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Quels effets de la Beta-alanine?

23/12/2017 | Etudes Compléments alimentaires


Ca me fait exactement ça, rien du tout!

C. SMITH JSCR December 2017 - Volume 31 - Supplement 1

Beta-alanine (BA) is a precursor to carnosine which functions
as an intracellular buffer assisting in the maintenance of
intracellular pH during high-intensity efforts. Rugby is a sport
characterized by multiple intermittent periods of maximal or
near maximal efforts with short periods of rest/active recovery.

Purpose: The purpose of this study was to evaluate the
impact of 6 weeks of beta-alanine supplementation on anaerobic
performance measures in collegiate rugby players.

Methods: Twenty-one male, collegiate rugby players were recruited
while 16 completed post-testing (21 6 1.5 years; 179
6 6.2 cm; 91.2 6 11.1 kg; 20.1 6 4.3% body fat). Supplementation
was randomized in a double-blind, placebo controlled
manner between 6.4 g d21 of BA and 6.4 g$d21 of
dextrose placebo (PLA). In identical pre/post testing sessions,
body composition using dual-energy x-ray absorptiometry
(DEXA), maximal strength (1RM), anaerobic endurance and
strength endurance was assessed. Body composition was assessed
using DEXA while 1RMs were determined using the
bench press and back squat exercise. Anaerobic endurance
was assessed using distance covered (yards) during a fieldbased
intermittent sprint running test. Upper-body (bench
press; USE) and lower-body (back squat; LSE) strength endurance
was assessed using a 5 set to fatigue protocol at 70%
1RM with completed repetitions recorded after each set.
Lower body peak power endurance (LPE) was evaluated by
changes in peak power from set to set using an accelerometer
attached to the barbell. Data was analyzed using a 2 3 2 (group
3 time) mixed factorial ANOVA with repeated measures on time.
All data are presented as mean 6 SD and all missing data were
replaced with the previous value.

Results: No significant interaction
effects were noted for body weight (p = 0.92), DEXA fat
mass (p = 0.92), DEXA fat-free mass (p = 0.51) and DEXA
percent fat (p = 0.93). No significant group 3 time interaction
effects were realized for back squat (p = 0.42), however, changes
in bench press 1RM did indicate a trend for PLA to increase
(p =
0.073). No significant differences (p . 0.05) in running distance
were seen for all 6 sets (p = 0.24–0.92) of the intermittent running
test as well as total yardage (p = 0.79). Total repetitions completed
during the USE (BA: 23.2 6 9.6 vs. PLA: 2.3 6 3.9 reps,
p = 0.11) and LSE (BA: 2.4 6 4.1 vs. PLA: 20.5 6 4.0 reps, p =
0.13) revealed no significant differences.

Conclusions: BA use
appears to exert no impact on body composition parameters.
Maximal upper-body strength levels tended to be greater in
PLA, but not for back squat. BA appeared to exert no impact
on maximal intermittent sprint running performance and total
repetitions completed during USE and LSE. These findings offer
limited support for the potential impact of BA supplementation to
improve anaerobic exercise performance, however, unsatisfactory
rates of noncompliance and attrition with the study population
led to low samples sizes that hindered statistical power to
determine differences between BA and PLA. Practical

Applications: While BA has been shown to serve as an ergogenic
aid in some exercising populations, conflicting evidence exists
for strength and power athletes. Present study results offer preliminary
evidence that BA use may exert limited to no impact on
anaerobic exercise performance. Acknowledgments: We would
like to thank the NSCA Foundation for funding this project. We also
thank the generous donation of supplement from CarnoSyn, and
thank the Lindenwood University Men’s Rugby team and coaching
staff for their time and cooperation.

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