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.     

Shorter gastrocnemius fascicle lengths in older adults associate with worse capacity to enhance push-off intensity in walking

BackgroundReduced push-off intensity during walking is thought to play an important role in age-related mobility impairment. We posit that an age-related shift toward shorter plantarflexor operating lengths during walking functionally limits force generation, and thereby the ability of those muscles to respond to increased propulsive demands during walking.Research QuestionTo determine whether gastrocnemius muscle fascicle lengths during normal walking: (1) are shorter in older than young adults, and (2) correlate with one’s capacity to increase the propulsive demands of walking to their maximum.MethodsWe used in vivo cine B-mode ultrasound to measure gastrocnemius fascicle lengths in 9 older and 9 young adults walking at their preferred speed, their maximum speed, and with horizontal impeding forces that increased in a ramped design at 1%BW/s to their maximum. A repeated measures ANOVA tested for effects of age and walking condition, and Pearson correlations assessed the relation between fascicle outcomes and condition performance.ResultsA tendency toward shorter medial gastrocnemius muscle fascicle lengths in older versus young adults was not statistically significant. However, older adults walked with reduced peak fascicle shortening during all conditions compared to young adults – an outcome not explained by reduced muscle-tendon unit shortening and exacerbated during tasks with greater than normal propulsive demand. As hypothesized, we found a strong and significant positive correlation in older subjects between gastrocnemius fascicle lengths during normal walking and performance on the ramped impeding force condition (p = 0.005, r² = 0.704), even after controlling for isometric strength (p = 0.011, r² = 0.792) and subject stature (p = 0.010, r² = 0.700).SignificanceOur findings provide muscle-level insight to develop more effective rehabilitation techniques to improve push-off intensity in older adults and assistive technologies designed to steer plantarflexor muscle fascicle operating behavior during functional tasks.     

Ankle dorsiflexors and plantarflexors neuromuscular electrical stimulation training impacts gait kinematics in older adults: A pilot study

BackgroundWhile ankle muscles, highly affected by aging, are highly implicated in the changes in gait kinematics and involved in the limitation of seniors' mobility, whether neuromuscular electrical stimulation (NMES) training of these muscles could impact gait kinematics in older adults has not been investigated yet.Research questionWhat are the effects of 12 weeks of ankle plantar and dorsiflexors NMES training on strength and gait kinematics in healthy older adults?MethodsFourteen older adults (73.6 ± 4.9 years) performed a three-time per week, three months long NMES training of both ankle plantar and dorsiflexors. Before and after training, neuromuscular parameters, gait kinematic parameters, and daily physical activity were measured.ResultsThe participants significantly increased their lower limb muscle mass and their plantar and dorsiflexors isometric strength after training. They reduced the hip abduction/adduction and the pelvic anterior tilt range of motion and variability during gait. However, the participants became less active after the training.SignificanceNMES training of ankle muscles, by increasing ankle muscle mass and strength,modified gait kinematics. NMES training of ankle muscles is feasible and effective to lower the hip implication and increment foot progression angle during gait. Further study should determine if this could lower the risk of falling.     

Compensatory sagittal plane ankle gait mechanics: Are they present in patients with a weak or stiff hip?

IntroductionSimulations suggest that subjects with reduced hip range of motion (ROM) and/or weakness can achieve more normal walking mechanics through compensations at the ankle. The aims of this study were to assess whether subjects with reduced hip ROM (Stiff hip) or hip flexor weakness (Weak hip) exhibit ankle compensations during walking and investigate redistribution of power in the lower extremity joints.MethodsRetrospective gait data were reviewed (IRB-approved hip registry). Preoperative kinematic/kinetic walking data were collected in patients with: adolescent hip dysplasia (AHD), femoral acetabular impingement (FAI), and Legg-Calvé Perthes disease (Perthes). AHD patients with significantly weak hip flexors on their affected side were included (Weak hip group). The Gait Profile Score (GPS) was calculated on the affected side of the FAI and Perthes groups to identify patients who had a Stiff hip. Patients who had undergone a hip arthrodesis (Fusion) were also included (Stiff hip group). Ankle kinematics/kinetics were compared to healthy participants (Control). The total positive work of sagittal plane hip, knee and ankle power were compared along with the distribution of power.ResultsPatients in the Weak/Stiff hip groups did not walk with greater ankle plantarflexion, peak push-off power or positive ankle work on their affected sides compared to Control. Ankle work contribution (percentage of total positive work) on the affected or unaffected sides was greater in the Perthes and Hip Fusion patients compared to Control. Significant gait abnormalities on the unaffected side were observed.ConclusionsPatients with a weak or stiff hip did exhibit altered ankle mechanics during walking. Greater percent ankle work contribution appeared to correspond with hip stiffness. In patients with hip pathology the redistribution of power among the lower extremity joints can highlight the importance of preserving ankle function.     

Benefits of multi-session balance and gait training with multi-modal biofeedback in healthy older adults

Real-time balance-relevant biofeedback from a wearable sensor can improve balance in many patient populations, however, it is unknown if balance training with biofeedback has lasting benefits for healthy older adults once training is completed and biofeedback removed. This study was designed to determine if multi-session balance training with and without biofeedback leads to changes in balance performance in healthy older adults; and if changes persist after training. 36 participants (age 60–88) were randomly divided into two groups. Both groups trained on seven stance and gait tasks for 2 consecutive weeks (3×/week) while trunk angular sway and task duration were monitored. One group received real-time multi-modal biofeedback of trunk sway and a control group trained without biofeedback. Training effects were assessed at the last training session, with biofeedback available to the feedback group. Post-training effects (without biofeedback) were assessed immediately after, 1-week, and 1-month post-training. Both groups demonstrated training effects; participants swayed less when standing on foam with eyes closed (EC), maintained tandem-stance EC longer, and completed 8 tandem-steps EC faster and with less sway at the last training session. Changes in sway and duration, indicative of faster walking, were also observed after training for other gait tasks. While changes in walking speed persisted post-training, few other post-training effects were observed. These data suggest there is little added benefit to balance training with biofeedback, beyond training without, in healthy older adults. However, transient use of wearable balance biofeedback systems as balance aides remains beneficial for challenging balance situations and some clinical populations.     

Normative spatiotemporal gait parameters in older adults

While factor analyses have characterized pace, rhythm and variability as factors that explain variance in gait performance in older adults, comprehensive analyses incorporating many gait parameters have not been undertaken and normative data for many of those parameters are lacking. The purposes of this study were to conduct a factor analysis on nearly two dozen spatiotemporal gait parameters and to contribute to the normative database of gait parameters from healthy, able-bodied men and women over the age of 70. Data were extracted from 294 participants enrolled in the Mayo Clinic Study of Aging. Spatiotemporal gait data were obtained as participants completed two walks across a 5.6-m electronic walkway (GAITRite^®). Five primary domains of spatiotemporal gait performance were identified: a “rhythm” domain was characterized by cadence and temporal parameters such as stride time; a “phase” domain was characterized by temporophasic parameters that constitute distinct divisions of the gait cycle; a “variability” domain encompassed gait cycle and step variability parameters; a “pace” domain was characterized by parameters that included gait speed, step length and stride length; and a “base of support” domain was characterized by step width and step width variability. Several domains differed between men and women and differed across age groups. Reference values of 23 gait parameters are presented which researchers or clinicians can use for assessing and interpreting gait dysfunction in aging persons.     

Two-year changes in gait variability in community-living older adults

BackgroundIncreases in stride-to-stride fluctuations (gait variability) are common among older adults, but little is known about the natural progression of gait variability with increasing age.Research questionDoes gait variability change with increasing age in a group of community-living older adults?MethodsThe participants were community-living volunteers between 70–81 years, who were tested with a two-year interval between tests. They walked 6.5 m under four different conditions: At preferred speed, at fast speed, during a dual task condition and on an uneven surface. Trunk accelerations in the anteroposterior (AP), mediolateral (ML) and vertical (V) direction were captured using a body-worn sensor worn at the lower back. Gait variability was estimated using an autocorrelation procedure, where coefficients tending towards 1.0 indicated low variability and 0.0 as high variability. To estimate change, we used an ANOVA-procedure with baseline gait speed as a covariate.ResultsAt baseline, 85 older adults were tested, and data for 56 of these were available for analysis over a two-year period of time. The average age at inclusion was 75.8 years (SD 3.43) and 60% were women. During preferred speed walking, variability increased in the AP direction (mean difference 0.05, p = .038), during fast speed walking it increased in the V direction (mean difference 0.04, p = .037) and during dual task-walking, it increased in the ML and V directions (mean differences 0.03, p = .032 and 0.09, p = .020 respectively).SignificanceThe findings from this study could be helpful for discriminating between normal and pathological progression of gait variability in older adults.     

Effect of augmented plantarflexion power on preferred walking speed and economy in young and older adults

With age, loss of skeletal muscle mass (sarcopenia) results in decreased muscle strength and power. Decreased strength and power, in turn, are closely linked with declines in physical function. Preferred walking speed, a marker of physical function, is slower in older adults compared to young adults. Research suggests that older adults may walk slower as a consequence of decreased plantarflexor power at push-off. In this study, we hypothesized that providing additional plantarflexion (PF) power during push-off would (1) increase preferred walking speed, and (2) reduce metabolic cost of transport (MCOT), in young and older adults. PF power was augmented using powered ankle-foot orthoses (PAFOs). The PAFOs, which use pneumatic actuators to provide an additional PF moment, were based on a design by Ferris et al. [Ferris DP, Czerniecki JM, Hannaford B. An ankle-foot orthosis powered by artificial pneumatic muscles. J Appl Biomech 2005;21:189–97.]. Nine young (23.3 ± 1.6 years) and seven older (74.6 ± 6.6 years) adults participated. For the young adults, eight out of nine increased their preferred walking speed when push-off power was augmented (1.18 ± 0.16 to 1.25 ± 0.16 m/s, p = 0.03). A similar, but non-significant, trend in preferred walking speed was observed for the older adults. With augmented push-off power, MCOT for young adults decreased from 0.395 ± 0.057 to 0.343 ± 0.047 (p = 0.008); indicating that the neuromuscular system was able to adapt to use external energy to reduce metabolic cost. Only three older adults were tested but MCOT values showed a similar trend. Augmenting PF power increases gait speed and reduces MCOT in young adults. Older adults may need a longer period to take advantage of additional push-off power.     

An observational treatment-based gait pattern classification method for targeting interventions for older adult males with mobility problems: Validity based on movement control and biomechanical factors

BackgroundA reliable and valid observational gait assessment intended to guide clinical intervention for gait deficits in older adults has not been proposed. A quick gait classification method which tailors clinical management for different patterns of gait dysfunction may be useful for clinicians with limited access to apply computer-assisted gait analyses.Research QuestionThis work aims to establish reliability and validity of the Treatment-Based Gait Pattern Classification (TBGPC) that can be used to quickly identify and classify mobility problems of older males, and possibly target interventions for specific gait deficits in clinical settings.MethodVideotapes of 116 older male veterans referred for mobility problems were analyzed in this cross-sectional study. The TBGPC defined by movement control (consistent, inconsistent) and postural biomechanical factors (usual, flexed, extended, crouched) was validated by comparing means of individual items of the Modified Gait Abnormality Rating Scale (GARS-M) across groups.ResultsKappas for interrater reliability of the TBGPC movement control and biomechanical components were 0.59 and 0.75, respectively; for intrarater reliability, 0.82 and 0.72, respectively. Both movement control and biomechanical components were validated. All GARS-M items were different between older males with consistent and inconsistent gait. Within the consistent and inconsistent group, hip ROM was one of the most differentiating GARS-M item between older males with usual and flexed gait and flexed and crouched group. Total GARS-M score and guardedness were two differentiating factors between the usual and crouched group.SignificanceGait patterns of older males were reliably recognized and validated by mean differences in abnormal characteristics of gait across patterns. The TBGPC may be useful to quickly identify and classify mobility problems of older males and to guide clinical intervention.     

Sex differences in the regularity and symmetry of gait in older adults with and without knee osteoarthritis

BackgroundThree-dimensional (3D) motion measured at the lower back during walking can describe the regularity and symmetry of gait that may be related to osteoarthritis (OA) and functional status. However, gait speed and inherent sex differences, regardless of the presence of OA, may confound these measures. Therefore, there is a need to understand the effect of OA separately among males and females, without the confounding influence of gait speed.ObjectiveTo investigate the difference in 3D gait regularity and symmetry measures between gait speed-matched males and females with and without knee OA.MethodGait regularity and symmetry were computed as autocorrelations of pelvic accelerations during treadmill walking in four groups of older adults: healthy asymptomatic females (AsymF; n = 44), healthy asymptomatic males (AsymM; n = 45), females diagnosed with knee OA (OAF; n = 44), and males diagnosed with knee OA (OAM; n = 45). Data were obtained from a larger research database, allowing for the matching of gait speed between groups. The main effect of OA, sex, and interaction effect between them was examined for the 3D gait regularity and symmetry measures at an alpha level of 0.05.ResultsThere was no main effect of OA on any variable, but there was a significant main effect of sex on mediolateral and anteroposterior gait regularity measures. Specifically, females demonstrated significantly greater gait regularity, most notably in the mediolateral directions compared to males.ConclusionOlder adult females were found to display significantly greater mediolateral gait regularity as compared to males, regardless of the presence of OA. Further, this difference exists among matched gait speeds, suggesting it is not the result of gait speed. Overall, these results highlight the importance of sex-specific analyses and considering gait speed when examining gait acceleration patterns near the center of mass for both cross sectional and longitudinal gait assessments.     

Head orientation and gait stability in young adults,dancers and older adults

BackgroundControl of body orientation requires head motion detection by the vestibular system and small changes with respect to the gravitational acceleration vector could cause destabilization.Research questionWe aimed to compare the effects of different head orientations on gait stability in young adults, dancers and older adults.MethodsThree groups of 10 subjects were evaluated, the first composed of young adults (aged 18–30 years), the second composed of young healthy dancers under high performance dance training (aged 18–30 years), and the third group composed of community-dwelling older adults (aged 65–80 years). Participants walked on a treadmill at their preferred speed in four distinct head orientation conditions for four minutes each: control (neutral orientation); dynamic yaw (following a target over 45° bilaterally); up (15° neck extension), and down (40° neck flexion). Foot and trunk kinematic data were acquired using a 3D motion capture system and the gait pattern was assessed by basic gait parameters (step length, stride width and corresponding variability) and gait stability (local divergence exponents and margins of stability). Main effects of conditions and groups, as well as their interaction effects, were evaluated by repeated-measures analysis of variance.ResultsInteractions of group and head orientation were found for both step length and stride width variability; main effects of head orientation were found for all evaluated parameters and main effects of group were found for step length and its variability and local divergence exponents in all directions.SignificanceAs expected, the older adults group showed less stable gait (higher local divergence exponent), the shortest step length and greater step length variability. However, contrary to expectation, the dancers were not more stable. The yaw condition was the most challenging for all groups and the down condition seemed to be least challenging.     

Obstacle crossing deficits in older adults: A systematic review

This systematic review and critical evaluation of the literature investigates whether advanced age compromises obstacle crossing for unconstrained and time-constrained conditions. Eight electronic databases were searched for articles with terms relating to obstacle crossing during walking in their title, abstract or keywords. 15 articles were reviewed from an initial yield of 727 articles. The methodological quality of each article was critiqued and data extracted by two reviewers. Young and older adults were shown to contact obstacles infrequently when adequate time was available to adapt foot placement in relation to the obstacle. When less time was available to adjust the foot trajectory, older adults contacted obstacles more often than younger people. Older adults adopted a slower, more conservative obstacle crossing strategy. They demonstrated greater hip flexion during the swing phase of gait for the lead and trail limbs as well as greater hip flexion, hip adduction and ankle dorsiflexion during the stance phase for the lead and trail limbs. There was also evidence of reduced internal moments across the hip and ankle during key events in the obstacle crossing gait cycle in older adults. Despite using a more conservative obstacle crossing strategy, older adults are at greater risk of contacting obstacles for time-constrained conditions.     

Trunk sway reductions in young and older adults using multi-modal biofeedback

This study investigated whether real-time biofeedback of angular trunk displacement could alter balance performance among healthy older and young adults. Healthy community-dwelling older adults (n = 32) and healthy young adults (n = 32) were included in the randomized control trial study. The intervention group received combined vibrotactile, auditory and visual biofeedback of angular trunk displacement in real-time during training on a battery of static and dynamic balance tasks and during the subsequent post-training balance re-assessment. The control group received balance training and were re-assessed in the absence of real-time biofeedback of their trunk displacement. The 90% range of angular trunk displacement was calculated for each balance task pre- and post-training. Significant age-related differences were observed independent of the intervention. Biofeedback intervention significantly changed the angular displacement of the trunk for both young and older participants on a number of balance tasks compared to control treatment (40–60% reduction in angular displacement). In some cases, biofeedback influenced balance in older adults, but not younger adults.     

Effects of gender on dual-tasking and prioritization in older adults

BackgroundThe ability to produce effective posture and balance while distracted (dual-tasking; DT), is critical for mobility. In particular, individuals implicit prioritization across posture and secondary, distracting stimuli may impact fall risk. However, the impact of gender on DT and prioritization during gait is poorly understood.Research questionDoes gender impact DT effects or prioritization while DT walking?MethodsOne hundred older adults participated. The timed up and go (TUG) was completed with and without a secondary cognitive task (counting backwards by 3′s). Gait (time to complete the TUG), and cognitive (rate of correct numbers listed) performance was recorded during both single tasks and while dual-tasking. DT effects were calculated for cognitive and gait performance. Prioritization was calculated as the difference between cognitive and gait DT effects. The effect of gender on DT and prioritization was assessed, controlling for age and cognitive ability.ResultsGender by condition (single vs. dual-task) interaction effects were observed (Gait: F_1,96 =8.7; p = 0.004; Cognition: F_1,96 =5.2; p = 0.024) such that, compared to male participants, females exhibited smaller cognitive DT effects, and larger gait DT effects. Further, females exhibited significantly larger prioritization scores (F_1,95 =10.0, p = 0.002), indicating a cognitive prioritization compared to males.SignificanceGiven the link between posture-second strategies and falls, the current findings may provide some insight into previous results suggesting an increased fall-risk in older-adult women. However, this study did not investigate falls. Therefore, additional work is necessary to confirm current findings and further investigate the relationship between gender, prioritization, and falls; and its possible clinical relevance.     

Accelerometer-based determination of gait variability in older adults with knee osteoarthritis

Knee osteoarthritis (KOA) can affect the spatiotemporal (ST) aspects of gait as well as the variability of select ST parameters based on standard linear measures of variability (e.g., standard deviation (SD) and coefficient of variation). Non-linear measures (e.g., fractal scaling index (FSI) and sample entropy) can be more sensitive to changes in gait variability, and have been used to quantify differences in the stride patterns of patients with Parkinson’s disease and the motion of ACL-deficient knees. However, the effect of KOA on the dynamic complexity of the stride pattern has not been investigated. Therefore, the purpose of this study was to investigate the effect of KOA on gait variability (linear and non-linear measures) in a group of older adults, and to compare these results to a healthy control group. Participants walked for 10 min with a tri-axial accelerometer placed at the lower back. Mean and SDs of stride time and step time as well as the FSI for the entire series of stride times were calculated for each participant. Participants with KOA had significantly greater mean stride time (p = 0.031) and step time (p = 0.024) than control group participants. While stride and step time variability (SD) were greater in the KOA group, the differences were not significant, nor was the difference in the FSI. Low statistical power (β = 0.40 and 0.30 for stride and step time SD, respectively) combined with the confounding effects of walking speed and heterogeneous KOA severity likely prevented significant differences from being found.     

Changes in gait while backward counting in demented older adults with frontal lobe dysfunction

BACKGROUND: Gait disorders caused by dementia have been associated with frontal lobe dysfunction. Dual-tasking is used to explore the involvement of cortical level in gait control. It has been shown that dual-task induced gait changes that could be related to (1) the efficiency of executive function, (2) the level of difficulty involved in the walking-associated task, or (3) the articulo-motor components comprised in the walking-associated task. A better understanding of dual-task related changes in demented subjects with frontal lobe dysfunction could help us to clarify the role of the frontal lobe in motor gait control. OBJECTIVE: To assess and compare the effects of two mental arithmetic tasks involving similar articulo-motor components but different level of difficulty on the mean values and coefficient of variation (CV) of stride time among demented older adults with impaired executive function. METHODS: The mean values and coefficients of variation of stride time were measured using a GAITRite-System among 16 demented older adults with impaired executive function while walking with and without forward counting (FC) and backward counting (BC). RESULTS: The mean values and CV of stride time were significantly higher under both dual-task conditions than during a simple walking task (p<0.05). The change in CV of stride time during BC was significantly higher when compared with the change during FC (p=0.015), whereas the change in mean value was not significant (p=0.056). There was no difference between the dual-task and single task condition as far the number of enumerated figures were concerned (p=0.678 for FC and p=0.069 for BC), but significantly fewer figures were enumerated while BC compared with FC (p<0.001). CONCLUSION: BC provoked more changes in gait parameters than FC with major modification in gait variability related to an inappropriate focusing of attention. These findings suggest that the CV may be a suitable criterion for the assessment of gait control.     

Backward relative to forward walking speed and falls in older adults with dementia

BackgroundAdults with dementia have a high risk of falls and fall-related injuries. A greater slowing of backward walking speed (BWS) relative to forward (FWS) has been indicated with older age, and slower BWS has been related to an increased risk of falls. Similarly, slow BWS relative to FWS has been observed in people with dementia.Research questionIs slower BWS, and slower BWS relative to FWS associated with increased risk of prospective falls in older adults with dementia?MethodsIn total, 52 women and 12 men with dementia living in nursing homes, mean age 86 years, and mean Mini-Mental State Examination score of 14.2 points were included. BWS and FWS was measured over 2.4 m, and the directional difference (DD) calculated (100*((FWS-BWS)/FWS)). Falls were followed for 6 months by review of fall incident reports in electronic medical records at nursing homes and the regional healthcare provider.ResultsAltogether, 95 falls occurred with mean incidence rate 3.1 falls per person-years. Of included participants, 15 (23%) fell once, and 17 (27%) fell twice or more. In negative binomial regression analyses, greater DD was associated with lower prospective incidence fall rate ratio, IRR (IRR= 0.96, p < .001), while BWS was not (IRR= 0.04, p = .126).SignificanceIn this study of adults with dementia, slower BWS was not associated with prospective falls. However, slower BWS relative to forward (greater DD) was associated with fewer falls, and possibly a protective response. This is novel research, yet results are promising and indicate that assessing walking speed in multiple directions may inform fall risk in adults with dementia.     

Ankle muscle coactivation during gait is decreased immediately after anterior weight shift practice in adults after stroke

Increased ankle muscle coactivation during gait has frequently been observed as an adaptation strategy to compensate for postural instability in adults after stroke. However, it remains unclear whether the muscle coactivation pattern increases or decreases after balance training. The aim of this study was to investigate the immediate effects of balance practice on ankle muscle coactivation during gait in adults after stroke. Standing balance practice performed to shift as much weight anteriorly as possible in 24 participants after stroke. The forward movement distance of the center of pressure (COP) during anterior weight shifting, gait speed, and ankle muscle activities during 10-m walking tests were measured immediately before and after balance practice. Forward movement of the COP during anterior weight shifting and gait speed significantly increased after balance practice. On the paretic side, tibialis anterior muscle activity significantly decreased during the single support and second double support phases, and the coactivation index at the ankle joint during the first double support and single support phases significantly decreased after balance practice. However, there were no significant relationships between the changes in gait speed, forward movement of the COP during anterior weight shifting, and ankle muscle coactivation during the stance phase. These results suggested that ankle muscle coactivation on the paretic side during the stance phase was decreased immediately after short-term anterior weight shift practice, which was not associated with improved gait speed or forward movement of the COP during anterior weight shifting in adults after stroke.     

Effects of dual task on turning ability in stroke survivors and older adults

BackgroundTurning is an integral component of independent mobility in which stroke survivors frequently fall.ObjectiveThis study sought to measure the effects of competing cognitive demands on the stepping patterns of stroke survivors, compared to healthy age-match adults, during turning as a putative mechanism for falls.MethodsWalking and turning (90°) was assessed under single (walking and turning alone) and dual task (subtracting serial 3 s while walking and turning) conditions using an electronic, pressure-sensitive walkway. Dependent measures were time to turn, variability in time to turn, step length, step width and single support time during three steps of the turn. Turning ability in single and dual task conditions was compared between stroke survivors (n = 17, mean ± SD: 59 ± 113 months post-stroke, 64 ± 10 years of age) and age-matched healthy counterparts (n = 15).ResultsBoth groups took longer, were more variable, tended to widen the second step and, crucially, increased single support time on the inside leg of the turn while turning and distracted.ConclusionsIncreased single support time during turning may represent biomechanical mechanism, within stepping patterns of turning under distraction, for increased risk of falls for both stroke survivors and older adults.