Muscle Response to Different Amounts of Dietary Protein During Leg Immobilization

NCT07069426 | Recruiting

• 2 other identifiers: 25-04HMO240092
• Study Type: interventional
• Target: 28
• Locations: 1 country
• Sites: 1

Brief Summary

Individuals who sustain musculoskeletal injuries (MSKI) can experience a rapid loss of muscle mass due to declines in muscle loading and activation that occur post-injury (i.e., disuse atrophy). Loss of muscle under these conditions is attributed to a persistent negative net muscle protein balance (muscle protein synthesis \[MPS\] \< muscle protein breakdown) that results, in part, from declines in postprandial MPS (i.e., anabolic resistance). Nutritional interventions that enhance postprandial MPS may be used to overcome disuse-induced anabolic resistance and preserve muscle mass to accelerate recovery and improve recovery outcomes. While supplemental protein has been explored as a potential countermeasure to disuse-induce anabolic resistance, the observed efficacy of such interventions has been mixed. Equivocal findings across studies may be attributed, in part, to an insufficient understanding of what constitutes an effective protein-based intervention. Importantly, no study to date has determined an optimal protein dose for overcoming disuse-induce anabolic resistance, or if there is a threshold for maximally stimulating postprandial MPS under disuse conditions. Therefore, the objective of this work is to determine rates of MPS at rest and in response to standard (20 g) or high (40 g) doses of whey protein during knee immobilization (DISUSE) compared with standard activity (ACTIVE)

Conditions

Muscle Disuse; Muscle Disuse Atrophy

Keywords

muscle protein synthesis; muscle disuse; muscle disuse atrophy; immobilization; anabolic resistance; dose-response

Outcome Measures

Primary Outcomes (1)

• Rates of postabsorptive and postprandial muscle protein synthesis assessed using 2H5-Phenylalanine stable isotope methodologies.

  Postabsorptive and postprandial muscle protein synthesis in response to 20 or 40 g of whey protein determined using 2H5-Phenylalanine stable isotope methodologies and expressed as fractional synthetic rate (FSR).

  After 5 days of muscle disuse

Study Arms (2)

Standard Protein Dose

ACTIVE COMPARATOR

Participants will consume 20 g of whey protein after 5 days of muscle disuse

Dietary Supplement: 20 grams protein

High Protein Dose

ACTIVE COMPARATOR

Participants will consume 40 g of whey protein after 5 days of muscle disuse

Dietary Supplement: 40 grams protein

Interventions

20 grams protein DIETARY_SUPPLEMENT

20 grams of whey protein provided as beverage

Standard Protein Dose

40 grams protein DIETARY_SUPPLEMENT

40 grams of whey protein provided as beverage

High Protein Dose

Eligibility Criteria

• Age: 17 Years - 39 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Men and women aged 18-39 years (17-39 years if military personnel)
• Body mass index (BMI) between 18.5-32 kg/m2
• Routinely participate in aerobic and/or resistance exercise at least 2 days per week.
• Willing to refrain from alcohol, smoking, smokeless nicotine products (includes e-cigarettes, vaping, chewing tobacco), and dietary supplements (i.e., vitamin D, probiotics) 24 hours before and during immobilization and final testing day.
• Willing to only consume caffeine products provided by study staff during the study.
• Supervisor approval for federal civilian employees and non-SRV active-duty military personnel stationed at NSSC.
• Biological females must have normal menstrual cycles between 26-32 days in duration; 5 menstrual cycles within the past 6 months; or on continuous hormonal contraception (i.e., IUD or oral contraceptives without placebo).

You may not qualify if:

• Musculoskeletal injuries that may interfere with the safe use of crutches.
• Personal or family history of thrombosis, or prior diagnosis of deep vein thrombosis (DVT) or pulmonary embolism (PE).
• Metabolic or cardiovascular abnormalities, gastrointestinal disorders, neuromuscular disorders, lower-limb amputation, or muscle/bone wasting disorders (e.g., diabetes, cardiovascular disease, Crohn's disease, etc.).
• Taking medication that affects macronutrient utilization (i.e., statins, corticosteroids, weight loss medications such as Ozempic, etc.).
• Significantly abnormal blood clotting as determined by USARIEM Office of Medical Oversight (OMSO) or home duty station medical support (HMS).
• Allergy to lidocaine (or similar local anesthetic).
• Present condition of alcoholism, anabolic steroid use, or other substance abuse issues as determined by OMSO or HMS.
• Blood donation within 8-wk of beginning the study.
• Pregnant, trying to become pregnant, and/or breastfeeding (results of urine pregnancy test and self-report for breastfeeding will be obtained before body composition testing).
• Unwilling or unable to consume study diets or foods provided due to personal preference and/or food allergies.
• Unwilling or unable to adhere to study physical restrictions (i.e., no structured physical activity or recreational activity beyond activities of daily living) 24 hours before and during immobilization, and the final testing day.
• Unwilling or unable to keep the knee brace on and walk with crutches during the immobilization phase.

Sponsors & Collaborators

• United States Army Research Institute of Environmental Medicine: lead

Study Sites (1)

US Army Research Institute of Environmental Medicine

Natick, Massachusetts, 01760, United States

RECRUITING

MeSH Terms

Conditions

Muscular Disorders, Atrophic

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Neuromuscular Diseases; Nervous System Diseases

Central Study Contacts

Emily E Howard, PhD

CONTACT

508-206-2309; emily.e.howard14.civ@health.mli

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: FED
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 21, 2025
• First Posted: July 16, 2025
• Study Start: September 1, 2025
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): September 1, 2026
• Last Updated: September 11, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)