Hormonal and functional responses to L-Arginine supplementation during recovery in football players

The physiological demands of soccer are complex, and is partly a consequence of the nature of the exercise pattern. The purpose of this study was to investigate the effect of L-Arginine supplementation on functional tests and blood Testosterone level after a football match.
This semi-experimental study with supplementation performed on football players. At first, written consents were obtained, then fasting blood samples were taken. Then, in the afternoon, speed, muscular power and aerobic endurance tests were performed. 48 hours later a football match was held. 10 min after the match, functional tests were re-tested. One day after the match, fasting blood samples were obtained. Then, players randomly divided in two groups: Supplement (N=11) and Placebo (N=11). During a 4-day recovery, supplement and placebo groups received 6 g L-Arginine and one tablet vitamin C 250 per day, respectively. After four days, fasting blood samples were drawn and subjects performed functional tests in the afternoon of the same day. To measure speed, muscular power and aerobic endurance, 35 Miter Speed, vertical jump and 1.5-Mile Run tests performed, respectively. To analyze data, repeated measures ANOVA was used.
Results showed that performance and testosterone concentration after the match decreased (p .05). Also, results showed that after recovery significant difference was found between groups only in aerobic endurance (p= .045).
After the football match, performance and testosterone concentration were decreased, and the consumption of L-Arginine during recovery significantly increased the aerobic endurance.