Ankle kinematics and kinetics during gait in healthy and rheumatoid arthritis post-menopausal women

Objective: In the literature, it is not clear whether rheumatoid arthritis (RA) post-menopausal women have different ankle biomechanical parameters than healthy post-menopausal women. This study aimed to compare the ankle kinematics and kinetics during the gait stance phase of RA post-menopausal women with age-matched healthy post-menopausal women.

Materials and methods: A three-dimensional motion analysis system (9 cameras; 200?Hz) synchronised with a force plate (1000?Hz) was used to assess ankle kinematics and kinetics during barefoot walking at a natural and self-selected speed. A biomechanical model was used to model body segments and joint centres (combined anthropometric measurements and the placement of 39 reflective markers). Thirty-six women (18 RA post-menopausal women and 18 age-matched healthy post-menopausal women) performed 14 valid trials (comprising seven left and seven right footsteps on a force plate). Lower limb muscle mass was evaluated by an octopolar bioimpedance analyser.

Results: RA post-menopausal women yielded a longer stance phase and controlled dorsiflexion sub-phase (p?<?0.001), higher dorsiflexion at the final controlled dorsiflexion sub-phase and lower plantar flexion at toe off (p?<?0.05), lower angular displacements (p?<?0.05), and lower ankle moment of force peak and ankle power peak (p?<?0.001). No intergroup differences were found in lower limb muscle mass.

Conclusions: RA post-menopausal women yielded changes in ankle kinematic and kinetic parameters during the gait stance phase, resulting in a lower capacity to produce ankle moment of force and ankle power during the propulsive gait phase.     

Coactivation during gait as an adaptive behavior after stroke

The aims of the present study were to quantify the impairment in ankle coactivation on the paretic and non-paretic sides of subjects with hemiparesis and to examine the relationship of ankle coactivation with postural instability, motor deficit of the paretic lower extremity and locomotor performance. Electromyography of the medial gastrocnemius (MG) and tibialis anterior (TA) muscles were recorded bilaterally during gait in 30 subjects (62.1±9.9 years) who had suffered a recent stroke (<6 months) as well as on one side of 17 healthy controls (59.3±9.1 years) walking at very slow speed. Ankle muscle coactivation was calculated by dividing the time of overlap between MG and TA signals (threshold of 20 μV) by the duration of the gait phases of interest: stance, swing, first and second double support sub-phases and single support sub-phase. The time spent in single support and the peak plantarflexor moment of force on the paretic side were used to measure, respectively, postural stability and dynamic strength of the paretic plantarflexors. The subjects with hemiparesis demonstrated less coactivation on the paretic side during the single support sub-phase (p<0.01) and more coactivation during first and second double support sub-phases on the non-paretic side (p<0.001) compared to control values. The patients with coactivation patterns that differed the most from controls were the patients with the more severe impairments and disabilities. While the reduced coactivation on the paretic side may contribute to poor postural stability and poor locomotor performance, the presence of excessive coactivation on the non-paretic side when both limbs were in ground contact may be an adaptation to help maintain postural stability during gait.     

Electromyographic analysis of upper limb muscles during standardized isotonic and isokinetic robotic exercise of spastic elbow in patients with stroke

Although it has been reported that strengthening exercise in stroke patients is beneficial for their motor recovery, there is little evidence about which exercise method is the better option. The purpose of this study was to compare isotonic and isokinetic exercise by surface electromyography (EMG) analysis using standardized methods.Nine stroke patients performed three sets of isotonic elbow extensions at 30% of their maximal voluntary isometric torque followed by three sets of maximal isokinetic elbow extensions with standardization of mean angular velocity and the total amount of work for each matched set in two strengthening modes. All exercises were done by using 1-DoF planner robot to regulate exact resistive torque and speed. Surface electromyographic activity of eight muscles in the hemiplegic shoulder and elbow was recorded. Normalized root mean square (RMS) values and co-contraction index (CCI) were used for the analysis.The isokinetic mode was shown to activate the agonists of elbow extension more efficiently than the isotonic mode (normalized RMS for pooled triceps: 96.0 ± 17.0 (2nd), 87.8 ± 14.4 (3rd) in isokinetic, 80.9 ± 11.0 (2nd), 81.6 ± 12.4 (3rd) in isotonic contraction, F[1, 8] = 11.168; P = 0.010) without increasing the co-contraction of muscle pairs, implicating spasticity or synergy.     

The effect on conventional gait model kinematics and kinetics of hip joint centre equations in adult healthy gait

The Conventional Gait Model (CGM) needs to benefit from large investigations on localization of the hip joint centre (HJC). Incorrect positions from the native equations were demonstrated (Sangeux et al., 2014; Harrington et al., 2007). More accurate equations were proposed but their impact on kinematics and kinetic CGM outputs was never evaluated. This short communication aims at examining if adoption of new HJC equations would alter standard CGM outputs. Sixteen able bodied participants underwent a full 3-D optoelectronic gait analysis followed by a 3-D ultrasound localization of their hips. Data were processed through the open source python package pyCGM2 replicating kinematic and kinetic processing of the native CGM. Compared with 3D ultrasound location, Hara equations improved the accuracy of sagittal plane kinematics (0.6°) and kinetics (0.02 N m kg⁻¹) for the hip. The worst case participant exhibited Harrington’s equations reached a deviation of 3° for the sagittal kinematics. In the coronal plane, Hara and Harrington equations presented similar differences (1°) for the hip whilst Davis equations had the largest deviation for hip abduction (2.7°) and hip abductor moment (0.10 N m kg⁻¹).Both Harrington and Hara equations improved the CGM location of the HJC. Hara equations improved results in the sagittal plane, plus utilise a single anthropometrics measurement, leg length, that may be more robust. However, neither set of equations had significant effect on kinematics. We reported some effects on kinetics, particularly in the coronal plane, which warrant caution in interpreting outputs using different sets of equations.     

Kalman smoothing improves the estimation of joint kinematics and kinetics in marker-based human gait analysis

We developed a Kalman smoothing algorithm to improve estimates of joint kinematics from measured marker trajectories during motion analysis. Kalman smoothing estimates are based on complete marker trajectories. This is an improvement over other techniques, such as the global optimisation method (GOM), Kalman filtering, and local marker estimation (LME), where the estimate at each time instant is only based on part of the marker trajectories. We applied GOM, Kalman filtering, LME, and Kalman smoothing to marker trajectories from both simulated and experimental gait motion, to estimate the joint kinematics of a ten segment biomechanical model, with 21 degrees of freedom. Three simulated marker trajectories were studied: without errors, with instrumental errors, and with soft tissue artefacts (STA). Two modelling errors were studied: increased thigh length and hip centre dislocation. We calculated estimation errors from the known joint kinematics in the simulation study. Compared with other techniques, Kalman smoothing reduced the estimation errors for the joint positions, by more than 50% for the simulated marker trajectories without errors and with instrumental errors. Compared with GOM, Kalman smoothing reduced the estimation errors for the joint moments by more than 35%. Compared with Kalman filtering and LME, Kalman smoothing reduced the estimation errors for the joint accelerations by at least 50%. Our simulation results show that the use of Kalman smoothing substantially improves the estimates of joint kinematics and kinetics compared with previously proposed techniques (GOM, Kalman filtering, and LME) for both simulated, with and without modelling errors, and experimentally measured gait motion.     

Ankle kinematics,center of pressure progression,and lower extremity muscle activity during a side-cutting task in participants with and without chronic ankle instability

This study assessed ankle kinematics, surface electromyography, and center-of-pressure (COP) progression relative to the medial border of the foot during a side-cutting task in individuals with and without chronic ankle instability (CAI). Thirty participants (CAI = 15; Controls = 15) performed a side-cutting task on a force platform while 3-dimentional ankle kinematics, COP position, and surface electromyography from the tibialis anterior, medial gastrocnemius, fibularis longus, fibularis brevis, vastus medialis, and semitendinosus were recorded on the testing leg. Ankle kinematics, root-mean-square muscle activity and COP position relative to the medial boarder of the foot were compared between CAI and healthy controls (p < 0.05). Significantly greater ankle internal rotation from 35–54% of the stance phase (p = 0.032) was found for the CAI group compared to controls. Furthermore, significantly greater tibialis anterior muscle activity from 86–94% of the stance phase (p = 0.022) and a more medial COP position from 81–100% (p < 0.05) and of the stance phase was also observed in the CAI group. Less lateral COP progression and increased tibialis anterior activation in the CAI group could reflect a protective movement strategy during anticipated side-cutting to avoid recurrent injury. However, greater ankle internal rotation during mid-stance highlights a potential ‘giving way’ mechanism in individuals with CAI.     

The effects of alignment of an articulated ankle-foot orthosis on lower limb joint kinematics and kinetics during gait in individuals post-stroke

Mechanical tuning of an ankle-foot orthosis (AFO) is important in improving gait in individuals post-stroke. Alignment and resistance are two factors that are tunable in articulated AFOs. The aim of this study was to investigate the effects of changing AFO ankle alignment on lower limb joint kinematics and kinetics with constant dorsiflexion and plantarflexion resistance in individuals post-stroke. Gait analysis was performed on 10 individuals post-stroke under four distinct alignment conditions using an articulated AFO with an ankle joint whose alignment is adjustable in the sagittal plane. Kinematic and kinetic data of lower limb joints were recorded using a Vicon 3-dimensional motion capture system and Bertec split-belt instrumented treadmill. The incremental changes in the alignment of the articulated AFO toward dorsiflexion angles significantly affected ankle and knee joint angles and knee joint moments while walking in individuals post-stroke. No significant differences were found in the hip joint parameters. The alignment of the articulated AFO was suggested to play an important role in improving knee joint kinematics and kinetics in stance through improvement of ankle joint kinematics while walking in individuals post-stroke. Future studies should investigate long-term effects of AFO alignment on gait in the community in individuals post-stroke.     

Combining muscle synergies and biomechanical analysis to assess gait in stroke patients

The understanding of biomechanical deficits and impaired neural control of gait after stroke is crucial to prescribe effective customized treatments aimed at improving walking function. Instrumented gait analysis has been increasingly integrated into the clinical practice to enhance precision and inter-rater reliability for the assessment of pathological gait. On the other hand, the analysis of muscle synergies has gained relevance as a novel tool to describe the neural control of walking. Since muscle synergies and gait analysis capture different but equally important aspects of walking, we hypothesized that their combination can improve the current clinical tools for the assessment of walking performance.To test this hypothesis, we performed a complete bilateral, lower limb biomechanical and muscle synergies analysis on nine poststroke hemiparetic patients during overground walking. Using stepwise multiple regression, we identified a number of kinematic, kinetic, spatiotemporal and synergy-related features from the paretic and non-paretic side that, combined together, allow to predict impaired walking function better than the Fugl-Meyer Assessment score. These variables were time of peak knee flexion, VAF_total values, duration of stance phase, peak of paretic propulsion and range of hip flexion. Since these five variables describe important biomechanical and neural control features underlying walking deficits poststroke, they may be feasible to drive customized rehabilitation therapies aimed to improve walking function.This paper demonstrates the feasibility of combining biomechanical and neural-related measures to assess locomotion performance in neurologically injured individuals.     

Multi-sensor assessment of dynamic balance during gait in patients with subacute stroke

The capacity to maintain upright balance by minimising upper body oscillations during walking, also referred to as gait stability, has been associated with a decreased risk of fall. Although it is well known that fall is a common complication after stroke, no study considered the role of both trunk and head when assessing gait stability in this population. The primary aim of this study was to propose a multi-sensor protocol to quantify gait stability in patients with subacute stroke using gait quality indices derived from pelvis, sternum, and head accelerations. Second, the association of these indices with the level of walking ability, with traditional clinical scale scores, and with fall events occurring within the six months after patients’ dismissal was investigated. The accelerations corresponding to the three abovementioned body levels were measured using inertial sensors during a 10-Meter Walk Test performed by 45 inpatients and 25 control healthy subjects. A set of indices related to gait stability were estimated and clinical performance scales were administered to each patient. The amplitude of the accelerations, the way it is attenuated/amplified from lower to upper body levels, and the gait symmetry provide valuable information about subject-specific motor strategies, discriminate between different levels of walking ability, and correlate with clinical scales. In conclusion, the proposed multi-sensor protocol could represent a useful tool to quantify gait stability, support clinicians in the identification of patients potentially exposed to a high risk of falling, and assess the effectiveness of rehabilitation protocols in the clinical routine.     

Hip joint muscle forces during gait in patients with femoroacetabular impingement syndrome are associated with patient reported outcomes and cartilage composition

Femoroacetabular impingement syndrome (FAIS) consists of abnormal hip joint morphology and pain during activities of daily living. Abnormal gait mechanics and potentially abnormal muscle forces within FAI patients leads to articular cartilage damage. Therefore, there is a necessity to understand the effects of FAI on hip joint muscle forces during gait and the link between muscle forces, patient reported outcomes (PRO) and articular cartilage health. The purposes of this study were to assess: (1) hip muscle forces between FAI patients and healthy controls and (2) the associations between hip muscle forces with PRO and cartilage composition (T_1ρ/T₂ mapping) within FAI patients. Musculoskeletal simulations were used to estimate peak muscle forces during the stance phase of gait in 24 FAI patients and 24 healthy controls. Compared to controls, FAI patients ambulated with lower vasti (30% body-weight, p = 0.01) and higher sartorius (4.0% body-weight, p < 0.01) forces. Within FAI patients, lower peak gluteus medius, gluteus minimus, sartorius and iliopsoas forces were associated with worse hip joint pain and function (R = 0.43–0.70, p = 0–0.04), while lower muscle forces were associated with increased T_1ρ and T₂ values (i.e. altered cartilage composition) within the hip joint cartilage (R = −0.44 to −0.58, p = 0.006–0.05). Although FAI patients demonstrate abnormal muscle forces, it is unknown whether or not these altered muscle force patterns are associated with pain avoidance or weak musculature. Further investigation is required in order to better understand the effects of FAI on hip joint muscle forces and the associations with hip joint cartilage degeneration.     

Assessment of isometric muscle strength and rate of torque development with hand-held dynamometry: Test-retest reliability and relationship with gait velocity after stroke

Isometric rate of torque development examines how quickly force can be exerted and may resemble everyday task demands more closely than isometric strength. Rate of torque development may provide further insight into the relationship between muscle function and gait following stroke. Aims of this study were to examine the test-retest reliability of hand-held dynamometry to measure isometric rate of torque development following stroke, to examine associations between strength and rate of torque development, and to compare the relationships of strength and rate of torque development to gait velocity. Sixty-three post-stroke adults participated (60 years, 34 male). Gait velocity was assessed using the fast-paced 10 m walk test. Isometric strength and rate of torque development of seven lower-limb muscle groups were assessed with hand-held dynamometry. Intraclass correlation coefficients were calculated for reliability and Spearman’s rho correlations were calculated for associations. Regression analyses using partial F-tests were used to compare strength and rate of torque development in their relationship with gait velocity. Good to excellent reliability was shown for strength and rate of torque development (0.82–0.97). Strong associations were found between strength and rate of torque development (0.71–0.94). Despite high correlations between strength and rate of torque development, rate of torque development failed to provide significant value to regression models that already contained strength. Assessment of isometric rate of torque development with hand-held dynamometry is reliable following stroke, however isometric strength demonstrated greater relationships with gait velocity. Further research should examine the relationship between dynamic measures of muscle strength/torque and gait after stroke.     

Predicting muscle forces in gait from EMG signals and musculotendon kinematics

An EMG-driven muscle model for determining muscle force-time histories during gait is presented. The model, based on Hill's equation (1938), incorporates morphological data and accounts for changes in musculotendon length, velocity, and the level of muscle excitation for both concentric and eccentric contractions. Musculotendon kinematics were calculated using three-dimensional cinematography with a model of the musculoskeletal system. Muscle force-length-EMG relations were established from slow isokinetic calibrations. Walking muscle force-time histories were determined for two subjects. Joint moments calculated from the predicted muscle forces were compared with moments calculated using a linked segment, inverse dynamics approach. Moment curve correlations ranged from r = 0.72 to R = 0.97 and the root mean square (RMS) differences were from 10 to 20 Nm. Expressed as a relative RMS, the moment differences ranged from a low of 23% at the ankle to a high of 72% at the hip. No single reason for the differences between the two moment curves could be identified. Possible explanations discussed include the linear EMG-to-force assumption and how well the EMG-to-force calibration represented excitation for the whole muscle during gait, assumptions incorporated in the muscle modeling procedure, and errors inherent in validating joint moments predicted from the model to moments calculated using linked segment, inverse dynamics. The closeness with which the joint moment curves matched in the present study supports using the modeling approach proposed to determine muscle forces in gait.     

Lower limb co-contraction during walking in subjects with stroke: A systematic review

PurposeThe aim of this paper was to identify and synthesise existing evidence on lower limb muscle co-contraction (MCo) during walking in subjects with stroke.MethodsAn electronic literature search on Web of Science, PubMed and B-on was conducted. Studies from 1999 to 2012 which analysed lower limb MCo during walking in subjects with stroke, were included.ResultsEight articles met the inclusion criteria: 3 studied MCo in acute stage of stroke, 3 in the chronic stage and 2 at both stages. Seven were observational and 1 had a pretest–posttest interventional design. The methodological quality was “fair to good” to “high” quality (only 1 study). Different methodologies to assess walking and quantify MCo were used. There is some controversy in MCo results, however subjects with stroke tended towards longer MCo in both lower limbs in both the acute and chronic stages, when compared with healthy controls. A higher level of post-stroke walking ability (speed; level of independence) was correlated with longer thigh MCo in the non-affected limb. One study demonstrated significant improvements in walking ability over time without significant changes in MCo patterns.ConclusionsSubjects with stroke commonly present longer MCo during walking, probably in an attempt to improve walking ability. However, to ensure recommendations for clinical practice, further research with standardized methodologies is needed.     

Reliability of surface electromyography for the gluteus medius muscle during gait in people with and without chronic nonspecific low back pain

The purpose of this study was to determine the intratester reliability of surface electromyography (EMG) assessment of the gluteus medius muscle in healthy people and people with chronic nonspecific low back pain (CNLBP) during barefoot walking. Gluteus medius muscle activity was measured twice in 40 people without and 30 people with CNLBP approximately 7 days apart. Walking gluteus medius muscle activity was normalised to maximal voluntary isometric contractions during side-lying hip abduction with manual resistance. Good intratester reliability (ICC > 0.75) was found for mean, peak, and peak to peak amplitude for healthy people. Only mean amplitude demonstrated good intratester reliability in those with CNLBP. Peak amplitude and peak to peak amplitude of the gluteus medius muscle of those with CNLBP, and the time of peak amplitude in both groups, demonstrated moderate reliability (ICC ranged from 0.50 to 0.58). Moderate to large standard error of measurement and minimal detectable change values were reported for outcome measurements. These results suggest that potentially large levels of random error can occur between sessions. Future research can build on this study for those with pathology and attempt to establish change values for EMG that are clinically meaningful.     

Contribution of muscle short-range stiffness to initial changes in joint kinetics and kinematics during perturbations to standing balance: A simulation study

Simulating realistic musculoskeletal dynamics is critical to understanding neural control of muscle activity evoked in sensorimotor feedback responses that have inherent neural transmission delays. Thus, the initial mechanical response of muscles to perturbations in the absence of any change in muscle activity determines which corrective neural responses are required to stabilize body posture. Muscle short-range stiffness, a history-dependent property of muscle that causes a rapid and transient rise in muscle force upon stretch, likely affects musculoskeletal dynamics in the initial mechanical response to perturbations. Here we identified the contributions of short-range stiffness to joint torques and angles in the initial mechanical response to support surface translations using dynamic simulation. We developed a dynamic model of muscle short-range stiffness to augment a Hill-type muscle model. Our simulations show that short-range stiffness can provide stability against external perturbations during the neuromechanical response delay. Assuming constant muscle activation during the initial mechanical response, including muscle short-range stiffness was necessary to account for the rapid rise in experimental sagittal plane knee and hip joint torques that occurs simultaneously with very small changes in joint angles and reduced root mean square errors between simulated and experimental torques by 56% and 47%, respectively. Moreover, forward simulations lacking short-range stiffness produced unreasonably large joint angle changes during the initial response. Using muscle models accounting for short-range stiffness along with other aspects of history-dependent muscle dynamics may be important to advance our ability to simulate inherently unstable human movements based on principles of neural control and biomechanics.     

Reduction in subluxation and improved muscle function of the hemiplegic shoulder joint after therapeutic electrical stimulation.

Seventeen hemiplegic patients with chronic shoulder subluxation secondary to a cerebrovascular accident (CVA) were divided into three groups, two of which were subjected to 6 weeks of therapeutic electrical stimulation (TES) for 15 minutes twice a day, in order to assess the effectiveness of the treatment in reducing subluxation, and in improving shoulder abduction function. The third group was used as a control (C group). After 6 weeks of electrical stimulation of the supraspinatus (S group) and deltoid (D group), a significant (p<0.05) reduction in subluxation was observed in both groups when compared to the C group. The maximal force of shoulder abduction showed a tendency to increase in the S group (p<0.10). A significant increase in maximal force was also observed in the D group. In most of the TES-treated muscles, the interference pattern of EMG at maximum voluntary contraction increased. The amplitude of the EMG activity of the stimulated muscle also increased. Thus, we concluded that electrical stimulation therapy of the supraspinatus and the deltoid muscle is an effective treatment modality for shoulder subluxation and shoulder abduction function in hemiplegic patients.     

Quantifying the effectiveness of the sustained muscle stretching treatments in stroke patients with ankle hypertonia.

Sustained muscle stretch (SMS) is commonly used to reduce hypertonia. The present study evaluates the effectiveness of three different SMS protocols, namely constant-angle, cyclic, and constant-torque stretching, in the immediate reducing of ankle hypertonia. Forty-seven hemiplegic subjects, 53.7+/-10.3 years old and 22.4+/-16.0 months after stroke, with hypertonic ankle joints were recruited to undergo three SMS applied to protocols treatment their hypertonic ankle joints using an integrated treatment/assessment system. The immediate post-treatment effectiveness of each stretching protocol was assessed by reference to the pre-treatment Modified Ashworth Scale (MAS), passive range of motion (ROM), and reactive torque measurement, from which the viscous-elastic components of the ankle joint were derived. All three SMS protocols successfully reduced MAS grade. Additionally, each stretching method yielded an increase in ankle ROM, from 9.7 degrees to 16 degrees , 9.6 degrees to 14.8 degrees , and 9.2 degrees to 18.3 degrees for the constant-angle, cyclic-stretching, constant-torque protocols, respectively, and reduction of the elastic and viscous properties of the ankle joint dorsiflexion (p<0.05). The changes in the ROM, elasticity, and viscosity were most pronounced in the case of the constant-torque stretching protocol. In addition to clinical scales, current biomechanical assessments indicate that three SMS protocols are all effective in reducing the immediate viscoelastic components of hypertonic ankle joints. Our quantitative analysis further shows that of the three treatment protocols, the constant-torque treatment is the most effective.     

Complications and mid-term outcome after percutaneous patent foramen ovale closure in patients with cryptogenic stroke

Background: Percutaneous patent foramen ovale (PFO) closure seems to reduce the risk of recurrent thromboembolism. We report the safety and efficacy of percutaneous PFO closure in our centre. Methods: All patients, >16 years of age, who underwent a percutaneous PFO closure in our centre were included. Reoccurrence of stroke, transient ischaemic attack (TIA) and peripheral thromboembolism were assessed. Periprocedural and midterm complications are reported. Results: Eighty-three consecutive patients (mean age 49±13 years) were included. Indications for PFO closure were cryptogenic stroke (59.0%), TIA (33.7%), peripheral embolism (2.4%) and other (4.8%). For PFO closure, a Cardioseal/Starflex device was used in 63 patients and an Amplatzer PFO occluder device in 20 patients. Stroke recurred in 1.2%, TIA in 3.6%, peripheral embolism in 0% during a mean follow-up of 1.9±1.2 years. Major periprocedural complications occurred in 1.2%. The mid-term complication rate was 2.4% and only consisted of minor complications. During follow-up, a residual right-to-left shunt was present in 5.7% of the patients. No significant difference in outcome, complications or residual shunting could be documented between the two device types. Conclusion: In our centre, the percutaneous closure of a PFO seems to be a safe and effective procedure to prevent recurrence of paradoxical thrombo-embolic events. (Neth Heart J 2008;16:332-6.)     

Effect of plantarflexion resistance of an ankle-foot orthosis on ankle and knee joint power during gait in individuals post-stroke

Plantarflexion resistance of an ankle-foot orthosis (AFO) plays an important role to prevent foot-drop, but its impact on push-off has not been well investigated in individuals post-stroke. The aim of this study was to investigate the effect of plantarflexion resistance of an articulated AFO on ankle and knee joint power of the limb wearing the AFO in individuals post-stroke. Gait analysis was performed on 10 individuals with chronic stroke using a Vicon 3-dimensional motion capture system and a Bertec split-belt instrumented treadmill. They walked on the treadmill under 4 plantarflexion resistance levels (S1 < S2<S3 < S4) set on the AFO with resistance adjustable ankle joints. The ankle and knee joint power calculations were performed using Visual3D, and mean values were plotted across a gait cycle. Statistical analyses revealed significant differences in the peak ankle joint power generation according to the plantarflexion resistance of the AFO (P = 0.008). No significant differences were found in the knee joint power. Peak ankle joint power generation [Median (IQR: Interquartile range)] were S1: 0.0517 (0.0238–0.1071) W/kg, S2: 0.0342 (0.0132–0.0862) W/kg, S3: 0.0353 (0.0127–0.0821) W/kg, and S4: 0.0234 (0.0087–0.06764) W/kg. Reduction of the peak ankle joint power generation appeared to be related to reduction in the peak plantarflexion angular velocity at late stance due to increases in the plantarflexion resistance of the AFO. This study showed that peak ankle joint power generation was significantly, and somewhat systematically, affected by plantarflexion resistance of the AFO in individuals post-stroke.