Seventy-eight recreational athletes who never resistance trained will be randomly assigned into three groups of twenty-six. Branched-chain amino acid will be supplemented for 18days at 0, 200 or 400 mg/body weight(kg)/day in jelly. Participants will be asked to perform elbow flexions on the 12th day of supplementation. Maximum voluntary contractions will be measured before, during and after the supplementation period to compare the effects of different doses of branched-chain amino acid has on muscle damage markers.
Previous studies have not been able to show consistent effects due to various reasons. The major limitations are the lack of enough data on the amount and duration of branched-chain amino acid supplementation, and the level of muscle damage for branched-chain amino acid to be effective. Based on a recent meta-analysis, it has been suggested that to be effective, branched-chain amino acid should be supplemented more than 200mg/kg/day before a low-to-moderate intensity exercise bout. Therefore, this study is designed based on the above suggestions and to compare the effect of different doses of branched-chain amino acid on muscle damage markers in healthy recreational active individuals. Three treatment groups (n=26) will be randomly assigned to be supplemented with either 200mg BCAA/kg/day (BCAA200), 400mg BCAA/kg/day (BCAA400) or placebo (fiber supplement; PL). Supplements will be provided in jelly in a single blind fashion to be ingested 1hour after each of the three main daily meals for 18days. Anthropometric measurements (body weight, lean mass, height), body temperature, ultrasound (US), strength assessment (maximal voluntary contraction, MVC), resting metabolic rate (RMR), rate of perceived exertion (RPE), delayed onset of muscle soreness (DOMS) and blood samples (duplicates; myoglobin; BCAA) will be collected before, during and after the supplementation period at different time points (see appendix for the above tables). Repeated-bout effect (RBE) on both arms will be measured 7 days after the damage inducing session.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
78
BCAA supplement based on 200mg/kg/day for 18 days.
Fiber supplement jelly for 18 days.
BCAA supplement based on 400mg/kg/day for 18 days.
Exercise Nutrition Laboratory (Western University)
London, Ontario, Canada
RECRUITINGChange in maximum voluntary contraction (MVC)
Participants will be asked to perform three repetitions of concentric elbow flexion at their maximal force (1RM) with both their dominant and non-dominant arm on an isokinetic dynamometer (Biodex).
Time frame: baseline (before supplementation) and at 1,3,24,48,72,96,120,144 hours after muscle damage
Change in blood myoglobin
Blood myoglobin will be measured with Enzyme-Linked Immunosorbent Assay.
Time frame: 10 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
Change in 3-methyl-histidine
Ultra-performance liquidchromatography tandem mass spectrometry (UPLC-MS/MS) using an Acquity Ultra Performance LC system coupled to a Waters Quattro Premier XE mass spectrometer (bothWaters Corporation, Milford, MA, USA) and the Waters MassLynx Software (Version 4.1).
Time frame: 10 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
Changes in insulin
Blood insulin will be measured with a standard insulin radioimmunoassay kit.
Time frame: 10 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
Change in muscle soreness
Perceived muscle soreness will be determined by asking participants to stand in the anatomical position while flexing the shoulder of the exercised arm at 90degrees and fully extending the elbow. Participants will be asked to determine their forearm flexor muscles soreness with the use of a visual analogue scale (VAS) and rate from 1 being no pain and 10 being extremely painful.
Time frame: 10 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
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Participants will be asked to perform muscle damaging elbow eccentric contraction exercise at 120% of 1RM for three sets of 15 repetitions with the dominant arm at maximal effort on a Biodex machine with a 3 minute rest period between each set.
Change in ultrasound images of the arm muscles
Ultrasound measurements will be used to scan the triceps brachii and the forearm flexors. A permanent marker will be used to mark the elbow joint as the origin and both the belly of the triceps and the belly of the flexor digitorum profundus as the end point so as to compare the echoic difference in both the upper and lower arms.
Time frame: 10 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
Change in limb girth
Limb girth of the upper arm (between the lateral epicondyle of the humerus and the acromion process) and the lower arm (between the lateral epicondyle of the humerus and the styloid process of the radius) will be measured with an anthropometric tape when the arm is naturally hanging down.
Time frame: 10 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
Change in body temperature
Body temperature will be measured with an ear thermometer
Time frame: 20 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
Change in resting metabolic rate
Resting metabolic rate will be measured with a metabolic cart
Time frame: 20 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage
Change in range of motion
Range of motion of the arm will be measured by asking the participant to stand in the anatomical position while fully flexing the shoulder of the exercised arm and then extending the elbow to an angle that they do not feel any pain in the arms. A goniometer will be used to measure the angles.
Time frame: 20 min before muscle damaging exercise and at each of 1,3,24,48,72,96,120,144 hours after muscle damage