Power Training Post-stroke
Hemiparesis, strictly defined as (muscular) weakness affecting one side of the body, is seen in three-quarters of individuals following stroke. Weakness in this population results from both neural and muscular factors which include, respectively, the ability to activate skeletal muscle as well as the force generating capacity of the muscle. Our overall goal is to improve walking in persons post-stroke by training subjects with an intervention that specifically targets existing neural and muscular impairments, thereby facilitating locomotor recovery.
|Study Design:||Allocation: Non-Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||Skeletal Muscle Plasticity As An Indicator of Functional Performance Post-Stroke|
- gait speed, [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
- muscle strength [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]The strength of your upper and lower leg muscles will be measured by asking you to contract your muscles as forcefully as possible. Testing will be conducted at a range of different movement speeds (0-240 �/s) on a specialized machine called an isokinetic dynamometer. Both legs may be tested. This testing is designed to assess your ability to generate muscle power. Before testing you will be asked to perform 5 minutes of low intensity cycling. Strength testing will include movements at the hip, knee and ankle in both legs.
|Study Start Date:||October 2013|
|Estimated Study Completion Date:||September 2017|
|Estimated Primary Completion Date:||September 2017 (Final data collection date for primary outcome measure)|
Individuals with chronic post-stroke hemiparesis will undergo training to improve muscle power generation for 24 sessions (3 times/week) that includes both resistive and task-specific elements. Session duration will be ~90 minutes/day (inclusive of rest intervals). Training will include five distinct resistance activities aimed at improving muscle power-- each previously reported to contribute to improved walking.
Behavioral: POWER training
Individuals with chronic post-stroke hemiparesis will undergo training to improve muscle power generation for 24 sessions (3 times/week) that includes both resistive and task-specific elements. Session duration will be ~90 minutes/day (inclusive of rest intervals). Training will include five distinct resistance activities aimed at improving muscle power-- each previously reported to contribute to improved walking
Other Name: strength training
A primary impairment associated with post-stroke hemiparesis is the failure to make rapid graded adjustment of muscle force (i.e. muscle power) within the context of purposeful complex synergies (e.g., coordination during walking). Not surprisingly, the impact of stroke on walking is significant, with less than 50% of survivors progressing to independent community ambulation. Even among those who achieve independent ambulation, significant residual deficits persist in balance and gait speed, with ~75% of persons post-stroke reporting limitations in mobility related to walking. Muscle weakness is the most prominent motor consequence among the nearly 6 million survivors of stroke living in the United States and the strongest predictor of functional disability in this large clinical cohort. To date, the physiological mechanisms that contribute to muscle dysfunction in hemiparetic subjects are largely unstudied. Moreover, evidence regarding the efficacy of interventions aimed at attenuating impaired muscle function and the ensuing functional consequences in the post-stroke population is equivocal and viable therapeutic options to remediate hemiparetic muscle weakness remain among the most pressing challenges for biomedical research. We propose that impaired muscle power (the product of muscle strength and velocity) generation is causal of functional (walking) disability post-stroke. In addition, coordination deficits are also critical determinants of functional performance. We have developed a comprehensive theoretical framework that defines and measures the factors underlying disordered muscle function and coordination and will apply this framework to Post-stroke Optimization of Walking using Explosive Resistance (POWER) training. Our goals over the four year funding period are to 1) quantify neural and muscular adaptations that contribute to impaired muscle power generation post-stroke; 2) assess effects of POWER training on neural and muscular adaptations in paretic and non-paretic muscle; and 3) determine the relationship between changes in neural and muscular adaptations following POWER training and locomotor improvements. Innovative aspects of the proposed work include the novel training intervention; the advanced magnetic resonance assessments; as well as the unique measure of the coordination that we propose. It is our belief that: a) neural and muscular adaptations following stroke are associated with impaired muscle power generation as well as locomotor ability, b) POWER training attenuates functional deficits by addressing the underlying neural and muscular elements and c) functional improvements following training are predicated on improving the most prominent neural and muscular contributors to muscle power generation. If correct, the data generated will provide an entirely new level of evidence regarding the effectiveness of this novel intervention strategy on improving functional performance as well as the importance of peripheral muscle properties as predictors of locomotor ability post-stroke.
|Contact: Chris M Gregory, PhD||(843) 792-1078||Christopher.Gregory@va.gov|
|United States, South Carolina|
|Ralph H. Johnson VA Medical Center, Charleston, SC||Recruiting|
|Charleston, South Carolina, United States, 29401-5799|
|Contact: Sarah A Jackson, BA MA 843-789-7587 firstname.lastname@example.org|
|Principal Investigator: Chris M. Gregory, PhD|
|Principal Investigator:||Chris M. Gregory, PhD||Ralph H. Johnson VA Medical Center, Charleston, SC|