Neuromuscular and Biomechanical Control of Lower Limb Loading in Individuals With Chronic Stroke

• ClinicalTrials.gov Identifier: NCT03694028
• Recruitment Status: Recruiting
• First Posted: October 3, 2018
• Last Update Posted: January 5, 2022
• Sponsor: University of Maryland, Baltimore
• Information provided by (Responsible Party): Vicki Gray, University of Maryland, Baltimore

Study Description

Brief Summary:

Stroke is the leading cause of long-term disability in the U.S. Individuals with hemiparesis due to stroke often have difficulty bearing weight on their legs and transferring weight from one leg to the other. The ability to bear weight on the legs is important during functional movements such as rising from a chair, standing and walking. Diminished weight transfer contributes to asymmetries during walking which commonly leads to greater energy expenditure. Moreover, deficits in bearing weight on the paretic leg contribute to lateral instability and are associated with decreased walking speed and increased risk of falling in individuals post-stroke. These functional limitations affect community participation and life quality. Thus, restoring the ability to bear weight on the legs, i.e., limb loading, is a critical goal for rehabilitation post-stroke. The purpose of this research is to identify the impairments in neuromechanical mechanisms of limb loading and determine whether limb loading responses can be retrained by induced forced limb loading.

Condition or disease	Intervention/treatment	Phase
Stroke; Hemiparesis	Other: Limb Loading; Other: Conventional Training	Not Applicable

Detailed Description:

Stroke is the leading cause of long-term disability in the U.S. Individuals with hemiparesis due to stroke often have difficulty bearing weight on the paretic lower extremity and transferring weight from one leg to the other. Impaired weight transfer and limb loading contribute to lateral instability and are associated with decreased walking speed and increased risk of falling. Consequently, restoring limb loading ability is an important goal for rehabilitation post-stroke. Despite considerable rehabilitation efforts aimed at enhancing paretic limb loading, their effectiveness on improving neuromotor and functional outcomes remains limited possibly due to poorly understood limb loading mechanisms and the reluctance to use the paretic limb. The coordination of neuromuscular actions to regulate loading force during weight acceptance is an important component of functional limb loading. Because altered neuromuscular control is common in persons with stroke, it is possible that these abnormalities may impair limb loading ability. The long-term objective of this project is to develop a mechanism-based framework for designing and testing the effectiveness of novel rehabilitation interventions to enhance lower limb weight transfer and limb loading to improve balance and mobility. This project aims to (1) identify the neuromuscular and biomechanical abnormalities in limb loading responses in individuals post-stroke, (2) determine the underlying mechanisms responsible for the deficits in limb loading, and (3) test the short-term effectiveness of a 6-week perturbation-induced limb load training program on improving limb loading responses and mobility function. The investigators propose to apply a sudden unilateral lowering of the supporting surface to induce lateral weight transfer that forces limb loading. Kinetic, kinematic, and lower extremity muscle activation patterns will be recorded. The investigators expect that, compared to healthy controls, individuals with stroke will show increased muscle co-activation of the knee musculature with decreased knee flexion and torque production, and irregular impact force regulation during loading that will disrupt weight transfer and loading of the paretic limb. Furthermore, the investigators hypothesize that compared to a conventional clinical weight-shift rehabilitation training program, the imposed limb loading group will show greater improvements during voluntary stepping and walking following training. Specifically, the investigators expect the knee muscle co-activation duration will be reduced, with increased knee joint torque, and the paretic single stance/double support time will increase, reflecting improved paretic limb loading ability during gait following training.

Study Design

• Study Type: Interventional (Clinical Trial)
• Estimated Enrollment: 36 participants
• Allocation: Randomized
• Intervention Model: Factorial Assignment
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: Neuromuscular and Biomechanical Control of Lower Limb Loading in Individuals With Chronic Stroke
• Actual Study Start Date: February 4, 2019
• Estimated Primary Completion Date: May 31, 2022
• Estimated Study Completion Date: May 31, 2022

Arms and Interventions

Arm	Intervention/treatment
Experimental: Limb Loading; This group will be exposed to a sudden unilateral lowering of the supporting surface to induce lateral weight transfer of the paretic limb.	Other: Limb Loading; Participants will be assigned to one of two interventions. The intervention will occur 3 times a week for six weeks (18 sessions) each session for one hour.
Active Comparator: Conventional Training; This group will practice weight shifting and step training that focuses on the paretic limb.	Other: Conventional Training; Participants will be assigned to one of two interventions. The intervention will occur 3 times a week for six weeks (18 sessions) each session for one hour.

Outcome Measures

Primary Outcome Measures :

1. Gait single stance time asymmetry and duration ratio [ Time Frame: Post training at 6 weeks ]
   single stance time asymmetry and duration ratio
2. Gait paretic double support/single stance [ Time Frame: Post training at 6 weeks ]
   paretic double support/single stance
3. Stepping weight transfer time [ Time Frame: Post training at 6 weeks ]
   weight transfer time
4. Stepping knee angular displacement [ Time Frame: Post training at 6 weeks ]
   knee angular displacement
5. Stepping peak torque [ Time Frame: Post training at 6 weeks ]
   peak torque

Eligibility Criteria

• Ages Eligible for Study: 18 Years and older (Adult, Older Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Criteria

Inclusion Criteria:

• Hemiparesis as a result of a stroke greater than 6 months previous to the study if participants with stroke.
• Able to walk 10 meters with or without a walking aid.
• Able to stand unsupported for 5 minutes.

Exclusion Criteria:

• Medical condition precluding participation in regular exercises, such as acute cardiac or respiratory conditions limiting activity and other health conditions significantly impacting the ability to walk beyond the effects of the stroke, such as other neurological conditions or peripheral neuropathies.
• Not able to follow commands.
• Pregnancy by self-report.

Contacts and Locations

Contacts

Contact: Vicki Gray, PhD; 410-706-3778; vicki.gray@som.umaryland.edu

Contact: Janice Abarro, B.S.; 410-706-0856; jabarro@som.umaryland.edu

Locations

United States, Maryland

PTRS Research Lab; Recruiting

Baltimore, Maryland, United States, 21201

Contact: Vicki L Gray, MPT, PhD 410-706-3778 vicki.gray@som.umaryland.edu

Contact: Janice Abarro, BS 410-706-0856 jabarro@som.umaryland.edu

Principal Investigator: Vicki L Gray, MPT, PhD

Sponsors and Collaborators

University of Maryland, Baltimore

Investigators

• Principal Investigator: Vicki L Gray, MPT, PhD; Assistant Professor

More Information

• Responsible Party: Vicki Gray, Assistant Professor, University of Maryland, Baltimore
• ClinicalTrials.gov Identifier: NCT03694028
• Other Study ID Numbers: HP-00072173
• First Posted: October 3, 2018
• Last Update Posted: January 5, 2022
• Last Verified: January 2022

Individual Participant Data (IPD) Sharing Statement:

• Plan to Share IPD: No

• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No

Keywords provided by Vicki Gray, University of Maryland, Baltimore:

biomechanical; kinematic; muscle coactivation; torque

Additional relevant MeSH terms:

Stroke; Paresis; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Neurologic Manifestations