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Power Training Post-stroke

This study is currently recruiting participants. (see Contacts and Locations)
Verified April 2017 by VA Office of Research and Development
Information provided by (Responsible Party):
VA Office of Research and Development Identifier:
First received: October 22, 2013
Last updated: April 20, 2017
Last verified: April 2017
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. The 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.

Condition Intervention Phase
Behavioral: POWER training
Phase 1
Phase 2

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Outcomes Assessor
Primary Purpose: Treatment
Official Title: Skeletal Muscle Plasticity As An Indicator of Functional Performance Post-Stroke

Further study details as provided by VA Office of Research and Development:

Primary Outcome Measures:
  • gait speed [ Time Frame: 8 weeks ]

Secondary Outcome Measures:
  • muscle strength [ Time Frame: 8 weeks ]
    The strength of the upper and lower leg muscles will be measured by asking the participants to contract their 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 the ability to generate muscle power. Before testing the participants 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.

Estimated Enrollment: 56
Actual Study Start Date: October 1, 2013
Estimated Study Completion Date: September 2017
Estimated Primary Completion Date: September 2017 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: POWER
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

Detailed Description:
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. The investigators 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. The investigators 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. The investigators' 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 the investigators propose. It is the investigators' 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.

Ages Eligible for Study:   50 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • age 50-70,
  • stroke within the past 6 to 24 months,
  • residual paresis in the lower extremity (Fugl-Meyer Lower Extremity motor score <34),
  • ability to walk without assistance and without an ankle foot orthotic (AFO) on the treadmill 30 seconds at speeds ranging from 0.3 - 0.8 m/s, and
  • provision of informed consent.
  • In addition, all subjects who meet criteria for the training portion must complete an exercise tolerance test and be cleared for participation by the study cardiologist.

Exclusion Criteria:

  • Unable to ambulate at least 150 feet prior to stroke, or experienced intermittent claudication while walking;
  • rating on Modified Ashworth Scale 3 at the knee or ankle;
  • limited lower extremity range of motion of the knee (passive flexion Range of Motion [ROM] < 90); hip (inability to achieve neutral 0 hip extension); or ankle (inability to achieve 0 of active dorsiflexion);
  • history of congestive heart failure, unstable cardiac arrhythmias, hypertrophic cardiomyopathy, severe aortic stenosis, angina or dyspnea at rest or during activities of daily living (ADLs);
  • History of chronic obstructive pulmonary disease (COPD) or oxygen dependence;
  • Preexisting neurological disorders, dementia or previous stroke;
  • History of major head trauma;
  • Legal blindness or severe visual impairment;
  • history of significant psychiatric illness
  • Life expectancy <1 yr.,
  • Severe arthritis or other problems that limit passive ROM;
  • post-stroke depression (PHQ-9 10),
  • History of deep vein thrombosis (DVT) or pulmonary embolism within 6 months;
  • Uncontrolled diabetes with recent diabetic coma, or frequent insulin reactions;
  • Severe hypertension with systolic >200 mmHg and diastolic >110 mmHg at rest;
  • Previous or current enrollment in a trial to enhance motor recovery;
  • Presence of non-magnetic resonance (MR) compatible implants, pregnancy or severe claustrophobia.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01970592

Contact: Chris M Gregory, PhD (843) 792-1078

United States, South Carolina
Ralph H. Johnson VA Medical Center, Charleston, SC Recruiting
Charleston, South Carolina, United States, 29401-5799
Contact: Chris M Gregory, PhD    843-792-1078   
Principal Investigator: Chris M Gregory, PhD         
Sponsors and Collaborators
VA Office of Research and Development
Principal Investigator: Chris M Gregory, PhD Ralph H. Johnson VA Medical Center, Charleston, SC
  More Information

Responsible Party: VA Office of Research and Development Identifier: NCT01970592     History of Changes
Other Study ID Numbers: O0844-R
Study First Received: October 22, 2013
Last Updated: April 20, 2017
Individual Participant Data  
Plan to Share IPD: No

Keywords provided by VA Office of Research and Development:

Additional relevant MeSH terms:
Cerebrovascular Disorders
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Vascular Diseases
Cardiovascular Diseases processed this record on May 25, 2017