No Effect of -alanine on Muscle Function and Kayak Performance

作者：Bech Signe Refsgaard; Nielsen Tobias Schmidt; Hald Martin; Jakobsen Jarl Pors; Nord**org Nikolai Baastrup^*

来源：Medicine and Science in Sports and Exercise, 2018, 50(3): 562-569.

DOI：10.1249/MSS.0000000000001447

• KAYAK ERGOMETER
• VO2
• MVC
• TWITCH FORCE
• EMG

Purpose If -alanine supplementation counteracts muscular fatigue development or improves athletic performance was investigated.
Methods Elite kayak rowers (10 men and 7 women) were supplemented with either 80 mgkg(-1) body massd(-1) of -alanine or placebo for 8 wk. Muscular fatigue development was investigated by applying a 2-min elbow flexor maximal voluntary contraction (MVC). EMG was recorded continuously, and voluntary activation was determined 30, 60, 90, and 115 s into the 2-min MVC. In addition, performance was evaluated as 1000-m and 5 x 250-m kayak ergometer rowing.
Results Force reduction during the 2-min MVC was similar before and after supplementation with -alanine (30.9% 10.3% vs 36.0% +/- 14.1%) and placebo (35.5% +/- 7.7% vs 35.1% +/- 8.0%). No time effect was apparent in voluntary activation during the 2-min MVC. In addition, there was no detectable effect of -alanine supplementation on 1000-m kayak ergometer performance (-alanine: 0.26% +/- 0.02% vs placebo: -0.18% +/- 0.02%) or accumulated 5 x 250-m time (-alanine: -1.0% +/- 0.3% vs placebo: -1.0% +/- 0.2%). In 5 x 250 m, mean power output was reduced to a similar extent from first to fifth interval before and after supplementation with -alanine (23% +/- 11% vs 22% +/- 10%) and placebo (26% +/- 13% vs 20% +/- 5%).
Conclusions Two-minute MVC characteristics are unaffected by -alanine supplementation in elite kayakers, and likewise, both a 1000-m kayak ergometer time trial lasting 4-5 min and a 5 x 250-m repeated sprint ability were unaltered by supplementation.

• 出版日期2018-3