Skeletal Muscle Response to Amino Acids and Load Carriage Exercise

Study Overview
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Brief Summary
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Warfighters often experience physical overload, as the uniform and associated gear that they carry burdens them with substantial loads. The loads increase energy expenditure to levels that exceed a Warfighter's typical energy intake. The typical assault load is approximately 25 kg, although loads as high as 55 kg are often carried, which when combined with extreme energy expenditures can degrade health and performance, and increase the risk of injury. Branched-chain amino acid (leucine) supplementation may confer protection against the negative effects of operational stress by stimulating muscle protein synthesis and reducing degradation. This study will determine if leucine-enriched nutrition supplementation confers protection against the negative consequences of sustained load carriage exercise, and explore the mechanisms by which leucine might impart protection.

Official Title
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Skeletal Muscle and Physical Performance Responses to Leucine-Enriched Nutrition Supplementation During Load Carriage

Conditions
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Muscle Loss, Muscle Anabolism, Muscle Performance

Intervention / Treatment
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* Other: Leucine-enriched nutritional supplement
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Weight stable (±5 lbs)with a body mass index between 22-29 kg/m2 and a VO2peak of 40 - 60 ml/kg/min Willing to refrain from taking any NSAIDS (i.e., aspirin, Advil®, Aleve®, Naprosyn®), or any aspirin-containing products, alchohol, and nicotine Females must be on oral contraception Exclusion Criteria: Metabolic or cardiovascular abnormalities, gastrointestinal disorders Disease or medication that affects macronutrient metabolism or the ability to participate in strenuous exercise Allergies or intolerance to foods (e.g. lactose intolerance/milk allergy), vegetarian practices, or medications (including, but not limited to, lidocaine or phenylalanine) to be used in the study Anemia (HCT <38) and Sickle Cell Anemia/Trait, abnormal PT/PTT test or problems with blood clotting Present condition of alcoholism, use of nutritional/sports supplements, anabolic steroids, or other substance abuse issues Musculoskeletal injuries that compromise the ability to exercise Blood donation within 8 weeks of enrollment Pregnancy and women not on oral contraceptives

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 39 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Load Carriage - Control<br>Load Carriage - with a calorie-free placebo | Other: Placebo<br> <br> |
| Experimental: Load Carriage - leucine-enriched nutrition supplement<br>Load Carriage with leucine-enriched amino acid supplementation | Other: Leucine-enriched nutritional supplement<br>* A protein and carbohydrate supplement with high levels of leucine<br>|
| Placebo Comparator: Conventional Exercise - Control<br>Conventional Exercise with a calorie-free placebo | Other: Placebo<br> <br> |
| Active Comparator: Conventional Exercise - Leucine-enriched Nutrition Supplement<br>Conventional Exercise with leucine-enriched Amino Acid supplementation | Other: Leucine-enriched nutritional supplement<br>* A protein and carbohydrate supplement with high levels of leucine<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in muscle protein synthesis and whole-body protein turnover during and after load carriage or conventional exercise with or without amino acid supplementation |  | 90 min exercise bout (exercise) and 180 min of recovery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in muscle performance in recovery from load carriage or conventional exercise with or without amino acid supplementation |  | 4, 24, 48, and 72 hours post exercise |