to vary prosthetic foot stiffness during the assessment phase of setting up a prosthesis could provide useful information to guide selection of the appropriate prosthetic device for acceptable performance across a range of activities. • Individuals exhibit different gait patterns which may influence prosthetic preference. • Variability in prosthetic foot stiffness perception and preference was reported. • Providing an option of varying stiffness during different gait tasks may benefit the user. [ABSTRACT FROM AUTHOR]

Inertial Measurement Units (IMUs) offer a promising alternative to optoelectronic systems to obtain joint lower-limb kinematics during gait. However, the associated methodologies, such as sensor-to-segment (S2S) calibration and multibody optimization, have been developed mainly for, and tested on, asymptomatic subjects. This study proposes to evaluate two personalizations of the methodology used to obtain lower-body kinematics from IMUs with pathological subjects: S2S calibration and multibody optimization. Based on previous studies, two decision trees were developed to select the best (in terms of accuracy and repeatability) S2S methods to be performed by the patient given his/her abilities. The multibody optimization was personalized by limiting the kinematic chain range of motion to the results of the subject's clinical examination. These two propositions were tested on 12 patients with various gait deficits. The patients were equipped with IMUs and reflective markers tracked by an optoelectronic system. They had to perform the postures and movements selected by the decision trees then walk back and forth along a walkway. Gait kinematics obtained from the IMUs directly (referred to as Direct kinematics), and after multibody optimization performed via the OpenSim software using the generic range of motion (referred to as Generic Optimized kinematics), and using the personalized range of motion (referred to as Personalized Optimized kinematics) were compared to those obtained with the Conventional Gait Model through Root Mean Square Errors (RMSE), Correlation Coefficients (CC) and Range of Motion differences (ΔROM). The RMSEs were smaller than 8.1° in the sagittal plane but greater than 7.4° in the transverse plane. The CCs, between 0.71 and 0.99 in the sagittal plane, deteriorate sharply in the frontal and transverse planes where they only measured between 0.15 and 0.68. The ΔROMs were mostly below 8.3°. Optimized kinematics did not improve compared to Direct kinematics. The personalization of the proposed S2S calibration method showed encouraging results, whereas multibody optimization did not impact the resulting joint kinematics. • Decision trees were built to select the most appropriate S2S calibration. • The kinematic chain RoM was limited to the results of the clinical examination. • The results were similar to those obtain with asymptomatic subjects. • Multibody optimization personalization had no noticeable impact on the kinematics. [ABSTRACT FROM AUTHOR]

Patients with cerebral palsy and increased femoral anteversion frequently show disturbing internal rotation gait which may be treated via femoral derotation osteotomy (FDO). A recent study monitored that hip rotation in gait may heavily depend on the procedure by which it is being determined. Traditional measures using the femoral epicondyles as reference for the knee axis (CONV) resulted in more severe transverse plane deviations compared to those using a functional method (FUNC) with relevant implications for treatment indication of FDO. Is mean hip rotation in stance (mHipRotSt) as obtained via FUNC the more sensitive measure for explaining functional changes after FDO compared to CONV method taking the femoral epicondyles as reference for the knee axis? 3D-gait analysis before and one year after FDO was performed in fourteen patients including functional joint axis determination of the knee of which MR imaging was available in eight patients both pre- and postoperatively. Transverse plane gait parameters were calculated using both approaches (CONV, FUNC). Differences between examinations as well as between methods were determined. Changes in femoral anteversion as measured by MR reasonably well confirm the structural changes as measured clinically and intraoperatively. The average change in mHipRotSt across the group was substantially smaller than the structural change implies. Further, using the FUNC approach led to much smaller values compared to when using the CONV approach. We address this to a mismatch between the axes determined in each method. In the presence of femoral deformity, the knee joint axis as determined via a functional method together with the conventional method (femoral epicondyles for the knee axis) allows to quantify knee rotation independent of torsional parameters of the tibia. It may therefore help to better quantify rotational malalignments in gait and improve decision making of FDO. • Gait and MRI before and after femoral derotation osteotomy is monitored in CP. • Conventional and functional method was applied for knee axis determination. • Structural changes measured clinically match surgery reports and findings with MRI. • Hip rotation largely differed between methods for knee axis determination. • The functional approach complements the conventional for quantifying knee rotation. [ABSTRACT FROM AUTHOR]

Stabilisation of the centre of mass (COM) trajectory is thought to be important during running. There is emerging evidence of the importance of leg length and angle regulation during running, which could contribute to stability in the COM trajectory The present study aimed to understand if leg length and angle stabilises the vertical and anterior-posterior (AP) COM displacements, and if the stability alters with running speeds. Data for this study came from an open-source treadmill running dataset (n = 28). Leg length (m) was calculated by taking the resultant distance of the two-dimensional sagittal plane leg vector (from pelvis segment to centre of pressure). Leg angle was defined by the angle subtended between the leg vector and the horizontal surface. Leg length and angle were scaled to a standard deviation of one. Uncontrolled manifold analysis (UCM) was used to provide an index of motor abundance (IMA) in the stabilisation of the vertical and AP COM displacement. IMA AP and IMA vertical were largely destabilising and always stabilising, respectively. As speed increased, the peak destabilising effect on IMA AP increased from −0.66(0.18) at 2.5 m/s to −1.12(0.18) at 4.5 m/s, and the peak stabilising effect on IMA vertical increased from 0.69 (0.19) at 2.5 m/s to 1.18 (0.18) at 4.5 m/s. Two simple parameters from a simple spring-mass model, leg length and angle, can explain the control behind running. The variability in leg length and angle helped stabilise the vertical COM, whilst maintaining constant running speed may rely more on inter-limb variation to adjust the horizontal COM accelerations. • Centre of mass (COM) stabilisation is thought to be important during running. • Peak stabilisation of vertical COM occurred at initial contact and toe-off. • Stabilisation of vertical COM increased with increasing running speed. • Stabilisation of vertical COM was anti-phase with anterior-posterior COM. • Two simple parameters, leg length and angle, can explain running control of COM. [ABSTRACT FROM AUTHOR]

The effect of Deep Brain Stimulation (DBS) on gait in Parkinson's Disease (PD) is poorly understood. Kinematic studies utilizing quantitative gait outcomes such as speed, cadence, and stride length have shown mixed results and were done mostly before and after acute DBS discontinuation. To examine longitudinal changes in kinematic gait outcomes before and after DBS surgery. We retrospectively assessed changes in quantitative gait outcomes via motion capture in 22 PD patients before and after subthalamic (STN) or globus pallidus internus (GPi) DBS, in on medication state. Associations between gait outcomes and clinical variables were also assessed. Gait speed reduced from 110.7 ± 21.3 cm/s before surgery to 93.6 ± 24.9 after surgery (7.7 ± 2.9 months post-surgery, duration between assessments was 15.0 ± 3.8 months). Cadence, step length, stride length, and single support time reduced, while total support time, and initial double support time increased. Despite this, there was overall improvement in the Movement Disorder Society-Unified Parkinson Disease Rating Scale-Part III score "on medication/on stimulation" score (from 19.8 ± 10.7–13.9 ± 8.6). Change of gait speed was not related to changes in levodopa dosage, disease duration, unilateral vs bilateral stimulation, or target nucleus. Quantitative gait outcomes in on medication state worsened after chronic DBS therapy despite improvement in other clinical outcomes. Whether these changes reflect the effects of DBS as opposed to ongoing disease progression is unknown. ● Kinematic gait parameters in Parkinson's disease change after deep brain stimulation. ● Gait velocity decreases despite improvement in motor function. ● Gait velocity change did not correlate with levodopa dose reduction. [ABSTRACT FROM AUTHOR]

Repetitive impacts during running are associated with some running injuries. Tibial acceleration is a proxy for tibial loading, and interventions that can decrease it are likely to be of interest to the running community. What effect do running gait cues have on peak vertical tibial acceleration at a comfortable and moderate running pace, and how will these cues be executed? Twenty-seven participants ran on a treadmill according to the following cues in random order: run softly and lightly, run with shorter steps, and increase preferred step rate by 7.5 %. Participants maintained each condition for one minute before returning to their 'preferred' running pattern for two minutes. Two tibia-mounted inertial measurement unit sensors were used to collect tibial acceleration data at a 'comfortable' and 'moderate' run pace. A repeated measures analysis of variance test was used to compare the means between running conditions. Compared to preferred running, the decrease step length (−8 %, p = 0.002, Cohen's d =0.33) and run softly and lightly (−9 %, p = 0.040, Cohen's d =0.38) cues provided a significant reduction in peak vertical tibial acceleration during a comfortable run pace. No significant difference was observed with an increase in step rate. Compared to preferred running, there was no significant difference in peak vertical tibial acceleration with any of the running gait cues during a moderate run pace. Instructing runners to decrease step length or run softly and lightly can result in small reductions in peak vertical tibial acceleration during a comfortable run pace, but running gait cues during a moderate run pace provide no effects. Differences in the execution of each cue are likely to influence overall tibial loading throughout the stride cycle. These findings provide novel biomechanical evidence for the potential effects of running retraining strategies for reducing tibial accelerations at different running paces. • Running gait cues can be effective in reducing tibial loads at a comfortable pace. • Using gait cues to reduce tibial loads at a moderate pace is more of a challenge. • Cues to increase step rate and decrease step length do not provide the same effect. [ABSTRACT FROM AUTHOR]

Individuals with highly pronated feet (PF) are more prone to lower extremity injuries than those with mildly PF. However, whether foot kinematics and ground reaction force (GRF) characteristics differ according to the severity of PF deformity is unclear. Are there differences in foot kinematics and GRF characteristics during walking between individuals with mildly PF and those with highly PF? Ten individuals with mildly PF and 10 with highly PF (six-item foot posture index scores: 6–9 and 10–12 points, respectively) participated in this study. A three-dimensional motion analysis system measured participants' foot kinematics and GRF characteristics during gait trials. Participants with highly PF exhibited significantly lower medial longitudinal arch heights than those with mildly PF from 0 % to 90 % of the stance phase (p < 0.05). No significant differences were observed in any of the angles between the foot segments. Additionally, participants with highly PF exhibited significantly larger posterior GRF than those with mildly PF from 2 % to 7 % of the stance phase (p < 0.05). Participants with highly PF also exhibited significantly larger anterior GRF than those with mildly PF, from 62 % to 82 % of the stance phase (p < 0.05). The results of this study suggest that the more severe the PF deformity, the more inefficient the foot ground force transmission, and the stronger the load applied to the foot. These results may be related to the higher incidence of lower extremity injuries in individuals with highly PF than in those with mildly PF. • Highly pronated feet (PF) are more prone to lower extremity injury than mildly PF. • We examined foot kinematics and ground reaction force characteristics when walking. • Highly PF showed lower medial longitudinal arch heights than mildly PF. • Highly PF exhibited a larger anteroposterior ground reaction force than mildly PF. • A stronger impact may be related to the higher injury incidence with highly PF. [ABSTRACT FROM AUTHOR]

Trunk muscle activity and thoraco-lumbar kinematics can discriminate between non-specific chronic low back pain (NSCLBP) subgroups and healthy controls. However, research commonly focuses on lumbar kinematics, with limited understanding of relationships between kinematics and muscle activity across clinical subgroups. Similarly, the thoracic spine, whilst intuitively associated with NSCLBP, has received less attention and potential relationships between spinal regions and muscle activity requires exploration. Is there a relationship between trunk muscle activation and regional thoracic and lumbar kinematics in NSCLBP subgroups during a forward bending task? Observational, case-control study. Fifty subgrouped NSCLBP motor control impairment participants (27 Flexion Pattern (FP-MCI), 23 Active Extension Pattern (AEP-MCI)) and 28 pain-free controls were evaluated using 3D motion analysis (Vicon™) and surface electromyography during a forward bending and return to upright task. Mean sagittal angles for the upper-thoracic (UTx), lower-thoracic (LTx), upper-lumbar (ULx) and lower-lumbar (LLx) regions were compared with normalised (% sub-maximal voluntary contraction) mean amplitude electromyography of bilateral transversus abdominis/internal oblique, external oblique, superficial lumbar multifidus and erector spinae (longissimus thoracis) muscles between groups. Pearson correlations were computed to assess relationships (significance p < 0.01). AEP-MCI individuals demonstrated statistically significant relationships between superficial lumbar multifidus and ULx and LLx kinematics (−.812 to.659). FP-MCI individuals exhibited statistically significant relationships between erector spinae and superficial lumbar multifidus and LLx and LTx kinematics (−.686 to.664) in both task phases, and between external oblique and LTx during forward bending) (−.459 to.572). Correlations were moderate to strong for all significant relationships (−.812 to.664). Relationships between muscle activity and regional spinal kinematics varied between NSCLBP subgroups, suggesting that those with flexion- or extension-related LBP adopt different motor control strategies when performing a bending task. As effectively mechanical biomarkers, these findings may inform treatment by improving understanding of varied motor strategies in subgroups. • Relationships between muscle activity and spinal kinematics vary in LBP subgroups. • Varied compensatory spinal behaviours indicate that regional insights are important. • As potential biomarkers, this could help personalise rehabilitation approaches. [ABSTRACT FROM AUTHOR]

Local dynamic stability (LDS) has become accepted as a gait stability indicator. The deterioration of gait stability is magnified in older adults. What is the current state in the field regarding rthe relationship between LDS and cognitive and/or physical function in older adults? A scoping review design was used to search for peer-reviewed literature or conference proceedings published through May 2023 for an association between LDS and cognitive (e.g., Montreal Cognitive Assessment) or physical performance (e.g., Timed Up & Go Test) in older adults. Only studies investigating gait stability via LDS during controlled walking, when dealing with a subject group consisting of healthy older adults, and quantifying LDS relationship to cognitive and/or physical measure were included. We analysed data from the studies in a descriptive manner. In total, 814 potentially relevant articles were selected, of which 15 met the inclusion criteria. We identified 37 LDS quantifiers employed in LDS-cognition and/or LDS-physical performance relationship assessment. Nine measures of cognitive and 20 measures of physical performance were analysed. Most studies estimated LDS quantities using triaxial acceleration data. However, there was a variance in sensor placement and signal direction. Out of the 56 studied relationships of LDS to physical performance measures, sixteen were found to be relevant. Out of 22 studied relationships between LDS and cognitive measures, only two were worthwhile. Considering the heterogeneity of the utilized LDS (caused by different sensors locations, signals, and signal directions as well as variety of computational approaches to estimate LDS) and cognitive/physical measures, the results of this scoping review does not indicate a current need for a systematic review with meta-analysis. To assess the overall utility of LDS to reveal a relationship between LDS to cognitive and physical performance measures, an analysis of other subject groups would be appropriate. • Stable gait in older adults is important in various contexts. • Fifteen studies were included in this review. • The analysed kinematic signals were varied, but mainly included acceleration. • Out of 9 tested cognitive measures, only MMSE showed a significant relationship to LDS. • The relationship of LDS to most physical performance measures is poor. [ABSTRACT FROM AUTHOR]

Balance impairments are common in children with cerebral palsy (CP). Muscle activity during perturbed standing is higher in children with CP than in typically developing (TD) children, but we know surprisingly little about how sensorimotor processes for balance control are altered in CP. Sensorimotor processing refers to how the nervous system translates incoming sensory information about body motion into motor commands to activate muscles. In healthy adults, muscle activity in response to backward support-surface translations during standing can be reconstructed by center of mass (CoM) feedback, i.e., by a linear combination of delayed (due to neural transmission times) CoM displacement, velocity, and acceleration. The level of muscle activity in relation to changes in CoM kinematics, i.e., the feedback gains, provides a metric of the sensitivity of the muscle response to CoM perturbations. Can CoM feedback explain reactive muscle activity in children with CP, yet with higher feedback gains than in TD children? We perturbed standing balance by backward support-surface translations of different magnitudes in 20 children with CP and 20 age-matched TD children and investigated CoM feedback pathways underlying reactive muscle activity in the triceps surae and tibialis anterior. Reactive muscle activity could be reconstructed by delayed feedback of CoM kinematics and hence similar sensorimotor pathways might underlie balance control in children with CP and TD children. However, sensitivities of both agonistic and antagonistic muscle activity to CoM displacement and velocity were higher in children with CP than in TD children. The increased sensitivity of balance correcting responses to CoM movement might explain the stiffer kinematic response, i.e., smaller CoM movement, observed in children with CP. The sensorimotor model used here provided unique insights into how CP affects neural processing underlying balance control. Sensorimotor sensitivities might be a useful metric to diagnose balance impairments. • Sensorimotor models yield insight into neural processes that control balance. • Center of mass feedback pathways might underlie balance control in CP. • Muscle activation in response to center of mass perturbations was increased in CP. • Increased sensitivity to CoM displacement and velocity impairs balance control. • Sensorimotor sensitivities might be a useful metric to diagnose balance impairments. [ABSTRACT FROM AUTHOR]

The longitudinal arch of the foot acts like a spring during stance and contributes to walking efficiency. Pronated foot characterized by a collapsed medial longitudinal arch may have the impaired spring-like function and poor walking efficiency. However, the differences in the energetic behavior during walking between individuals with pronated foot and neutral foot have not been considered. How does the energetic behavior within the foot and proximal lower limb joints in pronated foot affect walking efficiency? Twenty-one healthy young adults were classified into neutral foot and pronated foot based on the Foot Posture Index score. All subjects walked across the floor and attempted to have the rearfoot and forefoot segments contact separate force plates to analyze the forces acting on isolated regions within the foot. Kinematic and kinetic data were recorded by a three-dimensional motion capture system. The hip, knee, ankle, and mid-tarsal joint power was quantified using a 6-degree-of-freedom joint power method. To qualify total power within all structures of the foot and forefoot, we used a unified deformable segment analysis. Additionally, we calculated the center of mass power to quantify the total power of the whole body There is no difference in the mid-tarsal joint work between the pronated foot and neutral foot. On the other hand, pronated foot exhibited greater net negative work at structures distal to the forefoot during walking. Additionally, pronated foot exhibited less net positive work at the ankle and center of mass during walking compared to neutral foot. Individuals with pronated foot generate the mid-tarsal joint work by increasing the work absorbed at structures distal to the forefoot, which results in reduced energy efficiency during walking. That energy inefficiency may reduce positive work at the ankle and affect the walking efficiency in individuals with pronated foot. • We investigated the energetic behavior during walking in neutral and pronated foot. • There is no difference in the mid-tarsal joint work between groups. • Pronated foot had greater negative work at distal to forefoot and rearfoot. • Pronated foot had less positive work at the ankle and center of mass. • Energy loss at the foot affects ankle work and walking efficiency in pronated foot. [ABSTRACT FROM AUTHOR]

Dyskinetic cerebral palsy (DCP) is clinically characterized by involuntary movements and abnormal postures, which can aggravate with activity. While upper limb movement variability is often detected in the clinical picture, it remains unknown how movement patterns of individuals with DCP differ from typically developing (TD) peers. Do individuals with DCP show i) higher time-dependent standard deviations of upper limb joint angles and ii) altered upper limb kinematics in time and/or amplitude during functional upper limb tasks in comparison with TD individuals? Three-dimensional upper limb movement patterns were cross-sectionally compared in 50 individuals with and without DCP during three functional tasks: reach forward (RF), reach and grasp vertical (RGV) and reach sideways (RS). Mean and point-wise standard deviations of angular waveform of the upper limb joint angles were compared between groups to evaluate differences in time and/or amplitude using traditional and non-linear registration statistical parametric mapping. Thirty-five extremities from 30 individuals (mean age 17y4m, range 5–25 y; MACS level I(n = 2); II(n = 15); III(n = 16); IV(n = 2)) with DCP and twenty TD individuals (mean age 16y8m, range 8–25 y) were evaluated. The DCP compared to TD group showed higher point-wise standard deviations at the level of all joints, which was time-dependent and varied between tasks. Mean wrist and elbow flexion was higher for the DCP group during RF (0–83 % wrist; 57–100 % elbow), RGV (0–82 % wrist; 12–100 % elbow) and RS (0–43 % wrist; 70–100 % elbow). This is the first study exploring the movement patterns of individuals with DCP during reaching using quantitative measures. Analyzing these individual movement patterns by statistical parametric mapping (SPM) allows us to focus on both specific joint or on specific timing during the movement cycle. The individual information that this method yields can guide individual therapy aiming to improve reaching function in different parts of the movement cycle or evaluate intervention effects on upper extremity treatment. • We explored the variability of 3D upper limb waveforms in dyskinetic CP (DCP) with statistical parametric mapping (SPM). • This is the first study using non-linear registration SPM in 3D upper limb movements. • The DCP compared to typically developing group showed higher, task-dependent point-wise standard deviations in all tasks. • The DCP compared to typically developing group showed higher wrist/elbow flexion in the majority of the reaching cycle. [ABSTRACT FROM AUTHOR]

Adolescents undergo a period of motor incoordination during puberty characterized by high movement variability. It is unknown if differences in running kinematics variability exist among adolescent long-distance runners. Is kinematic variability different among male and female adolescent long-distance runners of different stages of physical maturation? We enrolled 114 adolescent long-distance runners (ages 8–19, F = 55, M = 59) in this secondary analysis of a larger cross-sectional study. Participants completed a three-dimensional overground running analysis at a comfortable self-selected speed. Peak frontal, sagittal, and transverse plane hip, knee, and ankle/shoe joint angles from the right leg were identified during stance phase for at least five trials. Variability in running kinematics was quantified as the standard deviation of the peak joint angles among the running trials for each participant. Participants were stratified by sex and stage of physical maturation (pre-, mid-, post-pubertal) and two-way ANOVAs compared between-subjects variability among groups (p ≤.05). Significant sex by maturation interactions were observed for hip external rotation and ankle external rotation variability. Sex differences were observed for hip internal rotation, with males demonstrating greater variability, and ankle internal rotation, with females demonstrating greater variability. Pre-pubertal runners demonstrated significantly greater variability than mid-pubertal runners for hip flexion, and greater variability than post-pubertal runners for hip flexion, hip adduction, hip internal rotation, and knee flexion. Pre-pubertal adolescent long-distance runners demonstrate greater stance phase variability in running kinematics than post-pubertal adolescent long-distance runners, while adolescent males and females demonstrate similar variability. Anthropometric and neuromuscular changes that occur during puberty likely influence running patterns and may contribute to more consistent kinematic patterns for post-pubertal runners. • Pre-pubertal runners demonstrate greater kinematic variability than post-pubertal runners. • Kinematic variability generally decreased as runners progressed from pre- to post-pubertal status. • Male and female runners demonstrate similar kinematic variability. [ABSTRACT FROM AUTHOR]

Individuals with Chronic Ankle Instability (CAI) demonstrate altered gait mechanics, impaired proprioception, and decreased postural control. In addition, individuals with CAI have been found to have complex neurophysiological changes, including during dual-task perturbations. However, the results of studies on whether cognitive tasks affect postural control are inconclusive. Do individuals with CAI have worse dual-task performance compared to healthy controls? We searched 4 electronic databases (PubMed, MEDLINE, Cumulative Index of Nursing and Allied Health Literature, and SPORTDiscus) from inception to October 2022. Search terms consisted of: ("dual-task*" OR "dual task*" OR dual-task OR Multitask* OR Multi-task* OR attention OR cognit*) AND (balance OR "postural control" OR "postural sway" OR kinetics OR kinematics OR gait) NOT (concussion OR "traumatic brain injury") combined using the operator "AND" ("ankle sprain" OR "ankle instability" OR CAI). Studies were included if the physical task was postural control or gait, and if they compared control and CAI groups. A total of 9 studies were included in the systematic-review portion, 5 of which were included in the meta-analysis. Due to assessing multiple types of dual-tasks, 10 effects were assessed for meta-analysis across postural control studies. A random-effects model for the control group in the mediolateral direction indicated a significant overall Fisher's Z mean effect size (Δ = 0.732, p = 0.029) with high heterogeneity between studies (Q =76.61; I 2 = 88.25% P < 0.001). There were no significant differences between dual-tasking in the CAI group individually or when comparing control to CAI groups. The results of our study indicate that cognitive loading did not affect the postural control except for the control group in the mediolateral direction. Variations in dual-task results may be due to the difficulty of the task as well as the heterogeneity of CAI groups. • No differences in dual-task effects between those with CAI and controls. • The most common cognitive load during dual-tasks in CAI research is a number-based task. • Walking nor static balance may not be challenging enough to elicit a dual-task response. [ABSTRACT FROM AUTHOR]

Cognitive interventions are among the effective training-on-gait parameters; however, the effects of such trainings on inter-joints coordination has not been much considered. Can dual task and executive function training affect inter-joint coordination during walking in elderly with poor balance? Thirty elderly men were purposefully divided into three groups: 1) dual-task training group (DTG), 2) executive function training group (EFG) and 3) control group. After the pre-test, the experimental groups participated in 24 training sessions while the control group were required to do their normal daily tasks. VICON three-dimensional motion analysis system with four T20 series cameras was used to evaluate inter-joints coordination during the experiment. Participants had to walk a 12-meter path while kinematics of their joints was recorded. The inter-joint coordination at the sagittal plane and in four phases were assessed using the vector coding technique. The findings of this study showed that the greatest effect of the intervention on the coordination between the joints was in the loading and mid-stance phases (p < 0.05). Also, the variability in the coupling angle showed a significant decrease in most phases (p < 0.05). Based on the obtained results, it can be argued that the loading and mid-stance are more involved in postural control and balance because the center of gravity is transferred between the legs and the person is normally on single-leg stance in these phases. • Cognitive training increased velocity and cadence in dual task walking. • Dual task and executive function training can affect the mean coupling angles. • Inter-joint coordination was changed in the loading and mid-stance. • The variability was decreased in training groups than that in control. [ABSTRACT FROM AUTHOR]