Voluntary Step Execution Research Articles

Examining Different Motor Learning Paradigms for Improving Balance Recovery Abilities Among Older Adults, Random vs. Block Training—Study Protocol of a Randomized Non-inferiority Controlled Trial

Introduction: Falls are the leading cause of fatal and nonfatal injuries among older adults. Studies showed that older adults can reduce the risk of falls after participation in an unexpected perturbation-based balance training (PBBT), a relatively novel approach that challenged reactive balance control. This study aims to investigate the effect of the practice schedule (i.e., contextual interference) on reactive balance function and its transfer to proactive balance function (i.e., voluntary step execution test and Berg balance test). Our primary hypothesis is that improvements in reactive balance control following block PBBT will be not inferior to the improvements following random PBBT.Methods and Analysis: This is a double-blind randomized controlled trial. Fifty community-dwelling older adults (over 70 years) will be recruited and randomly allocated to a random PBBT group (n = 25) or a block PBBT group (n = 25). The random PBBT group will receive eight training sessions over 4 weeks that include unexpected machine-induced perturbations of balance during hands-free treadmill walking. The block PBBT group will be trained by the same perturbation treadmill system, but only one direction will be trained in each training session, and the direction of the external perturbations will be announced. Both PBBT groups (random PBBT and block PBBT) will receive a similar perturbation intensity during training (which will be customized to participant’s abilities), the same training period, and the same concurrent cognitive tasks during training. The generalization and transfer of learning effects will be measured by assessing the reactive and proactive balance control during standing and walking before and after 1 month of PBBT, for example, step and multiple steps and fall thresholds, Berg balance test, and fear of falls. The dependent variable will be rank transformed prior to conducting the analysis of covariance (ANCOVA) to allow for nonparametric analysis.Discussion: This research will explore which of the balance retraining paradigms is more effective to improve reactive balance and proactive balance control in older adults (random PBBT vs. block PBBT) over 1 month. The research will address key issues concerning balance retraining: older adults’ neuromotor capacities to optimize training responses and their applicability to real-life challenges.Clinical Trial Registration: Helsinki research ethics approval has been received (Soroka Medical Center approval #0396-16-SOR; MOH_2018-07-22_003536; www.ClinicalTrials.gov, NCT04455607).

The Effects of Bicycle Simulator Training on Anticipatory and Compensatory Postural Control in Older Adults: Study Protocol for a Single-Blind Randomized Controlled Trial.

Background: Falls are the leading cause of fatal and non-fatal injuries among older adults. Perturbation-Based-Balance Training (PBBT) is a promising approach to reduce fall rates by improving reactive balance responses. PBBT programs are designed for older adults who are able to stand and walk on a motorized treadmill independently. However, frail older adults, whose fall rates are higher, may not have this ability and they cannot participate. Thus, there is a critical need for innovative perturbation exercise programs to improve reactive balance and reduce the fall risks among older adults in a wider range of functioning. Trunk and arms are highly involved in reactive balance reactions. We aim to investigate whether an alternative PBBT program that provides perturbations during hands-free bicycling in a sitting position, geared to improve trunk and arm reactive responses, can be transferred to reduce fall risks and improve balance function among pre-frail older adults.Methods: In a single-blinded randomized-controlled trial, 68 community-dwelling pre-frail older adults are randomly allocated into two intervention groups. The experimental group receives 24-PBBT sessions over 12-weeks that include self-induced internal and machine-induced external unannounced perturbations of balance during hands-free pedaling on a bicycle-simulator system, in combination with cognitive dual-tasks. The control group receives 24 pedaling sessions over 12-weeks by the same bicycle-simulator system under the same cognitive dual-tasks, but without balance perturbations. Participants' reactive and proactive balance functions and gait function are assessed before and after the 12-week intervention period (e.g., balance reactive responses and strategies, voluntary step execution test, postural stability in upright standing, Berg Balance Test, Six-meter walk test, as well as late life function and fear of falling questionnaires).Discussion: This research addresses two key issues in relation to balance re-training: (1) generalization of balance skills acquired through exposure to postural perturbations in a sitting position investigating the ability of pre-frail older adults to improve reactive and proactive balance responses in standing and walking, and (2) the individualization of perturbation training to older adults' neuromotor capacities in order to optimize training responses and their applicability to real-life challenges.Clinical Trial Registration: www.clinicaltrials.gov, NCT03636672 / BARZI0104; Registered: July 22, 2018; Enrolment of the first participant March: 1, 2019. See Supplementary File.

Voluntary step execution in patients with knee osteoarthritis: Symptomatic vs. non-symptomatic legs

BackgroundIndividuals with osteoarthritis fall at a greater rate than the general population, likely as a result of weakness, pain, movement limitations, and a decline in balance. Due to the high prevalence of osteoarthritis in the population, understanding the mechanisms leading to greater fall risk is an important issue to better understand. Research questionWhat is the influence of unilateral knee osteoarthritis on the characteristics of performing a voluntary step (i.e., similar to that performed to avoid a fall after a perturbation), compared to healthy age-matched controls? MethodsCase-control study performed in a Health maintenance organization physical therapy clinic. The research group consisted of a referred sample of 21 patients with unilateral knee osteoarthritis. The control group consisted of 22 age-matched healthy individuals. All participants were over 65 years of age. Participants were excluded if they had a surgical procedure to back or lower limb within one year before testing, oncological or neurological disease or a deficit in tactile sense. Movements were performed with and without dual tasking. MeasurementsDuration of the initiation phase (cue to step initiation), preparatory phase (step initiation to foot off) and swing phase (foot off to foot contact). ResultsIn the preparatory phase and swing phase, the osteoarthritis group moved more slowly than the control group, and these differences were larger for forward compared to backward movements. Dual-tasking slowed responses in the pre-movement initiation stage across groups. SignificanceThe differences in basic parameters, and the slower movements in the osteoarthritis group, are consistent with known features of osteoarthritis, being a disease commonly regarded as primarily "mechanical", and are likely to increase fall risk. These response deficits suggest we should take advantage of advanced rehabilitation techniques, including cognitive loading, to help prevent falls in older adults with osteoarthritis.

Effects of mechanical perturbation gait training on gait and balance function in patients with stroke: A pre-post research study

Patients with stroke (PwS) demonstrate impaired gait and balance, and asymmetric gait, placing them at high risk of falls. We aimed to investigate the effects of a single training session that included mechanical external perturbation which resists forward movement of the paretic leg during its swing phase of walking on gait and balance in PwS. In a pre-post pilot study, gait asymmetry and balance function were assessed in 22 first-event chronic PwS (i.e., unilateral hemiparesis). PwS underwent tests during baseline and one week later, after participating in a single training session that resisted forward stepping during the swing phase of walking with a device secured around the patient's waist and connected diagonally to the patient’s foot by a tension cord. Ground reaction forces and center of pressure were sampled during treadmill gait to assess step length asymmetry. Performance-oriented mobility assessment (POMA), a two-minute walk test (2MWT), and the voluntary step execution test were also measured. We found no significant improvement in step length asymmetry. However, POMA scores, as well as voluntary step execution tests improved with a moderate effect size. It seems that applying diagonal resistance force to the swinging leg resulted in insufficient horizontal force. However, the improvement in the preparation phase, i.e., better weight-bearing abilities during the voluntary stepping, may be due to the compression force applied to the lower limb joints thus providing proprioceptive training. This suggests that proprioceptive training may improve gait performance in stroke patients in a very short training period.

Modulation of EMG-EMG Coherence in a Choice Stepping Task.

The voluntary step execution task is a popular measure for identifying fall risks among elderly individuals in the community setting because most falls have been reported to occur during movement. However, the neurophysiological functions during this movement are not entirely understood. Here, we used electromyography (EMG) to explore the relationship between EMG-EMG coherence, which reflects common oscillatory drive to motoneurons, and motor performance associated with stepping tasks: simple reaction time (SRT) and choice reaction time (CRT) tasks. Ten healthy elderly adults participated in the study. Participants took a single step forward in response to a visual imperative stimulus. EMG-EMG coherence was analyzed for 1000 ms before the presentation of the stimulus (stationary standing position) from proximal and distal tibialis anterior (TA) and soleus (SOL) muscles. The main result showed that all paired EMG-EMG coherences in the alpha and beta frequency bands were greater in the SRT than the CRT task. This finding suggests that the common oscillatory drive to the motoneurons during the SRT task occurred prior to taking a step, whereas the lower value of corticospinal activity during the CRT task prior to taking a step may indicate an involvement of inhibitory activity, which is consistent with observations from our previous study (Watanabe et al., 2016). Furthermore, the beta band coherence in intramuscular TA tended to positively correlate with the number of performance errors that are associated with fall risks in the CRT task, suggesting that a reduction in the inhibitory activity may result in a decrease of stepping performance. These findings could advance the understanding of the neurophysiological features of postural adjustments in elderly individuals.

Unexpected perturbations training improves balance control and voluntary stepping times in older adults - a double blind randomized control trial.

BackgroundFalls are common among elderly, most of them occur while slipping or tripping during walking. We aimed to explore whether a training program that incorporates unexpected loss of balance during walking able to improve risk factors for falls.MethodsIn a double-blind randomized controlled trial 53 community dwelling older adults (age 80.1±5.6 years), were recruited and randomly allocated to an intervention group (n = 27) or a control group (n = 26). The intervention group received 24 training sessions over 3 months that included unexpected perturbation of balance exercises during treadmill walking. The control group performed treadmill walking with no perturbations. The primary outcome measures were the voluntary step execution times, traditional postural sway parameters and Stabilogram-Diffusion Analysis. The secondary outcome measures were the fall efficacy Scale (FES), self-reported late life function (LLFDI), and Performance-Oriented Mobility Assessment (POMA).ResultsCompared to control, participation in intervention program that includes unexpected loss of balance during walking led to faster Voluntary Step Execution Times under single (p = 0.002; effect size [ES] =0.75) and dual task (p = 0.003; [ES] = 0.89) conditions; intervention group subjects showed improvement in Short-term Effective diffusion coefficients in the mediolateral direction of the Stabilogram-Diffusion Analysis under eyes closed conditions (p = 0.012, [ES] = 0.92). Compared to control there were no significant changes in FES, LLFDI, and POMA.ConclusionsAn intervention program that includes unexpected loss of balance during walking can improve voluntary stepping times and balance control, both previously reported as risk factors for falls. This however, did not transferred to a change self-reported function and FES.Trial registrationClinicalTrials.gov Registration number: NCT01439451.

The Effect of a Cognitive-Motor Intervention on Voluntary Step Execution under Single and Dual Task Conditions in Older Adults: A Randomized Controlled Pilot Study

The Effect of a Cognitive-Motor Intervention on Voluntary Step Execution under Single and Dual Task Conditions in Older Adults: A Randomized Controlled Pilot Study

A water-based training program that includes perturbation exercises improves speed of voluntary stepping in older adults: A randomized controlled cross-over trial

This study evaluated the effects of a water exercise training program that includes perturbation exercises (WEP) to improve the speed of voluntary stepping reaction in older adults. Speed of voluntary stepping considered as an important skill to prevent a fall when balance is lost. In a single-blinded randomized controlled trial with a crossover design thirty-six independent old adults (64–88 years old) were divided into two groups. Group A received WEP for the first 12 weeks, followed by no intervention for the second 12 weeks. Group B did not receive intervention for the first 12 weeks and received WEP for the second 12 weeks. Voluntary Step Execution Test and postural stability in upright standing (eyes open and closed conditions) were measured at baseline, 12 weeks, and 24 weeks. A significant interaction effect between group and time was found for the step execution, due to improvement in initiation phase and swing phase durations in the WEP group. Also significant improvement in postural stability parameters in eyes open and closed conditions is noted. The present results indicate that the primary benefit of WEP that include perturbations to induce stepping, was a reduction in voluntary stepping times. The WEP generalized to a better control of balance in up-right standing.

Improving balance control and self-reported lower extremity function in community-dwelling older adults: a randomized control trial

Objectives: To evaluate the effect of a group-based functional and specific balance training programme that included dual-task exercises on balance function in healthy older adults. Design: A single-blind randomized controlled trial. Setting: General community. Participants: Sixty-six community-dwelling older adults (age 77.0 ± 6.5 years), without functional balance impairment were recruited and allocated at random to an intervention group (n = 33) or a reference group (n = 33). Intervention: The intervention group received 24 training sessions over three months that included perturbation as well as dual-task exercises. The reference group received no intervention. Outcome measures: The voluntary step execution times during single- and dual-task conditions, stabilogram-diffusion analysis in upright standing, and self-reported physical function; all were measured assessed at baseline and at the end of intervention. The intervention group was retested after six months. Results: Compared with the reference group, participation in group-based functional and specific balance training led to faster voluntary step execution times under single-task (P = 0.02; effect size (ES) = 0.34) and dual-task (P = 0.036; ES = 0.55) conditions; lower transition displacement and shorter transition time of the stabilogram-diffusion analysis under eyes-closed conditions (P = 0.007, ES = 0.30 and P = 0.08, ES = 0.44, respectively); and improved self-reported lower extremity function (P = 0.006, ES = 0.37). Effects were lost at six-month follow-up. Conclusions: Functional and specific balance training can improve voluntary stepping and balance control in healthy older non-fallers, parameters previously found to be related to increased risk of falls and injury in older adults.

The effect of a cognitive-motor intervention on voluntary step execution under single and dual task conditions in older adults: a randomized controlled pilot study.

BackgroundThis randomized controlled pilot study aimed to explore whether a cognitive-motor exercise program that combines traditional physical exercise with dance video gaming can improve the voluntary stepping responses of older adults under attention demanding dual task conditions.MethodsElderly subjects received twice weekly cognitive-motor exercise that included progressive strength and balance training supplemented by dance video gaming for 12 weeks (intervention group). The control group received no specific intervention. Voluntary step execution under single and dual task conditions was recorded at baseline and post intervention (Week 12).ResultsAfter intervention between-group comparison revealed significant differences for initiation time of forward steps under dual task conditions (U = 9, P = 0.034, r = 0.55) and backward steps under dual task conditions (U = 10, P = 0.045, r = 0.52) in favor of the intervention group, showing altered stepping levels in the intervention group compared to the control group.ConclusionA cognitive-motor intervention based on strength and balance exercises with additional dance video gaming is able to improve voluntary step execution under both single and dual task conditions in older adults.

Do voluntary step reactions in dual task conditions have an added value over single task for fall prediction? A prospective study

Stepping reactions play a critical role in responding to balance perturbations, whether they are a consequence of external perturbation or self-induced in nature. The aim of the present study was to determine prospectively the capacity of voluntary stepping performance in singleand dual-task conditions, to predict future falls among older community-dwelling persons. We also aimed to assess whether dual task conditions have an added value over single tasks for fall prediction. A total of 100 healthy old volunteers (mean age 78.4±5.7 yrs), from two self-care protected retirement homes for older adults, performed the Voluntary Step Execution Test in single- and dual-task conditions as a reaction time task while standing on a single force platform. Step initiation, preparatory and swing phases, and foot-contact time were extracted from data on center of pressure and ground reaction force. One-year fall incidences were monitored. Ninety-eight subjects completed the one-year follow-up, 49 non-fallers, 32 one-time fallers, and 17 recurrent fallers (two or more falls). Recurrent fallers had significantly slower voluntary step execution times in both single- and dual-task conditions, especially due to a slower preparation phase. Two stepwise (backward) logistic regression models showed that longer step execution times have strong predictive value for falls in both single- and dual-task conditions (odds ratio (OR) 8.7 and 5.4, respectively, p<0.05). Voluntary Step Execution Test in both single- and dual-task conditions is a simple and safe examination which can potentially and effectively predict future falls, with no added value to dual- over single-task condition.

Voluntary stepping behavior under single- and dual-task conditions in chronic stroke survivors: A comparison between the involved and uninvolved legs

Objective If balance is lost, quick step execution can prevent falls. Research has shown that speed of voluntary stepping was able to predict future falls in old adults. The aim of the study was to investigate voluntary stepping behavior, as well as to compare timing and leg push-off force–time relation parameters of involved and uninvolved legs in stroke survivors during single- and dual-task conditions. We also aimed to compare timing and leg push-off force–time relation parameters between stroke survivors and healthy individuals in both task conditions. Methods Ten stroke survivors performed a voluntary step execution test with their involved and uninvolved legs under two conditions: while focusing only on the stepping task and while a separate attention-demanding task was performed simultaneously. Temporal parameters related to the step time were measured including the duration of the step initiation phase, the preparatory phase, the swing phase, and the total step time. In addition, force–time parameters representing the push-off power during stepping were calculated from ground reaction data and compared with 10 healthy controls. Results The involved legs of stroke survivors had a significantly slower stepping time than uninvolved legs due to increased swing phase duration during both single- and dual-task conditions. For dual compared to single task, the stepping time increased significantly due to a significant increase in the duration of step initiation. In general, the force time parameters were significantly different in both legs of stroke survivors as compared to healthy controls, with no significant effect of dual compared with single-task conditions in both groups. Conclusions The inability of stroke survivors to swing the involved leg quickly may be the most significant factor contributing to the large number of falls to the paretic side. The results suggest that stroke survivors were unable to rapidly produce muscle force in fast actions. This may be the mechanism of delayed execution of a fast step when balance is lost, thus increasing the likelihood of falls in stroke survivors.

Regular Exercise in the Elderly Is Effective to Preserve the Speed of Voluntary Stepping under Single-Task Condition but Not under Dual-Task Condition

Background: Stepping response may be considered the most important postural reaction to prevent a fall because it is the inability to respond effectively to a loss of balance that ultimately determines whether a fall occurs. However, very little has been studied on the effect of exercising on step execution behavior in the elderly. Objectives: To explore whether older persons who exercise regularly have faster voluntary stepping times than sedentary elderly persons. Additionally, we investigated the association between step execution behavior, self-reported physical function, and balance performance. Methods: Case-control study of 48 elderly adults aged 65–91 years who live independently in retirement homes. Participants were classified as 24 exercisers (reporting >2 exercise training activities/week) and 24 age- and gender-matched inactive elderly individuals (who do not exercise regularly). The Voluntary Step Execution Test was performed as a reaction time task while standing on a force platform under single-task and dual-task conditions. Step initiation phase, foot off time, foot contact time, preparatory, and swing phases were extracted from center of pressure and ground reaction force data. Self-reported function was examined using Late-Life Function and Disability Instrument; Berg Balance Test was also performed. Results: Exercisers had significantly faster voluntary step times in single-task condition (959 vs. 1,158 ms) but not during dual-task condition (1,170 vs. 1,303 ms). Exercisers had a significantly higher Berg Balance Test (53.7 ±3.6 vs. 49.8 ±5.3), consumed less medication (3.3 ±2.3 vs. 5.6 ±2.9), and their lower extremity function scores were higher (88.61 ±2.3 vs. 73.1 ±2.7) than those of inactive subjects. Conclusion: Exercising regularly protects from physical functioning loss in older persons and against a decrease in voluntary step execution times during single-task but not during dual-task conditions. Lack of specificity (dual-task exercises) during the training may be the cause of insignificant differences in dual-task stepping performance. Thus, adding dual-task training may improve dual-task performance in the elderly.

Application of the voluntary step execution test to identify elderly fallers

To assess the use of the Voluntary Step Execution Test to identify fallers. Cross-sectional retrospective. Two self-care, residential facilities. a total of 100 healthy old volunteers (mean age = 78.4 +/- 5.7). The study investigated the use of the Voluntary Step Execution Test to identify fallers under single and dual-task conditions. Berg Balance Test (BBS) and Timed Get Up and Go (TUG) were used to assess balance and gait function. There were no significant differences found between fallers and non-fallers in BBS and TUG (50.5 +/- 4.6 versus 52.5 +/- 3.4 and 9.4 +/- 3.4 versus 7.98 +/- 2.3 respectively). There were no statistically significant differences between non-fallers and fallers across all step execution parameters under the single-task condition. However, adding cognitive load to the Voluntary Step Execution Test revealed statistically significant increases in duration of the preparatory phase, swing time and the time to foot-contact (P = 0.035;P = 0.033 and P = 0.037, respectively). Based on the coefficients of the logistic regression model participants with dual-task step execution times of > or =1,100 ms had five times the risk of falling than participants with execution times of <1,100 ms. The study provides evidence that a simple, safe measure of step execution under dual-task conditions can identify elderly individuals at risk for falls.

Reliability of voluntary step execution behavior under single and dual task conditions

BackgroundThe current study investigated the repeatability (test-retest reliability) of ground reaction force parameters recorded during a voluntary step execution under single (motor task) and dual task (motor and cognitive task) conditions for healthy adults and elderly individuals as well as the number of trials required to produce repeatable results.MethodsTwenty-four healthy adults (21–63 years old) and 16 elderly adults (66–87 years) performed a voluntary rapid step execution following a tap on their heel while standing on a force platform under single and dual task conditions on three separate occasions. The first two tests were performed 30–60 minutes apart and the third test was performed a week later. Variables analyzed from the ground reaction force data included onset latency of step initiation (initiation phase), preparation and swing phases, foot-off and foot-contact times.ResultsIntraclass correlation coefficients (ICC(2,1)) were good to excellent across all parameters and test conditions for the pooled population and for elderly (0.74–0.92 and 0.62–0.88, respectively) except for the swing phase duration where lower values were seen (0.54–0.60 and 0.32–0.64 respectively). Values were similar under single and dual task conditions.ConclusionA voluntary step execution test, performed under single and dual task conditions especially foot-off and foot-contact times, is a reliable outcome measure that may be a useful tool to asses dynamic balance function for diagnostic purposes as well as clinical intervention trials.