Short Term Immobilization of the Lower Limb (STILL)

Short-term Immobilization and Rehabilitation of the Lower Limb: Changes in Strength, Size, and Neuromuscular Function

The purpose of this study is to determine the effects of one week of knee-joint immobilization on muscle size, strength, neuromuscular function, and brain function. In addition, the effects of two different interventions (i.e., neuromuscular electrical stimulation and action observation/mental imagery) throughout immobilization will be determined. Following the immobilization period, participants that have lost strength will be rehabilitated with twice weekly resistance training sessions, and sex-based differences in rehabilitation timelines will be examined.

Study Overview

• Status: Completed
• Conditions: Muscle Weakness; Muscle Atrophy; Muscle Loss; Weakness, Muscle; Injury, Knee
• Intervention / Treatment: Other: Neuromuscular Electrical Stimulation; Other: Action Observation + Mental Imagery

Detailed Description

This study will utilize a repeated measures design in healthy adults aged 18-40 years. After a thorough familiarization visit, muscular size, strength, neuromuscular responses, and corticospinal excitability/inhibition will be measured before (PRE) and after (POST) one week of unilateral knee joint immobilization of the left leg. Four groups will be examined: 1) immobilization only, 2) immobilization + daily neuromuscular electrical stimulation, 3) immobilization + daily action observation/mental imagery training, 4) a control group. Throughout the immobilization period, participants will be in a leg brace locked at 90 degrees knee flexion. They will perform daily range of motion exercises and wear a compression sock at all times to mitigate the risk of blood clots. Following completion of the immobilization period, participants that have lost strength will complete a supervised rehabilitation program of twice weekly lower body resistance training sessions until they have returned to baseline levels of strength. Group assignment will be randomized and blocked on sex to ensure an equal number of participants within each group consisting of a relatively equal number of males and females.

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Orlando, Florida, United States, 32816
      • University of Central Florida

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy men and women between the ages of 18-40 years
• Body mass index >20 kg/m2 or < 35 kg/m2

Exclusion Criteria:

• Body mass index <20 kg/m2 or > 35 c
• Experience of major joint pain/discomfort of the upper or lower limbs, back, or neck within the previous six months.
• History of major musculoskeletal injury or surgery
• Neuromuscular disease (e.g., Parkinson's, MS, ALS)
• Metabolic disease (e.g., diabetes, thyroid disorder, metabolic syndrome)
• Personal or family history of blood clots
• Trouble using or controlling one's muscles
• History of cancer
• History of stroke
• History of heart attack
• History of arthritis
• Use of an assistive walking device or mobility aids within the past six months
• Use of anabolic steroids within the past six months
• History of convulsions, seizures, or syncope
• History of concussion as diagnosed by a physician
• Certain medications (e.g., muscle relaxants, benzodiazepines)
• Very thick hair or certain hairstyles that would impede the TMS coil from making direct contact with the scalp
• Allergy to rubbing alcohol
• Lack of transportation to and from the laboratory
• Implant of any kind
• Pregnancy
• Allergy to silver
• Diagnosis of any psychiatric condition

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Immobilization; Participants in the immobilization groups will undergo one week of unilateral knee joint immobilization of the left leg.	Other: Neuromuscular Electrical Stimulation; Participants in this group will perform twice daily neuromuscular electrical stimulation training sessions of the quadriceps muscles (specifically, the vastus lateralis and rectus femoris) or the immobilized left leg.; Other: Action Observation + Mental Imagery; Participants in this group will perform daily action observation + mental imagery training via video and audio recordings.
No Intervention: Control; The control group will not undergo any intervention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscular strength	Changes in muscular strength will be measured via maximal voluntary contraction torque	15 minutes
Muscular size	Changes in muscular size will be measured via ultrasonography of the quadriceps	10 minutes
Corticospinal responses	Corticospinal responses will be measured with transcranial magnetic stimulation targeting the lower limbs	30 minutes
Motor unit behavior	Motor unit recruitment threshold and firing rate will be measured with surface electromyography signals detected from the quadriceps	10 minutes
Voluntary activation	Voluntary activation will be measured using the interpolated twitch technique	15 minutes
Rate of recovery	The time taken to recover strength lost will be measured via number of resistance training sessions needed after immobilization	1.5 hours per session

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Compliance	Compliance will be measured via the use of accelerometers around both ankles. Compliance will be calculated as the number of participants that following the crutch/brace protocol as described.	one week
Physical activity (Step count)	Physical activity will be assessed via step counts and compared to changes in primary outcome measures via accelerometers around both ankles	one week

Collaborators and Investigators

• Sponsor: University of Central Florida
• Investigators: Principal Investigator: Matt S Stock, PhD, University of Central Florida

Publications and helpful links

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start (Actual): October 11, 2021
• Primary Completion (Actual): June 1, 2022
• Study Completion (Actual): July 1, 2022

Study Registration Dates

• First Submitted: September 28, 2021
• First Submitted That Met QC Criteria: September 28, 2021
• First Posted (Actual): October 11, 2021

Study Record Updates

• Last Update Posted (Actual): August 19, 2022
• Last Update Submitted That Met QC Criteria: August 17, 2022
• Last Verified: August 1, 2022

More Information

Terms related to this study

• Keywords: rehabilitation; muscle strength; neuromuscular electrical stimulation; action observation; immobilization; muscle atrophy; mental imagery
• Additional Relevant MeSH Terms: Pathologic Processes; Nervous System Diseases; Neurologic Manifestations; Wounds and Injuries; Leg Injuries; Musculoskeletal Diseases; Muscular Diseases; Neuromuscular Manifestations; Pathological Conditions, Anatomical; Muscle Weakness; Muscular Atrophy; Atrophy; Knee Injuries; Asthenia
• Other Study ID Numbers: 00003289

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: IPD will be shared by the PI upon reasonable request. Personal identifiable information will not be shared; however, physiological data and outcome measures may be shared if requested.
• IPD Sharing Time Frame: Data will be made available upon reasonable request after the time of study completion and manuscript publication
• IPD Sharing Access Criteria: To access IPD, please contact the study PI.
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No