Protein dose effects on muscle during five days of one-leg immobilization
Official title: The Effects of Varying Protein Intakes on Muscle Protein Synthesis During Injury-Mediated Muscle Disuse
Run by United States Army Research Institute of Environmental Medicine · NCT07069426 · Data updated 2026-11-12
This test compares 20 grams versus 40 grams of whey protein to see which dose better preserves muscle protein synthesis in healthy 18–39-year-olds during five days of one-leg immobilization.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 17 Years to 39 Years |
| Sex | All |
| Enrollment | 28 (estimated) |
| Sponsor | United States Army Research Institute of Environmental Medicine Federal |
| Locations | 1 site (Natick, Massachusetts) |
| Status | Recruiting |
| Started | September 1, 2025 |
| Main results expected | September 2026 |
| Study ends | September 2026 |
| Registry record updated | September 11, 2025 |
| Trial ID | NCT07069426 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal participants are healthy, recreationally active men and women aged 18–39 with BMI 18.5–32 kg/m2 who can safely use crutches, follow a standardized diet, and tolerate muscle biopsies.
✕Probably not a fit
People outside the age or BMI ranges, those with musculoskeletal injuries that prevent safe crutch use, older adults, or individuals with chronic health conditions are unlikely to receive direct benefit from this protocol.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
Healthy, recreationally active men and women aged 18–39 will be randomized in a double-blind, parallel design to receive either 20 g or 40 g of whey protein after five days of unilateral leg immobilization. Immobilization is achieved with a rigid knee brace set at about 60° of flexion while participants ambulate with crutches and consume a standardized diet. At the end of the immobilization period participants undergo a protein feeding protocol with primed, continuous stable isotope infusions, serial blood draws, and muscle biopsies from both the immobilized and control legs. Muscle protein synthesis responses to the two protein doses will be compared to determine whether a higher protein dose overcomes disuse-induced anabolic resistance.
Why it matters
Potential benefit: If successful, the findings could identify a protein dosing strategy that helps preserve muscle mass and speed recovery after short-term limb immobilization.
How similar studies have gone: Previous protein supplementation studies during disuse have produced mixed results, and this direct 20 g versus 40 g dose comparison using stable isotope tracers and biopsies is a relatively novel way to clarify effective protein amounts.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * 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). Exclusion Criteria: * 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.
Where it's running
-
US Army Research Institute of Environmental Medicine
Natick, Massachusetts, United States Recruiting
Study contacts
- Study coordinator: Emily E Howard, PhD
- Email: emily.e.howard14.civ@health.mli
- Phone: 508-206-2309
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.