NCT07069426

Muscle Response to Different Amounts of Dietary Protein During Leg Immobilization

The Effects of Varying Protein Intakes on Muscle Protein Synthesis During Injury-Mediated Muscle Disuse

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 28 (estimated)
• Sponsor: United States Army Research Institute of Environmental Medicine · Federal
• Sex: All
• Age: 17 Years – 39 Years
• Healthy volunteers: Accepted

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)

Detailed description

Healthy, recreationally active men and women will complete this randomized, double-blind, parallel study. Muscle disuse will be implemented for five days using a unilateral leg immobilization model with one leg assigned to immobilization (DISUSE) and the contralateral leg used as a control (ACTIVE). Immobilization will be implemented with a rigid knee brace fixed at \~60° of flexion and participants will ambulate using crutches. Diets will be standardized during the immobilization phase. Participants will complete a protein feeding study at the end of immobilization consisting of primed, continuous stable isotope infusions, serial blood draws, and muscle biopsies. MPS will be assessed in both the DISUSE and ACTIVE legs in response to standard (20 g) or high (40 g) doses of whey protein. Findings from this work will directly inform the development of targeted nutritional countermeasures for overcoming disuse-induced anabolic resistance and preserving muscle mass after MSKI to optimize physical performance recovery.

Conditions

• Muscle Disuse
• Muscle Disuse Atrophy

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	20 grams protein	20 grams of whey protein provided as beverage
DIETARY_SUPPLEMENT	40 grams protein	40 grams of whey protein provided as beverage

Timeline

• Start date: 2025-09-01
• Primary completion: 2026-09-01
• Completion: 2026-09-01
• First posted: 2025-07-16
• Last updated: 2025-09-11

Locations

1 site across 1 country: United States