Effect of a gentle Iyengar yoga program on gait in the elderly: an exploratory study

OBJECTIVE: To determine if a tailored yoga program could improve age-related changes in hip extension, stride length, and associated indices of gait function in healthy elders, changes that have been linked to increased risk for falls, dependency, and mortality in geriatric populations. DESIGN: Single group pre-post test exploratory study. A 3-dimensional quantitative gait evaluation, including kinematic and kinetic measurements, was performed pre- and postintervention. Changes over time (baseline to postintervention) in primary and secondary outcome variables were assessed using repeated-measures analysis of variance. SETTING: Yoga exercises were performed in an academic medical center (group classes) and in the subjects' homes (yoga home-practice assignments). Pre- and postassessments were performed in a gait laboratory. PARTICIPANTS: Twenty-three healthy adults (age range, 62-83 y) who were naive to yoga were recruited; 19 participants completed the program. INTERVENTION: An 8-week Iyengar Hatha yoga program specifically tailored to elderly persons and designed to improve lower-body strength and flexibility. Participants attended two 90-minute yoga classes per week, and were asked to complete at least 20 minutes of directed home practice on alternate days. MAIN OUTCOME MEASURES: Peak hip extension, average anterior pelvic tilt, and stride length at comfortable walking speed. RESULTS: Peak hip extension and stride length significantly increased (F1,18=15.44, P<.001; F1,18=5.57, P=.03, respectively). We also observed a trend toward reduced average pelvic tilt (F1,18=4.10, P=.06); adjusting for the modifying influence of frequency of home yoga practice strengthened the significance of this association (adjusted F1,17=14.30, P=.001). Both the frequency and duration of yoga home practice showed a strong, linear, dose-response relationship to changes in hip extension and average pelvic tilt. CONCLUSIONS: Findings of this exploratory study suggest that yoga practice may improve hip extension, increase stride length, and decrease anterior pelvic tilt in healthy elders, and that yoga programs tailored to elderly adults may offer a cost-effective means of preventing or reducing age-related changes in these indices of gait function.     

踝足矫形器对偏瘫患者步行速度的影响

目的：了解踝足矫形器（ａｎｋｌｅ－ｆｏｏｔ ｏｒｔｈｏｓｉｓ,ＡＦＯ）对偏瘫患者步行速度的影响。方法：３０例偏瘫患者在步态分析实验分别穿鞋和赤足行走两次,用摄像机录下患者的步行过程,用运动动态分析软件进行数据分析。结果：不穿ＡＦＯ者穿鞋和赤足的步行速度无显著性差异（Ｐ〉０．０５）;不穿ＡＦＯ者穿鞋与穿ＡＦＯ者穿鞋加ＡＦＯ时步行速度无显著性差异（Ｐ〉０．０５）;不穿ＡＦＯ者与穿ＡＦＯ者赤足时步行速度     

Maintenance of aquatic training-induced benefits on mobility and lower-extremity muscles among persons with unilateral knee replacement

Valtonen A, Pöyhönen T, Sipilä S, Heinonen A. Maintenance of aquatic training-induced benefits on mobility and lower-extremity muscles among persons with unilateral knee replacement.

Objective

To evaluate the maintenance of observed aquatic training-induced benefits at 12-month follow-up.

Design

Twelve-month follow-up of a randomized controlled study.

Setting

Research laboratory and hospital rehabilitation pool.

Participants

Population-based sample of 55 to 75-year-old women and men 4 to 18 months (on average 10mo) after unilateral knee replacement. Fifty people were willing to participate in the exercise trial and 42 people in the follow-up study.

Intervention

Twelve-month follow-up of 12-week progressive aquatic resistance training, or no intervention.

Main Outcome Measures

Isokinetic knee extensor and flexor power, thigh muscle cross-sectional area (CSA), habitual walking speed, stair ascending time, and sit-to-stand test.

Results

After a 12-month follow-up, a 32% (95% confidence interval [CI], 10–53) training effect in knee extensor power (P=.008) and 50% (95% CI, 9–90) in knee flexor power (P=.005) of the operated knee remained. In muscle CSA, the training-induced benefit had disappeared at the follow-up. All the significant 12-week improvements in habitual walking speed, stair ascending time, and sit-to-stand in the training group compared with controls were lost at follow-up.

Conclusions

After the 12-month follow-up, the 12-week aquatic training-induced benefits in knee extensor and flexor power were maintained, whereas the mobility benefits had disappeared. Aquatic resistance training should be continued at least on some level to maintain the training-induced benefits in mobility.     

Comparative effect of walking meditation and rubber-band exercise on ankle proprioception and balance performance among persons with chronic ankle instability: A randomized controlled trial

BackgroundAnkle proprioception and balance impairments are usual consequences of chronic ankle instability (CAI). The impairments affect functional and sport activities and can lead to recurrent ankle sprain. Mind-body practice is claimed to improve ankle proprioception and balance.ObjectiveTo investigate the effects of walking meditation, a mind-body practice, and compare it with the rubber-band exercise on ankle proprioception and balance among individuals with CAI.Study designA randomized controlled trial.MethodsThirty-two participants with CAI aged 20.3 ± 1.8 years were randomized into three groups; 1) walking meditation (WM, n = 10), 2) Rubber-band exercise (RE, n = 11) and 3) control (n = 11). WM and RE were enrolled on a 4-week training regimen (30 min/day, 3 days/week). Before and after the training, ankle proprioception was evaluated by angular error of the ankle reposition test (AEA) at three positions, randomly, i.e., plantarflexion-5°, plantarflexion-10° and dorsiflexion-5°. Balance performance was assessed by the star excursion balance test (SEBT).ResultsAs adjusted by pre-training baseline, no significant difference in AEA and SEBT was found among three groups. However, after training, only the WM group revealed a significant decrease in AEA at plantarflexion-5° (p = 0.007) and plantarflexion-10° (p = 0.04) compared to the baseline. For SEBT, the WM and RE groups showed significant improvements compared to the baseline in 4 directions each (p < 0.05), while the control group improved only 2 directions (p < 0.05).ConclusionsWM and RE groups significantly improved SEBT after 4-week training when compared to before training. Additionally, WM group also improved ankle proprioception. Therefore, WM demonstrates feasibility as a promising intervention that could be applied for balance and ankle proprioceptive rehabilitations in persons with CAI.     

The influence of ankle-foot orthosis stiffness on walking performance in individuals with lower-limb impairments

Background

Passive-dynamic ankle-foot orthoses utilize stiffness to improve gait performance through elastic energy storage and return. However, the influence of ankle-foot orthosis stiffness on gait performance has not been systematically investigated, largely due to the difficulty of manufacturing devices with precisely controlled stiffness levels. Additive manufacturing techniques such as selective laser sintering have been used to successfully manufacture ankle-foot orthoses with controlled stiffness levels. The purpose of this study was to use passive-dynamic ankle-foot orthoses manufactured with selective laser sintering to identify the influence of orthosis stiffness on walking performance in patients with lower-limb neuromuscular and musculoskeletal impairments.

Methods

Thirteen subjects with unilateral impairments were enrolled in this study. For each subject, one passive-dynamic ankle-foot orthosis with stiffness equivalent to the subject's clinically prescribed carbon fiber orthosis, one 20% more compliant and one 20% more stiff, were manufactured using selective laser sintering. Three-dimensional kinematic and kinetic data and electromyographic data were collected from each subject while they walked overground with each orthosis at their self-selected velocity and a controlled velocity.

Findings

As the orthosis stiffness decreased, ankle range of motion and medial gastrocnemius activity increased while the knee became more extended throughout stance. Minimal changes in other kinematic, kinetic and electromyographic quantities were observed.

Interpretation

Subjects effectively compensated for changes in ankle-foot orthosis stiffness with altered gastrocnemius activity, and the stiffness levels analyzed in this study had a minimal effect on overall walking performance.     

Lower extremity physical performance, self-reported mobility difficulty, and use of compensatory strategies for mobility by elderly women

Ganesh SP, Fried LP, Taylor DH Jr, Pieper CF, Hoenig HM. Lower extremity physical performance, self-reported mobility difficulty, and use of compensatory strategies for mobility by elderly women.

Objective

To describe the relationship between lower extremity physical performance, self-reported mobility difficulty, and self-reported use of compensatory strategies (CSs) for mobility inside the home.

Design

Cross-sectional exploratory study.

Setting

Community-dwelling elders.

Participants

Disabled, cognitively intact women 65 years or older (N=1002), from the Women's Health and Aging Study I.

Interventions

Not applicable.

Main Outcome Measures

CS scale: no CS, behavioral modifications (BMs) only, durable medical equipment (DME) with or without use of BMs, and any use of human help (HH); and 3 dichotomous CS measures: any CS (vs none); DME+HH (vs BMs only, among users of any CS); any HH (vs DME only, among users of any DME/HH).

Results

Self-reported mobility difficulty and physical performance were significantly correlated with one another (r=−.57, P<.0001) and with the CS scale ([r=.51, P<.001] and [r=−.54, P<.0001], respectively). Sequential logistic regressions showed self-reported difficulty and physical performance were significant independent predictors of each category of CS. For the any CS and DME+HH models, the odds ratio for self-reported difficulty decreased by approximately 50% when physical performance was included in the model, compared with difficulty alone ([18.0 to 8.6] and [7.3 to 3.8], respectively), but both physical performance and difficulty remained significant predictors (P<.0001). The effects of covariates differed for the various CS categories, with some covariates having independent relationships to CS, and others appearing to have moderating or mediating effects on the relationship of self-reported difficulty or physical performance to CS.

Conclusions

Physical performance, self-reported difficulty, health conditions, and contextual factors have complex effects on the way elders carry out mobility inside the home.     

老年患者非骨水泥固定型全髋关节置换术后早期负重锻炼的效果

目的探讨老年患者非骨水泥固定型全髋关节置换(THA)术后早期负重锻炼的可行性及效果.方法将48例(52髋)60岁以上非骨水泥固定型THA术患者随机分为两组,实验组23例(25髋),术后第1天即下地完全负重行走,并依据THA术后功能锻炼程序进行系统练习;对照组25例(27髋),按传统方法于术后第3周开始部分负重,至术后6周完全负重.两组于术后12周和术后2年分别进行临床和X线摄片评价.结果术后12周实验组Harris评分与对照组比较差异有显著性(t＝4.57,P<0.01),术后2年两组在临床效果和X线摄片评价方面无显著性差异.结论老年患者非骨水泥固定型THA术后早期负重锻炼是安全有效的.     

运动锻炼对老年人抑郁程度的影响

目的探讨运动锻炼对老年人抑郁程度的影响。方法采用问卷调查方法,对上海市杨浦区60岁及60岁以上的1000位老年人进行问卷调查,对老年人运动锻炼情况及抑郁程度进行调查。结果老年人中经常运动的只占52.6%;不经常运动的老年人抑郁等级高于经常运动的老年人(χ2=71.427,P<0.01)。不经常运动的老年人抑郁量表的平均分[(10.02±6.65)分]高于经常运动[(6.48±3.96)分]的老年人,差异有统计学意义(t=-9.729,P<0.01)。结论运动锻炼能够降低老年人抑郁程度,应鼓励老年人多参加运动。     

A pilot study of mindful walking training on physical activity and health outcomes among adults with inadequate activity

IntroductionMindful walking is a meditation practice that combines physical activity and mindfulness practice. Some mindful walking interventions expect four weeks of attendance (as compared with the traditional 8-week models of mindfulness-based interventions, or MBIs), a practice that could make MBIs more accessible to working-age adults. This study examined whether a 4-week mindful walking intervention increased physical activity and improved mental health outcomes.MethodsWe conducted a randomized experiment among adults with inadequate physical activity (N = 38), whereby the intervention group received a four-week, one-hour-per-week mindful walking intervention and the control group received instructions to increase physical activity. Everyone in both groups received a wrist-worn step count device as participation incentive. Physical activity (as measured by the Rapid Assessment of Physical Activity questionnaire, RAPA) and other health outcomes were assessed with online surveys at baseline (T1), post-intervention (T2), and one month after the intervention (T3). Those mental health outcomes included perceived stress (Perceived Stress Scale), depression (Brief Edinburgh Depression Scale), and Mental Health Inventory (MHI). The primary outcome of device-measured step count was recorded at T1 and T2. Independent two-sample t-tests were used to compare the primary outcomes at T1. Generalized linear mixed models (GLMM) with a random intercept for each subject were used to compare the two groups on the primary outcomes at all time points. The independent variables in the model included a binary variable for group assignment (intervention vs. control), a 3-level categorical variable for time, and their interaction. Age, gender and race/ethnicity are used as covariates in the model. Estimated changes (either differences or ratios between outcomes at time points T1 and T2/T3) are reported to assess change within groups.ResultsBoth groups exhibited significant improvements in the RAPA measures of physical activity and depression. However, between-group differences were not statistically significant. There was no within-group or between-group difference on device-measured step count, though both groups yielded an average daily step count close to the recommended level of 8,000 steps per day for older adults. The intervention group exhibited a significant reduction in perceived stress, and this reduction was significantly greater than that of the control group at T2 (p = .025) although the difference was insignificant at T3. No significant difference in MHI was found.DiscussionWhile these adults with inadequate physical activity increased their physical activity, no significant between-group differences in physical activity were identified. Potential reasons for the lack of significant findings could be due to the ceiling effect (the step count device for everyone in both groups might have encouraged more activity in both groups), limited sample size and low-dose 4-week intervention used in this study. On the other hand, it is encouraging to see that this low-dose, short-duration 4-week intervention (as compared with those popular 8-week MBIs) achieved significantly greater stress reduction among the intervention group than among the control group, even though the between-group difference at one-month follow-up was statistically insignificant. Further studies with larger sample sizes and longer follow-up are needed to assess the possible benefits of these short-duration mindful walking interventions.     

The effect of custom-made braces for the ankle and hindfoot on ankle and foot kinematics and ground reaction forces

OBJECTIVE: To assess the effects on gait of custom-made polypropylene orthoses: ankle-foot orthosis (AFO), rigid hindfoot orthosis (HFO-R), and articulated hindfoot orthosis (HFO-A). DESIGN: Experimental assessment. SETTING: Institutional practice, motion analysis laboratory. PARTICIPANTS: Twenty asymptomatic normative subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Three-dimensional kinematics, ground reaction force, and time-related factors in 4 conditions: shoe only, and shod with the AFO, HFO-R, and HFO-A. RESULTS: The AFO and HFO-R limited sagittal and coronal plane ankle-hindfoot motion. The HFO-A limited hindfoot coronal motion while allowing normal sagittal motion. At the midfoot, the AFO and HFO-A limited transverse motion, but the HFO-A also limited sagittal and coronal motion. Use of the HFO-R resulted in exaggerated midfoot sagittal and coronal motion. Braces that limited motion to a greater degree were associated with more atypical kinetic variables, indicative of less dynamic gait. The HFO-A resulted in ground reaction forces most similar to unbraced conditions. CONCLUSIONS: Alteration in gait was affected by orthosis design. Orthoses with a rigid component crossing a joint restricted motion at that joint, but potentially compromised typical gait kinetic factors. For immobilizing the hindfoot, the HFO-A may be more comfortable and still provide more stability than the HFO-R or AFO.     

综合康复训练在步行痉挛型脑瘫患儿中的应用效果

目的 探讨综合康复训练在步行痉挛型脑瘫患儿中的应用效果。 方法 选取我院收治的118例步行痉挛型脑瘫患儿为研究对象,按随机数字表法将其分为对照组57例和研究组61例。对照组采取责任制整体护理,研究组在对照组基础上给予综合康复训练。比较2组综合痉挛量表(compopsites pasticity scale,CSS)评分、踝关节活动度、10m 步行测试(10 meters walk test,10mWT)时间和步数、Berg平衡量表(Berg balance scale,BBS)评分、三维步态时空参数和下肢表面肌电水平。 结果 干预后,研究组CSS评分、踝关节活动度、10mWT时间和步数均低于对照组(P＜0.05);BBS评分高于对照组(P＜0.001);三维步态时空参数中,研究组支撑相、双支撑相水平低于对照组(P＜0.001),摆动相、步长、步幅高于对照组(P＜0.001);研究组下肢肌电水平好于对照组(P＜0.05)。 结论 综合康复训练可有效缓解步行痉挛型脑瘫患儿肢体痉挛,改善患儿步态与下肢表面肌电参数,提高其步行能力及运动功能,值得在临床推广应用。     

The effects of hip and ankle stretching on gait function of older people

Christiansen CL. The effects of hip and ankle stretching on gait function of older people.

Objective

To examine effects of hip and ankle stretching on gait function of older people.

Design

Randomized controlled trial.

Setting

Flexibility training was performed in participants' homes. Assessments were performed in a biomechanics laboratory.

Participants

Forty healthy volunteers (mean age ± SD, 72.1±4.7y) randomized to 2 groups: intervention (n=20) and control (n=20).

Intervention

Intervention participants performed an 8-week stretching program, and control group participants maintained activity level for 8 weeks. One investigator made weekly visits to instruct and monitor participants.

Main Outcome Measures

Primary outcome measures were passive joint motion for hip extension and ankle dorsiflexion and freely chosen gait speed. Secondary outcome measures were gait parameters during freely chosen gait speed and set gait speed walking (stride length, joint displacement).

Results

Compared with the control group, the intervention group had increased combined hip and knee motion (P=.023), ankle motion (P=.020), and freely chosen gait speed (P=.016). The intervention group showed statistically nonsignificant trends of increased stride length at freely chosen gait speed and set gait speed.

Conclusions

Findings suggest joint motion is a modifiable impairment that is effectively targeted with flexibility training for older people. Participants in the intervention group had improvements in joint motion as well as increased freely chosen gait speed. Mechanisms responsible for changes in freely chosen gait speed warrant further investigation.     

A randomized controlled trial of an implantable 2-channel peroneal nerve stimulator on walking speed and activity in poststroke hemiplegia

OBJECTIVE: To determine the effect of a new implantable 2-channel peroneal nerve stimulator on walking speed and daily activities, in comparison with the usual treatment in chronic stroke survivors with a drop foot. DESIGN: Randomized controlled trial. SETTING: All subjects were measured 5 times in the gait laboratory. PARTICIPANTS: Twenty-nine stroke survivors with chronic hemiplegia with drop foot who fulfill the predefined inclusion and exclusion criteria were included in the study. INTERVENTION: The intervention group received an implantable 2-channel peroneal nerve stimulator for correction of their drop foot. The control group continued using their conventional walking device, consisting of an ankle-foot orthosis, orthopedic shoes, or no device. MAIN OUTCOME MEASURES: Walking speed, assessed both by a six-minute walk test (6MWT) and by using a 10-m walkway, was selected as primary outcome measure and activity monitoring data, consisting of percentage time spent on stepping, standing, and sitting/lying were selected as secondary outcome measure. RESULTS: Functional electric stimulation (FES) resulted in a 23% improvement of walking speed measured with the 6MWT, whereas the improvement in the control group was only 3% (P=.010). Comfortable walking speed measured on a 10-m walkway was also significantly improved in favor of FES (P=.038). The percentage time spent on stepping deteriorated with 3% in the intervention and 0.8% in control group, which was not statistically significant between both groups (P=.13). CONCLUSIONS: The present study shows a clinically relevant effect of the implantable 2-channel peroneal nerve stimulator on walking speed in the sample of stroke survivors included in our study.     

The reliability and validity of the physiological cost index in healthy subjects while walking on 2 different tracks

OBJECTIVE: To investigate the reliability and validity of the Physiological Cost Index (PCI) scores, as a measure of energy expenditure, when healthy subjects walk on 2 different tracks (20-m and 12-m figure eight tracks). DESIGN: Intra- and interrater reliability and construct validity. SETTING: Physiotherapy division of a university in London, UK. PARTICIPANTS: Forty healthy subjects (15 men, 25 women; mean age +/- standard deviation, 34.5+/-12.6 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Heart rate (in beats/min) and speed (in m/min) were used to calculate the PCI (in beats/m). Rate of oxygen consumption (VO2, in mL x kg(-1) x min(-1)) and oxygen cost (EO2, in mL x kg(-1) x m(-1)) were used as criterion estimates of energy cost EO2. Pearson correlation coefficients between the PCI, components of the PCI, EO2, and VO2 were used to quantify validity. Intrarater reliability was assessed in all participants and interrater reliability was assessed on a subset of 13 subjects using intraclass correlation coefficients and Bland-Altman plots. RESULTS: Intrarater (r=.73, r=.79) and interrater (r=.62, r=.66) reliability were acceptable between PCI scores from 20-m and 12-m tracks, respectively. Correlations between VO2 and EO2 with PCI were weak. PCI scores from the 20-m track were significantly lower than those on the 12-m track (P=.002). Subjects walked significantly faster on the 20-m track (P<.001). Results suggest a large difference in PCI scores would be necessary to indicate a "true" alteration in performance (52% for 20-m track, 43.4% for the 12-m track). CONCLUSIONS: The PCI is reliable but not valid as a measure of the energy cost of walking in healthy subjects, on either track. The 20-m track is recommended for clinical use because it enables subjects to walk at a faster pace.     

The effect of cold-water immersion on physical performance

Cold modalities are widely used after athletic injuries, with known physiological effects. The aim of this study was to determine the effects of cold-water immersion on physical performance.Thirty healthy volunteers (average age of 19–23 years) took part in this pre-post interventional study. First, participants performed two tasks: a 40-yard dash run (to measure speed) and a vertical jump (to measure lower limb power). Then, both legs were immersed in a water bath at 5 °C for 15 min. Following cold-water immersion, the measurements were repeated after 2, 5, 10, 15, 20, 25 and 30 min.Immediately (2 min) after cold-water immersion, there was a decline in both the vertical jump and 40-yard dash tests compared to pre-intervention scores. While this effect lasted up to 20 min after cryotherapy for the 40-yard dash test, for the jump test, the effect only remained up to 10 min.The results showed a decrease in physical performance immediately and 20 min after immersion in cold water (p < 0.05). In addition, there was a gradual increase in the level of physical function over time. Therefore, before returning athletes to activity after the use of cold modalities, care should be taken.     

The effect of cognitive dual tasks on balance during walking in physically fit elderly people

OBJECTIVE: To evaluate the effect on balance of 3 different cognitive dual tasks performed while walking without and with standardization for gait velocity, and measured with both foot placements and trunk movements. DESIGN: Cross-sectional study. SETTING: Community. PARTICIPANTS: Fifty-nine physically fit elderly people (mean age, 73.5y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Stride length and time variability measured with an electronic walkway, body sway measured with an angular velocity instrument, and gait velocity. RESULTS: Overall, dual tasks resulted in decreased gait velocity (1.46 to 1.23m/s, P<.001), increased stride length (1.4% to 2.6%), and time variability (1.3% to 2.3%) (P<.001), and had no significant effect on body sway. After standardization for gait velocity, the dual tasks were associated with increased body sway (111% to 216% of values during walking without dual task, P<.001) and increased stride length and time variability (41% to 223% increase, P<.001). CONCLUSIONS: In physically fit elderly people, cognitive dual tasks influence balance control during walking directly as well as indirectly through decreased gait velocity. Dual tasks increase stride variability with both mechanisms, but the increase in body sway is only visible after standardization for gait velocity. The decreased gait velocity can be a strategy with which to maintain balance during walking in more difficult circumstances.     

The effects of added prosthetic mass on physiologic responses and stride frequency during multiple speeds of walking in persons with transtibial amputation

OBJECTIVES: To determine the effect of 3 prosthetic mass conditions on selected physiologic responses during multiple speed treadmill walking in persons with transtibial amputation. DESIGN: A repeated-measures design for 3 prosthetic mass conditions and 5 walking speeds. SETTING: University research laboratory. PARTICIPANTS: Eight ambulatory men with unilateral traumatic transtibial amputation. INTERVENTIONS: The 3 prosthetic mass conditions were 60%, 80%, and 100% of the estimated intact limb below-knee mass. The multiple-speed treadmill walking test (4min at each speed: 54, 67, 80, 94, 107m/min) was performed on an instrumented treadmill according to randomly assigned mass conditions. MAIN OUTCOME MEASURES: Oxygen consumption, gait efficiency, relative exercise intensity (percentage of age-predicted maximal heart rate), and stride frequency. RESULTS: Prosthetic mass did not significantly alter oxygen consumption or gait efficiency (P>.05). From the 60% to the 100% prosthetic mass conditions, relative exercise intensity significantly increased and stride frequency significantly decreased (P<.05). CONCLUSIONS: A heavier prosthesis (up to 100% of estimated intact limb below-knee mass) did not significantly increase the energy costs of walking for the 5 speeds examined. Further study of gait symmetry with the use of a heavier prosthesis is warranted.     

The effect of a dual-task on obstacle crossing in healthy elderly and young adults

OBJECTIVE: To investigate the effect of a dual-task on step initiation over an obstacle. DESIGN: Repeated-measures design between groups. SETTING: University laboratory. PARTICIPANTS: Ten healthy, community-dwelling elderly adults and 10 healthy young adults. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The effect of a reaction time task on ground reaction forces, toe clearance, and temporal events in stepping over an obstacle. RESULTS: Ground reaction forces of the swing limb before toe-off did not differ between the groups and was not affected by task difficulty. Stepping with a random stimulus after toe-off was the most difficult task, whereas stepping with a predictable stimulus before toe-off was the easiest task. Reaction time and stepping time were greater and toe clearance was less for the elderly subjects. Both groups had a decrease in toe clearance and an increase in reaction time and stepping time as the task became more difficult. CONCLUSIONS: Our findings indicate that even healthy older adults may be at risk for falls in situations where they are engaged in concurrent tasks. The data support the inclusion of dual-task activities in fall prevention programs.