Effects of Muscle Cooling on Motor Unit Firing of the Quadriceps

Official title

Effects of Muscle Cooling on Motor Unit Firing of the Quadriceps: A Pilot Feasibility Study

Overview

The overall objective of this pilot study is to establish the feasibility and methodological validity of using high-density surface electromyography to characterize motor unit behavior of the quadriceps under thermoneutral and locally cooled conditions, and to generate preliminary data to inform the design of a larger, hypothesis-driven study.

Detailed description

This randomized, cross-over pilot study will recruit 24 healthy young adults (12 men and 12 women) between the ages of 18 and 35 years. Participants will attend two in-person laboratory visits separated by a minimum of 48 hours. Visit 1 will include informed consent, eligibility confirmation, baseline assessments, and familiarization procedures. Visit 2 will include experimental testing under thermoneutral and cooled conditions.

Interventions

• Procedure Cryotherapy
  For the cold condition, an Aircast Thigh Pad (Aircast), connected to the Cryo Cuff IC cooler (DJO Global, Vista, California, USA) will be applied to the dominant thigh. The system circulates ice water maintained at approximately 10-15°C with intermittent compression. Cooling duration will be individualized based on mid-thigh skinfold thickness, consistent with published recommendations that account for the effect of subcutaneous tissue on intramuscular cooling9. Participants with a mid-thigh ski

Primary outcome measures

• Motor Unit (MU) Yield [Time frame: Immediately after the intervention]
• HDsEMG Decomposition Accuracy [Time frame: Immediately after the intervention]
• Proportion of Analyzable MVC Trials [Time frame: Immediately after the intervention]

Secondary outcome measures (2)

• Slope of MUAP-FR relationship [Time frame: Immediately after the intervention]
• Y-intercept of MUAP-FR relationship [Time frame: Immediately after the intervention]

Eligibility criteria

Inclusion criteria

• Men and women between the ages of 18 and 35 years
• Healthy adults, defined as absence of significant acute/chronic medical condition, injury, and/or illness that may compromise subject safety, limit the ability of the participant to complete the study, and/or compromise the objectives of the study as determined by the Principal Investigator.

Exclusion criteria

• Current diagnosis or history of:

• major metabolic disease (e.g., type I and type II diabetes),
• neuromuscular disease (e.g., cervical spondylotic radiculomyelopathy, lumbar spondylosis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, and acquired demyelinating polyneuropathies),
• cardiovascular disease (e.g., stage II hypertension, heart failure, myocardial infarction/ischemia, peripheral vascular disease, Raynaud's phenomenon, or other conditions associated with impaired peripheral circulation),
• significant myocardial or pericardial diseases (e.g. amyloidosis, constriction),
• moderate or severe valvular disease,
• pulmonary/respiratory disease (e.g., asthma, chronic bronchitis, emphysema, chronic obstructive pulmonary disease),
• cancer,
• renal disease,
• liver disease,
• or anemia.
• Current or recent musculoskeletal injury (e.g. fracture, sprain, dislocation) or any physical disability that precludes safe and adequate testing.
• Pregnancy or breastfeeding.
• Thigh circumference greater than 23 inches
• Mid-thigh skinfold thickness greater 40 mm

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Crossover

Masking

Open label

Primary purpose

Basic science

Study locations

United States · 1 center

• Department of Health and Exercise Science at Wake Forest University — Winston-Salem

Identifiers

NCT: NCT07381920 · IRB00026267

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗