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Protein Distribution and Leucine Supplementation Effects on Body Composition and Performance in Tactical Athletes
Sponsor: Tel Aviv University
Summary
This randomized controlled trial will examine the effects of within-day protein distribution and leucine supplementation on body composition, physical performance, and biomarkers of muscle damage in tactical athletes during an 8-week intensive training program. Sixty-nine healthy male participants (18-35 years) enrolled in a Ministry of Defense training course will be randomly assigned to one of three iso-caloric dietary groups providing 1.6 g/kg/day of protein: (1) evenly distributed protein across three meals (EVEN), (2) a 16-hour daily protein fasting pattern with protein concentrated at lunch and dinner (FAST), or (3) the same fasting pattern with 5 g leucine supplementation at breakfast (FAST-RESCUE). Primary outcomes include changes in lean body mass. Secondary outcomes include strength, anaerobic performance, and biochemical markers of muscle damage, including urinary titin N-terminal fragment (UTF). Assessments will be conducted at baseline, Week 5, and Week 8.
Official title: The Effect of Protein Distribution and Leucine Supplementation on Body Composition, Physical Performance, and Myofibrillar Damage in Tactical Athletes: a Randomized Controlled Trial During 8 Weeks of Intensive Training
Key Details
Gender
MALE
Age Range
18 Years - 35 Years
Study Type
INTERVENTIONAL
Enrollment
69
Start Date
2026-03
Completion Date
2028-12
Last Updated
2026-03-02
Healthy Volunteers
Yes
Conditions
Interventions
L-leucine supplementation
Participants ingest 5 g free-form L-leucine at breakfast (\~08:00) daily for 8 weeks. Leucine is provided as unflavored, pharmaceutical-grade instantized powder, reconstituted in water and consumed at the protein-free breakfast meal.
Even Protein Distribution
Iso-caloric diet providing 1.6 g/kg/day protein evenly distributed across three daily meals for 8 weeks.
Skewed Protein Distribution (16-hour Protein-Fasting Window)
Iso-caloric diet providing 1.6 g/kg/day protein with protein omitted at breakfast and concentrated at lunch and dinner, creating a 16-hour daily protein-free window for 8 weeks.