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Background: Toe-out foot positioning is increasingly analyzed as a compensatory body-mechanical strategy to reduce pain and joint constraints in people with degenerative joint disease during gait. However, its influence during functional tasks, such as sit-to-stand, has not been reported.Research Question: How uni- and bilateral toe-out foot positioning influence body-dynamics during a STS task?Methods: The study was conducted on 15 healthy participants. Seven feet conditions were tested: neutral (N); right toe-out angle of 10° (U10), 20° (U20), and 30° (U30); bilateral toe-out angle of 10° (B10), 20° (B20), and 30° (B30). Execution time, trunk kinematic, vertical ground reaction force ratio as well as maximal knee and hip joint moments were analyzed and compared.Results: A significant difference was found across conditions in the STS execution time (p = 0.036) showing a main effect on temporal parameters using both uni- and bilateral toe-out foot positioning. A significant difference between conditions was also obtained for the vertical force ratio (p = 0.018) and the maximal knee flexion moment (p = 0.008). Post-hoc tests demonstrated a significant difference on force ratio and on knee flexion moment only while using a more pronounced unilateral toe-out foot positioning.Significance: The influence of toe-out foot positioning on body-dynamics during STS supports the idea of an alteration of body-mechanical strategy, as reported in literature gait studies. The results could have an impact on the management of patients using these strategies in order to reduce the onset of secondary joint diseases such as osteoarthritis. [ABSTRACT FROM AUTHOR]

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Abstract: Objective: To compare the well-recognized solid ankle cushion heel (SACH) foot with the prosthetic foot developed by the International Committee of the Red Cross (CR Equipements SACH) during gait. Design: Double-blind study was conducted to compare the influence on the biomechanics of gait of the CR Equipements SACH foot and the SACH foot. Setting: University hospital research center. Participants: Participants with unilateral transtibial amputation (N=15) were included. Interventions: Three-dimensional motion analysis system and 2 forceplates were used to capture body motion and ground reaction forces during gait at a self-selected speed and at 1.2m/s. Main Outcome Measures: Nonparametric Wilcoxon matched-pairs tests were used to compare the 2 prosthetic feet with respect to their spatiotemporal (gait velocity, stride length, and percentage of stance phase), kinematic (range and peak angles of the pelvis, hip, knee, and ankle), and kinetic (peak moment and power of the hip, knee, and ankle) parameters. Results: Compared with the SACH foot, the CR Equipements SACH foot demonstrated a significantly greater stance phase symmetry ratio (SACH: 94% vs CR Equipements SACH: 97%), a more extensive ankle range of motion in the sagittal plane (SACH: 7° vs CR Equipements SACH: 12°), a greater maximal dorsiflexion angle during the terminal stance phase (SACH: 10° vs CR Equipements SACH: 13°), and a higher ankle power (SACH: .31W/kg vs CR Equipements SACH: .40W/kg). No significant difference was found for the examined knee, hip, and pelvis parameters. Conclusions: The CR Equipements SACH foot provides more symmetry and improves ankle kinematics and kinetics in the sagittal plane compared with the SACH foot. This study suggests that individuals using the CR Equipements SACH foot improve their gait biomechanics compared when using the SACH foot. [Copyright &y& Elsevier]

Abstract: This study investigated the full-body strategies utilized during a sit-to-stand (STS) task in patients with knee osteoarthritis (OA) and the association between STS alterations and clinical measurements. Twenty-five patients with advanced knee OA and twenty healthy elderly adults were recruited to participate in this study. Patients were asked to stand up from a chair four times without using their arms. A 3D motion analysis system was used to capture the full-body kinematics during the task. Two force plates were used to capture the forces under each leg. The following parameters were investigated in the knee OA group and compared with the control group: the time to realize STS, the force ratio between both limbs, the knee and hip kinetics and the trunk kinematics. The pain and functional capacity were obtained from the WOMAC. The results showed that patients with knee OA put 10% additional weight on the contralateral side when compared with the symmetrical strategy of the control group. Patients with knee OA showed a significantly lower knee flexion moment (0.51Nm/kg vs. 0.72Nm/kg), a higher maximal trunk flexion (46.4° vs. 37.5°), and a higher lateral trunk lean on the contralateral side (2.4° vs. 0.9°) when compared with the control group. The main correlations were found between pain and the averaged time to complete the STS task (r =0.55). With the quantification of the full-body mechanisms utilized during the STS task, which includes both distal and proximal compensations, our study brings new insights, leading to a better understanding of the functional alterations in patients with advanced knee OA. [Copyright &y& Elsevier]

Abstract: Objective: : The purpose of this systematic review was to identify which biomechanical and physiological parameters are the most relevant, commonly used, able to discriminate and/or have specific clinical relevance for the gait analysis of lower-limb amputees (LLA). Methods: : We performed an electronic search via the PubMed, EMBASE and ISI Web of Knowledge databases from 1979 to May 2009. Two independent reviewers assessed the title and abstract of each identified study. The quality assessment of the full text was undertaken using a 13-item checklist divided into three levels: A, B, and C. Results: : The literature search identified 584 abstracts to be considered. After applying the inclusion criteria, we reviewed the full text of a total of 89 articles. The mean article quality was 8±2. No A-level article was found; the primary reason was a negative score in blinded outcome assessment. Sixty-six articles (74%) corresponded to a B-level, and two articles (2%) corresponded to a C-level. Twenty-one articles (24%) did not acquire enough points to be assigned to any level. In this study, we present and discuss the most commonly used and most relevant 32 parameters. Many of the parameters found were not reported in enough studies or in enough detail to allow a useful evaluation. Conclusion: : This systematic review can help researchers compare, choose and develop the most appropriate gait evaluation protocol for their field of study, based on the articles with best scores on the criteria list and the relevance of specific biomechanical and physiological parameters. [Copyright &y& Elsevier]

This study presents a new method to estimate 3-D linear accelerations at tibia! and femoral functional coordinate systems. The method combines the use of 3-D accelerometers, 3-D gyroscopes and reflective markers rigidly fixed on an exoskeleton and, a functional postural calibration method. Marker positions were tracked by a six-camera optoelectronic system (VICON 460, Oxford Metrics). The purpose of this study was to determine if this method could discriminate between media! osteoarthritic and asymptomatic knees during gait. Nine patients with osteoarthritic knees and nine asymptomatic control subjects were included in this study. Eighteen parameters representing maximal, minimal, and range of acceleration values were extracted during the loading and preswing to mid-swing phase periods, and were compared in both groups. Results show good discriminative capacity of the new method. Eight parameters were significantly different between both groups. The proposed method has the potential to be used in comprehending and monitoring gait strategy in patients with osteoarthritic knee. [ABSTRACT FROM AUTHOR]

The phenotyping of patients undergoing total knee arthroplasty (TKA) aims at identifying patient's profiles to plan and target patient-specific treatments, and provide personalised information before surgery. Up to date, the identification of functional phenotypes focused on knee kinematics and kinetics during gait [1]. Classification of patient's phenotypes based on full body kinematics during gait could help to understand typical patient's compensation. Which functional phenotypes can be indentified from the full-body kinematics during gait before surgery for patients undergoing TKA? And, do their clinical outcome differ one-year post-surgery? 79 patients with end-stage osteoarthritis and planned for primary TKA (69.5±7.4 years, 1.64±0.1 m, 81.0±14.9 kg) were included. Patients had two visits: before and one year after surgery. Each visit included clinical gait analysis [2] and patient reported outcomes (WOMAC, SF12, pain during gait, satisfaction after one year). Long axis X-rays were performed before surgery. Patient's were clustered with the K-means method on the lower limb joints, pelvis and thorax angles time-series. The optimal number of clusters was identified with the silhouette criterion [3]. Differences between phenotypes were assessed with statistical parametric mapping [4] for the kinematics, with one-way ANOVA and post-hoc Student's t-test for clinical differences of continuous variables and with Chi-square test to compare proportions. [Display omitted] Three clusters were selected with the main kinematic differences based on the pre-operative deformity of the lower limb in the frontal plane. One cluster was in varus, one in valgus and one had a neutral alignment. The ANOVA showed a group effect on sex, gait speed before and after surgery, and on the pre-surgery anatomical axis. The varus group had 50% females, presented more hip abduction and had higher walking speed pre- and post-surgery. The valgus group had over 80% females. The neutral cluster was characterized by over 90% females, higher pelvic retroversion and reduced hip flexion, typical of elderly gait. There were no significant differences between groups in terms of age, satisfaction, WOMAC, SF12, pain, BMI, and proportion of bilateral affection. The full-body analysis of gait kinematics identified three phenotypes of end-stage OA patients. Two profiles seem related to mechanical sources of joint wear due to misalignment of the knee with one varus (50% females) and one valgus group (>80% female). The last group had neutral knee alignment and was characterized by >90% females, with patterns typical of elderly gait but with no significant difference in age. Analysis of the time-series of gait kinematics was strongly influenced by gender, since two out of three groups were mainly females. A higher statistical power may help characterising better those groups in terms of clinical parameters. As previously underlined in the litterature, differences in gait kinematics do not necessarily relate to differences in PROMs function score [5]. [ABSTRACT FROM AUTHOR]

Abstract: Background: Interpreting gait data is challenging due to intersubject variability observed in the gait pattern of both normal and pathological populations. The objective of this study was to investigate the impact of using principal component analysis for grouping knee osteoarthritis (OA) patients'' gait data in more homogeneous groups when studying the effect of a physiotherapy treatment. Methods: Three-dimensional (3D) knee kinematic and kinetic data were recorded during the gait of 29 participants diagnosed with knee OA before and after they received 12weeks of physiotherapy treatment. Principal component analysis was applied to extract groups of knee flexion/extension, adduction/abduction and internal/external rotation angle and moment data. The treatment''s effect on parameters of interest was assessed using paired t-tests performed before and after grouping the knee kinematic data. Findings: Increased quadriceps and hamstring strength was observed following treatment (P <0.05). Except for the knee flexion/extension angle, two different groups (G1 and G2) were extracted from the angle and moment data. When pre- and post-treatment analyses were performed considering the groups, participants exhibiting a G2 knee moment pattern demonstrated a greater first peak flexion moment, lower adduction moment impulse and smaller rotation angle range post-treatment (P <0.05). When pre- and post-treatment comparisons were performed without grouping, the data showed no treatment effect. Interpretation: The results of the present study suggest that the effect of physiotherapy on gait mechanics of knee osteoarthritis patients may be masked or underestimated if kinematic data are not separated into more homogeneous groups when performing pre- and post-treatment comparisons. [Copyright &y& Elsevier]

Background: Most previous studies reported biomechanical deficits in individuals with a trans-tibial amputation (TTA) during gait using zero-dimensional analyses. However, these analyses do not allow to precisely determine during which part of the gait cycle these deficits occur. There is a need to use more appropriate methods to map the differences, such as one-dimensional statistical parametric mapping.Research Question: What are the most relevant phases of the gait cycle during which the biomechanical deficits in TTA occur?Methods: Eight TTA and 15 healthy counterparts (CON) underwent one biomechanical gait analysis. Pelvis, hip, knee and ankle kinematics, total support moment (TSM) and gastrocnemius lateralis, vastus lateralis and tibialis anterior muscle activity were compared between the amputated (AmLL), the intact (InLL) and the control (CnLL) lower limbs using one-dimensional statistical parametric mapping.Results: More ankle dorsiflexion and knee flexion were observed for the AmLL compared to the InLL and CnLL (ankle only) from the end of the stance phase to the beginning of the swing phase. Less knee flexion was also found for the AmLL during early stance phase. More pelvis posterior tilt and rotation toward the contralateral limb was observed during most of the gait cycle for the AmLL compared to the InLL. TSM was smaller for the AmLL compared to the CnLL during early stance phase.Significance: Using a one-dimensional statistical parametric mapping approach for TTA gait analysis, this study provides novel insights on their biomechanical gait deficits compared to CON. Greater reliance on the InLL was observed in TTA as suggested by the asymmetric kinematic and kinetic profiles. [ABSTRACT FROM AUTHOR]

Aging is associated with changes in neuromuscular control that can lead to difficulties in performing daily living tasks. Muscle synergy analysis allows the assessment of neuromuscular control strategies and functional deficits. However, the age-related changes of muscle synergies during functional tasks are scattered throughout the literature. This review aimed to synthesize the existing literature on muscle synergies in elderly people during daily-living tasks and examine how they differ from those exhibited by young adults. The Medline, CINAHL and Web of Science databases were searched. Studies were included if they focused on muscle synergies in elderly people during walking, sit-to-stand or stair ascent, and if muscle synergies were obtained by a matrix factorization algorithm. Seventeen studies were included after the screening process. The muscle synergies of 295 elderly people and 182 young adults were reported, including 5 to 16 muscles per leg, or leg and trunk. Results suggest that: 1) elderly people and young adults retain similar muscle synergies' number, 2) elderly people have higher muscles weighting during walking, and 3) an increased inter and intra-subject temporal activation variability during specific tasks (i.e., walking and stair ascent, respectively) was reported in elderly people compared to young adults. This review gives a comprehensive understanding of age-related changes in neuromuscular control during daily living tasks. Our findings suggested that although the number of synergies remains similar, metrics such as spatial and temporal structures of synergies are more suitable to identify neuromuscular control deficits between young adults and elderly people. • Elderly individuals retain similar synergies number compared to young adults. • Elderly individuals showed high inter-subject temporal activation variability during stair ascent. • Increased intra and inter-subject temporal activation variability during walking was observed in elderly. • This review highlighted the presence of common synergies between walking and sit-to-stand. [ABSTRACT FROM AUTHOR]

Background Individuals with knee osteoarthritis (OA) show variability during the sit-to-stand (STS) task, so they may not perform the STS in the same way. This study aimed to determine whether individuals with knee OA have different strategies in performing the STS. Methods Participants with knee OA and able-bodied individuals underwent STS evaluation at a self-selected pace with use of a motion measurement system consisting of 12 cameras and 2 force plates. Results In total, 101 participants (57 women) with knee OA showed 3 main STS strategies. As compared with the 27 controls (14 women), 24 OA participants, compensated STS, showed greater trunk flexion (47.1° vs. 38.3°; P < 0.01) and trunk obliquity (4.6° vs. –0.8°; P < 0.001) when completing the STS task in the same amount of time as controls (2.4 vs. 2.7 s; P = 0.999). The second group ( n = 59), inadequately compensated STS, also compensated with trunk flexion (47.7° vs. 38.3°; P < 0.01) and trunk obliquity (1.6° vs. –0.8°; P < 0.001) but took longer than controls (3.4 vs. 2.7 s; P = 0.001). The third group ( n = 18), severe impaired STS, took an extended amount of time to execute the STS (6 s), with marked trunk flexion (59.2°) and obliquity (4.1°), so participants in this group were perhaps severely impaired in completing the STS. Conclusion This study identified 3 groups STS trunk strategies among participants with STS. Moreover, the data reveal a concise representation of the relations among strategy variables. The findings could be used to simplify the characterization of the STS among patients with knee OA and aid with follow-up. [ABSTRACT FROM AUTHOR]

Individuals with a lower limb amputation use compensatory strategies during essential tasks such as sit-to-stand and stair ascent leading to secondary physical conditions. The ensuing biomechanical parameters outlining the motion strategies they put in place need to be identified and described. We searched three databases (Embase, IEEE Xplore and PubMed) for articles on the spatiotemporal, the kinematics and the kinetics that compared the amputated, the intact lower limbs, or the trunk of individuals with a unilateral transtibial or transfemoral amputation with the limbs of a control group. We found twenty articles. During sit-to-stand, individuals with a lower limb amputation increased the trunk inclination angle toward the intact lower limb, explaining higher ground reaction forces and peak knee sagittal power generation. During stair ascent, individuals with a lower limb amputation increased the stance phase duration on the intact lower limb. Moreover, individuals with a lower limb amputation increased both lower limbs hip extension moment and power, and the amputated lower limb knee extension moment. In both tasks, the individuals with a transfemoral amputation presented larger differences than those with transtibial compared to the control group. Both lower limbs intact joint moment and power were increased to compensate for the prosthesis passive joint and to ensure stability. Stair gait studies mainly focused on the lower limbs' biomechanical changes in the sagittal plane, while sit-to-stand studies focused on asymmetries without comparing the lower limbs independently. Better methodological descriptions are essential to enhance the external validity of previous results. • Stair gait and sit-to-stand are crucial for individuals with lower limb amputation. • Trunk and lower limbs need to be investigated during both tasks. • This review identified the most relevant parameters underlying movement strategies. • Moment and power show that residual joints compensate for the prosthetic joint. • Trunk and lower limb need to be more investigated during both tasks. [ABSTRACT FROM AUTHOR]