Timing of propulsion-related biomechanical variables is impaired in individuals with post-stroke hemiparesis

BackgroundIn individuals with post-stroke hemiparesis, reduced paretic leg propulsion, measured through anterior ground reaction forces (AGRF), is a common and functionally-relevant gait impairment. Deficits in other biomechanical variables such as plantarflexor moment, ankle power, and ankle excursion contribute to reduced propulsion. While reduction in the magnitude of propulsion post-stroke is well studied, here, our objective was to compare the timing of propulsion-related biomechanical variables.Research questionAre there differences in the timing of propulsion and propulsion-related biomechanical variables between able-bodied individuals, the paretic leg, and non-paretic leg of post-stroke individuals?MethodsNine able-bodied and 13 post-stroke individuals completed a gait analysis session comprising treadmill walking trials at each participant’s self-selected speed. Two planned independent sample t-tests were conducted to detect differences in the timing of dependent variables between the paretic versus non-paretic leg post-stroke and paretic leg versus the dominant leg of able-bodied individuals.ResultsPost-stroke individuals demonstrated significantly earlier timing of peak AGRF of their paretic leg versus their non-paretic leg and able-bodied individuals. Post-stroke participants displayed earlier timing of peak power of their paretic leg versus their non-paretic leg and able-bodied individuals, and earlier timing of peak ankle moment of the paretic leg versus able-bodied. No significant differences were detected in the timing of peak ankle angle.SignificanceThe earlier onset of peak AGRF, peak ankle power, and peak ankle moment may be an important, under-studied biomechanical factor underlying stroke gait impairments, and a potential therapeutic target for stroke gait retraining. Future investigations can explore the use of interventions such as gait biofeedback to normalize the timing of these peaks, thereby improving propulsion and walking function post-stroke.     

Comparison of the effects of real-time propulsive force versus limb angle gait biofeedback on gait biomechanics

BackgroundReduced forward propulsion during gait, measured as the anterior component of the ground reaction force (AGRF), may contribute to slower walking speeds in older adults and gait dysfunction in individuals with neurological impairments. Trailing limb angle (TLA) is a clinically important gait parameter that is associated with AGRF generation. Real-time gait biofeedback can induce modifications in targeted gait parameters, with potential to modulate AGRF and TLA. However, the effects of real-time TLA biofeedback on gait biomechanics have not been studied thus far.Research questionWhat are the effects of unilateral, real-time, audiovisual trailing limb angle biofeedback on gait biomechanics in able-bodied individuals?MethodsTen able-bodied adults participated in one session of treadmill-based gait analyses comprising 60-second walking trials under three conditions: no biofeedback, AGRF biofeedback, and TLA biofeedback. Biofeedback was provided unilaterally to the right leg. Dependent variables included AGRF, TLA, ankle moment, and ankle power. One-way repeated measures ANOVA with post-hoc tests were conducted to determine the effect of the biofeedback conditions on gait parameters.ResultsCompared to no biofeedback, both AGRF and TLA biofeedback induced significant increases in targeted leg AGRF without concomitant changes to the non-targeted leg AGRF. Targeted leg TLA was significantly larger during TLA biofeedback compared to AGRF biofeedback. Only AGRF biofeedback induced significant increases in ankle power; and only the TLA biofeedback condition induced increases in the non-targeted leg TLA.SignificanceOur novel findings provide support for the feasibility and promise of TLA as a gait biofeedback target. Our study demonstrates that comparable magnitudes of feedback-induced increases in AGRF in response to AGRF and TLA biofeedback may be achieved through divergent biomechanical strategies. Further investigation is needed to uncover the effects of TLA biofeedback on gait parameters in individuals with neuro-pathologies such as spinal cord injury or stroke.     

Effects of gait training with auditory biofeedback on biomechanics and talar cartilage characteristics in individuals with chronic ankle instability: A randomized controlled trial

BackgroundAltered walking gait is a typical impairment following ankle sprains which may increase susceptibility to recurring injuries and development of posttraumatic osteoarthritis at the ankle. There is a lack of targeted gait training interventions focusing on specific modifications in individuals with chronic ankle instability (CAI). Additionally, there is a need to focus on cartilage health changes following gait training to mitigate osteoarthritis progression.Research questionTo determine the immediate and retention effects of gait training using auditory biofeedback (AudFB) in patients with chronic ankle instability (CAI) on biomechanics and talar cartilage characteristics.MethodsEighteen participants with CAI were randomly assigned into Control (n = 7) or AudFB (n = 11) groups. Each group completed 8-sessions of 30-minute treadmill walking. The AudFB group received biofeedback through a pressure sensor fashioned to the lateral foot and instructions to walk while avoiding noise from the sensor. The Control group did not receive instructions during sessions. An in-shoe insole system measured peak pressure, maximum force, and center of the pressure gait line (COP) during walking. Ultrasonography captured talar cartilage thickness and echo intensity before and after walking. Biomechanics and ultrasound were measured at baseline, immediately, and 1-week after the intervention. Repeated measures mixed-methods analysis of variance assessed changes within groups across time.ResultsThe AudFB group significantly reduced pressure and force in the lateral foot and medially shifted their COP at Immediate and 1-week Post. There were no observed changes in the Control group. In addition, neither group demonstrated changes in ultrasound measures at follow-up.SignificanceImplementation of auditory biofeedback during gait training can be a valuable tool for clinicians treating patients with CAI.     

Normative Achilles and patellar tendon shear wave speeds and loading patterns during walking in typically developing children

BackgroundMotion analysis is commonly used to evaluate joint kinetics in children with cerebral palsy who exhibit gait disorders. However, one cannot readily infer muscle-tendon forces from joint kinetics. This study investigates the use of shear wave tensiometry to characterize Achilles and patellar tendon forces during gait.Research QuestionHow do Achilles and patellar tendon wave speed and loading modulate with walking speed in typically developing children?MethodsTwelve typically developing children (9–16 years old) walked on an instrumented treadmill with shear wave tensiometers over their Achilles (n = 11) and patellar (n = 9) tendons. Wave speeds were recorded at five leg length-normalized walking speeds (very slow to very fast). Achilles and patellar tendon moment arms were measured with synchronized ultrasound and motion capture. The tendon wave speed-load relationship was calibrated at the typical walking speed and used to estimate tendon loading at other walking speeds.ResultsCharacteristic Achilles and patellar tendon wave speed trajectories exhibited two peaks over a gait cycle. Peak Achilles tendon force closely aligned with peak ankle plantarflexor moment during pushoff, though force exhibited less modulation with walking speed. A second peak in late swing Achilles loading, which was not evident from the ankle moment, increased significantly with walking speed (p < 0.001). The two peaks in patellar tendon loading occurred at 12 ± 1% and 68 ± 6% of the gait cycle, matching the timing of peak knee extension moment in early stance and early swing. Both patellar tendon load peaks increased significantly with walking speed (p < 0.05).SignificanceThis is the first study to use shear wave tensiometry to characterize Achilles and patellar tendon loading during gait in children. These data could serve as a normative comparison when using tensiometry to identify abnormal tendon loading patterns in individuals who exhibit equinus and/or crouch gait.     

Biomechanics of slow running and walking with a rocker shoe

Evidence suggests a link between the loading of the Achilles tendon and the magnitude of the ankle internal plantar flexion moment during late stance of gait, which is clinically relevant in the management of Achilles tendinopathy. Some studies showed that rocker shoes can reduce the ankle internal plantar flexion moment. However, the existing evidence is not conclusive and focused on walking and scarce in running. Sixteen healthy runners participated in this study. Lower extremity kinetics, kinematics and electromyographic (EMG) signals of triceps surae and tibialis anterior were quantified for two types of shoes during running and walking. The peak ankle plantar flexion moment was reduced significantly in late stance of running (0.27 Nm/kg; p < 0.001) and walking (0.24 Nm/kg; p < 0.001) with the rocker shoe compared to standard shoe. The ankle power generation and plantar flexion moment impulse were also reduced significantly when running and walking with the rocker shoe (p < 0.001). No significant changes in the knee and hip moments were found in running and walking. A significant delay of the EMG peak, approximately 2% (p < 0.001), was present in the triceps surae when walking with rocker shoes. There were no significant changes in the EMG peak amplitude of triceps surae in running and walking. The peak amplitude of tibialis anterior was significantly increased (64.7 μV, p < 0.001) when walking with rocker shoes. The findings show that rocker shoes reduce the ankle plantar flexion moment during the late stance phase of running and walking in healthy people.     

Greater knee varus angle and pelvic internal rotation after landing are predictive factors of a non-contact lateral ankle sprain

ObjectivesThis study aimed to clarify the kinematic, kinetic characteristics associated with lateral ankle sprain.DesignA 16-month prospective cohort study.SettingLaboratory.ParticipantsA total of 179 college athletes.Main outcome measuresJoint kinematics, moment during single-leg landing tasks, and ankle laxity were measured. The attendance of each participating team, injury mechanism, existence of body contact, presence of orthosis, with or without medical diagnosis, and periods of absence were recorded.ResultsTwenty-nine participants incurred lateral ankle sprain during non-contact motion. The Cox regression analysis revealed that greater knee varus peak angle (hazard ratio: 1.16 [95% confidence interval: 1.10–1.22], p < 0.001) and greater pelvic internal rotation peak angle toward the support leg were associated with lateral ankle sprain (hazard ratio: 1.08 [95% confidence interval: 1.02–1.15], p = 0.009). The cut-off values for each predictive factor were −0.17° (area under the curve = 0.89, p < 0.001) and 6.63° (area under the curve = 0.74, p < 0.001), respectively.ConclusionsA greater knee varus peak angle and pelvic internal rotation peak angle after single-leg landing are predictive factors for lateral ankle sprain.     

Ankle power biofeedback attenuates the distal-to-proximal redistribution in older adults

BackgroundCompared to young adults, older adults walk slower, with shorter strides, and with a characteristic decrease in ankle power output. Seemingly in response, older adults rely more than young on hip power output, a phenomenon known as a distal-to-proximal redistribution. Nevertheless, older adults can increase ankle power to walk faster or uphill, revealing a translationally important gap in our understanding.Research questionOur purpose was to implement a novel ankle power biofeedback paradigm to encourage favorable biomechanical adaptations (i.e. reverse the distal-redistribution) during habitual speed walking in older adults.Methods10 healthy older adults walked at their preferred speeds while real-time visual biofeedback provided target increases and decreases of 10 and 20% different from preferred ankle power. We evaluated the effect of changes in ankle power on joint kinetics, kinematics, and propulsive ground reaction forces. Pre and post overground walking speed assessments evaluated the effect of increased ankle power recall on walking speed.ResultsBiofeedback systematically elicited changes in ankle power; increasing and decreasing ankle power by 14% and 17% when targeting ±20% different from preferred, respectively. We observed a significant negative correlation between ankle power and hip extensor work. Older adults relied more heavily on changes in ankle angular velocity than ankle moment to modulate ankle power. Lastly, older adults walked almost 11% faster when recalling increased ankle power overground.SignificanceOlder adults are capable of increasing ankle power through targeted ankle power biofeedback – effects that are accompanied by diminished hip power output and attenuation of the distal-to-proximal redistribution. The associated increase in preferred walking speed during recall suggests a functional benefit to increased ankle power output via transfer to overground walking. Further, our mechanistic insights allude to translational success using ankle angular velocity as a surrogate to modulate ankle power through biofeedback.     

Effects of bi-axial ankle strengthening on muscle co-contraction during gait in chronic stroke patients: A randomized controlled pilot study

IntroductionAnkle dysfunction in patients with stroke is a common but serious cause of balance and gait impairments. However, comprehensive paretic ankle training seldom exists. Thus, we investigated the effects of a bi-axial ankle muscle training program using visual feedback as a means to improve ankle strength and performance of functional activities in patients with stroke.MethodsThis study was a randomized controlled pilot trial with concealed allocation and assessor blinding and intention-to-treat analysis. Twenty-five patients with stroke and difficulty in walking (e.g., foot drop) or ankle muscle weakness receiving inpatient rehabilitation were included. The experimental group underwent ankle muscle training consisting of passive stretching, control of ankle muscles, and active-resistive strengthening using visual feedback for 40 min per day, 5 times per week for 4 weeks. The control group underwent ankle-related physical therapy, including ankle range-of-motion exercises. The amount of time for training was equal between the two groups. The outcome measurements were isometric ankle contraction force to assess the strength of ankle muscles, ankle proprioception, Fugl–Meyer lower extremity score, Berg balance scale score, walking speed, and ankle co-contraction index to assess muscle efficiency during gait.ResultsThe analysis revealed significant between-group differences in the ankle muscle strength in each direction (P < 0.05), Fugl–Meyer score (P < 0.01), and stance-phase co-contraction index (P < 0.05). After training, the experimental group displayed significant within-group differences in the strength of the ankle muscles in each direction (P < 0.01), ankle proprioception (P < 0.05), and walking speed (P < 0.05).ConclusionsOur findings demonstrate the significant short-term effects of ankle muscle training on strength, walking speed, and muscle efficiency in patients with chronic stroke.     

Walking while resisting a perturbation: Effects on ankle dorsiflexor activation during swing and potential for rehabilitation

Motor control studies have shown that when walking is performed while resisting a perturbation applied to the lower limb, the muscle activation pattern can be temporarily modified. The objective of the present study is to validate if such an approach, targeting the ankle, could specifically promote an increased activation of the ankle dorsiflexor muscles that are of key importance for the rehabilitation of foot drop.

Methods

12 adults, with no gait deficit, walked on a treadmill for three periods of 5 min: before, during and after exposure to a torque perturbation applied by a robotized ankle-foot orthosis that tended to plantarflex the ankle during the swing phase. Spatiotemporal gait parameters, ankle and knee kinematics, and the electromyographic activity of five lower limb muscle groups were recorded.

Results

The perturbation initially caused a deviation of the ankle towards plantarflexion. This movement error was rapidly reduced and associated with a large increase (78.2%; p < 0.001) in tibialis anterior (ankle dorsiflexor; TA) activation, specifically in the stance-to-swing burst. This increase carried over to post-perturbation walking, gradually disappearing over several strides. Interestingly, these aftereffects led to an increase in peak ankle dorsiflexion of approximately 7° during the swing phase.

Conclusions

Walking while resisting a torque perturbation applied at the ankle during swing promotes an increase in TA muscle activation that carries over after perturbation removal, leading to an increased ankle dorsiflexion. Training based on this approach may have the potential of improving the gait of persons with foot drop.     

The effect of dual tasking on foot kinematics in people with functional ankle instability

BackgroundSome cases of repeated inversion ankle sprains are thought to have a neurological basis and are termed functional ankle instability (FAI). In addition to factors local to the ankle, such as loss of proprioception, cognitive demands have the ability to influence motor control and may increase the risk of repetitive lateral sprains.ObjectiveThe purpose of this study was to investigate the effect of cognitive demand on foot kinematics in physically active people with functional ankle instability.Methods21 physically active participants with FAI and 19 matched healthy controls completed trials of normal walking (single task) and normal walking while performing a cognitive task (dual task). Foot motion relative to the shank was recorded. Cognitive performance, ankle kinematics and movement variability in single and dual task conditions was characterized.ResultsDuring normal walking, the ankle joint was significantly more inverted in FAI compared to the control group pre and post initial contact. Under dual task conditions, there was a statistically significant increase in frontal plane foot movement variability during the period 200 ms pre and post initial contact in people with FAI compared to the control group (p < 0.05). Dual task also significantly increased plantar flexion and inversion during the period 200 ms pre and post initial contact in the FAI group (p < 0.05).Conclusionparticipants with FAI demonstrated different ankle movement patterns and increased movement variability during a dual task condition. Cognitive load may increase risk of ankle instability in these people.     

Dynamic joint stiffness of the ankle in chronic ankle instability patients

BackgroundWhile Individuals with chronic ankle instability (CAI) exhibit altered ankle joint movement and moments during stance phase of gait, the interaction or dynamic joint stiffness (DJS) between these is not fully understood. Little attention has been placed on DJS during gait, limiting our understanding of how the most common dynamic task during daily life could affect cartilage loading.Research questionDo Individuals with CAI exhibit altered ankle DJS and mechanical energy exerted at the ankle joint during stance phase of gait?MethodsEighty-four physically active individuals, consisting of 42 individuals with CAI (12 M and 30 F) and 42 control (12 M and 30 F) participants were recruited in this study. Three-dimensional gait analysis was conducted. The sagittal ankle joint angle and moment during stance phase of walking gait were obtained. Stance phase was divided into three sub-phases: controlled plantarflexion, controlled dorsiflexion, and powered plantarflexion. Ankle DJS was represented by the slope of the joint moment plotted as a function of the joint angle. The coefficient of determination was calculated to determine how accurately data fit a linear model. Net work was calculated by the difference between work produced and absorbed. Further, sex specific exploratory analyses of DJS and work between individuals with and without CAI were conducted.ResultsLower DJS during the controlled plantarflexion (CPF) sub-phase, work produced, and net work was found in the CAI group. Males with CAI exhibited lower ankle moment changes during controlled dorsiflexion (CDF) sub-phase and work absorbed. Females with CAI exhibited lower ankle moment changes during CPF and CDF sub-phases, lower DJS during the CPF sub-phase, and lower net work.SignificanceIndividuals with CAI have alterations in DJS and work relative to uninjured controls. Females with CAI showed greater DJS related alterations, relative to controls, than their male CAI counterparts.     

Spatial-temporal parameters,pelvic and lower limb movements during gait in individuals with reduced passive ankle dorsiflexion

BackgroundProper ankle dorsiflexion range of motion (ADF-ROM) allows the anterior roll of the tibia relative to the foot during the midstance phase of gait, which contributes to forward movement of the body. Individuals with reduced passive ADF-ROM may present altered movement patterns during gait due to an inefficient anterior tibial roll over the support foot during the stance phase.Research question: What is the influence of reduced passive ADF-ROM on the pelvic and lower limb movements and spatiotemporal parameters during gait?MethodThirty-two participants divided into two groups according to the degree of passive ADF-ROM—less than 10° (lower ADF-ROM group) or greater than 15° (higher ADF-ROM group) —were subjected to gait assessment using a three-dimensional motion analysis system. Independent t-tests were used to compare the pelvic and lower limb movements and spatiotemporal gait parameters between the groups on this cross-sectional study.ResultsThe lower ADF-ROM group had shorter step length, lower peak of pelvic ipsilateral rotation angle, and lower hip and knee maximum flexion angles in the stance phase (p < 0.05). In addition, the peaks of the ankle and forefoot-rearfoot dorsiflexion angles were smaller in the reduced ADF-ROM group (p < 0.05). The between-group differences presented effect sizes varying from moderate to large.SignificanceIndividuals with reduced passive ADF-ROM presented reduced foot and ankle dorsiflexion, knee and hip flexion, and pelvis rotation movements and shorter step length during gait. However, no differences in foot pronation were noted between groups. Therefore, individuals with reduced passive ADF-ROM present alterations in the lower limb and pelvic movements during gait.     

Gait outcomes following proximal tibial tumor resection and endoprosthetic reconstruction

BackgroundDespite the proximal tibia being a common site of primary malignant bone tumors, there is limited information about gait function following proximal tibial tumor resection and endoprosthetic reconstruction (PTR).Research questionWhat is the impact of PTR on gait and quality of life?MethodsThis was a cross-sectional study of patients ≥18 years old who were ≥2 years post-PTR compared to a control group of similar age and sex distribution. Eighteen participants (9 PTR, 9 Control) were recruited. Gait spatial-temporal data, joint kinematics and kinetics were collected at preferred and fast walking speeds. Community walking cadence, health-related quality of life (SF-36) and knee joint torque were assessed. Comparisons were performed using one-way ANOVAs with Bonferroni corrections for multiple comparisons. Nonparametric tests were used for data not normally distributed.ResultsMean age was 31 years for each group (PTR range = 18–42 yrs, Control range = 18–44 yrs). Compared to both control and nonsurgical limbs, the surgical limb exhibited significantly decreased % single limb support time, reduced heel rise during terminal stance and an absence of normally occurring knee flexion angles, extensor moments and power generation during initial double limb support. Additionally, a reduced peak plantar flexor moment was found for the surgical as compared to the control limb. The number of gait abnormalities increased during fast walking. Significantly reduced surgical knee extensor torque on isokinetic testing and weakness of the knee and ankle on clinical examination support gait findings. During community walking, the number of low frequency strides was an average of 5.3 % greater for the PTR group (p < 0.05). Norm-based PTR group SF-36 component scores were within normal values (53.4 physical, 56.5 mental).SignificanceGait abnormalities were consistent with ankle muscle resection and transposition and knee extensor mechanism disruption. Despite these deficits, walking speed and quality of life were relatively normal.     

Lower back kinetic demands during induced lower limb gait asymmetries

BackgroundGait asymmetries are common in many clinical populations (e.g., amputation, injury, or deformities) and are associated with a high incidence of lower back pain. Despite this high incidence, the impact of gait asymmetries on lower back kinetic demands are not well characterized due to experimental limitations in these clinical populations. Therefore, we artificially and safely induced gait asymmetry during walking in healthy able-bodied participants to examine lower back kinetic demands compared to their normal gait.Research questionAre lower back kinetic demands different during artificially induced asymmetries than those during normal gait?MethodsL5/S1 vertebral joint kinetics and trunk muscle forces were estimated during gait in twelve healthy men and women with a musculoskeletal lower back model that uniquely incorporated participant-specific responses using an EMG optimization approach. Five walking conditions were conducted on a force-measuring treadmill, including normal unperturbed “symmetrical” gait, and asymmetrical gait induced by unilaterally altering leg mass, leg length, and ankle joint motion in various combinations. Gait symmetry index and lower back kinetics were compared with repeated-measures ANOVAs and post hoc tests (α = .05).ResultsThe perturbations were successful in producing different degrees of step length and stance time gait asymmetries (p < .01). However, lower back kinetic demands associated with asymmetrical gait were similar to, or only moderately different from normal walking for most conditions despite the observed asymmetries.SignificanceOur findings indicate that the high incidence of lower back pain often associated with gait asymmetries may not be a direct effect of increased lower back demands. If biomechanical demands are responsible for the high incidence of lower back pain in such populations, daily tasks besides walking may be responsible and warrant further investigation.     

Differences in temporal gait mechanics are associated with decreased perceived ankle joint health in individuals with chronic ankle instability

BackgroundChronic ankle instability (CAI) is associated with an increased risk of developing post-traumatic osteoarthritis (PTOA). Altered temporal gait parameters likely contribute to the early development and progression of PTOA in CAI. However, it is unknown if increased clinical symptoms of ankle PTOA influence temporal gait parameters among those with CAI.Research questionCompare temporal gait parameters and Ankle Osteoarthritis Scale (AOS) scores between individuals with and without CAI.MethodsThirty CAI participants and 30 healthy-controls volunteered to participate in this retrospective case-control study. Participants completed the Pain and Disability subscales of the AOS. Temporal gait parameters were assessed using a GAITRite® electronic walkway. Participants performed 5 walking trials, which were subsequently combined into a single test. Temporal variables (swing, stance, single-limb support and double-limb support) were extracted for the involved limb and normalized to percent of gait cycle (%GC).ResultsParticipants with CAI had higher scores on the Pain (P < 0.001) and Disability (P = 0.001, d = 0.87[0.33,1.39]) subscales of the AOS. CAI individuals spent less time during swing (P = 0.022]) and single-limb support (P = 0.030) phases and more time during the double-limb support (P = 0.021) phase. Single-limb support time was moderately correlated with higher scores on the AOS pain (r=-0.416, P = 0.011) and disability (r=-0.473 P = 0.004) subscales.SignificanceIndividuals with CAI spend varying times in each phase of the gait cycle compared to uninjured controls. Individuals with CAI may adopt this abnormal gait strategy due to increased clinical symptoms of ankle PTOA. Rehabilitation programs should focus on minimizing the symptoms of ankle PTOA to restore normal temporal gait parameters.     

Immediate effect of walking with talus-stabilizing taping on ankle kinematics in subjects with limited ankle dorsiflexion

ObjectiveTo determine the effects of walking with talus-stabilizing taping (TST) on ankle dorsiflexion (DF) and heel-off time in the stance phase of gait and ankle DF passive range of motion (PROM).DesignPre- and post-intervention study.SettingUniversity motion analysis laboratory.ParticipantsTen subjects participated in this study. Sixteen ankles with limited ankle DF PROM were tested.Main outcome measuresAnkle DF PROM was measured using a goniometer, and maximum ankle DF before heel-off and time to heel-off in the stance phase of gait were measured using a 3D motion analysis system before and after walking with TST. Data were analyzed using a paired t-test.ResultsAnkle maximum DF before heel-off (p = 0.001), time to heel-off during the stance phase of gait (p = 0.005), and ankle DF PROM (p < 0.001) were significantly increased post-intervention compared with pre-intervention.ConclusionsWalking with TST is an effective self-exercise for improving ankle kinematics during gait and increasing ankle DF PROM in individuals with limited ankle DF PROM.     

Lower limb kinematics during single leg landing in three directions in individuals with chronic ankle instability

ObjectivesTo compare the lower limb kinematics of participants with chronic ankle instability (CAI) and healthy participants during forward, lateral, and medial landings.DesignCross-sectional study.SettingLaboratory.ParticipantsEighteen athletes with CAI and 18 control athletes.Main outcome measuresHip, knee, and ankle joint kinematics during forward, lateral, and medial single-leg landings were compared between the groups using two-way ANOVA for discrete values and statistical parametric mapping two-sample t-tests for time-series data.ResultsThe CAI group had significantly greater ankle dorsiflexion than the control group (P ≤ 0.013), which was observed from the pre-initial contact (IC) for lateral and medial landings and post-IC for forward landing. The CAI group showed greater knee flexion than the control group from the IC for lateral landing and post-IC for forward landing (P ≤ 0.014). No significant differences in ankle inversion kinematics were found between the CAI and control groups. Lateral landing had a greater peak inversion angle and velocity than forward and medial landings (P < 0.001). Medial landing had a greater inversion velocity than forward landing (P < 0.001).ConclusionsThis study suggests that individuals with CAI show feedforward protective adaptations in the pre-landing phase for lateral and medial landings.     

Test-retest reliability and minimal detectable change of ankle kinematics and spatiotemporal parameters in MS population

BackgroundMany people with multiple sclerosis (pwMS) experience walking impairments often including foot drop, evident as either reduced dorsiflexion at initial contact and/or at the swing phase of the gait cycle. To measure even subtle differences in ankle kinematics, 3D gait analysis is considered a ‘gold’ standard. However, the psychometric properties of ankle kinematics in the MS population have not yet been examined.ObjectiveThe aim of the study was to examine test-retest relative and absolute reliability of sagittal ankle kinematics and spatiotemporal parameters in two groups of pwMS with different levels of walking impairment.MethodsTwo groups of pwMS underwent 3D gait analysis on two occasions 7–14 days apart. Group A consisted of 21 (14 female) people with Expanded Disability Status Scale (EDSS) 1–3.5 and group B consisted of 28 participants (14 female) with EDSS 4-6. The Intraclass Correlation Coefficient (ICC_2,2), standard error of measurement (SEM) and minimal detectable change (MDC_95%) were calculated for peak dorsiflexion (DF) in swing, ankle angle at initial contact (IC), gait profile score (GPS), walking speed, cadence and step length.ResultsBoth groups presented ‘excellent’ ICC values (>0.75) for DF in swing, IC and step length of most and least affected limbs, walking speed and cadence, with GPS for both limbs exhibiting ‘fair’ to ‘good’ ICCs (0.489–0.698). The MDC_95% values for all ankle kinematic parameters in group A were lower (1.9°–4.2°) than those in group B (2.2°–7.7°).ConclusionThe present results suggest that ankle kinematic and spatiotemporal parameters derived from 3D gait analysis are reliable outcome measures to be used in the MS population. Further, this study provides indices of reliability that can be applied to both clinical decision making and in the design of studies aimed at treating foot drop in people with MS.     

Redistribution of joint moments and work in older women with and without hallux valgus at two walking speeds

BackgroundHallux valgus (HV) is a highly prevalent foot deformity in older women. Differences in lower extremity joint function of older women with and without HV during walking at slower and faster speeds are unknown.Research questionDoes walking speed affect lower extremity joint range of motion (ROM) and net extensor joint moment and associated work in older women with and without HV?MethodsThirteen older women with HV and 13 controls completed five walking trials at 1.1 and 1.3 m·s⁻¹ as kinematic marker position and ground reaction force data were collected. Net ankle, knee, and hip joint moments were computed using inverse dynamics during the stance phase. Positive joint work was calculated by integrating hip power in early stance, knee power in mid stance, and ankle power in late stance.ResultsAverage ankle ROM and plantarflexor moment did not increase with walking speed in the HV group, while in the control group these variables were greater for the faster compared to the slower speed (p < 0.05). The magnitude of increase in ankle joint work with speed was 12 % lesser in the HV compared to the control group (p = 0.008). The hip ROM, extensor moment, and associated work was greater in the HV compared to the control group (p < 0.05). Knee and hip joint ROM, extensor moments, and work increased with walking speed in both groups (p < 0.05).SignificanceOlder women with HV compared to older women without HV demonstrate a distal-to-proximal redistribution by increasing hip motion and effort to compensate for reduced ankle contribution during walking.     

Effects of varus knee alignment on gait biomechanics and lower limb muscle activity in boys: A cross sectional study

BackgroundThere is evidence that frontal plane lower limb malalignment (e.g., genu varus) is a risk factor for knee osteoarthritis development. However, only scarce information is available on gait biomechanics and muscle activity in boys with genu varus.Research questionTo examine the effects of knee varus alignment on lower limb kinematics, kinetics and muscular activity during walking at self-selected speed in boys with genu varus versus healthy age-matched controls.MethodsThirty-six boys were enrolled in this study and divided into a group of boys with genu varus (n = 18; age: 11.66 ± 1.64 years) and healthy controls (n = 18; age: 11.44 ± 1.78 years). Three-dimensional kinematics, ground reaction forces, loading rates, impulses and free moments of both limbs were recorded during five walking trials at self-selected speed. Surface electromyography was recorded for rectus femoris and vastus lateralis/medialis muscles.ResultsNo significant between-group differences were found for gait speed. Participants in the genu varus group versus controls showed larger peak knee flexion (p = 0.030; d = 0.77), peak knee adduction (p < 0.001; d = 1.63), and peak ankle eversion angles (p < 0.001; d = 2.06). Significantly higher peak ground reaction forces were found at heel contact (vertical [p = 0.002; d = 1.16] and posterior [p < 0.001; d = 1.63] components) and at push off (vertical [p = 0.010; d = 0.93] and anterior [p < 0.001; d = 1.34] components) for genu varus versus controls. Peak medial ground reaction force (p = 0.032; d = 0.76), vertical loading rate (p < 0.001; d = 1.52), anterior-posterior impulse (p = 0.011; d = 0.92), and peak negative free moment (p = 0.030; d = 0.77) were significantly higher in genu varus. Finally, time to reach peak forces was significantly shorter in genu varus boys compared with healthy controls (p < 0.01; d = 0.73–1.60). The genu varus group showed higher activities in vastus lateralis (p < 0.001; d = 1.82) and vastus medialis (p = 0.013; d = 0.90) during the loading phase of walking.SignificanceOur study revealed genu varus specific gait characteristics and muscle activities. Greater knee adduction angle in genu varus boys may increase the load on the medial compartment of the knee joint. The observed characteristics in lower limb biomechanics and muscle activity could play a role in the early development of knee osteoarthritis in genu varus boys.