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Background Previous research showed that hallux rigidus (HR) affects foot and ankle kinematics during gait. It is unclear if HR affects lower limb kinematics as well. Research question Does HR affect lower limb kinematics, and if so, is gait deviation correlated with patient-reported outcome? Methods This was a retrospective case-control study, including 15 HR patients and 15 healthy controls who underwent three-dimensional gait analysis by using the Plug-in Gait lower body model. The Gait Profile Score (GPS), a gait index score describing gait deviation and composed out of nine Gait Variable Scores (GVS), and intersegmental range of motion of lower limb joints were assessed. Patient-reported outcome was assessed with the Foot Function Index (FFI) and Manchester-Oxford Foot Questionnaire (MOXFQ). Data were analysed with Student t-tests and Spearman rank correlations. Results HR significantly affects gait, reflected by a higher GPS in HR subjects as compared to healthy controls. Gait deviation was seen in ankle flexion (GVSankle flexion) and to a lesser extent in pelvic rotation (GVSpelvic rotation). Interestingly, these differences were not detected when lower limb kinematics were evaluated by comparing the intersegmental ranges of motion of these joints. Positive correlations were present between patient-reported outcomes and GPS, especially functional subdomains, were positively correlated with GPS and GVSankle flexion. Significance This study demonstrated that HR, next to foot kinematics, additionally affects lower limb kinematics evaluated with an objective gait index score, i.e. GPS. The positive correlation between the GPS and patient-reported outcome can be seen as the first step in defining whether objectively measured gait indices can be used in considering surgery since most of the benefit of surgery will be expected in the patients with most gait deviation.

Background The head, arms and trunk segment constitute a large proportion of the body’s mass. Therefore, small alterations in trunk inclination may affect lower limb joint moments and muscle activation patterns. Although previous research has investigated the effect of changing frontal plane inclination of the trunk, it is not clear how increasing trunk flexion will impact on the activation of the lower limb muscles. Research question What is the effect of independently manipulating trunk flexion angle on lower limb kinematics, moments and muscle function? Methods Gait analysis was carried out on 20 healthy people under four trunk flexion conditions: normal walking (NW), NW-5°, NW+5° and NW+10°. For the latter three conditions, a biofeedback approach was used to tightly control trunk flexion angle. A linear mixed model was used to investigate the effect of changing trunk flexion on joint angles, moments, and knee muscle activation. Results There were clear increases in hip and ankle moments as trunk flexion was increased, but no change in knee moments. The results also showed a linear increase in knee flexor muscle activity and a corresponding increase in co-contraction as trunk flexion increased. Interestingly, there was a dramatic change in the profile of hamstring activity. In the medial hamstrings, this change led to a 100% increase in activation during early stance as flexion was increased by 5° from NW. Significance This is the first study to demonstrate a strong dependence of knee flexor muscle activity on trunk flexion. This is important as people with knee osteoarthritis have been observed to walk with elevated muscle activation and this has been linked to increased joint loads. It is possible that these altered muscle patterns may result from increased trunk flexion during walking.

Understanding the effects of leg length discrepancy (LLD) on the biomechanics of gait and determining as to what extent of LLD alters gait is essential. A total of 91 biomechanical data were assessed from 14 lower limbs of healthy individuals walking under random conditions: shod only and with a 5, 10, 15, 20, 30 and 40 mm sole lift. Lower limb kinematics and dynamic leg length (DLL) were measured by a motion capture system. Hotelling's T-Square test was used to evaluate the differences in DLLs throughout the gait cycle in conjunction with differences between the sides based on the maximal stance phase and minimal swing phase DLLs. Kinematics were compared using the one-way blocked analysis of variance and Post-hoc analysis by the paired t-test. Significant dynamic shortening of the longer limb, mainly during the swing phase, and significant change in maximal stance and minimal swing phase DLL relationship started at a 10 mm lift condition (p 0.05). Thirteen kinematic variables produced a significant angular main effect (p 0.05), with a more flexed position of the longer limb and extended shorter limb beginning at a 5 mm lift. An increase in hip abduction and external foot rotation during the swing phase was also found. This study demonstrates that simulated LLD, as low as 5 mm, causes biomechanical changes in the lower limbs during gait revealed in both kinematics and dynamic leg length, suggesting that LLD, as small as 5-10 mm, should not be ignored.

Inertial sensor systems are increasingly used in the assessment of persons with knee osteoarthritis (KOA) and total knee replacement (TKR). This systematic review aims to (1) investigate the application of inertial sensor systems and kinematics derived from these systems, and (2) assess if current assessment protocols consist of tasks which are, according to the International Classification of Functioning, Disability and Health (ICF) for KOA, relevant for persons with KOA and TKR. A search was conducted in six electronic databases (ACM, CINAHL, EMBASE, IEEE, PubMed, Web of Science) to include papers assessing the knee and one or more adjacent joints by means of inertial sensors in healthy persons or persons with KOA or TKR. Two reviewers checked the methodological quality. Twenty-three papers were included: 18 in healthy persons and five in persons with KOA or TKR. In healthy persons, 11 tasks were related to metrics of the ICF-function and ICF-activity level. In persons with KOA, only walking was assessed. Apart from walking, four additional tasks were related to the ICF-function and ICF-activity level in persons with TKR. In healthy persons, joints located proximally and distally to the knee were assessed, while in persons with KOA and TKR, only the knee and ankle were assessed. This is a shortcoming since hip and trunk motion potentially contain clinically relevant information, in terms of identifying (mal)adaptive compensatory movement strategies. Additionally, physically more demanding tasks should be evaluated as these might be superior in detecting compensatory movement strategies. Former considerations warrant attention in future research. ispartof: Gait & Posture vol:59 pages:229-241 ispartof: location:England status: published

Assessments using dynamic postural control tests, like the Star Excursion Balance Test (SEBT), in combination with three-dimensional (3D) motion analysis can yield critical information regarding a subject's lower limb movement patterns. 3D analysis can provide a clear understanding of the mechanisms that lead to specific outcome measures on the SEBT. Currently, the only technology for 3D motion analysis during such tests is expensive marker-based motion analysis systems, which are impractical for use in clinical settings. In this study we validated the use of the Microsoft Kinect as a cost-effective and marker-less alternative to more complex and expensive gold-standard motion analysis systems. Ten healthy subjects performed the SEBT while their lower limb kinematics were measured concurrently using a traditional motion capture system and a single Kinect v2 sensor. Analyses revealed errors in lower limb kinematics of less than 5°, except for the knee frontal-plane angle (5.7°) in the posterior-lateral direction. Ensemble curve analyses supported these findings, showing minimal between-system differences in all directions. Additionally, we found that the Kinect displayed excellent agreement (ICC3,k=0.99) and consistency (ICC2,k=0.99) when assessing reach distances in all directions. These results indicate that this low-cost and easy to implement technology may provide to clinicians a simple tool to simultaneously assess reach distances while developing a clearer understanding of the lower extremity movement patterns associated with SEBT performance in healthy and injured populations.

While studying detailed lower limb mechanics of dynamic sports manoeuvres like side cutting it is often desirable but practically difficult to directly measure velocity profiles of the whole-body centre of mass (CoM). In the current study, representations of CoM, either based on a single marker placed on the pelvis or thorax, or based on segment kinematics of lower limbs with or without inclusion of trunk, were evaluated against whole-body CoM representation. Using the 95% limits of agreement method for comparison of two methods, strongest agreement was found between velocity of whole-body CoM and CoM representation based on lower limbs with the addition of the trunk. The CoM representation based on lower limbs only showed weaker agreement, but this representation was still markedly superior to single marker representations.

Interpersonal synchronization of stepping during side-by-side walking may assist in the rehabilitation of gait for mildly impaired individuals. However, little is known regarding the effects of step synchronization on lower limb movement kinematics. The purpose of this study was to compare normal treadmill walking to walking under conditions of intentional and unintentional synchronization of stepping. Twenty pairs of subjects walked on side-by-side treadmills independently, paired (side-by-side under conditions in which unintentional synchronization was likely to occur), and paired with forced synchronization (instructed to purposely synchronize stepping). Of these 20 pairs, six pairs (12 individuals) demonstrated unintentional synchronization for over 99% of the paired walking trial. An optical motion capture system was used to compare lower limb kinematics for each of the three walking conditions in these six pairs. The data indicated that forced synchronization of stepping resulted in steps that were significantly smaller and faster when compared to independent and unintentional synchronization conditions. In addition, stride time standard deviation was reduced for both the intentional and unintentional synchronization conditions, but these reductions were not significant. No differences were noted between the unintentional synchronization and independent walking conditions. These results suggest that unintentional synchronization might be preferable to intentional synchronization for gait rehabilitation in certain individuals. Additional work is necessary to understand the effects of side-by-side walking and its potential for use in a therapeutic setting.

The authors regret that an error was made in the calculation of effect sizes (standardised mean difference – Cohen’s d) that are presented in Table 5 and Fig. 2. Consequently, the magnitude of these results were classified and interpreted as small in the abstract, discussion and conclusion sections. Using the classification scale outlined in the methods section, the corrected effect sizes are classified as large, except for three results that are classified as moderate. These corrected findings, therefore, indicate moderate to large changes in the mean difference relative to the variability in the data and may increase the likelihood that such kinematic effects are clinically meaningful. Amendments have been made to Table 5 and Fig. 2, as well as where we make reference to them in the abstract, discussion and conclusion sections of the manuscript. The amendments are outlined below in the order that they appear in the original article. In the second last sentence of the abstract, the interpretation of effect sizes was amended, the sentence now reads as follows: Five article compared kinematics parameters between different foot postures – there was some evidence for increased motion in planus feet with large effect sizes. Seven articles investigated associations between foot posture and kinematics – there was evidence that increasing planus foot posture was positively associated with increased frontal plane motion of the rearfoot. In the final two sentences of the third paragraph within the subsection of the Discussion titled: ‘4.1. Quality assessment and effect size’, the interpretation of effect sizes was amended. The sentences now read as follows: As illustrated in Table 5 and Fig. 2, all effect sizes were large, except for three that were classified as moderate. Effect sizes of this magnitude indicate moderate to large changes in the mean difference relative to the variability in the data and may increase the likelihood that such kinematic effects are clinically meaningful. In the third sentence of the conclusion, the reference to effect sizes in the interpretation of the quality of evidence has been removed. The sentence now reads as follows: However, the quality of evidence is poor due to methodological issues with the included studies. The authors sincerely apologise for any inconvenience caused by this error.

INTRODUCTION and AIM Classifying gait patterns in children with cerebral palsy (CP) and reducing the vast amount of data from gait analysis into a set of clinically relevant gait features remains a challenge [1]. A priori selection of gait features, often based on clinical expert knowledge, can result in either incomplete or redundant data [2]. The goal is to quantify differences in lower limb kinematics between CP children and typically developing controls using principal component analysis (PCA). Secondly, for features that differ between CP and controls, a discriminant analysis (DA) will be applied to determine which features discriminate best between both groups.