Effects of dynamic stepping training on nonlocomotor tasks in individuals poststroke

Taking the Next Step in Neurologic Rehabilitation: Contributions of Intensity and Variability of Stepping Tasks During Locomotor Training

Research over the past 20 years indicates the amount of task-specific walking practice provided to individuals with stroke, brain injury, or incomplete spinal cord injury can strongly influence walking recovery. However, more recent data suggest that attention toward 2 other training parameters, including the intensity and variability of walking practice, may maximize walking recovery and facilitate gains in non-walking outcomes. The combination of these training parameters represents a stark contrast from traditional strategies, and confusion regarding the potential benefits and perceived risks may limit their implementation in clinical practice. The purpose of this perspective is to delineate the evidence regarding the contributions of intensity and variability of locomotor training to improve mobility outcomes in individuals with acute-onset brain and spinal cord injury. The rationale and evidence supporting the utility of these training parameters in controlled laboratory settings is first described by integrating concepts in the field of neuroscience, motor learning, biomechanics, and exercise physiology into a rehabilitation intervention. Subsequently, the evidence supporting the efficacy of this paradigm is addressed, including discussions of some of the misconceptions regarding perceived negative consequences of these strategies in an effort to mitigate common clinical concerns. Finally, the utility of these strategies implemented during inpatient rehabilitation is delineated to facilitate a more comprehensive understanding of the feasibility and potential benefits early following neurologic injury. A greater understanding of how and why to integrate higher intensity, variable stepping practice will support therapists to take the next step to maximize mobility in the patients they serve.

Walking as a Mediator Between Strength and Health-Related Quality of Life in Multiple Sclerosis

Background and Purpose: Lower limb (LL) weakness and gait impairment are prevalent among persons with multiple sclerosis (PwMS) and can impede functional independence and impact health-related quality of life (HR-QoL). The purpose of this study was to examine the mediation effect of walking speed and perceived walking ability on the relationship between LL weakness and HR-QoL in ambulatory PwMS.

METHODS

Participants (n = 175) were PwMS in this secondary analysis of a cross-sectional study. Demographics, pain (visual analog scale), fatigue (5-item Modified Fatigue Impact Scale), LL strength (hip extensors [HE] and flexors [HF], knee extensors [KE] and flexors [KF], and ankle plantarflexors [APF] and dorsiflexors [ADF]), Timed 25-Foot Walk, 12-item MS Walking Scale, and HR-QoL (MS Impact Scale-Physical [MSIS-29-Phys] and Psychological [MSIS-29-Psych]) were collected. Bivariate and mediation analyses using Hayes' PROCESS were performed to determine if LL strength had an indirect effect through walking speed or perceived walking ability on physical and psychological HR-QoL while controlling for fatigue and pain.

RESULTS

There were significant ( P < 0.01) correlations for all strength measures with the MSIS-29-Phys and for HF, KE, KF, and APF with the MSIS-29-Psych. In the mediation analyses, LL strength indirectly influenced PwMS' MSIS-29-Phys through walking speed and perceived walking ability. There was only partial mediation between HE, HF, KF, ADF, and MSIS-29-Phy when walking speed was in the model. LL strength did not influence MSIS-29-Psych.

DISCUSSION AND CONCLUSIONS

LL strength impacts physical HR-QoL through walking but does not indirectly affect PwMS' perceived psychological HR-QoL. These findings may prompt physical therapists to create individualized care plans that address LL weakness and walking impairments with the goal of promoting optimal outcomes and improving HR-QoL.

VIDEO ABSTRACT AVAILABLE

for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A504 ).

Feasibility and safety of in-bed cycling/stepping in critically ill patients: A study protocol for a pilot randomized controlled clinical trial

BACKGROUND

Intensive care unit (ICU)-acquired weakness (ICU-AW) is one of the most common complications of post-ICU syndrome. It is the leading cause of gait disturbance, decreased activities of daily living, and poor health-related quality of life. The early rehabilitation of critically ill patients can reduce the ICU-AW. We designed a protocol to investigate the feasibility and safety of conventional rehabilitation with additional in-bed cycling/stepping in critically ill patients.

METHODS

The study is designed as a single-center, single-blind, pilot, randomized, parallel-group study. After the screening, participants are randomly allocated to two groups, stratified by mechanical ventilation status. The intervention group will be provided with exercises of in-bed cycling/stepping according to the level of consciousness, motor power, and function in addition to conventional rehabilitation. In contrast, the control group will be provided with only conventional rehabilitation. The length of intervention is from ICU admission to discharge, and interventions will be conducted for 20 minutes, a maximum of three sessions per day.

RESULTS

The outcomes are the number and percentage of completed in-bed cycling/stepping sessions, the duration and percentage of in-bed cycling/stepping sessions, and the number of cessations of in-bed cycling/stepping sessions, the interval from ICU admission to the first session of in-bed cycling/stepping, the number and percentage of completed conventional rehabilitation sessions, the duration and percentage of conventional rehabilitation sessions, the number of cessations of conventional rehabilitation sessions, the number of adverse events, level of consciousness, functional mobility, muscle strength, activities of daily living, and quality of life.

DISCUSSION

This study is a pilot clinical trial to investigate the feasibility and safety of conventional rehabilitation with additional in-bed cycling/stepping in critically ill patients. If the expected results are achieved in this study, the methods of ICU rehabilitation will be enriched.

TRIAL REGISTRATION

clinicialtrials.gov, Clinical Trials Registration #NCT05868070.

Utilization of overground exoskeleton gait training during inpatient rehabilitation: a descriptive analysis

BACKGROUND

Overground exoskeleton gait training (OEGT) after neurological injury is safe, feasible, and may yield positive outcomes. However, no recommendations exist for initiation, progression, or termination of OEGT. This retrospective study highlights the clinical use and decision-making of OEGT within the physical therapy plan of care for patients after neurological injury during inpatient rehabilitation.

METHODS

The records of patients admitted to inpatient rehabilitation after stroke, spinal cord injury, or traumatic brain injury who participated in at least one OEGT session were retrospectively reviewed. Session details were analyzed to illustrate progress and included: "up" time, "walk" time, step count, device assistance required for limb swing, and therapist-determined settings. Surveys were completed by therapists responsible for OEGT sessions to illuminate clinical decision-making.

RESULTS

On average, patients demonstrated progressive tolerance for OEGT over successive sessions as shown by increasing time upright and walking, step count, and decreased assistance required by the exoskeleton. Therapists place preference on using OEGT with patients with more functional dependency and assess feedback from the patient and device to determine when to change settings. OEGT is terminated when other gait methods yield higher step repetitions or intensities, or to prepare for discharge.

CONCLUSION

Our descriptive retrospective data suggests that patients after neurological injury may benefit from OEGT during inpatient rehabilitation. As no guidelines exist, therapists' clinical decisions are currently based on a combination of knowledge of motor recovery and experience. Future efforts should aim to develop evidence-based recommendations to facilitate functional recovery after neurological injury by leveraging OEGT.

Design and evaluation of an independent 4-week, exosuit-assisted, post-stroke community walking program

Chronic impairment in the paretic ankle following stroke often requires that individuals use compensatory patterns such as asymmetric propulsion to achieve effective walking speeds needed for community engagement. Ankle exosuit assistance can provide ankle biomechanical benefit in the lab, but such environments inherently limit the amount of practice available. Community walking studies without exosuits can provide massed practice and benefit walking speed but are limited in their ability to assist proper mechanics. In this study, we combined the positive aspects of community training with those of exosuit assistance. We developed and evaluated a community Robotic Exosuit Augmented Locomotion (cREAL) program. Four participants in the chronic stage of stroke independently used our community ankle exosuit for walking in the community 3-5 days/week for 4 weeks. We performed lab evaluations before and after the 4-week program. Two participants significantly improved their unassisted paretic propulsion by an average of 27% after the program and walked on average 4001 steps/day more in the week following the program. Despite the small number of participants, this study provides preliminary evidence for the potential of exosuits to augment gait training and rehabilitation in the community.

Increasing the Amount and Intensity of Stepping Training During Inpatient Stroke Rehabilitation Improves Locomotor and Non-Locomotor Outcomes

BACKGROUND

The efficacy of traditional rehabilitation interventions to improve locomotion post-stroke, including providing multiple exercises targeting impairments and activity limitations, is uncertain. Emerging evidence rather suggests attempts to prioritize stepping practice at higher cardiovascular intensities may facilitate greater locomotor outcomes.

OBJECTIVE

The present study was designed to evaluate the comparative effectiveness of high-intensity training (HIT) to usual care during inpatient rehabilitation post-stroke.

METHODS

Changes in stepping activity and functional outcomes were compared over 9 months during usual-care (n = 131 patients < 2 months post-stroke), during an 18-month transition phase with attempts to implement HIT (n = 317), and over 12 months following HIT implementation (n = 208). The transition phase began with didactic and hands-on education, and continued with meetings, mentoring, and audit and feedback. Fidelity metrics included percentage of sessions prioritizing gait interventions and documenting intensity. Demographics, training measures, and outcomes were compared across phases using linear or logistic regression analysis, Kruskal-Wallis tests, or χ2 analysis.

RESULTS

Across all phases, admission scores were similar except for balance (usual-care>HIT; P < .02). Efforts to prioritize stepping and achieve targeted intensities during HIT vs transition or usual-care phases led to increased steps/day (P < .01). During HIT, gains in 10-m walk [HIT median = 0.13 m/s (interquartile range: 0-0.35) vs usual-care = 0.07 m/s (0-0.24), P = .01] and 6-min walk [50 (9.3-116) vs 2.1 (0-56) m, P < .01] were observed, with additional improvements in transfers and stair-climbing.

CONCLUSIONS

Greater efforts to prioritize walking and reach higher intensities during HIT led to increased steps/day, resulting in greater gains in locomotor and non-locomotor outcomes.

Gains in Daily Stepping Activity in People With Chronic Stroke After High-Intensity Gait Training in Variable Contexts

OBJECTIVE

Many physical therapist interventions provided to individuals with chronic stroke can lead to gains in gait speed or endurance (eg, 6-Minute Walk Test [6MWT]), although changes in objective measures of participation are not often observed. The goal of this study was to determine the influence of different walking interventions on daily stepping (steps per day) and the contributions of demographic, training, and clinical measures to these changes.

METHODS

In this secondary analysis of a randomized clinical trial, steps per day at baseline and changes in steps per day following 1 of 3 locomotor interventions were evaluated in individuals who were ambulatory and >6 months after stroke. Data were collected on 58 individuals who received ≤30 sessions of high-intensity training (HIT) in variable contexts (eg, tasks and environments; n = 19), HIT focused on forward walking (n = 19), or low-intensity variable training (n = 20). Primary outcomes were steps per day at baseline, at post-training, and at a 3-month follow-up, and secondary outcomes were gait speed, 6MWT, balance, and balance confidence. Correlation and regression analyses identified demographic and clinical variables associated with steps per day.

RESULTS

Gains in steps per day were observed across all groups combined, with no between-group differences; post hoc within-group analyses revealed significant gains only following HIT in variable contexts. Both HIT groups showed gains in endurance (6MWT), with increases in balance confidence only following HIT in variable contexts. Changes in steps per day were associated primarily with gains in 6MWT, with additional associations with baseline 6MWT, lower-extremity Fugl-Meyer scores, and changes in balance confidence.

CONCLUSION

HIT in variable contexts elicited gains in daily stepping, with changes primarily associated with gains in gait endurance.

IMPACT

Providing HIT in variable contexts appears to improve measures of participation (eg, daily stepping) that may be associated with clinical measures of function. Gains in multiple measures of mobility and participation with HIT in variable contexts may improve the efficiency and value of physical therapy services.

High Level Mobility Training in Ambulatory Patients with Acquired Non-Progressive Central Neurological Injury: a Feasibility Study

The purpose of this study was to test the feasibility and safety of High-Level Mobility (HLM) training on adults with Acquired Brain Injury (ABI). Our hypotheses were that HLM training would be feasible and safe. This study was a pilot randomized control trial with a Simple Skill Group (SSG) and a Complex Skill Group (CSG). Both groups received 12 sessions over 8 weeks and completed 4 testing sessions over 16 weeks. The SSG focused on locomotion, while CSG focused on the acquisition of running. Feasibility was assessed in terms of process, resources, management, and scientific metrics, including safety. Among the 41 participants meeting inclusion criteria, 28 consented (CSG, n = 13, SSG, n = 15), 20 completed the assigned protocol and 8 withdrew (CSG n = 4, SSG n = 4). Adherence rate to assigned protocol was 100%. There were two Adverse Events (AEs), 1 over 142 SSG sessions and 1 over 120 CSG sessions. The AE Odd Ratio (OR) (CSG:SSG) was 1.18 (95% CI: 0.07, 19.15). The data support our hypotheses that HLM training is feasible and safe on ambulatory adults with ABI.

The Value of High Intensity Locomotor Training Applied to Patients With Acute-Onset Neurologic Injury

Long-standing research in animal models and humans with stroke or incomplete spinal cord injury (iSCI) indicate that specific physical training variables, such as the specificity and amount of practice, may influence neurologic recovery and locomotor function. More recent data highlight the contributions of exercise intensity, as estimated indirectly by cardiovascular exertion, as potentially more important than previously considered. The effects of exercise intensity are well described in neurologically intact individuals, although confusion regarding the definitions of intensity and safety concerns have limited its implementation during physical rehabilitation of patients with neurologic injury. The purpose of this review is to delineate some of the evidence regarding the effects of exercise intensity during locomotor training in patients with stroke and iSCI. We provide specific definitions of exercise intensity used within the literature, describe methods used to ensure appropriate levels of exertion, and discuss potential adverse events and safety concerns during its application. Further details on the effects of locomotor training intensity on clinical outcomes, and on neuromuscular and cardiovascular function will be addressed as available. Existing literature across multiple studies and meta-analyses reveals that exercise training intensity is likely a major factor that can influence locomotor function after neurologic injury. To extend these findings, we describe previous attempts to implement moderate to high intensity interventions during physical rehabilitation of patients with neurologic injury, including the utility of specific strategies to facilitate implementation, and to navigate potential barriers that may arise during implementation efforts.

Stepwise Regression and Latent Profile Analyses of Locomotor Outcomes Poststroke

BACKGROUND AND PURPOSE

Previous data suggest patient demographics and clinical presentation are primary predictors of motor recovery poststroke, with minimal contributions of physical interventions. Other studies indicate consistent associations between the amount and intensity of stepping practice with locomotor outcomes. The goal of this study was to determine the relative contributions of these combined variables to locomotor outcomes poststroke across a range of patient demographics and baseline function.

METHODS

Data were pooled from 3 separate trials evaluating the efficacy of high-intensity training, low-intensity training, and conventional interventions. Demographics, clinical characteristics, and training activities from 144 participants >1-month poststroke were included in stepwise regression analyses to determine their relative contributions to locomotor outcomes. Subsequent latent profile analyses evaluated differences in classes of participants based on their responses to interventions.

RESULTS

Stepwise regressions indicate primary contributions of stepping activity on locomotor outcomes, with additional influences of age, duration poststroke, and baseline function. Latent profile analyses revealed 2 main classes of outcomes, with the largest gains in those who received high-intensity training and achieved the greatest amounts of stepping practice. Regression and latent profile analyses of only high-intensity training participants indicated age, baseline function, and training activities were primary determinants of locomotor gains. Participants with the smallest gains were older (≈60 years), presented with slower gait speeds (<0.40 m/s), and performed 600 to 1000 less steps/session.

CONCLUSIONS

Regression and cluster analyses reveal primary contributions of training interventions on mobility outcomes in patients >1-month poststroke. Age, duration poststroke, and baseline impairments were secondary predictors. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02507466 and NCT01789853.

Task-Specific Versus Impairment-Based Training on Locomotor Performance in Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study

Background. Many research studies attempting to improve locomotor function following motor incomplete spinal cord injury (iSCI) focus on providing stepping practice. However, observational studies of physical therapy strategies suggest the amount of stepping practice during clinical rehabilitation is limited; rather, many interventions focus on mitigating impairments underlying walking dysfunction. Objective. The purpose of this blinded-assessor randomized trial was to evaluate the effects of task-specific versus impairment-based interventions on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI >1-year duration performed either task-specific (upright stepping) or impairment-based training for up to 20 sessions over ≤6 weeks, with interventions alternated after >4 weeks delay. Both strategies focused on achieving higher cardiovascular intensities, with training specificity manipulated by practicing only stepping practice in variable contexts or practicing tasks targeting impairments underlying locomotor dysfunction (strengthening, balance tasks, and recumbent stepping). Results. Significantly greater increases in fastest overground and treadmill walking speeds were observed following task-specific versus impairment-based training, with moderate associations between differences in amount of practice and outcomes. Gains in balance confidence were also observed following task-specific vs impairment-based training, although incidence of falls was also increased with the former protocol. Limited gains were observed with impairment-based training except for peak power during recumbent stepping tests. Conclusion. The present study reinforces work from other patient populations that the specificity of task practice is a critical determinant of locomotor outcomes and suggest impairment-based exercises may not translate to improvements in functional tasks. Clinical Trial Registration URL. https://clinicaltrials.gov/ ; Unique Identifier: NCT02115685.

Task-Specific Versus Impairment-Based Training on Locomotor Performance in Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study

Background. Many research studies attempting to improve locomotor function following motor incomplete spinal cord injury (iSCI) focus on providing stepping practice. However, observational studies of physical therapy strategies suggest the amount of stepping practice during clinical rehabilitation is limited; rather, many interventions focus on mitigating impairments underlying walking dysfunction. Objective. The purpose of this blinded-assessor randomized trial was to evaluate the effects of task-specific versus impairment-based interventions on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI >1-year duration performed either task-specific (upright stepping) or impairment-based training for up to 20 sessions over ≤6 weeks, with interventions alternated after >4 weeks delay. Both strategies focused on achieving higher cardiovascular intensities, with training specificity manipulated by practicing only stepping practice in variable contexts or practicing tasks targeting impairments underlying locomotor dysfunction (strengthening, balance tasks, and recumbent stepping). Results. Significantly greater increases in fastest overground and treadmill walking speeds were observed following task-specific versus impairment-based training, with moderate associations between differences in amount of practice and outcomes. Gains in balance confidence were also observed following task-specific vs impairment-based training, although incidence of falls was also increased with the former protocol. Limited gains were observed with impairment-based training except for peak power during recumbent stepping tests. Conclusion. The present study reinforces work from other patient populations that the specificity of task practice is a critical determinant of locomotor outcomes and suggest impairment-based exercises may not translate to improvements in functional tasks. Clinical Trial Registration URL. https://clinicaltrials.gov/ ; Unique Identifier: NCT02115685.

Backward locomotor treadmill training combined with transcutaneous spinal direct current stimulation in stroke: a randomized pilot feasibility and safety study

Walking impairment impacts nearly 66% of stroke survivors and is a rising cause of morbidity worldwide. Despite conventional post-stroke rehabilitative care, the majority of stroke survivors experience continued limitations in their walking speed, temporospatial dynamics and walking capacity. Hence, novel and comprehensive approaches are needed to improve the trajectory of walking recovery in stroke survivors. Herein, we test the safety, feasibility and preliminary efficacy of two approaches for post-stroke walking recovery: backward locomotor treadmill training and transcutaneous spinal direct current stimulation. In this double-blinded study, 30 chronic stroke survivors (>6 months post-stroke) with mild-severe residual walking impairment underwent six 30-min sessions (three sessions/week) of backward locomotor treadmill training, with concurrent anodal (N = 19) or sham transcutaneous spinal direct current stimulation (N = 11) over the thoracolumbar spine, in a 2:1 stratified randomized fashion. The primary outcomes were: per cent participant completion, safety and tolerability of these two approaches. In addition, we collected data on training-related changes in overground walking speed, cadence, stride length (baseline, daily, 24-h post-intervention, 2 weeks post-intervention) and walking capacity (baseline, 24-h post-intervention, 2 weeks post-intervention), as secondary exploratory aims testing the preliminary efficacy of these interventions. Eighty-seven per cent (N = 26) of randomized participants completed the study protocol. The majority of the study attrition involved participants with severe baseline walking impairment. There were no serious adverse events in either the backward locomotor treadmill training or transcutaneous spinal direct current stimulation approaches. Also, both groups experienced a clinically meaningful improvement in walking speed immediately post-intervention that persisted at the 2-week follow-up. However, in contrast to our working hypothesis, anodal-transcutaneous spinal direct current stimulation did not enhance the degree of improvement in walking speed and capacity, relative to backward locomotor treadmill training + sham, in our sample. Backward locomotor treadmill training and transcutaneous spinal direct current stimulation are safe and feasible approaches for walking recovery in chronic stroke survivors. Definitive efficacy studies are needed to validate our findings on backward locomotor treadmill training-related changes in walking performance. The results raise interesting questions about mechanisms of locomotor learning in stroke, and well-powered transcutaneous spinal direct current stimulation dosing studies are needed to understand better its potential role as a neuromodulatory adjunct for walking rehabilitation.

Implementation of High-Intensity Stepping Training During Inpatient Stroke Rehabilitation Improves Functional Outcomes

Background and Purpose- Therapeutic strategies that capitalize on the intrinsic capacity for neurological recovery early poststroke to improve locomotion are uncertain. Emerging data suggest that task-specific stepping practice provided at higher cardiovascular intensities may be critical dosage parameters that could maximize locomotor recovery. The purpose of this investigation was to determine the comparative effectiveness of providing high-intensity training on locomotor capacity early poststroke as compared with usual care. Methods- A quasi-experimental design was used to compare changes in stepping activity (StepWatch), walking, and balance outcomes during usual care (n=56) versus high-intensity stepping intervention (n=54) in inpatient stroke patients. Primary outcomes assessed weekly included self-selected and fastest gait speed, 6-minute walk test, and the Berg Balance Scale, with secondary outcomes of Swedish Postural Assessment Scale for Stroke-Norwegian version, Functional Ambulation Category, 30-s sit-to-stand, strength (average manual muscle testing), and Barthel Index. Regression analyses identified relationships between demographics, baseline function, and training activities (steps per day; duration achieved, 70%-85% maximum heart rates) and primary outcomes at discharge. Results- Following implementation of high-intensity stepping, average steps per day (5777±2784) were significantly greater than during usual care (3917±2656; P<0.001). Statistically different and clinically meaningful changes in self-selected speed (0.39±0.28 versus 0.16±0.26 m/s) and fastest gait speed (0.47±0.41 versus 0.17±0.38 m/s; both P<0.001) were observed following high-intensity interventions versus usual care and at every assessment throughout the length of stay. Changes in Berg Balance Scale and 6-minute walk test were also statistically and clinically different between groups, while secondary measures of Functional Ambulation Category and strength were also different at discharge. Primary predictors of improved walking capacity were steps per day, baseline impairments, and age. Conclusions- Provision of high-intensity stepping training applied during inpatient rehabilitation resulted in significantly greater walking and balance outcomes. This training paradigm should be further tested in other contexts to determine the generalizability to real-world and community settings.

High-Intensity Variable Stepping Training in Patients With Motor Incomplete Spinal Cord Injury: A Case Series

BACKGROUND AND PURPOSE

Previous data suggest that large amounts of high-intensity stepping training in variable contexts (tasks and environments) may improve locomotor function, aerobic capacity, and treadmill gait kinematics in individuals poststroke. Whether similar training strategies are tolerated and efficacious for patients with other acute-onset neurological diagnoses, such as motor incomplete spinal cord injury (iSCI), is unknown. Individuals with iSCI potentially have greater bilateral impairments. This case series evaluated the feasibility and preliminary short- and long-term efficacy of high-intensity variable stepping practice in ambulatory participants for more than 1 year post-iSCI.

CASE SERIES DESCRIPTION

Four participants with iSCI (neurological levels C5-T3) completed up to 40 one-hour sessions over 3 to 4 months. Stepping training in variable contexts was performed at up to 85% maximum predicted heart rate, with feasibility measures of patient tolerance, total steps/session, and intensity of training. Clinical measures of locomotor function, balance, peak metabolic capacity, and gait kinematics during graded treadmill assessments were performed at baseline and posttraining, with more than 1-year follow-up.

OUTCOMES

Participants completed 24 to 40 sessions over 8 to 15 weeks, averaging 2222 ± 653 steps per session, with primary adverse events of fatigue and muscle soreness. Modest improvements in locomotor capacity where observed at posttraining, with variable changes in lower extremity kinematics during treadmill walking.

DISCUSSION

High-intensity, variable stepping training was feasible and tolerated by participants with iSCI although only modest gains in gait function or quality were observed. The utility of this intervention in patients with more profound impairments may be limited.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A200).

Contributions of Stepping Intensity and Variability to Mobility in Individuals Poststroke

Background and Purpose- The amount of task-specific stepping practice provided during rehabilitation poststroke can influence locomotor recovery and reflects one aspect of exercise dose that can affect the efficacy of specific interventions. Emerging data suggest that markedly increasing the intensity and variability of stepping practice may also be critical, although such strategies are discouraged during traditional rehabilitation. The goal of this study was to determine the individual and combined contributions of intensity and variability of stepping practice to improving walking speed and distance in individuals poststroke. Methods- This phase 2, randomized, blinded assessor clinical trial was performed between May 2015 and November 2018. Individuals between 18 and 85 years old with hemiparesis poststroke of >6 months duration were recruited. Of the 152 individuals screened, 97 were randomly assigned to 1 of 3 training groups, with 90 completing >10 sessions. Interventions consisted of either high-intensity stepping (70%-80% heart rate reserve) of variable, difficult stepping tasks (high variable), high-intensity stepping performing only forward walking (high forward), and low-intensity stepping in variable contexts at 30% to 40% heart rate reserve (low variable). Participants received up to 30 sessions over 2 months, with testing at baseline, post-training, and a 3-month follow-up. Primary outcomes included walking speeds and timed distance, with secondary measures of dynamic balance, transfers, spatiotemporal kinematics, and metabolic measures. Results- All walking gains were significantly greater following either high-intensity group versus low-variable training (all P<0.001) with significant correlations with stepping amount and rate (r=0.48-60; P<0.01). Additional gains in spatiotemporal symmetry were observed with high-intensity training, and balance confidence increased only following high-variable training in individuals with severe impairments. Conclusions- High-intensity stepping training resulted in greater improvements in walking ability and gait symmetry than low-intensity training in individuals with chronic stroke, with potential greater improvements in balance confidence. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT02507466.

The Effects of a Divided-Attention Timed Stepping Accuracy Task on Balance, Strength, Endurance, and Functional Performance in Healthy Older Adults: A Pilot Study

The aim of this study was to investigate whether a 6-week Divided-Attention Stepping Accuracy Task (DATSAT) intervention improved the primary outcome measure, maximal step length; other balance measures (Berg Balance scale and Timed Up and Go test); leg strength; endurance (6-min walk test); and functional tasks in 15 community-dwelling healthy older adults ( x¯ age: 71.5 years, female: 46.7%) compared with 15 community-dwelling healthy older adults in a Bike and Strength (B&S) program ( x¯ age: 73.8 years, female: 33.3%). Participants trained 3× per week, 30-60 min per session. Stepping-group differences were significant for all measures. B&S group improved in maximal step length (anterior and lateral), strength, and one functional task. Stepping group outperformed B&S group in Timed Up and Go and maximal step length posterior. B&S group outperformed stepping group in two strength measures. Exertion scores were lower for the stepping group. Overall, Divided-Attention Timed Stepping Accuracy Task training resulted in more within-group improvements and two between-group measures with less perceived effort and shorter intervention times.

Compensation or Recovery? Altered Kinetics and Neuromuscular Synergies Following High-Intensity Stepping Training Poststroke

BACKGROUND

High-intensity, variable stepping training can improve walking speed in individuals poststroke, although neuromuscular strategies used to achieve faster speeds are unclear. We evaluated changes in joint kinetics and neuromuscular coordination following such training; movement strategies consistent with intact individuals were considered evidence of recovery and abnormal strategies indicative of compensation.

METHODS

A total of 15 individuals with stroke (duration: 23 ± 30 months) received ≤40 sessions of high-intensity stepping in variable contexts (tasks and environments). Lower-extremity kinetics and electromyographic (EMG) activity were collected prior to (BSL) and following (POST) training at peak treadmill speeds and speeds matched to peak BSL (MATCH). Primary measures included positive (concentric) joint and total limb powers, measures of interlimb (paretic/nonparetic powers) and intralimb compensation (hip/ankle or knee/ankle powers), and muscle synergies calculated using nonnegative matrix factorization.

RESULTS

Gains in most positive paretic and nonparetic joint powers were observed at higher speeds at POST, with decreased interlimb compensation and limited changes in intralimb compensation. There were very few differences in kinetic measures between BSL to MATCH conditions. However, the number of neuromuscular synergies increased significantly following training at both POST and MATCH conditions, indicating gains from training rather than altered speeds. Despite these results, speed improvements were associated primarily with changes in nonparetic versus paretic powers.

CONCLUSION

Gains in locomotor function were accomplished by movement strategies consistent with both recovery and compensation. These and other data indicate that both strategies may be necessary to maximize walking function in patients poststroke.

A multidirectional gravity-assist algorithm that enhances locomotor control in patients with stroke or spinal cord injury

Gait recovery after neurological disorders requires remastering the interplay between body mechanics and gravitational forces. Despite the importance of gravity-dependent gait interactions and active participation for promoting this learning, these essential components of gait rehabilitation have received comparatively little attention. To address these issues, we developed an adaptive algorithm that personalizes multidirectional forces applied to the trunk based on patient-specific motor deficits. Implementation of this algorithm in a robotic interface reestablished gait dynamics during highly participative locomotion within a large and safe environment. This multidirectional gravity-assist enabled natural walking in nonambulatory individuals with spinal cord injury or stroke and enhanced skilled locomotor control in the less-impaired subjects. A 1-hour training session with multidirectional gravity-assist improved locomotor performance tested without robotic assistance immediately after training, whereas walking the same distance on a treadmill did not ameliorate gait. These results highlight the importance of precise trunk support to deliver gait rehabilitation protocols and establish a practical framework to apply these concepts in clinical routine.

Impact of Early High-protein Diet on Neurofunctional Recovery in Rats with Ischemic Stroke

BACKGROUND Ischemic stroke, featuring high incidence, morbidity, and mortality, is one of the three major diseases troubling human beings. The purpose of the study was to examine the impact of early high-protein diet on neurofunctional recovery in rats with ischemic stroke as well as their cerebral infarct areas and molecular expressions of oxidative stress. MATERIAL AND METHODS The middle cerebral artery occlusion model (MCAO) was established, and 48 adult, male Sprague Dawley (SD) rats of clean grade aged seven to eight months (250-280 g body weight) were randomized into four groups: the MCAO group with high-protein diet (MH), the MCAO group with standard-protein diet (MS), the sham group with high-protein diet (SH), and the sham group with standard-protein diet (SS). High-protein diet intervention started on the first day of the surgery, and the rats' body weights and their neurological deficit scores were measured on each postoperative day while the scores of motors coordination and balance ability were recorded every other day. In addition, their cerebral infant areas and the molecular expressions of oxidative stress injuries were detected as well. RESULTS Compared to the MS group, the rats in the MH group gained faster weight growth (p<0.05), presented significantly lower neurological impairment scores (p<0.05), remarkably improved motor coordination and balance ability (p<0.05) as well as showed smaller cerebral infarct areas (p<0.05), increased expression of SOD (superoxide dismutase), and reduced expressions of MDA (malondialdehyde) and iNOS (inducible nitric oxide synthase). However, there was no significant difference between the SS group and the SH group (p>0.05). CONCLUSIONS Early high-protein diet facilitates the recovery of body weights and neurological functions as well the reduction of the cerebral infarct areas of rats, thus alleviating ischemic stroke-caused oxidative stress injuries.

Influence of skill and exercise training parameters on locomotor recovery during stroke rehabilitation

PURPOSE OF REVIEW

Research findings from the fields of motor learning and exercise physiology suggest specific training parameters that can be manipulated during physical rehabilitation profoundly influence skilled task performance. This review details the rationale for some of these training variables and their application in selected intervention studies focused on improving walking function in patients poststroke.

RECENT FINDINGS

Basic and applied studies have shown that the amount, intensity, and variability of specific task practice applied during rehabilitation interventions can affect recovery of walking poststroke. Many studies detailing the effects of conventional, therapist, and mechanically assisted interventions may incorporate some of these training parameters but minimize others, and their relative contributions may influence walking outcomes. Specific patient factors, such as the stroke acuity and degree of impairments, appear to influence the relative contributions of these training variables, and different patient subgroups may benefit from greater emphasis on specific parameters.

SUMMARY

The present findings suggest these training parameters should be considered when evaluating or implementing physical interventions directed toward improving locomotor function poststroke. More work is needed to understand their optimal combinations to maximize walking outcomes in patients with different levels of impairment poststroke.

A Backward Walking Training Program to Improve Balance and Mobility in Acute Stroke: A Pilot Randomized Controlled Trial

BACKGROUND AND PURPOSE

Strategies to address gait and balance deficits early poststroke are minimal. The postural and motor control requirements of Backward Walking Training (BWT) may provide benefits to improve balance and walking speed in this population. This pilot study (1) determined the feasibility of administering BWT during inpatient rehabilitation and (2) compared the effectiveness of BWT to Standing Balance Training (SBT) on walking speed, balance, and balance-related efficacy in acute stroke.

METHODS

Eighteen individuals 1-week poststroke were randomized to eight, 30-minute sessions of BWT or SBT in addition to scheduled therapy. Five-Meter Walk Test, 3-Meter Backward Walk Test, Activities-Specific Balance Confidence Scale, Berg Balance Scale, Sensory Organization Test, and Function Independence Measure-Mobility were assessed pre- and postintervention and at 3 months poststroke.

RESULTS

Forward gait speed change (BWT: 0.75 m/s; SBT: 0.41 m/s), assessed by the 5-Meter Walk Test, and backward gait speed change (BWT: 0.53 m/s; SBT: 0.23 m/s), assessed by the 3-Meter Backward Walk Test, preintervention to 1-month retention were greater for BWT than for SBT (P < 0.05). Group difference effect size from preintervention to 1-month retention was large for Activities-Specific Balance Confidence Scale, moderate for Berg Balance Scale and Function Independence Measure-Mobility, and small for Sensory Organization Test.

DISCUSSION AND CONCLUSIONS

Individuals 1-week poststroke tolerated 30 min/d of additional therapy. At 1-month postintervention, BWT resulted in greater improvements in both forward and backward walking speed than SBT. Backward walking training is a feasible important addition to acute stroke rehabilitation. Future areas of inquiry should examine BWT as a preventative modality for future fall incidence.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A193).

Effects of Training Intensity on Locomotor Performance in Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study

BACKGROUND

Many physical interventions can improve locomotor function in individuals with motor incomplete spinal cord injury (iSCI), although the training parameters that maximize recovery are not clear. Previous studies in individuals with other neurologic injuries suggest the intensity of locomotor training (LT) may positively influence walking outcomes. However, the effects of intensity during training of individuals with iSCI have not been tested.

OBJECTIVE

The purpose of this pilot, blinded-assessor randomized trial was to evaluate the effects of LT intensity on walking outcomes in individuals with iSCI.

METHODS

Using a crossover design, ambulatory participants with iSCI >1 year duration performed either high- or low-intensity LT for ≤20 sessions over 4 to 6 weeks. Four weeks following completion, the training interventions were alternated. Targeted intensities focused on achieving specific ranges of heart rate (HR) or ratings of perceived exertion (RPE), with intensity manipulated by increasing speeds or applying loads.

RESULTS

Significantly greater increases in peak treadmill speeds (0.18 vs 0.02 m/s) and secondary measures of metabolic function and overground speed were observed following high- versus low-intensity training, with no effects of intervention order. Moderate to high correlations were observed between differences in walking speed or distances and differences in HRs or RPEs during high- versus low-intensity training.

CONCLUSION

This pilot study provides the first evidence that the intensity of stepping practice may be an important determinant of LT outcomes in individuals with iSCI. Whether such training is feasible in larger patient populations and contributes to improved locomotor outcomes deserves further consideration.

Feasibility and Impact of High-Intensity Walking Training in Frail Older Adults

To investigate the impact of high-intensity walking training (HIWT) on prefrail and frail older adults, five assisted living residents underwent a supervised 12-session intervention. The intervention consisted of 30 min of HIWT at 70–80% of heart rate reserve or ratings of 15 to 17 (hard to very hard) on the Borg Rating of Perceived Exertion scale. Training included walking at fast speeds, multi-directions, stairs, and outdoor surfaces with and without an assistive device. Training significantly reduced frailty using the SHARE-FI (p = .008), increased fast gait speed (p = .01), improved 6-min walk test distance (p = .03), and enhanced Berg Balance Scale scores (p = .03). There were no adverse events and all participants reached target training intensity in all 12 sessions. Participants viewed the walking intervention as highly satisfactory (9.6/10 on a Likert scale) and 100% recommended that the assisted living facility should offer HIWT as part of routine programming.

Alterations in Aerobic Exercise Performance and Gait Economy Following High-Intensity Dynamic Stepping Training in Persons With Subacute Stroke

BACKGROUND AND PURPOSE

Impairments in metabolic capacity and economy (O2cost) are hallmark characteristics of locomotor dysfunction following stroke. High-intensity (aerobic) training has been shown to improve peak oxygen consumption in this population, with fewer reports of changes in O2cost. However, particularly in persons with subacute stroke, inconsistent gains in walking function are observed with minimal associations with gains in metabolic parameters. The purpose of this study was to evaluate changes in aerobic exercise performance in participants with subacute stroke following high-intensity variable stepping training as compared with conventional therapy.

METHODS

A secondary analysis was performed on data from a randomized controlled trial comparing high-intensity training with conventional interventions, and from the pilot study that formed the basis for the randomized controlled trial. Participants 1 to 6 months poststroke received 40 or fewer sessions of high-intensity variable stepping training (n = 21) or conventional interventions (n = 12). Assessments were performed at baseline (BSL), posttraining, and 2- to 3-month follow-up and included changes in submaximal (Equation is included in full-text article.)O2 ((Equation is included in full-text article.)O2submax) and O2cost at fastest possible treadmill speeds and peak speeds at BSL testing.

RESULTS

Significant improvements were observed in (Equation is included in full-text article.)O2submax with less consistent improvements in O2cost, although individual responses varied substantially. Combined changes in both (Equation is included in full-text article.)O2submax and (Equation is included in full-text article.)O2 at matched peak BSL speeds revealed stronger correlations to improvements in walking function as compared with either measure alone.

DISCUSSION AND CONCLUSIONS

High-intensity stepping training may elicit significant improvements in (Equation is included in full-text article.)O2submax, whereas changes in both peak capacity and economy better reflect gains in walking function. Providing high-intensity training to improve locomotor and aerobic exercise performance may increase the efficiency of rehabilitation sessions.Video Abstract available for more insights from the authors (see Supplemental Digital Content, http://links.lww.com/JNPT/A142).

Altered Sagittal- and Frontal-Plane Kinematics Following High-Intensity Stepping Training Versus Conventional Interventions in Subacute Stroke

BACKGROUND

Common locomotor deficits observed in people poststroke include decreased speeds and abnormal kinematics, characterized by altered symmetry, reduced sagittal-plane joint excursions, and use of compensatory frontal-plane behaviors during the swing phase of gait. Conventional interventions utilized to mitigate these deficits often incorporate low-intensity, impairment-based or functional exercises focused on normalizing kinematics, although the efficacy of these strategies is unclear. Conversely, higher-intensity training protocols that provide only stepping practice and do not focus on kinematics have demonstrated gains in walking function, although minimal attention toward gait quality may be concerning and has not been assessed.

OBJECTIVE

The present study evaluated changes in spatiotemporal and joint kinematics following experimental, high-intensity stepping training compared with conventional interventions.

DESIGN

Kinematic data were combined from a randomized controlled trial comparing experimental and conventional training and from a pilot experimental training study.

METHODS

Individuals with gait deficits 1 to 6 months poststroke received up to 40 sessions of either high-intensity stepping training in variable contexts or conventional lower-intensity interventions. Analyses focused on kinematic changes during graded treadmill testing before and following training.

RESULTS

Significant improvements in speed, symmetry, and selected sagittal-plane kinematics favored experimental training over conventional training, although increases in compensatory strategies also were observed. Changes in many kinematic patterns were correlated with speed changes, and increased compensatory behaviors were associated with both stride length gains and baseline impairments.

LIMITATIONS

Limitations include a small sample size and use of multiple statistical comparisons.

CONCLUSIONS

Improved speeds and selected kinematics were observed following high-intensity training, although such training also resulted in increased use of compensatory strategies. Future studies should explore the consequences of utilizing these compensatory strategies despite the observed functional gains.

Defining Optimal Aerobic Exercise Parameters to Affect Complex Motor and Cognitive Outcomes after Stroke: A Systematic Review and Synthesis

Although poststroke aerobic exercise (AE) increases markers of neuroplasticity and protects perilesional tissue, the degree to which it enhances complex motor or cognitive outcomes is unknown. Previous research suggests that timing and dosage of exercise may be important. We synthesized data from clinical and animal studies in order to determine optimal AE training parameters and recovery outcomes for future research. Using predefined criteria, we included clinical trials of stroke of any type or duration and animal studies employing any established models of stroke. Of the 5,259 titles returned, 52 articles met our criteria, measuring the effects of AE on balance, lower extremity coordination, upper limb motor skills, learning, processing speed, memory, and executive function. We found that early-initiated low-to-moderate intensity AE improved locomotor coordination in rodents. In clinical trials, AE improved balance and lower limb coordination irrespective of intervention modality or parameter. In contrast, fine upper limb recovery was relatively resistant to AE. In terms of cognitive outcomes, poststroke AE in animals improved memory and learning, except when training was too intense. However, in clinical trials, combined training protocols more consistently improved cognition. We noted a paucity of studies examining the benefits of AE on recovery beyond cessation of the intervention.

Variable Intensive Early Walking Poststroke (VIEWS): A Randomized Controlled Trial

BACKGROUND

Converging evidence suggests that the amount of stepping practice is an important training parameter that influences locomotor recovery poststroke. More recent data suggest that stepping intensity and variability are also important, although such strategies are often discouraged early poststroke.

OBJECTIVE

The present study examined the efficacy of high-intensity, variable stepping training on walking and nonwalking outcomes in individuals 1 to 6 months poststroke as compared with conventional interventions. Methods Individuals with unilateral stroke (mean duration = 101 days) were randomized to receive ≤40, 1-hour experimental or control training sessions over 10 weeks. Experimental interventions consisted only of stepping practice at high cardiovascular intensity (70%-80% heart rate reserve) in variable contexts (tasks or environments). Control interventions were determined by clinical physical therapists and supplemented using standardized conventional strategies. Blinded assessments were obtained at baseline, midtraining, and posttraining with a 2-month follow-up. Results A total of 32 individuals (15 experimental) received different training paradigms that varied in the amount, intensity, and types of tasks performed. Primary outcomes of walking speed (experimental, 0.27 ± 0.22 m/s vs control, 0.09 ± 0.09 m/s) and distances (119 ± 113 m vs 30 ± 32 m) were different between groups, with stepping amount and intensity related to these differences. Gains in temporal gait symmetry and self-reported participation scores were greater following experimental training, without differences in balance or sit-to-stand performance. Conclusion Variable intensive stepping training resulted in greater improvements in walking ability than conventional interventions early poststroke. Future studies should evaluate the relative contributions of these training parameters.

Feasibility of Focused Stepping Practice During Inpatient Rehabilitation Poststroke and Potential Contributions to Mobility Outcomes

BACKGROUND

Optimal physical therapy strategies to maximize locomotor function in patients early poststroke are not well established. Emerging data indicate that substantial amounts of task-specific stepping practice may improve locomotor function, although stepping practice provided during inpatient rehabilitation is limited (<300 steps/session).

OBJECTIVE

The purpose of this investigation was to determine the feasibility of providing focused stepping training to patients early poststroke and its potential association with walking and other mobility outcomes.

METHODS

Daily stepping was recorded on 201 patients <6 months poststroke (80% < 1 month) during inpatient rehabilitation following implementation of a focused training program to maximize stepping practice during clinical physical therapy sessions. Primary outcomes included distance and physical assistance required during a 6-minute walk test (6MWT) and balance using the Berg Balance Scale (BBS). Retrospective data analysis included multiple regression techniques to evaluate the contributions of demographics, training activities, and baseline motor function to primary outcomes at discharge.

RESULTS

Median stepping activity recorded from patients was 1516 steps/d, which is 5 to 6 times greater than that typically observed. The number of steps per day was positively correlated with both discharge 6MWT and BBS and improvements from baseline (changes; r = 0.40-0.87), independently contributing 10% to 31% of the total variance. Stepping activity also predicted level of assistance at discharge and discharge location (home vs other facility).

CONCLUSION

Providing focused, repeated stepping training was feasible early poststroke during inpatient rehabilitation and was related to mobility outcomes. Further research is required to evaluate the effectiveness of these training strategies on short- or long-term mobility outcomes as compared with conventional interventions.