Walking Biomechanics Research Articles

Association between gait mechanics and ultrasonographic measures of femoral cartilage thickness in individuals with ACL reconstruction

BackgroundIndividuals with anterior cruciate ligament reconstruction (ACLR) are at greater risk for knee osteoarthritis, which may be in part due to altered gait biomechanics. Articular cartilage thickness is typically imaged using magnetic resonance imaging, which is costly and lacks portability. Ultrasonography may provide an alternative imaging method for articular cartilage. It is unclear if ultrasonographic measurements of cartilage thickness are associated with gait biomechanics in individuals with ACLR. Research QuestionTo evaluate the association between sagittal and frontal plane knee mechanics during gait and resting femoral cartilage thickness from ultrasonography. MethodsTwenty-five females with ACLR (age = 21.7 ± 2.6 years, time since ACLR = 60.6 ± 24.8 months) completed assessments of walking biomechanics and resting femoral cartilage thickness. Linear regression examined the association between gait biomechanics and cartilage thickness at the medial (MC) and lateral (LC) femoral condyles, and intercondylar notch (IC) after accounting for time since ACLR, meniscal injury, and gait speed. ResultsIn the ACLR limb, larger vertical ground reaction force (ΔR2 = 0.21, pΔ = 0.03), knee flexion angle (ΔR2 = 0.15, pΔ = 0.05), knee flexion excursion (KFE) (ΔR2 = 0.16, pΔ = 0.04), and knee flexion impulse (KFI) (ΔR2 = 0.23, pΔ = 0.02) were associated with thicker MC cartilage. A larger knee adduction angle (ΔR2 = 0.20, pΔ = 0.03) and knee adduction moment (KAM) (ΔR2 = 0.20, pΔ = 0.03) were associated with thinner MC thickness. Larger KFE (ΔR2 = 0.20, pΔ = 0.03) was associated with thicker LC cartilage. Gait biomechanics were not associated with IC cartilage thickness. After accounting for co-variates, the combination of KFI and KAM was predictive of MC thickness (ΔR2 = 0.37, pΔ = 0.01; Total R2 = 0.52, p = 0.02). Meniscal injury, KAM, and KFI were significant predictors in the model. In the contralateral limb, KFE was associated with thicker MC cartilage (ΔR2 = 0.16, pΔ = 0.05). SignificanceSagittal and frontal plane knee mechanics during gait are uniquely associated with ultrasonographic measurements of femoral cartilage thickness in individuals with ACLR. Furthermore, concomitant medial meniscal injury was associated with thinner MC cartilage.

A Soft Wearable Robotic Suit for Ankle and Hip Assistance: a Preliminary Study.

As a walking assistive device, one of major goals should be reduce wearer's metabolic cost as much as possible. Toward this goal, this paper presents the preliminary study on a new soft wearable robotic suit for ankle and hip assistance for daily life activities. The presented robotic suit is lightweight, and it almost does not restrict the lower limb motion range. In addition, its structure is simple, and thus wearers can easily take the device on and off by themselves. Experimental results on two young subjects show that the robotic suit reduced metabolic cost with averaged reductions of 10.2 % and 6.8 %, respectively, by not drastically disrupting the normal walking biomechanics of the subjects.

Biomechanics and energetics of walking in powered ankle exoskeletons using myoelectric control versus mechanically intrinsic control

BackgroundControllers for assistive robotic devices can be divided into two main categories: controllers using neural signals and controllers using mechanically intrinsic signals. Both approaches are prevalent in research devices, but a direct comparison between the two could provide insight into their relative advantages and disadvantages. We studied subjects walking with robotic ankle exoskeletons using two different control modes: dynamic gain proportional myoelectric control based on soleus muscle activity (neural signal), and timing-based mechanically intrinsic control based on gait events (mechanically intrinsic signal). We hypothesized that subjects would have different measures of metabolic work rate between the two controllers as we predicted subjects would use each controller in a unique manner due to one being dependent on muscle recruitment and the other not.MethodsThe two controllers had the same average actuation signal as we used the control signals from walking with the myoelectric controller to shape the mechanically intrinsic control signal. The difference being the myoelectric controller allowed step-to-step variation in the actuation signals controlled by the user’s soleus muscle recruitment while the timing-based controller had the same actuation signal with each step regardless of muscle recruitment.ResultsWe observed no statistically significant difference in metabolic work rate between the two controllers. Subjects walked with 11% less soleus activity during mid and late stance and significantly less peak soleus recruitment when using the timing-based controller than when using the myoelectric controller. While walking with the myoelectric controller, subjects walked with significantly higher average positive and negative total ankle power compared to walking with the timing-based controller.ConclusionsWe interpret the reduced ankle power and muscle activity with the timing-based controller relative to the myoelectric controller to result from greater slacking effects. Subjects were able to be less engaged on a muscle level when using a controller driven by mechanically intrinsic signals than when using a controller driven by neural signals, but this had no affect on their metabolic work rate. These results suggest that the type of controller (neural vs. mechanical) is likely to affect how individuals use robotic exoskeletons for therapeutic rehabilitation or human performance augmentation.

Biomechanics of Walking in Healthy Adults at Different Gait Speeds

Lower extremity biomechanical parameters during gait are of interest in degenerative pathologies, such as knee osteoarthritis. However, few investigations have looked at the effect of walking speed on knee biomechanics (e.g., moments). METHODS: 10 healthy volunteers (25.6 ± 5.0 years, 1.68 ± 0.11 m, 70.3 ± 18.0 kg) completed 3 trials each of walking at 4 different speeds [preferred (PS), fast (FS), slow (SS), & very slow (VSS)]. The range for each speed was determined by measuring a percentage of the participants PS: FS = (120 ± 5%), SS = (80 ± 5%), and VSS = (50 ± 5%). Speed was determined using timing gates (Power Systems Brower) placed 2.4 meters apart. Data was collected using a motion capture system (VICON, 200Hz) while participants walked across a ~6-meter walkway; 4 in-line force plates (Bertec, 1000Hz) captured ground reaction force. Sagittal and frontal plane kinematics and kinetics at the knee were calculated for the 4 speeds using Visual 3D. Differences between the 4 speeds were analyzed using a repeated-measures GLM with pairwise comparisons (p<0.05). RESULTS: Average speed for the 4 conditions were: PS = 1.06 ± .17 m/s, FS = 1.29 ± .21 m/s, SS = .90 ± .16 m/s, and VSS = .73 ± .11 m/s. There was a significant main effect for speed (F2, 8 = 28.7, p = 0.034). Pairwise comparisons indicated a statistically significant difference in knee flexor moment for PS versus FS (PS = .181 ± .019, FS = .079 ± .015, p < .05) as well as in knee internal adductor moment for FS versus PS, SS, and VSS (FS = .026 ± .083, PS = -.437 ± .068, SS = -.579 ± .170, VSS = -.363 ± .112, p < .05). Knee flexor moments were smaller for FS versus PS, while FS was also smaller than PS, SS, and VSS for the knee adductor moment. CONCLUSION: Our findings agree with previous research that identified differences in knee flexor and adductor moments at different gait speeds. For pathological populations it is important to understand the effect of gait speed on knee adductor moment since it is a surrogate measure for joint loading. However, our sample size was small; therefore, the effect of gait speed on knee flexor and adductor moments should be further investigated. Future studies will seek to understand the relative contribution of the quadriceps’s muscles at different speeds and its impact on knee joint loads.

Magnitude and variability of gait characteristics when walking on an irregular surface at different speeds

Different modes of perturbations have been used to understand how individuals negotiate irregular surfaces, with a general notion that increased locomotion variability induces a positive training stimulus. Individuals tend to walk slower when initially exposed to such locomotion tasks, potentially influencing the magnitude and variability of biomechanical parameters. This study investigated theeffects of gait speed on lower extremity biomechanics when walking on an irregular (IS) and regular surface (RS). Twenty physically active males walked on a RS and IS at three different speeds (4 km/h, 5 km/h, 6 km/h). Lower extremity kinematics (300 Hz) and surface electromyography (3000 Hz) were recorded during the first 90 s of gait. Two-factor repeated measures ANOVA was used to determine surface and speed effects (p < 0.05). Gait speed influences walking biomechanics (kinematic and muscle activity parameters) the same irrespective of surface condition. As walking speed increased, sagittal shoe-surface angle, maximum ankle inversion, ankle abduction, knee and hip flexion increased during stance phase when walking on the IS and RS (p < 0.05). Increasing walking speed caused increased muscle activity of the tibialis anterior, peroneus longus, gastrocnemius medialis, vastus medialis and biceps femoris (p < 0.05) on the IS and RS during the gait cycle. Increased gait, kinematic and muscle activity variability was reported at lower walking speed on both the IS and RS. Further, irrespective of gait speed, walking on an IS triggers postural adjustments, higher muscle activity and increased gait variability compared to RS walking. Our findings suggest the benefits of training on the irregular surface may be further enhanced at slower gait speeds.

Heel impact forces during barefoot versus minimally shod walking among Tarahumara subsistence farmers and urban Americans.

Despite substantial recent interest in walking barefoot and in minimal footwear, little is known about potential differences in walking biomechanics when unshod versus minimally shod. To test the hypothesis that heel impact forces are similar during barefoot and minimally shod walking, we analysed ground reaction forces recorded in both conditions with a pedography platform among indigenous subsistence farmers, the Tarahumara of Mexico, who habitually wear minimal sandals, as well as among urban Americans wearing commercially available minimal sandals. Among both the Tarahumara (n = 35) and Americans (n = 30), impact peaks generated in sandals had significantly (p < 0.05) higher force magnitudes, slower loading rates and larger vertical impulses than during barefoot walking. These kinetic differences were partly due to individuals' significantly greater effective mass when walking in sandals. Our results indicate that, in general, people tread more lightly when walking barefoot than in minimal footwear. Further research is needed to test if the variations in impact peaks generated by walking barefoot or in minimal shoes have consequences for musculoskeletal health.

Gluteal tendinopathy and hip osteoarthritis: Different pathologies, different hip biomechanics

BackgroundGluteal tendinopathy (GT) and hip osteoarthritis (OA) are the most common causes of hip pain and associated disability in older adults. Pain and altered walking biomechanics are common to both conditions. This study aimed to compare three-dimensional walking biomechanics between individuals with unilateral, symptomatic GT and HOA. MethodsSixty individuals with symptomatic unilateral GT confirmed by magnetic-resonance-imaging and 73 individuals with symptomatic unilateral HOA (Kellgren-Lawrence Grade ≥ 2) underwent three-dimensional gait analysis. Maximum and minimum values of the external sagittal hip moment, the first peak, second peak and mid-stance minimum of the hip adduction moment (HAM), sagittal plane hip excursion and hip joint angles, pelvic obliquity and trunk lean, at the three HAM time points during stance phase of walking were compared between groups. ResultsCompared to individuals with HOA, those with GT exhibited a greater hip peak extension moment (P < 0.001) and greater HAM throughout the stance phase of walking (P = 0.01–P < 0.001), greater hip adduction (P < 0.001) and internal rotation (P < 0.01–P < 0.001) angles and lower hip flexion angles and excursion (P = 0.02 – P < 0.001). Individuals with HOA exhibited a greater forward trunk lean (P ≤ 0.001) throughout stance, and greater ipsilateral trunk lean in the frontal plane (P < 0.001) than those with GT. ConclusionDespite presence of pain in both conditions, hip kinematics and kinetics differ between individuals with symptomatic unilateral GT and those with symptomatic unilateral HOA. These condition-specific impairments may be targets for optimization of management of HOA and GT.

Влияние биомеханики ходьбы на формирование патологии стоп

Влияние биомеханики ходьбы на формирование патологии стоп

Robust Ground Reaction Force Estimation and Control of Lower-Limb Prostheses: Theory and Simulation

Ground reaction force (GRF) characteristics of amputee walking are important for the analysis of clinical gait data, and also to update model reference adaptive impedance (MRAI) controllers. GRF estimation is a better alternative than direct GRF measurement because of the disadvantages of load cells, such as high cost, integration difficulties due to weight and physical dimensions, the possibility of overload, and measurement noise. This paper presents four robust MRAI observer/controller combinations for GRF estimation-based control of a prosthesis and a legged robot model in the presence of parametric uncertainties and unmodeled dynamics, in which the robot model is employed to mimic able-bodied walking. Since unknown GRFs can reduce the performance of prosthesis control systems, the proposed MRAI controllers are designed to compensate their effects. All four proposed observer/controller combinations enable the system to imitate the biomechanics of able-bodied walking as defined by mechanical impedance, and provide flexible and smooth gait. Lyapunov analysis of the observer/controller combinations is used to prove stability. The four MRAI controllers are compared with each other from the perspective of GRF estimation accuracy, prosthetic knee angle tracking accuracy, parameter estimation accuracy, control effort, and computational effort. Simulation results show that all four MRAI controllers achieve good tracking performance, stable limit cycles, and accurate GRF estimation.

Maintaining stable transfemoral amputee gait on level, sloped and simulated uneven conditions in a virtual environment

Purpose: Describe and quantify how people with transfemoral amputations (TFA) maintain stable gait over a variety of surfaces; including, downhill and uphill, top and bottom-cross-slopes, medial-lateral translations, rolling hills and simulated rocky surfaces.Methods: Ten TFA and ten matched people without amputations (NA) walked in a virtual environment with level, sloped and simulated uneven surfaces on a self-paced treadmill. Stability was quantified using medial-lateral margin of stability (ML-MoS), step parameters, and gait variability (standard deviations for speed, temporal-spatial parameters, foot clearance and root-mean-square of medial-lateral trunk acceleration).Results and conclusions: TFA and NA adapted to non-level conditions by changing their walking speed, step width, and foot clearance. Variability for most parameters increased across conditions, compared to level. TFA walked slower than NA with shorter, wider and longer duration steps (most differences related to speed). ML-MoS did not change compared to level; however, ML-MoS was greater on the prosthetic side than both intact side and NA limbs. Foot clearance and root-mean-square of medial-lateral trunk acceleration were greater on the prosthetic side than the intact side and NA limbs. This research provides a comprehensive analysis of the different adaptations made by people without amputations compared to people with transfemoral amputations over non-level conditions and establishes significant differences between slopes and simulated uneven surfaces for TFA.Implications for RehabilitationTransfemoral amputation and no amputation groups adapted walking biomechanics when traversing non-level surfaces.Greatest temporal-spatial gait adaptations were walking speed, step width and foot clearance.Gait parameter variability typically increased from the level condition in both groups.Transfemoral amputation group walked slower than no amputation group with shorter, wider steps and longer duration steps. This was related to speed.Transfemoral amputation group had more trunk motion variability on the prosthetic side than no amputation group; could be related to prosthetic fit.

Gait patterns, symptoms, and function in patients with isolated tibiofemoral osteoarthritis and combined tibiofemoral and patellofemoral osteoarthritis.

The purpose of this study was to compare hip and knee biomechanics during walking in individuals with isolated tibiofemoral osteoarthritis (TFOA), combined TFOA and patellofemoral osteoarthritis (PFOA), and those without knee osteoarthritis (OA), and to compare patient-reported symptoms and function in individuals with isolated TFOA and those with combined TFOA and PFOA. Participants with and without knee OA were assessed and categorized into (i) no OA, (ii) isolated TFOA, and (iii) combined TFOA and PFOA, based on Kellgren and Lawrence diagnostic criteria. Quantitative motion analyses were conducted during walking, and hip and knee kinematics, and external moments were calculated. Peak values in the sagittal and frontal planes during stance phase were computed. Patient-reported symptoms and function data were obtained using the Western Ontario McMaster Universities Arthritis Index. Multivariate analyses of variance were conducted to compare between-group differences in gait and patient-reported symptoms and function data. The results showed no statistically significant differences in hip and knee kinematics and external moments between the three groups. Relative to those with isolated TFOA, individuals with combined TFOA and PFOA had greater pain (mean difference [95%CI]: 1.5 [0.05-3.1]), stiffness (0.8 [0.02-1.5]), and poorer function (5.4 [0.2-10.7]). In conclusion, the combined TFOA and PFOA radiographic disease pattern is associated with worse pain and function compared to the isolated TFOA disease pattern. The results of the present study provide no indications that treatments designed to change walking biomechanics should differ between individuals with isolated TFOA and those with combined TFOA and PFOA. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1666-1672, 2018.

Kinematic Changes during Prolonged Fast-Walking in Old and Young Adults.

Walking biomechanics is known to be influenced by speed. However, most of the research examining the effects of walking speed and gait characteristics has been conducted after a fast-walking task, neglecting the changes that may occur during the task. The aim of the present study was to determine the impact of fast-walking over time on kinematics in young and old adults. Twenty-seven young adults (26.6 ± 6.0 years) and 23 old adults (71.0 ± 5.6 years) walked at 70% of their maximum heart rate for 20 min or until exhaustion, and the effects of fast-walking on temporospatial parameters and on angular kinematics were analyzed during the activity. During the protocol, both age-groups increased step-width variability. Significant effects of time were found for the ankle and hip at toe off for the older group. For the younger group, only the ankle angle at heel strike changed over time. For both groups, fast-walking induced changes in the coordination among the lower-limb angles that were more prominent during the swing phase of the gait. In conclusion, lower-limb kinematics changes in young adults were compatible with early signs of fatigue. The increased step-width variability in older adults may indicate an augmented risk of falling. Changes in the lower-limb walking kinematics of old adults suggest that the adjustments for weight acceptance and body propulsion were restricted to the hip and ankle joints. The kinematic changes among the lower-limb joint angles during the swing phase may compromise the quality of gait. These findings provide a foundation for future studies in the assessment of the risk of falls in older adults associated with walking at a faster pace.

Approach for gait analysis in persons with limb loss including residuum and prosthesis socket dynamics.

Musculoskeletal modeling and marker-based motion capture techniques are commonly used to quantify the motions of body segments, and the forces acting on them during human gait. However, when these techniques are applied to analyze the gait of people with lower limb loss, the clinically relevant interaction between the residual limb and prosthesis socket is typically overlooked. It is known that there is considerable motion and loading at the residuum-socket interface, yet traditional gait analysis techniques do not account for these factors due to the inability to place tracking markers on the residual limb inside of the socket. In the present work, we used a global optimization technique and anatomical constraints to estimate the motion and loading at the residuum-socket interface as part of standard gait analysis procedures. We systematically evaluated a range of parameters related to the residuum-socket interface, such as the number of degrees of freedom, and determined the configuration that yields the best compromise between faithfully tracking experimental marker positions while yielding anatomically realistic residuum-socket kinematics and loads that agree with data from the literature. Application of the present model to gait analysis for people with lower limb loss will deepen our understanding of the biomechanics of walking with a prosthesis, which should facilitate the development of enhanced rehabilitation protocols and improved assistive devices.

Identifying biomechanical gait parameters in adolescent boys with haemophilia using principal component analysis.

Improvements in the medical management for those with haemophilia have resulted in improved clinical outcomes. However, current treatment regimens do not alleviate all joint haemarthroses with the potential for long-term joint deterioration remaining. The evaluation of functional activities such as gait, using standardized tools to monitor children with haemophilia is emerging. This study explored differences in sagittal plane biomechanics of walking in adolescent boys aged 11-18years with haemophilia and an age-matched group of typically developing boys. A motion capture system and 2 force platforms were used to collect sagittal plane kinematic, kinetic and temporal spatial data during level walking. Principal component analysis (PCA) was applied to kinematic and kinetic waveform variables. Group differences in temporal spatial and principal component scores for each kinematic and kinetic variable were evaluated using independent t tests. Significant alterations (P<.05) in temporal spatial and kinetic parameters were found in adolescent boys with haemophilia. Compared with typically developing adolescent boys, boys with haemophilia walked with reduced stance phase duration and altered pattern of external ankle joint moments during push off and the beginning of swing. The use of PCA rather than predetermined discriminatory variables provided additional insight into biomechanical alterations in adolescent boys with haemophilia, with adaptations occurring during terminal double support and early swing, affecting the ankle joint. This finding might be a key biomechanical marker that could be used to evaluate the joint function and the progression of early haemophilic arthropathy.

Analyses of Gait Parameters of Younger and Older Adults During (Non-)Isometric Virtual Walking.

Understanding real walking in virtual environments (VEs) is important for immersive experiences, allowing users to move through VEs in the most natural way. Previous studies have shown that basic implementations of real walking in virtual spaces, in which head-tracked movements are mapped isometrically to a VE, are not estimated as entirely natural. Instead, users estimate a virtual walking velocity as more natural when it is slightly increased compared to the user's physical locomotion. However, these findings have been reported in most cases only for young persons, e.g., students, whereas older adults are clearly underrepresented in such studies. Recently, virtual reality (VR) has received significant public and media attention. Therefore, it appears reasonable to assume that people at different ages will have access to VR, and might use this technology more and more in application scenarios such as rehabilitation or training. To better understand how people at different ages walk and perceive locomotion in VR, we have performed a study to investigate the effects of (non-)isometric mappings between physical movements and virtual motions in the VE on the walking biomechanics across generations, i.e., younger and older adults. Three primary domains (pace, base of support and phase) of spatio-temporal parameters were identified to evaluate gait performance. The results show that the older adults walked very similar in the real and VE in the pace and phasic domains, which differs from results found in younger adults. In contrast, the results indicate differences in terms of base of support domain parameters for both groups while walking within a VE and the real world. For non-isometric mappings, we found in both younger and older adults an increased divergence of gait parameters in all domains correlating with the up- or down-scaled velocity of visual self-motion feedback. The results provide important insights into the design of future VR applications for older adults in domains ranging from medicine and psychology to rehabilitation.

A NOVEL BIOMECHANICS-BASED APPROACH FOR PERSON RE-IDENTIFICATION BY GENERATING DENSE COLOR SIFT SALIENCE FEATURES

Currently, identifying humans using biomechanics-based approaches has gained a lot of significance for person re-identification. Biomechanics-based approaches use knee-hip angle–angle relationships and body movements for person re-identification. Generally, biomechanics of human walking and running is used for person re-identification. In fact, person re-identification is a complex and important task in academia as well as industry and remains an unsolved issue in the computer vision field. The subjects most commonly addressed regarding person re-identification include significant feature extraction that can function accurately with invariant appearance and robust classification. In this study, a significant color feature descriptor is proposed by combining dense color-SIFT and global convex hull salience region features. First convex hull boundary points are detected using the SIFT technique. Furthermore, it is extended with Grubb’s outlier test to eliminate the outlier points detected by SIFT and mark the saliency region via convex hull. Then dense-SIFT and dense-CHF methods are used to extract local and global features within the convex hull region, respectively. Finally, the pre-ranked common nearest neighbor selection technique is applied to minimize overhead of dataset and generate more robust rank classification. The proposed technique is tested using three-camera database video sequences and three publicly available datasets, namely i-LIDS, VIPeR and GRID. Performance of re-identification system is evaluated using a statistical method with CMC curves. The results show better re-identification accuracy in solving the aforementioned problems.

A cross-sectional study of the effects of load carriage on running characteristics and tibial mechanical stress: implications for stress-fracture injuries in women

BackgroundLoad carriage is associated with musculoskeletal injuries, such as stress fractures, during military basic combat training. By investigating the influence of load carriage during exercises on the kinematics and kinetics of the body and on the biomechanical responses of bones, such as the tibia, we can quantify the role of load carriage on bone health.MethodsWe conducted a cross-sectional study using an integrated musculoskeletal-finite-element model to analyze how the amount of load carriage in women affected the kinematics and kinetics of the body, as well as the tibial mechanical stress during running. We also compared the biomechanics of walking (studied previously) and running under various load-carriage conditions.ResultsWe observed substantial changes in both hip kinematics and kinetics during running when subjects carried a load. Relative to those observed during running without load, the joint reaction forces at the hip increased by an average of 49.1% body weight when subjects carried a load that was 30% of their body weight (ankle, 4.8%; knee, 20.6%). These results indicate that the hip extensor muscles in women are the main power generators when running with load carriage. When comparing running with walking, finite element analysis revealed that the peak tibial stress during running (tension, 90.6 MPa; compression, 136.2 MPa) was more than three times as great as that during walking (tension, 24.1 MPa; compression, 40.3 MPa), whereas the cumulative stress within one stride did not differ substantially between running (15.2 MPa · s) and walking (13.6 MPa · s).ConclusionsOur findings highlight the critical role of hip extensor muscles and their potential injury in women when running with load carriage. More importantly, our results underscore the need to incorporate the cumulative effect of mechanical stress when evaluating injury risk under various exercise conditions. The results from our study help to elucidate the mechanisms of stress fracture in women.

Biochemical markers of cartilage metabolism are associated with walking biomechanics 6‐months following anterior cruciate ligament reconstruction

The purpose of our study was to determine the association between biomechanical outcomes of walking gait (peak vertical ground reaction force [vGRF], vGRF loading rate [vGRF-LR], and knee adduction moment [KAM]) 6 months following anterior cruciate ligament reconstruction (ACLR) and biochemical markers of serum type-II collagen turnover (collagen type-II cleavage product to collagen type-II C-propeptide [C2C:CPII]), plasma degenerative enzymes (matrix metalloproteinase-3 [MMP-3]), and a pro-inflammatory cytokine (interleukin-6 [IL-6]). Biochemical markers were evaluated within the first 2 weeks (6.5 ± 3.8 days) following ACL injury and again 6 months following ACLR in eighteen participants. All peak biomechanical outcomes were extracted from the first 50% of the stance phase of walking gait during a 6-month follow-up exam. Limb symmetry indices (LSI) were used to normalize the biomechanical outcomes in the ACLR limb to that of the contralateral limb (ACLR/contralateral). Bivariate correlations were used to assess associations between biomechanical and biochemical outcomes. Greater plasma MMP-3 concentrations after ACL injury and at the 6-month follow-up exam were associated with lesser KAM LSI. Lesser KAM was associated with greater plasma IL-6 at the 6-month follow-up exam. Similarly, lesser vGRF-LR LSI was associated with greater plasma MMP-3 concentrations at the 6-month follow-up exam. Lesser peak vGRF LSI was associated with higher C2C:CPII after ACL injury, yet this association was not significant after accounting for walking speed. Therefore, lesser biomechanical loading in the ACLR limb, compared to the contralateral limb, 6 months following ACLR may be related to deleterious joint tissue metabolism that could influence future cartilage breakdown. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2288-2297, 2017.

No effects of functional exercise therapy on walking biomechanics in patients with knee osteoarthritis: exploratory outcome analyses from a randomised trial

AimTo assess the effects of a functional and individualised exercise programme on gait biomechanics during walking in people with knee OA.MethodsSixty participants were randomised to 12 weeks of facility-based functional...

Single Session of Functional Electrical Stimulation-Assisted Walking Produces Corticomotor Symmetry Changes Related to Changes in Poststroke Walking Mechanics.

Recent research demonstrated that the symmetry of corticomotor drive with the paretic and nonparetic plantarflexor muscles was related to the biomechanical ankle moment strategy that people with chronic stroke used to achieve their greatest walking speeds. Rehabilitation strategies that promote corticomotor balance might improve poststroke walking mechanics and enhance functional ambulation. The study objectives were to test the effectiveness of a single session of gait training using functional electrical stimulation (FES) to improve plantarflexor corticomotor symmetry and plantarflexion ankle moment symmetry and to determine whether changes in corticomotor symmetry were related to changes in ankle moment symmetry within the session. This was a repeated-measures crossover study. On separate days, 20 people with chronic stroke completed a session of treadmill walking either with or without the use of FES of their ankle dorsi- and plantarflexor muscles. We calculated plantarflexor corticomotor symmetry using transcranial magnetic stimulation and plantarflexion ankle moment symmetry during walking between the paretic and the nonparetic limbs before and after each session. We compared changes and tested relationships between corticomotor symmetry and ankle moment symmetry following each session. Following the session with FES, there was an increase in plantarflexor corticomotor symmetry that was related to the observed increase in ankle moment symmetry. In contrast, following the session without FES, there were no changes in corticomotor symmetry or ankle moment symmetry. No stratification was made on the basis of lesion size, location, or clinical severity. These findings demonstrate, for the first time (to our knowledge), the ability of a single session of gait training with FES to induce positive corticomotor plasticity in people in the chronic stage of stroke recovery. They also provide insight into the neurophysiologic mechanisms underlying improvements in biomechanical walking function.