Search

Interlimb transfer of sequential motor learning (SML) refers to the positive influence of prior experiences in performing the same sequential movements using different effectors. Despite evidence from intermanual SML, and while most daily living activities involve interlimb cooperation and coordination between the four limbs, nothing is known about bilateral SML transfer between the upper and lower limbs. We examined the transfer of bilateral SML from the upper to the lower limbs and vice versa. Twenty-four participants had to learn an initial bilateral SML task using the upper limbs and then performed the same sequence using the lower limbs during a transfer SML task. They performed the reversed situation 1 month apart. The performance was evaluated at the beginning and the end of both initial and transfer SML practice phases. Significant and reciprocal transfer gains in performance were observed regardless of the effectors. Greater transfer gains in performance were observed at the beginning of the transfer SML from the lower to the upper limbs (44 %) but these gains vanished after practice with the transfer effectors (5 %). Although smaller gains were initially achieved in the transfer of SML from the upper to the lower limbs (15 %), these gains persisted and remained significant (9 %) after practice with the transfer effectors. Our results provide evidence of a reciprocal and asymmetrical interlimb transfer of bilateral SML between the upper and lower limbs. These findings could be leveraged as a relevant strategy in the context of sports and functional rehabilitation. • Reciprocal transfer of sequential motor learning between the upper and lower effectors. • Transfer gains is asymmetrical between the upper and lower effectors. • Early and greater benefits in performance from the lower to the upper effectors. • Durable transfer gains in performance from the upper to the lower limb effectors • Upper and lower effectors transfer may be exploited in functional rehabilitation. [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]

Biomechanical evaluations of sport-specific jump-landing tasks may provide a more ecologically valid interpretation compared to generic jump-landing tasks. For accurate interpretation of longitudinal research, it is essential to understand the reliability of biomechanical parameters of sport-specific jump-landing tasks. How reliable are hip, knee and ankle joint angles and moment curves during two volleyball-specific jump-landing tasks and is this comparable with the reliability of a generic jump-landing task? Three-dimensional (3D) biomechanical analyses of 27 male volleyball players were performed in two sessions separated by one week. Test-retest reliability was analyzed by calculating integrated as well as 1D intraclass correlation coefficient (ICC) and integrated standard error of measurement (SEM) for hip, knee and ankle angles and moments during a spike and block jump (volleyball-specific tasks), and during a drop vertical jump (generic task). Reliability of joint angles of volleyball-specific and generic jump-landing tasks are similar with excellent-to-good integrated ICC for hip, knee and ankle flexion/extension (ICC= 0.61–0.89) and hip and knee abduction/adduction (ICC=0.61–0.78) but fair-to-poor ICC for ankle abduction/adduction (ICC=0.28–0.52) and hip, knee and ankle internal/external rotation (ICC=0.29–0.53). Reliability of hip, knee and ankle joint moments was good-to excellent (ICC= 0.62–0.86) except for hip flexion moment during spike jump and drop vertical jump (ICC=0.43–0.47) and knee flexion moment during both volleyball-specific tasks (ICC=0.56–0.57). For all tasks, curve analysis revealed poorer reliability at start and end of the landing phase than during the midpart. Our data suggests that kinematic evaluations of volleyball-specific jump-landing tasks are reliable to use in screening programs, especially in the sagittal plane. Notably, reliability is poorer at the beginning and end of the landing phase, requiring careful interpretation. In conclusion, the results of this study indicate the potential for integration of sport-specific jump-landing tasks in screening programs, which will be more ecologically valid. • Kinematics and kinetics of volleyball-specific and generic landing tasks are similar reliable. • Ankle frontal plane and transversal plane angles of all joints are poor reliable. • Start and end of the landing phase are poorer reliable than the midpart. • Biomechanical analysis of sport-specific tasks could be used in screening programs. [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]

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]

Enhancing traditional three-dimensional gait analysis with a portable ultrasound device at the lower-limb muscle-tendon level enables direct measurement of muscle and tendon lengths during walking. However, it is important to consider that the size of the ultrasound probe and its attachment on the lower limb may potentially influence gait pattern. What is the effect of wearing an ultrasound probe at the lower limb in adolescents with cerebral palsy and typically developing peers? Eleven individuals with cerebral palsy and nine age-matched typically developing peers walking barefoot at their self-selected speed were analyzed. Data collection occurred under three conditions: the reference condition (GAIT), and two conditions involving placement of the ultrasound probe over the distal medial gastrocnemius-Achilles tendon junction (MTJ) and over the medial gastrocnemius mid-belly to capture fascicles (FAS). Data processing included calculating differences between conditions using root mean square error (RMSE) for joint kinematics and comparing them to the overall mean difference. Additionally, Spearman correlations were calculated to examine the relationship between kinematic RMSEs and walking speed. No significant differences in stance phase duration or walking speed were observed among the three conditions. Average RMSEs were below 5° for all parameters and condition comparisons in both groups. In both the TD and CP groups, RMSE values during the swing phase were higher than those during the stance phase for all joints. No significant correlations were found between height or body mass and swing phase RMSEs. In the CP group, there was a significant correlation between joint kinematics RMSEs and differences in walking speed at the hip, knee and ankle joints when comparing the MTJ condition with the GAIT condition. This study confirms joint kinematics alterations are smaller than 5° due to wearing to the leg an ultrasound probe during walking. • Wearing an ultrasound probe during gait does not alter lower limb joint kinematics. • The effect of the probe on kinematics is within the clinical acceptable error. • Kinematic outcomes are affected by large differences in walking speed. [ABSTRACT FROM AUTHOR]

Despite the significance of muscle oscillation frequency, previous research has not established a correlation with muscle performance due to the challenges of applying resistance without altering natural motion during functional tests. What is the correlation between muscle oscillation frequency and lower limb muscle strength, power, and work during an instrumented sit-to-stand and stand-to- sit (iSTS-TS) task among sedentary subjects? In a cross-sectional study, the oscillation frequency of the gastrocnemius medialis (GM), biceps femoralis (BF), and vastus medialis (VM) muscles in both the dominant (D) and non-dominant (ND) legs was assessed with a handheld myotonometer in 34 sedentary individuals before performing the iSTS-TS task. In the isokinetic mode, no significant correlations were found. In the isotonic mode, the BF muscle oscillation frequency in the D and ND legs exhibited significant positive correlations with peak force, peak power, and work during sitting down, as well as peak power and work during standing up. Positive correlations were observed in both legs between the GM oscillation frequency and sitting down peak force and work. Additionally, significant positive correlation was found with standing up work in the D leg. Muscle oscillation frequency of the VM exhibited a positive correlation with sitting down peak force in the ND leg. Due to a greater number of correlations found, it is advisable to use the isotonic mode when assessing muscle oscillation frequency in relation to muscle performance during functional iSTS-TS tasks in sedentary subjects. • Oscillation frequency correlates with limb performance in iSTS-TS task. • Isotonic mode reveals significant muscle performance correlations. • Assessment of iSTS-TS muscles in sedentary subjects via isotonic mode is recommended. [ABSTRACT FROM AUTHOR]

• Markerless motion capture systems presented a more time-efficient alternative to marker-based systems. • The paper is the first to compare markerless and marker-based systems with rigorous statistical methods. • Running speed exacerbates the differences in the sagittal plane kinetic parameters estimated by the two systems. • These differences potentially stem from the two systems' different estimations of inertial parameters. • The kinetic differences estimated by the two systems could lead to differential predictions of risk factors. The development of computer vision technology has enabled the use of markerless movement tracking for biomechanical analysis. Recent research has reported the feasibility of markerless systems in motion analysis but has yet to fully explore their utility for capturing faster movements, such as running. Applied studies using markerless systems in clinical and sports settings are still lacking. Thus, the present study compared running biomechanics estimated by marker-based and markerless systems. Given running speed not only affects sports performance but is also associated with clinical injury prevention, diagnosis, and rehabilitation, we aimed to investigate the effects of speed on the comparison of estimated lower extremity joint moments and powers between markerless and marker-based technologies during treadmill running as a concurrent validating study. Kinematic data from marker-based/markerless technologies were collected, along with ground reaction force data, from 16 young adults running on an instrumented treadmill at 3 speeds: 2.24 m/s, 2.91 m/s, and 3.58 m/s (5.0 miles/h, 6.5 miles/h, and 8.0 miles/h). Sagittal plane moments and powers of the hip, knee, and ankle were calculated by inverse dynamic methods. Time series analysis and statistical parametric mapping were used to determine system differences. Compared to the marker-based system, the markerless system estimated increased lower extremity joint kinetics with faster speed during the swing phase in most cases. Despite the promising application of markerless technology in clinical settings, systematic markerless overestimation requires focused attention. Based on segment pose estimations, the centers of mass estimated by markerless technologies were farther away from the relevant distal joint centers, which led to greater joint moments and powers estimates by markerless vs. marker-based systems. The differences were amplified by running speed. [Display omitted] [ABSTRACT FROM AUTHOR]

Traumatic lower limb injuries can result in chronic pain. Orthotic interventions are a leading conservative approach to reduce pain, manage loading, and protect the foot. Robust carbon fiber custom dynamic orthoses (CDOs) designed for military service members have been shown to reduce foot loading. However, the effect of carbon fiber orthosis design, including designs widely used in the civilian sector, on foot loading is unknown. Determine if carbon fiber orthoses alter foot loading during gait. Loadsol insoles were used to measure peak forces and force impulse acting on the forefoot, midfoot, hindfoot, and total foot. Nine healthy, able-bodied individuals participated. Force impulse was quantified as cumulative loading throughout stance phase. Participants walked without an orthosis and with three carbon fiber orthoses of differing designs: a Firm stiffness CDO, a Moderate stiffness CDO, and a medial and lateral strut orthosis (MLSO). There were significant main effects of orthosis condition on peak forefoot forces as well as forefoot and hindfoot force impulse. Peak forefoot forces were significantly lower in the Moderate and Firm CDOs compared to no orthosis and MLSO. Compared to walking without an orthosis, forefoot force impulse was significantly lower and hindfoot force impulse was significantly greater in all carbon fiber orthoses. Additionally, hindfoot force impulse in the Firm CDO was significantly higher than in the MLSO and Moderate CDO. The three carbon fiber orthosis designs differed regarding foot loading, with more robust orthoses providing greater forefoot offloading. Orthosis-related changes in forefoot loading suggest that carbon fiber orthoses could reduce loading-associated pain during gait. However, increased hindfoot force impulse suggests caution should be used when considering carbon fiber orthoses for individuals at risk of skin breakdown with repetitive loading. • Compared to walking without an orthosis, peak forefoot forces decreased with carbon fiber custom dynamic orthosis use. • All carbon fiber orthoses significantly decreased forefoot force impulse compared to walking without an orthosis. • All carbon fiber orthoses significantly increased hindfoot force impulse compared to walking without an orthosis. [ABSTRACT FROM AUTHOR]

The linear-envelope peak (LEP) of surface EMG signal is widely used in gait analysis to characterize muscular activity, especially in clinics. This study is designed to evaluate LEP accuracy in identifying muscular activation and assessing activation timing during walking. Surface EMG signals from gastrocnemius lateralis (GL) and tibialis anterior (TA) were analyzed in 100 strides per subject (31 healthy subjects) during ground walking. Signals were full-wave rectified and low-pass filtered (cut-off frequency=5 Hz) to extract the linear envelope. LEP accuracy in identifying muscle activations and the associated error in peak detection were assessed by direct comparison with a reference method based on wavelet transform. LEP accuracy in identifying the timing of higher signalenergy levels was also assessed, increasing the reference-algorithm selectivity. The detection error (percentage number of times when LEP falls outside the correspondent reference activation interval) is close to zero. Detection error increases up to 70% for intervals including only signal energy higher than 90% of energy peak. Mean absolute error (MAE, the absolute value of the distance between LEP timing and the correspondent actual timing of the sEMG-signal peak computed by reference algorithm) is 54.1±20.0 ms. Detection error and MAE are significantly higher (p<0.05) in TA data compared to GL signals. Differences among MAE values detected adopting different values for LE cut-off frequency are not statistically significant. LEP was found to be accurate in identifying the number of muscle activations during walking. However, the use of LEP to assess the timing of highest sEMG-signal energy (signal peak) should be considered carefully. Indeed, it could introduce a relevant inaccuracy in muscle-activation identification and peak-timing quantification. The type of muscle to analyze could also influence LEP performances, while the cut-off frequency chosen for envelope extraction appears to have a limited impact. • Linear envelope peak (LEP) is widely used to identify muscle activation during gait. • LEP accuracy is tested in 3100 strides of 31 subjects vs. a wavelet-based algorithm. • LEP provides an accurate identification of the number of activations in a stride. • The use of LEP introduces a relevant error in the quantification of EMG-peak timing. • LEP performances are also influenced by the type of muscle being analyzed. [ABSTRACT FROM AUTHOR]

« Couteau-suisse » de la chirurgie reconstructrice, le lambeau de grand dorsal est de plus en plus délaissé au profit des lambeaux fasciocutanés. L'objectif de cette étude était d'analyser les modalités de réalisation de ce lambeau ainsi que l'évolution de ses indications afin de définir sa place actuelle en traumatologie. Quarante-quatre cas ont été recensés rétrospectivement de janvier 2000 à décembre 2020 au sein de l'HIA Percy, dont 37 cas de lambeaux libres, principalement réalisés pour des reconstructions de pertes de substance étendues avec exposition osseuse et/ou articulaire. Il était également réalisé dans 10,8 % des cas en sauvetage après échec d'une autre solution de reconstruction. Cette analyse a permis de confirmer l'intérêt du lambeau de grand dorsal dans le cas de pertes de substances délabrantes du membre inférieur, mais également chez le grand brûlé, à des fins de réhabilitation fonctionnelle ou de couverture, afin de permettre une rééducation précoce. Reconstructive surgery's workhorse, the latissimus dorsi flap is increasingly abandoned in favour of fasciocutaneous flaps. The purpose of this study was to analyse the methods used to perform this flap and the evolution of its indications in order to define its current place in traumatology. Forty-four cases were recorded retrospectively from January 2000 to December 2020 at HIA Percy, including 37 cases of free flaps, mainly performed for reconstruction of extensive loss of substance with bone and/or joint exposure. It was also performed in 10.8% of cases for salvage after failure of an alternative reconstruction solution. This analysis confirms the value of the latissimus dorsi flap in cases of significant substance loss in the lower limb, but also in burn patients for functional rehabilitation or to allow early rehabilitation. [ABSTRACT FROM AUTHOR]

Genu valgum is a common lower limb deformity seen in children. There are multiple causes for the development of genu valgum but to be able to accurately assess the child it is important to understand the physiological development of the lower limbs. Although often asymptomatic and idiopathic, genu valgum can be associated with underlying pathology, such as rickets, previous proximal tibia fracture leading to valgus deformity, tumours and dysplasias which often require a multidisciplinary approach to management of the condition. This article will review the common causes of genu valgum in children, explain how to clinically assess the child and cover possible management options for each condition. [ABSTRACT FROM AUTHOR]

Exertional leg pain is a common problem in the athletic population, presenting with a constellation of similar symptoms. Delayed or incorrect diagnosis and treatment may result in significant morbidity and avoidable cessation of activity. Multiple causes such as chronic exertional compartment syndrome (CECS), medial tibial stress syndrome (MTSS), nerve or vascular entrapment syndromes may be responsible. A thorough history and focused clinical examination is mandated, and may yield clues as to the definitive diagnosis. Investigative adjuncts include imaging, compartment pressure measurement and electrodiagnostic studies. Whilst specific management depends on the underlying cause, the mainstay of initial management is activity modification, with surgery reserved for those who fail to respond to conservative measures. [ABSTRACT FROM AUTHOR]

The study discussed in this paper focuses on additive manufacturing (AM) of intricate geometrically structured components of a prosthetic leg. The objective is to optimize the original design to reduce the need for support structures while maximizing stiffness and reducing weight. Making a prosthetic leg lighter can improve the mobility of a person and reduce the energy required to climb stairs, enhancing their quality of life and independence. Traditional manufacturing methods, such as injection molding and computerized numerical control (CNC) machining, have limitations in terms of design flexibility. The study used Selective Laser Melting (SLM) technology with 316L-A stainless steel powder. The optimization process focused on the knee, upper leg, lower leg, hydraulic, and oil support system. The workflow procedure for additive manufacturing was discussed. Overall, the study successfully reduced the weight of the prosthetic leg by 50% from the original model. [ABSTRACT FROM AUTHOR]

The aim of the study was to explore the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and regional body fat deposition in 2011–2018 National Health and Nutrition Examination Survey participants aged 18 to 59 years. We hypothesized that serum 25(OH)D concentrations were negatively associated with total, appendicular, and truncal fat deposition. Serum 25(OH)D concentration was categorized into sufficient (≥75.0 nM), insufficient (50.0–74.9 nM), and deficient (<50.0 nM) groups. Fat mass (FM) was measured by dual-energy X-ray absorptiometry, and FM index (FMI) was calculated by dividing FM (kg) with height2 (m2). Multivariant linear regression and Granger causal analysis were performed to assess the causal relationship between vitamin D status and regional FMIs. Overall serum 25(OH)D concentrations were negatively associated with total (β = –0.029, standard error [SE] = 0.002), trunk (β = –0.015, SE = 0.001), arms (β = –0.004, SE = 3.09 × 10−4), and legs (β = –0.010, SE = 0.001) FMIs in all participants (P <.001, respectively); however, after stratified by vitamin D status and BMI, the negative associations were only observed in individuals with vitamin D deficiency and obesity. The causal analysis indicated that serum 25(OH)D concentrations may causally reduce the arms (F = 4.917, probability [ P ] = 0.007), legs (F = 5.783, P = 0.003), and total (F = 3.202, P = 0.041) FMIs except for trunk FMI but not vice versa. In conclusion, poor vitamin D status was associated with increased total and appendicular body fat deposition in US adults, particularly in participants with obesity. The aim of the study was to explore the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and body fat deposition in adults. The results showed that poor vitamin D status was associated with increased total and appendicular body fat deposition in US adults, particularly in participants with obesity. [Display omitted] [ABSTRACT FROM AUTHOR]

Successful recovery following a perturbation during walking depends on a quick well-coordinated response from the body. As such, lower limb joint power and work provide critical information characterizing the success of the recovery after a perturbation. Therefore, this study aimed to investigate lower-limb joint power and the relative contribution of each joint to the total leg work during the recovery following a trip-induced perturbation. Twenty-four young male volunteers walked at 1.1 m/s for 2 min, followed by two unexpected perturbations induced by rapidly decelerating the right belt of the split-belt treadmill. Joint moments and powers were calculated using an inverse dynamic approach. Joint work was found as the integral of joint power with respect to time. Statistical parametric mapping (SPM) and paired-sample t-tests were used to compare joint power and work between recovery and unperturbed steps. Compared to normal walking, recovery from the trip required a significant increase in both positive (+27 %, p < 0.05) and negative(+28 %,p < 0.05) leg work. During unperturbed walking, the ankle was the key contributor to both positive (ankle=50 %, hip=34 %, and knee=15 %) and negative (ankle=62 %, knee=32 %, and hip=6 %) leg work. During recovery, the knee eccentric work significantly increased (+83 %,p < 0.05) making it the main contributor to the negative leg work (knee=46 %, ankle=45 %, and hip=9 %). The hip positive work also increased during recovery (+62.7 %, p < 0.05), while ankle and the knee positive work remained unchanged. These findings highlight the importance of eccentric work of the knee, and concentric work of the hip joint during recovery from trip-induced perturbations. The additional mechanical demand of producing and absorbing more power during recovery is primarily imposed on the knee and hip, rather than the ankle. This new insight into the specific functions of lower-limb joints during recovery from trip-induced perturbations has important implications for the design of targeted fall prevention interventions. • Trip perturbations altered lower-limb joints contribution to leg work. • Knee joint played the most crucial role in absorbing energy during recovery. • The excessive demand of producing more power was mainly imposed on the hip joint. [ABSTRACT FROM AUTHOR]

Cutting is a quick change of direction that challenges body balance and stability. As the cut-angle increases, the elite athlete can achieve higher performance by pre-adjusting the posture of the lower limb joints. However, it is unclear how the cut-angle affects the neuromuscular control of cutting and the step before cutting, which is essential for daily training and preventing injury in large-angle cutting. The purpose of this study was to determine how neuromuscular control strategies change under different angles for cutting and the step before cutting Non-negative matrix factorisation and K-means clustering were used to extract muscle synergy in the trunk and lower limbs of 12 athletes when cutting at different angles. Uncontrolled manifold analysis was used to clarify whether the muscle synergy fluctuations in the step before cutting were beneficial in stabilising the COP during the cutting. This study found that the angle did not affect the number of muscle synergies either in the cutting or the step before the cutting. As the angle increases, the activation timing of synergy module 2 during cutting moves forward and is tightly integrated with module 1. The combined synergy at 90° accounted for the largest proportion of either cutting or the step before cutting and had a lower synergy index. Muscle synergy can respond to large-angle cutting through flexible combinations. The muscle synergy for 90° cutting is less regular and has a lower degree of anticipatory synergy adjustments, which may result in poorer postural stability and an increased risk of lower limb joint injury during cutting. • The cut-angle does not affect the number of synergy modules during cutting. • Different degrees of anticipatory synergy adjustments with different cut-angles. • The weakest degree of muscle synergy and its anticipatory adjustments occurs in 90°. [ABSTRACT FROM AUTHOR]

Une revue systématique visant à évaluer l'apport de l'échographie dans la détection de l'enthésite chez les patients porteurs d'arthrite juvénile idiopathique (AJI). Une recherche bibliographique a été menée dans les bases de données PubMed et Embase pour la période comprise entre janvier 1966 et mai 2021 ; les articles qui répondaient aux critères d'inclusion selon la définition de l'enthésite échographique et les propriétés métrologiques étudiées ont été sélectionnés. Nous avons évalué les caractéristiques cliniques de la population cible, le design de l'étude, le type et le nombre d'enthèses examinées, la définition et le système de cotation de l'enthésite échographique ainsi que les propriétés métrologiques définies par le filtre OMERACT (vérité, discrimination et faisabilité). La qualité méthodologique des études a été analysée au moyen de l'échelle QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2). Cinq publications remplissaient les critères d'inclusion (26 à 146 patients et 1 à 10 sites d'enthèse examinés bilatéralement). Toutes les études étaient axées sur les enthèses des membres inférieurs. Les lésions élémentaires incluses dans la définition de l'enthésite chez l'adulte ont été généralement évaluées. Peu d'études ont rapporté la fiabilité de l'échographie et aucune n'a évalué sa sensibilité au changement. Les anomalies échographiques des enthèses étaient visibles chez 9,4 % à 53 % des patients atteints d'AJI et 20 % à 83 % des cas d'arthrite liée à l'enthésite (ERA). Il n'a été retrouvé aucune anomalie significative chez les sujets sains. L'exploration échographique a été faiblement corrélée à l'examen clinique. La qualité globale des études était faible, en raison notamment de l'absence de test de référence. L'échographie est un outil qui affiche une bonne sensibilité pour la détection des anomalies des enthèses dans l'AJI. D'après les données actuelles, il n'existe pas de définition échographique standardisée de l'enthésite dans la population pédiatrique. Par ailleurs, les critères de validité externe et interne de l'échographie n'ont pas été établis. A systematic review to assess the value of ultrasonography (US) for detecting enthesitis in juvenile idiopathic arthritis (JIA). PubMed and Embase databases were searched for articles published from January 1966 to May 2021; we selected those meeting the inclusion criteria according to the US definition of enthesitis and metric properties studied. We assessed the clinical features of the population, study design, the type and number of entheses examined, the definition and scoring system of US enthesitis and metric properties according to the OMERACT filter (truth, discrimination, feasibility). The quality of the studies was evaluated with the Quality Assessment of Diagnostic Accuracy Studies 2. Five publications met the inclusion criteria (26 to 146 patients and 1 to 10 bilaterally examined entheses). All studies focused on lower-limb entheses. The elementary lesions included in the definition of adult enthesitis were generally assessed. Few studies reported US reliability, and none evaluated sensitivity to change of US. US revealed entheseal abnormalities in 9.4 % to 53 % of JIA patients and 20 % to 83 % of enthesitis-related arthritis cases. No significant abnormalities were found in healthy children. US findings were poorly correlated with clinical examination. The overall quality of the studies was low, mainly because of the lack of a reference standard. US is a sensitive tool to detect entheseal abnormalities in JIA. The current evidence highlights that a standardized US definition of enthesitis in children is lacking and US criteria and discriminant validity have not been established. [ABSTRACT FROM AUTHOR]

Retinacula of the ankle are thickening of the deep fascia of the leg (crural fascia) and foot i.e. inseparable structures. Recent studies report their crucial role in functional stability and proprioception of the ankle. A 38-yr-old Caucasian man - with a history of lateral malleolus fracture 12 years ago, obesity and right ankle osteoarthritis - was referred to a physiatrist for a right ankle pain that had significantly worsened over the last year. During walking, the patient experienced stinging pain in the area of tibialis anterior and peroneus tertius muscles, and the superior extensor retinaculum. Magnetic resonance imaging and ultrasonography showed clear thicknening (2.05 mm) of the oblique superomedial band of the inferior extensor retinaculum. Sonopalpation was performed to precisely evaluate/confirm the site of maximum pain. Foot function index (FFI) score was 42. Subsequently, the patient was prescribed fascial manipulation, and he had clinical improvement after the first session (FFI: 21). At 1-month follow-up, the patient was still asymptomatic without any functional limitation (FFI: 24). US imaging confirmed the decreased thickness of the oblique superomedial band of the extensor retinaculum (1.35 mm). Fascial Manipulation ® appears to be a useful tool to reduce thickness, stiffness, and pain in this case as displayed by the ultrasound Imaging. [ABSTRACT FROM AUTHOR]

Open limb fractures are a time-critical orthopaedic emergency that present to jurisdictional ambulance services. This study describes the demographic characteristics and epidemiological profile of these patients We undertook a retrospective analysis of all patients that presented to Queensland Ambulance Service with an open limb fracture (fracture to the humerus, radius/ulna, tibia/fibula or femur) over a two-year period (January 2018 – December 2019). Overall, 1020 patients were included. Patients were mainly male (65.9%) and middle-aged (age 41 years, IQR 22–59). Fractures predominately occurred in the lower extremities (64.9%) with transport crashes the primary mechanism of injury (47.8%). The location of the fracture varied depending on the cause of injury, with femur fractures associated with motorcycle crashes, and fractures to the radius/ulna attributed to falls of greater than one metre (p = 0.001). The median prehospital episode of care was 83 min (IQR 62–144) with aeromedical air ambulance involvement and the attendance of a critical care paramedic or emergency physician, both independent factors that increased this time interval. Open limb fractures are a relatively infrequent injury presentation encountered by ambulance clinicians. The characteristics of these patients is consistent with previously described national and international out-of-hospital trauma cohorts [ABSTRACT FROM AUTHOR]

It is difficult for a humanoid leg driven by two groups of antagonistic pneumatic muscles (PMs) to achieve a flexible humanoid gait, and its inherent strong coupling nonlinear characteristics make it hard to achieve good tracking performance in a large range of motion. Therefore, a four-bar linkage bionic knee joint structure with a variable axis and a double closed-loop servo position control strategy based on computed torque control are designed to improve anthropomorphic characteristics and the dynamic performance of the bionic mechanical leg powered by servo pneumatic muscle (SPM). Firstly, the relationship between the joint torque, the initial jump angle and the bounce height of the mechanical leg is established, and then we design a double-joint PM bionic mechanical leg containing a four-bar linkage mechanism of the knee joint. Secondly, a cascade position control strategy is developed, which consists of the outer position loop and the inner contraction force loop, and the mapping relationship is designed between joint torque and antagonistic PM contraction force. Finally, we further project bounce action timing of mechanical leg to realize the periodic jumping movement of the mechanical leg, and simulation and physical experiments of the real-style machine platform have been provided to demonstrate the effectiveness of the designed SPM controller. • A double-joint PM bionic mechanical leg containing four-bar linkage mechanism of the knee joint is designed. For the mechanical leg, a mapping relationship is proposed between the contraction force of muscles and the torque of joints. • By using the cascade control strategy with the position outside loop and the contraction force inner loop based on computed torque control method, the mechanical leg robot can achieve joints angle tracking well. • To achieve the periodic rebound of mechanical leg, we plan the periodic bouncing action into three stages and design a bouncing action sequence. At the time of the maximum rising speed, the strategies of leg retraction and foot leaping off the ground are formulated. [ABSTRACT FROM AUTHOR]

Flexible flatfoot has demonstrated biomechanical linkages between distal and proximal lower extremities. However, supporting evidence is required to investigate the benefits of short foot exercise (SF) and short foot exercise in combination with lower extremity training (SFLE) on dynamic foot function. This study aimed to determine the effects of a 6-week SF, 6-week SFLE, or control condition (no intervention) on dynamic foot function during gait in individuals with flexible flatfoot. Forty-five individuals with flexible flatfoot were randomly assigned into three conditions: (1) SF, (2) SFLE, and (3) control conditions. Participants in two intervention programs performed daily training via telerehabilitation and a home-based exercise program. Foot kinematics and center of pressure excursion index (CPEI) during the gait, intrinsic foot muscle test, and navicular drop test were assessed at baseline and after the 6-week intervention program. Post-intervention participants in the SF and SFLE conditions showed a shorter time to the lowest medial longitudinal arch (MLA) and improved MLA motion during the stance phase compared with the baseline. In addition, participants in the SFLE conditions showed greater changes in CPEI than in the SF and control conditions. Improvements in intrinsic foot muscle and navicular drop tests were also observed in participants in both intervention programs post-intervention. A major finding of the study was the improvement in dynamic foot function during gait in individuals with flexible flatfoot after the six weeks of the SF and SFLE intervention programs. Both intervention programs appear to have the potential for inclusion in a corrective program for individuals with flexible flatfoot. • Short foot exercises can be done online. • Short foot exercises improved medial longitudinal arch and dynamic gait. • Short foot with lower extremity exercise changed the center of pressure index. [ABSTRACT FROM AUTHOR]

Gait analysis relies on the accurate and precise identification of anatomical landmarks to provide reliable and reproducible data. More specifically, the precision of marker placement among repeated measurements is responsible for increased variability in the output gait data. The objective of this study was to quantify the precision of marker placement on the lower limbs by a test-retest procedure and to investigate its propagation to kinematic data. The protocol was tested on a cohort of eight asymptomatic adults involving four evaluators, with different levels of experience. Each evaluator performed, three repeated marker placements for each participant. The standard deviation was used to calculate the precision of the marker placement, the precision of the orientation of the anatomical (segment) coordinate systems, and the precision of the lower limb kinematics. In addition, one-way ANOVA was used to compare the intra-evaluator marker placement precision and kinematic precisions among the different levels of the evaluator's experience. Finally, a Pearson correlation between marker placement precision and kinematic precision was analyzed. Results have shown a precision of skin markers within 10 mm and 12 mm for intra-evaluator and inter-evaluator, respectively. Analysis of kinematic data showed good to moderate reliability for all parameters apart from hip and knee rotation that demonstrated poor intra- and inter-evaluator precision. Inter-trial variability was observed reduced than intra- and inter-evaluator variability. Moreover, experience had a positive impact on kinematic reliability since evaluators with higher experience showed a statistically significant increase in precision for most kinematic parameters. However, no correlation was observed between marker placement precision and kinematic precision which indicates that an error in the placement of one specific marker can be compensated or enhanced, in a non-linear way, by an error in the placement of other markers. • Evaluator's experience plays positive role on some kinematic parameters of gait. • No correlation between marker placement precision and kinematic variability. • Wands and femoral epicondyle markers are the lowest precise in marker placement. [ABSTRACT FROM AUTHOR]

• First systematic computational study supporting transcranial direct current stimulation (tDCS) montages for lower limb. • Group-level analysis of electric field considers polarity-dependent effects of tDCS. • Significant electric field intensities can reach deeper regions of the lower-limb motor area with uniform polarization. Transcranial direct current stimulation (tDCS) injects a weak electric current into the brain via electrodes attached to the scalp to modulate cortical excitability. tDCS is used to rebalance brain activity between affected and unaffected hemispheres in rehabilitation. However, a systematic quantitative evaluation of tDCS montage is not reported for the lower limbs. In this study, we computationally investigated the generated electric field intensity, polarity, and co-stimulation of cortical areas for lower limb targeting using high-resolution head models. Volume conductor models have thus been employed to estimate the electric field in the brain. A total of 18 head models of healthy subjects were used to calculate the group-level electric fields generated from four montages of tDCS for modulation of lower limbs. C1-C2 montage delivered higher electric field intensities while reaching deeper regions of the lower-limb motor area. It produced a uniform polarization on the same hemisphere target with comparable intensities between hemispheres but with higher variability. Proper montage selection allows reaching deeper regions of the lower-limb motor area with uniform polarization. First systematic computational study providing support to tDCS experimental studies using montages for the lower limb while considering polarity factor for balancing brain activity. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate the relationships between relative strength of the lower limbs and composite indices of femoral neck strength (compression strength index [CSI], bending strength index [BSI] and impact strength index [ISI]) in a group of young adult men. In all, 54 Lebanese young men whose ages range from 20 to 30 years (24.4 ± 3.1 years) participated in our study. Body composition and hip bone mineral density were assessed by DXA. CSI, BSI and ISI were calculated. One-repetition maximum (1-RM) half-squat, 1-RM deadlift and 1-RM bench-press were measured. 1-RM half-squat/body mass was positively correlated to CSI (r = 0.35; P < 0.01), BSI (r = 0.33; P < 0.05) and ISI (r = 0.32; P < 0.05), but negatively correlated to fat mass percentage (r = −0.37; P < 0.01). The current study suggests that relative muscular strength of lower limbs is positively correlated to composite indices of femoral neck strength in young men. [ABSTRACT FROM AUTHOR]

Past work has identified relationships between postural stability and joint kinematics during balance and sit-to-stand tasks. However, this work has not been extended to a thorough examination of these relationships during gait, and how these relationships change with age. An improved understanding of age-related changes in these relationships during gait is necessary to identify early predictors of gait impairments and implement targeted interventions to prevent functional decline in older adulthood. How does age affect relationships between time-varying signals representing joint/segment kinematics and postural stability during gait? Three-dimensional, whole-body motion capture data from 48 participants (19 younger, 29 older) performing overground gait were used in this secondary analysis. Lower extremity joint angles, trunk segment angles, and margins of stability in the antero-posterior and mediolateral directions were subsequently derived. Pairings of angle and margin of stability signals were cross-correlated across the gait cycle. Metrics representing the strength of relationships were extracted from the cross-correlation functions and compared between groups. At the ankle, significant age-related differences were only identified in the mediolateral direction, with older adults' coefficients being of greater magnitude and more tightly clustered, relative to younger adults. Differences were observed in both directions at the hip, with an overall trend of greater-magnitude and more tightly clustered coefficients among younger adults. For the trunk, the groups exhibited coefficients of opposite signs in the antero-posterior direction. While overall gait performance was similar between groups, age-related differences were identified in relationships between postural stability and kinematics, with stronger relationships at the hip and ankle for younger and older adults, respectively. Relationships between postural stability and kinematics may have potential as a marker for the early identification of gait impairment and/or dysfunction in older adulthood, and for quantifying the effectiveness of interventions to reduce gait impairment. • Relationships between postural stability and lower limb kinematics were quantified. • Relationship strengths differed between younger and older adults. • The nature of these age-related differences was joint-dependent. • These relationships may be an indicator of age-related declines in gait function. [ABSTRACT FROM AUTHOR]

Children with cerebral palsy (CP) have demonstrated higher rates of overweight and obesity than their typically developed peers. Limited studies have assessed how being overweight or obese affect lower limb kinematics during gait in these children. How are lower limb kinematics during gait affected in children with CP who progress from a healthy weight to being overweight or obese compared to a well-matched healthy weight CP control group? A retrospective analysis of the movement analysis laboratory database was conducted.Children with CP were included if they were aged between 4 and 17 years at baseline,had a follow-up assessment with a minimum of 12 months between assessments, and had no orthopaedic interventions between assessments. A matched control group of children with CP with the same inclusion criteria, except for a requirement of healthy BMI at follow-up, was included. Temporal-spatial and full 3-dimensional lower limb kinematic data were examined. Normalized speed and step length reduced from baseline to follow-up for both groups,with no difference in the amount of change between groups. Children with increased BMI demonstrated increased external hip rotation during stance at follow-up not evident in the control group. Results demonstrated similar changes over time between groups. Increased external hip rotation in children with increased BMI was considered small and within the threshold of error associated with transverse plane kinematics. Our results suggest that being overweight or obese does not result in a meaningful change in lower limb kinematics in children with CP. • Paper presenting the impact of increased BMI on gait in children with CP. • Matched control group of children with CP with healthy BMI included. • Compared to matched controls there are no kinematic differences. • Increased BMI does not result in a meaningful change in gait in these children. [ABSTRACT FROM AUTHOR]

Symptomatic muscle herniae are an uncommon cause of chronic exercise induced leg pain. The most common site for muscle hernia is the tibialis anterior muscle. This study evaluates the outcome of a minimal incision fasciotomy in patients with a symptomatic muscle hernia of the tibialis anterior muscle, and their return to normal daily activities including sport. The study reports mid-term results in a series of 22 consecutive patients (17 males and 5 females, median age: 22 years) with a unilateral tibialis anterior MH who had undergone minimally invasive fasciotomy between 2008 and 2019. Clinical outcomes were assessed with SF-36 and European Quality of Life-5 Dimensions scale (EQ-5D). The ability to participate in sport before and after surgery, and the time to return to training (RTT) and to sport (RTS) were recorded. At a median follow up after surgery of 23 months, both questionnaires showed a statistically significant improvement (P < 0.005). At the latest follow up, 16 of patients (73%) had returned to pre-injury or higher levels of sport/activity. The median time to return to training and to return to sport was 7 and 11 weeks respectively. No severe complications and no recurrence of symptoms were recorded. Minimally invasive fasciotomy is effective and safe for patients suffering from muscle hernia of the tibialis anterior muscle with good results in the mid-term. IV. • Symptomatic muscle herniae (MH) are an uncommon cause of exercise induced leg pain. • The tibialis anterior muscle (TAM) is most frequently affected. • We used minimal incision fasciotomy in MH of the TAM. • Patients returned to training and sport by 7 and 11 weeks respectively, without severe complications. • Minimally invasive fasciotomy is effective in patients with MH of TAM. [ABSTRACT FROM AUTHOR]

To compare Down Syndrome (DS) adolescents' physical fitness after a six-month multicomponent intervention program. Sixteen adolescents (15.22 ± 2.44 years-old, nine boys) participated in the study. The multicomponent intervention was performed in three areas involving physical exercises, nutrition education classes and parental support. Body composition was measured using DXA and physical fitness tests to assess cardiorespiratory fitness (CRF), upper and lower limbs strength, flexibility, agility and coordination were done, according to ALPHA (shuttle-run, handgrip, horizontal jump, sit and reach, and 4 × 10 agility test) and KTK (shifting platforms and side jumps) protocols at baseline and post-intervention. Data were analyzed using Bayesian repeated-measures ANOVA in JAPS (14.0) and the BF10 was adopted (evidence for alternative hypothesis). Lower limbs strength showed the highest Bayes factor (BF10 = 189.407) considered an extreme evidence, but upper limb strength, CRF, agility, flexibility and lean mass had a BF positive (BF10 = 13.06, 7.09, 4.92, 3.65, and 1.17, respectively) with anecdotal (> 1), moderate (> 3), and strong (> 10) evidence. [ABSTRACT FROM AUTHOR]

Rowing, when practiced as a sport, is currently typically conducted on sliding-seat boats which permit efficient lower limb use. Nevertheless, traditional fixed-seat rowing, with its own particular technique, is experiencing a revival and competitions utilizing this technique are held on a regular basis around the world. This paper investigated injuries sustained by competitive fixed-seat rowers when compared to rowers using the more widely studied sliding-seat technique. Two cohorts of male rowers, who train and compete on fixed-seat and sliding seat boats at national levels were asked to fill in a questionnaire looking into musculoskeletal injuries sustained as a result of their particular rowing style. Portuguese sliding-seat rowers rowed standard World Rowing (FISA) approved boats whilst fixed-seat rowers from Malta used traditional wooden boats and oars. Injury probabilities between the two cohorts were compared. Statistically significant diminution, P = 0.022, of knee injuries in the fixed-seat group was observed when compared to standard sliding-seat rowing, something which may be explained from the biomechanics of the stroke. Also, pelvic, other lower limb, neck and rib injuries were absent in the fixed-seat cohort. The incidence of back, shoulder, forearm and wrist injuries was comparable in both groups despite the increased reliance on the upper body, in the fixed-seat stroke. This means that contrary to common perception, fixed-seat rowing is a safe sport to practice. Furthermore, with its reduced risk of lower limb injuries, this technique could potentially form part of rehabilitation programs for rowers with such injuries. [ABSTRACT FROM AUTHOR]

Previous research has demonstrated that force control in various muscles of the lower limb (measured according to the magnitude of force fluctuations) explains significant variance in static balance. Given the dynamic nature of many functional activities and sports, assessment of balance and its determinants under dynamic conditions is of importance. Does muscle force control explain significant variance in dynamic balance, as measured using the Y balance test (YBT)? YBT performance and knee extensor muscle force control were measured in 28 healthy participants. The YBT involved stance on the right leg and attempting maximal reach with the left leg in the anterior, posteromedial, and posterolateral directions. Force control was assessed during isometric knee extension contractions of the right leg at 10%, 20% and 40% maximal voluntary contraction (MVC) and was quantified according to the magnitude (using the coefficient of variation [CV]), and the temporal structure (using sample entropy, SampEn; and detrended fluctuation analysis α), of force fluctuations. Significant correlations were observed for YBT anterior reach and muscle force CV (r = –0.44, P = 0.02) and SampEn (r = 0.47, P = 0.012) during contractions at 40% MVC. A subsequent regression model demonstrated that muscle force CV and SampEn at 40% MVC significantly explained 54% of variance in YBT anterior reach. Significant correlations were also observed for YBT posteromedial reach and MVC (r = 0.39, P = 0.043) and muscle force CV during contractions at 40% MVC (r = –0.51, P = 0.006). The regression model demonstrated that MVC and muscle force CV at 40% MVC significantly explained 53.9% of variance in YBT posteromedial reach. These results are the first to indicate that a moderate amount of variance in dynamic balance can be explained by measures of isometric force control. • Knee extensor force CV and SampEn are correlated with Y balance test anterior reach. • Knee extensor force MVC and CV are correlated with Y balance test posteromedial reach. • Indices of muscle force control explain significant variance in dynamic balance. [ABSTRACT FROM AUTHOR]

The conventional gait model (CGM1) is extensively used for 3D clinical gait analysis. It uses lateral wand-mounted markers for the thigh and shank segments to avoid colinearity of the tracking markers. However, gait analysts may be tempted to use skin-mounted markers instead. Does it matter if the lateral markers for the thigh and shank segments are mounted on wands or directly taped to the skin when using the CGM1? Gait sessions from 147 and 73 patients equipped with wand-mounted and skin-mounted markers, respectively, were extracted from the database of a single clinical gait laboratory. The marker trajectories were reprocessed with the CGM1. The risk of marker colinearity was assessed from the planar angle constructed from the proximal joint center, the lateral joint marker and the lateral segmental marker (i.e. skin or wand). We assessed the effect of marker misplacement and soft-tissue artefact on kinematics. The averaged planar angles calculated from static ranged from 10° to 30° and 7° to 21° for the skin-mounted thigh and shank markers respectively, while planar angles were always larger than 25° with wand-mounted markers. One cm misplacement of the thigh marker altered hip rotation by 10° if skin-mounted against 5° if wand-mounted. Soft tissue artefact led to 7.6° or 4.3° depending if it was skin- or wand-mounted, respectively. Our analysis showed moderate risk of collinearity, increased effect of STA, and larger potential effect of marker misplacement with the use of skin- rather than wand-mounted markers. • Wand-mounted markers are recommanded for the conventional gait model. • Kinematic ouputs from wand-mounted markers and skin-mounted markers were compared. • The risk of collinearity was moderate with skin-mounted markers. • Soft-tissue artefact and misplacement errors increased with skin-mounted markers. [ABSTRACT FROM AUTHOR]

Assessments of lower limb torsion are ubiquitous in clinical gait analysis practice as pathologic lower limb rotational deformity may contribute to gait abnormalities, anterior knee pain, as well as other debilitating conditions. Understandably, the overall utility of any torsional assessment is dependent on the measurement method's intrinsic accuracy, precision, and robustness to clinical interference factors. Recently, biplanar radiography (BPR) measurements of torsion have been shown to be both accurate and precise, but the robustness of BPR to potential interference factors is unknown. How robust are BPR lower limb torsional assessments to six potential interference factors: amount of torsion, skeletal maturity, radiograph quality, prior osteotomy, presence of implants, and observer training background and experience? In this retrospective cohort study, four observers of diverse backgrounds and experience generated digital 3D reconstructions of 44 lower limbs using BPR images obtained during standard of care visits (age range 7–35 years). From each reconstruction, four lower limb torsional parameters were computed: femoral torsion, femorotibial rotation, tibial torsion, and transmalleolar axis equivalent. The mean absolute deviation (MAD) of each torsional parameter – calculated across the four observers – was used as the measure of reliability and tested against all interference factors. Results demonstrated that the average MAD was 2.1 degrees for femoral torsion, 3.0 degrees for transmalleolar axis equivalent, 3.8 degrees for femorotibial rotation, and 4.7 degrees for tibial torsion. None of the six potential interference factors were found to systematically influence BPR reliability across all four torsional parameters. Of the factors found to statistically influence one or more torsional parameter, none affected MAD values to a clinically meaningful extent. In addition to being accurate and precise, BPR appears to be robust to several clinical factors relevant to children and young adults with or at risk for pathological lower limb torsion. • Biplanar radiography produced reliable measurements of lower limb torsion. • Robustness was not systematically affected by any of the six interference factors. • Study utilized observers with diverse training background and experience. • Femoral anteversion and transmalleolar axis equivalent were the most reliable. [ABSTRACT FROM AUTHOR]

Free flaps are commonly used for head and neck reconstruction. However, flap dimensions are still evaluated by visual and tactile assessment. The aim of this study was to enable preoperative planning of flap dimensions for soft tissue reconstruction based on clinical parameters. Computed tomography records from 230 patients dated from 2009 to 2019 were analysed retrospectively. A virtual, three-dimensional anterolateral thigh flap model was standardized, aligned to segmented leg models in two positions, and flap thicknesses and volumes were determined. Associations of flap thickness and volume with clinical parameters were evaluated, and an approximative calculation method was derived. The laterally positioned anterolateral thigh flap showed an average (interquartile range) thickness of 15.6 mm (8.7 mm) and volume of 1.5 cm3 (0.9 cm3) per cm2. The medially positioned anterolateral thigh flap showed an average (interquartile range) thickness of 16.3 mm (8.7 mm) and volume of 1.6 cm3 (0.9 cm3) per cm2. For both flap positions, leg circumference was the strongest predictor of flap thickness (β = 0.545, P < 0.001 and β = 0.529, P < 0.001) and flap volume (β = 0.523, P < 0.001 and β = 0.480, P < 0.001). Flap dimensions can be calculated based on leg circumference, and this preoperative planning of flap dimensions can help the surgeon to select the appropriate flap. [ABSTRACT FROM AUTHOR]

Texting while walking (TWW) is a dual-task activity that young adults perform in their everyday lives. TWW has been reported to affect gait characteristics such as gait speed, stride length, and cadence. However, the influence of TWW on lower extremity gait function has not been investigated. Therefore, the purpose of this study was to quantify gait function by examining gait symmetry and using a time series analysis. Twenty-eight young adults (14 males, 14 females) walked at their preferred speed for 10 m as a baseline condition and a 10 m TWW task. Three-dimensional segment tracking was achieved utilizing a lower extremity and trunk marker set and the Model Statistic was used to test for statistical differences between the hip, knee, and ankle angular joint positions. The hip yielded the most asymmetries (25 out of 101 points) throughout the gait cycle, while asymmetries for the knee and ankle joints yielded 16 out of 101 points and 11 out of 101 points, respectively. The outcomes of this study suggest there are differences between baseline and TWW gait symmetry, however, the percentage of the gait cycle affected was less than 25 % - indicating gait function is not strongly influenced by texting while walking in young adults. • Asymmetries exist in the lower limbs between texting while walking and baseline • Texting is prioritized over walking during dual-task movements • Gait speed is decreased when TWW while stride length is unaffected [ABSTRACT FROM AUTHOR]

The study investigated the effects of unilateral and bilateral lower extremity fatigue on both postural stability and postural adjustments. Fourteen young male subjects performed unilateral and bilateral dynamic lower extremity pedaling exercises with 5 sets of 20 times at 50 % maximum voluntary contraction. Center of pressure (COP) signals were recorded before and after the fatigue exercise. Electromyography activities of six trunk and leg muscles were recorded and analyzed during the anticipatory (APAs) and compensatory (CPAs) postural adjustments. The results showed that both fatiguing exercises caused an increase in COP and larger APAs and CPAs in the rectus femoris and tibialis anterior during externally initiated perturbation. However, the observed indicators showed no clear difference between unilateral and bilateral fatigue. These results validated that when enlarged APAs were not sufficient to resist the external perturbation, the central nervous system increased the strength of CPAs to maintain the stability of the body. These findings provided a perspective on the association between APAs and CPAs, which may apply to the athletic training or rehabilitation on postural control. [ABSTRACT FROM AUTHOR]

To explore the effect and value of the modified low dose direct method CTV in the diagnosis of lower extremity varicose veins. Thirty-eight patients with superficial varicose veins of the lower extremities were examined by modified low-dose direct method CTV imaging in V1 and V2 phases. Two radiologists scored the image quality, and recorded the number of perforating veins in V1 of the deep venous phase and V2 of the total venous phase. The development of perforating veins in V1 was defined as positive perforating veins, and no perforating veins in V1 was defined as negative perforating veins. Objective evaluation: measurement of iliac vein in V1; Femoral vein; Popliteal vein; Tibial vein; The CT value (unit: Hu) of varicose veins and perforating veins in V1 and V2 were calculated, and the corresponding signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Iliac vein; Femoral vein; Popliteal vein; Tibial vein; Varicose veins; The CT values of perforating veins in V1 and V2 phases were 941.8±198.0, 824.4 ±277.9, 987.7±309.7, 1091.9±275.8, 858.1±330.7, 728.9±394.7, 743.7±232.6. The lowest CT value of perforating veins was 130HU, with an average of 736.32Hu, which was significantly higher than the average CT value of muscle tissue in the same layer of region of interest (61.3±7.56 Hu). Among the subjective evaluation indicators, 34 cases (89.5%) had good image quality and 4 cases (10.5%) had general image quality. Among 58 limbs of 38 patients, 29 patients (76.3%) had positive perforating veins in V1 stage, and 45 limbs (77.6%) had positive perforating veins. A total of 159 perforating veins were detected, and 443 perforating veins were detected in V2 stage. Modified CTV can accurately display the range and location of varicose veins, identify the number and location of abnormal perforating branches, and has a high diagnostic accuracy rate, which can better serve the clinical treatment. [ABSTRACT FROM AUTHOR]

During Percutaneous trans-luminal angioplasty, the patient's uncooperative movements cause delays in the procedure time, and unnecessary radiation exposure. Therefore, in this study, we attempted to investigate the usefulness of the vaccum-lock device, which is usually used in radiation therapy, by applying it to interventional radiology patients. Three experimental groups were set up for this study. First, an Optical stimulated luminescense dosimeter was used on pig feet to determine the radiation exposure dose that changes when the vaccum-lock device is applied. Second, for patients who received the procedure on both legs, the vaccum-lock device was applied only to one side and NOT to the other side. Afterwards, the captured images were compared. Third, in the case of a patient who received the procedure on only one leg, the vaccum-lock device was applied before percutaneous transluminal angioplasty, and the device was removed after ballooning was completed. We compared the images before and after applyung the device.When vacuum-lock deivce was applied, the average core dose increased by 0.24 mSv compared to the case without it, and the surface dose increased by 0.29 mSv. As a result of examining the difference in radiation exposure due to the application of vacuum-lock device, it was found that there was no significant difference in the deep dose and shallow dose that the patient received due to the application of the vacuum-lock device. A study was conducted on 20 patients to prove the hypothesis that the patient's movements would be inhibited by applying the Vacuum-Lock Device. As a result, 14 of the 20 patients studied showed differences before and after applying the Vacuum-Lock Device. It was found that there was a significant effect on movement inhibition. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this paper is to propose the Neuromusculoskeletal Epidemiological Outcome (NEO) Matrix, an injury classification based on anatomical location and primary tissue type to classify NMSKI of the trunk and extremities in orthopaedic and sports medicine epidemiological research.Materials and Methods: In the proposed NEO matrix, NMSKI diagnosis (International Classification of Disease) codes are classified by the anatomical complex affected. These regional anatomical complexes are frequently employed in orthopaedic and sports medicine disciplines in biomechanical and clinical research. The complexes are arranged from distal to proximal in the lower extremity, inferior to superior in the trunk and head, and proximal to distal in the upper extremity. Injuries are characterized by the primary tissue type affected (Osseous; Articular; Musculotendinous; Neural; Non-specific) based on classified using International Classification of Disease codes.Discussion: The expected patterns of impairment and healing rates of bone, cartilage, ligaments, muscles, tendons, and neural structures vary considerably by the tissue type based on the differences in function, perfusion, and metabolic physiology. Using knowledge of the function of the tissues, expected minimum healing times, and expected sequelae of residual body system impairments, an estimation of morbidity and expected recovery times can be made. While heterogeneity is certainly expected due to varying pathomechanics involved and intrinsic and environmental factors, the NEO matrix classifies the ICD diagnosis codes in framework that qualifies the expected patterns of impairment based on the body system type.Conclusion: The NEO matrix provides an alternative approach for characterizing NMSKI in epidemiological research. [ABSTRACT FROM AUTHOR]

Introduction: Phantom limb syndrome is a debilitating complication after extremity amputation that poses significant challenges to recovery. This study aims to examine the relationship between phantom limb syndrome and mental and physical comorbidities, including a comparison between phantom limb pain and phantom limb syndrome without pain in below knee amputees.Methods: This is a retrospective cohort study of patients who underwent below knee amputation of the lower extremity in the PearlDiver database, as identified using CPT codes. Analysis was carried out to evaluate the absence or presence of phantom limb syndrome. Matched bivariate analysis accounting for age, sex, Charlson Comorbidity Index score, and region was used to assess whether the presence of pain in phantom limb syndrome patients was associated with increased comorbidity.Results: In total, 44,028 patients with below knee amputation were examined: 95% (42,493 patients) did not develop phantom limb syndrome while 4.8% (1,535 patients) of patients did develop phantom limb syndrome. Phantom limb syndrome was significantly associated with increased odds of coexistent major depressive disorder (OR = 1.86, p <0.0001), generalized anxiety disorder (OR = 2.14, p = 0.04), posttraumatic stress disorder (OR = 1.7, p <0.0001), suicidal ideation (OR = 1.62, p <0.0001), obesity (OR = 1.28, p = 0.0007), osteoarthritis (OR = 1.53, p <0.0001), osteoporosis (OR = 1.64, p <0.0001), and low back pain (OR = 2.31, p <0.0001). Analysis of patient cohorts of phantom limb syndrome with pain and those without pain did not reveal a statistically significant relationship between the presence of pain and any dependent variable.Conclusions: This investigation of over 44,000 patients with below knee amputation revealed that patients with phantom limb syndrome exhibit significantly higher rate of psychiatric comorbidities compared to those without documented phantom limb pain. Suicidal ideation, major depressive disorder, generalized anxiety disorder, and post-traumatic stress disorder were especially common, and consequently a multi-disciplinary approach to management is essential. [ABSTRACT FROM AUTHOR]

Background: Prefabricated and customized insoles are used in clinical practice to reduce foot pronation. Although data exist on the effects at key points within the stance phase, exploring the impact of different insoles using time series analysis may reveal more detail about their efficacy.Research Question: What are the effects revealed by a time series analysis of arch-supported prefabricated insoles (PREFABRICATED) versus arch-supported prefabricated insoles customized with a 6º medial wedge (CUSTOMIZED) on the lower limb biomechanics during walking, stepping up and down tasks in individuals with pronated feet?Methods: Nineteen individuals with excessive foot pronation performed walking, stepping up and down tasks using three insoles: CONTROL (flat insole), CUSTOMIZED, and PREFABRICATED. Angles and moments of ankle and knee coronal and hip transverse planes were compared between conditions using statistical parametric mapping (SPM).Results: For walking, CUSTOMIZED reduced ankle eversion moment compared to CONTROL during midstance and PREFABRICATED during propulsion. CUSTOMIZED decreased KAM during midstance and propulsion compared to PREFABRICATED. Compared to CONTROL, CUSTOMIZED and PREFABRICATED reduced hip internal rotation during propulsion and loading response, respectively. CUSTOMIZED decreased eversion movement during midstance and propulsion for the stepping up task. PREFABRICATED reduced eversion movement during midstance in comparison to CONTROL. For the stepping down task, CUSTOMIZED increased eversion movement during propulsion compared to PREFABRICATED. CUSTOMIZED reduced hip internal rotation angle for stepping up task during propulsion, decreased medial rotation movement during midstance compared to CONTROL, and reduced medial rotation during midstance compared to PREFABRICATED. CUSTOMIZED increased KAM for stepping up and down tasks during propulsion.Significance: These findings suggest that both CUSTOMIZED and PREFABRICATED reduce foot pronation. However, non-local effects, such as changes in KAM and hip internal rotation, were seen only in the CUSTOMIZED. Therefore, CUSTOMIZED may be preferable if the objective is to modify the knee and hip mechanics. [ABSTRACT FROM AUTHOR]

Background: Patients demonstrate decreased knee loading and energy absorption after anterior cruciate ligament reconstruction (ACLR). This study aimed to determine the differences in the contribution of joints to the absorbed energy between athletes with and without radiological signs of knee OA 2 years after ACLR during drop jump (DJ) landing from 20, 30, and 40 cm.Methods: Forty-one (level I/II) athletes 2 years after ACLR participated in this cross-sectional study and completed motion analysis testing of DJ. Proportional contribution of the joints (foot, ankle, knee, and hip) to the absorbed energy were computed. Posterior-anterior bent-knee radiographs were completed and graded in the medial compartment of the reconstructed knee using the Kellgren-Lawrence (KL) system (OA group: KL ≥2; Non-OA group: KL<2) RESULTS: Thirteen (31.7%) athletes showed radiological signs of knee OA in the medial compartment. There was a significant joint-by-group-by-limb interaction for the contribution of joints to absorbed energy during DJ 40 cm (p ≤ 0.019) and a joint-by-group interaction for the contribution of joints during DJ 20 cm (p = 0.018). The OA group had a lower involved knee (p = 0.043) and higher involved hip contributions (p = 0.014) compared to the Non-OA group, and the non-involved knee (p = 0.007). While the Non-OA group had a lower involved ankle contribution (p = 0.045) compared to their non-involved ankle during DJ 40 cm. The OA group also had higher involved hip contribution than the Non-OA group (p = 0.010), lower involved knee (p = 0.002), and higher involved hip contribution than the non-involved limb during DJ 20 cm.Significance: The OA group may have adopted a compensatory pattern characterized by a decreased involved knee and increased involved hip to attenuate absorbed energy compared to the Non-OA group and their non-involved limb. The contribution of joints to the absorbed energy during DJ landing might be used as an assessment tool to identify patients with radiological signs of knee OA after ACLR. [ABSTRACT FROM AUTHOR]

Backgrounds: Previous reports revealed that balance and stability are essential for human physical activity. The present study aimed to evaluate the comparative outcome of a novel beginning movement load training (BMLT) versus conventional leg press training in terms of improvement of lower-extremity stability.Research Question: Does the leg press training improve the stability of lower extremities?Methods: Twenty adult, asymptomatic and active amateur basketball players were enrolled in this study and randomized in equal numbers into a BMLT group (study group) and a conventional leg press training group (control group).Results: The results after eight-week course of training showed that conventional leg press training had an opposite effect on dynamic stability in the left leg (p = 0.015) and backward movement of the right leg (p = 0.038). The athletes in the study group revealed superior dynamic stability maintenance in both legs backwards (p = 0.001), the left leg (p = 0.013), the right leg backwards (p = 0.022) and overall stability (p = 0.002).Significance: The study group showed better postural stability in terms of the medial/lateral index (p = 0.017), and the athletes in the control group exhibited a significant inability to maintain postural stability in the medial/lateral aspect after the training (p = 0.016). Rotational BMLT lower-extremity press training yielded superior enhancement of dynamic stability and maintenance of center of gravity and postural stability. [ABSTRACT FROM AUTHOR]

Background: The single-leg squat (SLS) is often used to measure two-dimensional frontal plane motion; however, there is a variability in the SLS depth across studies.Research Question: Are knee abduction (KABD), hip adduction (HADD), pelvic drop (PD), and lateral trunk flexion (LTF) angles different at greater knee flexion angles during a SLS?Methods: Twenty pain-free females (age=22.3 ± 1.1 years, height=1.68 ± 0.06 m, mass=63.1 ± 11.7 kg) participated in this cross-sectional study. Participants performed five SLSs to the lowest depth comfortable, keeping pace with a metronome, while being video recorded in the frontal and sagittal planes. The middle three SLSs were used for analysis. KABD, HADD, PD, and LTF angles were measured at 30º, 45º, 60º, 75º, and 90º of knee flexion using extracted images. Linear mixed model analyses were used to compare across knee flexion angles and clinical significance was determined by comparing angle changes to the standard error of measurement (SEM).Results: We observed significant differences for KABD (F=14.69, p < .001), HADD (F=46.29, p < .001), and PD (F=27.27, p < .001) among knee flexion angles. Post-hoc analyses revealed that KABD significantly increased at every increase of knee flexion angle (p ≤ .05, d=0.54-1.95), as did HADD (p ≤ .05, d=0.64-3.85) and PD (p ≤ .05, d=0.61-3.03). Changes in KABD, HADD, and PD often exceeded SEM for all changes in knee flexion angles.Significance: Knee, hip, and pelvic frontal plane motions are influenced by knee flexion angles during 2D analysis of a SLS task. Our results highlight the importance of standardizing SLS depth during research and clinical practice to ensure appropriate comparisons across measurements. [ABSTRACT FROM AUTHOR]

Background: Lower cadence has been previously associated with injury in long-distance runners. Variations in cadence may be related to experience, speed, and anthropometric variables. It is unknown what factors, if any, predict cadence in healthy youth long-distance runners.Research Question: Are demographic, anthropometric and/or biomechanical variables able to predict cadence in healthy youth long-distance runners.Methods: A cohort of 138 uninjured youth long-distance runners (M = 62, F = 76; Mean ± SD; age = 13.7 ± 2.7; mass = 47.9 ± 13.6 kg; height = 157.9 ± 14.5 cm; running volume = 19.2 ± 20.6 km/wk; running experience: males = 3.5 ± 2.1 yrs, females = 3.3 ± 2.0 yrs) were recruited for the study. Multiple linear regression (MLR) models were developed for total sample and for each sex independently that only included variables that were significantly correlated to self-selected cadence. A variance inflation factor (VIF) assessed multicollinearity of variables. If VIF≥ 5, variable(s) were removed and the MLR analysis was conducted again.Results: For all models, VIF was > 5 between speed and normalized stride length, therefore we removed normalized stride length from all models. Only leg length and speed were significantly correlated (p < .001) with cadence in the regression models for total sample (R2 = 51.9 %) and females (R2 = 48.2 %). The regression model for all participants was Cadence = -1.251 *Leg Length + 3.665 *Speed + 254.858. The regression model for females was Cadence = -1.190 *Leg Length + 3.705 *Speed + 249.688. For males, leg length, cadence, and running experience were significantly predictive (p < .001) of cadence in the model (R2 = 54.7 %). The regression model for males was Cadence = -1.268 *Leg Length + 3.471 *Speed - 1.087 *Running Experience + 261.378.Significance: Approximately 50 % of the variance in cadence was explained by the individual's leg length and running speed. Shorter leg lengths and faster running speeds were associated with higher cadence. For males, fewer years of running experience was associated with a higher cadence. [ABSTRACT FROM AUTHOR]

Background: The biomechanics of barefoot and shod running are different for typically developing children but unknown for children with cerebral palsy (CP). Such differences may have implications for injury and performance.Aims: The primary aims of this study were to compare the lower limb biomechanics of barefoot and shod running in children with CP, and to determine whether any differences were the same in GMFCS levels I and II.Methods: This cross-sectional study examined 38 children with CP (n = 24 (GMFCS) level I; n = 14 GMFCS II), running overground at 3 speeds (jog, run, sprint) in barefoot and shod conditions. Marker trajectories and force plate data were recorded, and lower limb kinematics, kinetics and spatiotemporal variables were derived. Differences between barefoot and shod running were analysed using linear mixed models.Results: For both GMFCS levels, barefoot running resulted in higher loading rates, but smaller impact peaks at all speeds. Barefoot running was associated with greater hip and knee power; less ankle dorsiflexion and hip flexion at initial contact, and less ankle and knee range of motion during stance, compared to shod running, at all speeds. Barefoot stride length was shortened, and cadence increased compared to shod during jogging and running but not sprinting. For GMFCS level I only, barefoot running involved a higher incidence of forefoot strike, greater ankle power generation and less hip range of motion during stance.Significance: Running barefoot may facilitate running performance by increasing power generation at the ankle in children with CP, GMFCS level I. Higher barefoot loading rates may have implications for performance and injury. [ABSTRACT FROM AUTHOR]

Background: The step-down tap (SDT) is a commonly used task to assess unilateral neuromuscular control and to identify deficient movement patterns of the trunk and lower extremities. However, instruction of the SDT varies greatly in recent reports, which may alter the clinical interpretation of potential movement deficiencies.Research Question: The purpose of this study was to identify differences in trunk and lower extremity kinematics between variations of a step-down tap that differ based on step direction, fixing the arms or stance foot, and trial collection methods.Methods: This study followed a single-group repeated measures design in a laboratory setting. Three-dimensional angles of the trunk, hip, and knee of 18 participants were evaluated at 60 degrees of knee flexion and at maximum squat depth during six SDT variations. Wilcoxon signed rank tests were performed to determine the effects of an anterior verse lateral step direction, a fixed arm or stance foot position, and an individual verse continuous trial collection method.Results: Knee flexion, external pelvic rotation, and external trunk rotation were greater in the anterior SDT, while the lateral SDT elicited greater pelvic tilt and hip flexion. Additionally, overall squat depth was greater across participants during the anterior SDT. Few clinically significant differences (≥3°) were observed due to fixing arm or stance foot position, and no differences were identified based on trial collection methods.Significance: The standardization of task instructions for motion analysis protocols utilized for research purposes and/or clinical decision-making is crucial. Specifically, for the SDT, the authors recommend using the anterior step direction. A fixed arm and stance foot position is not necessary, and trials may be collected individually or continuously based on convenience for a small number of repetitions. [ABSTRACT FROM AUTHOR]