Bescos, R., Gonzalez-Haro, C., Pujol, P., Drobnic, F., Galilea, P. A., Alonso, E., Santolaria, M. L., & Ruiz, O. (2008). Effect of L-Arginine enriched diet on running economy of elite tennis players. ACSM 55th Annual Meeting Indianapolis. Presentation number 2199.

This study determined whether L-Arginine supplementation modified the different parameters related with running economy during a running test on a treadmill. On three occasions, elite male tennis players (N = 9) ingested L-Arginine diets over three consecutive days with a wash-out period of four days in between occasions. A control condition consisted of ~5.5 g/day of L-Arginine. A moderate supplementation condition consisted of ~9.0 g/day of L-Arginine. A high-dose condition consisted of ~20.5 g/day of L-Arginine. The day after every treatment, plasma and urine nitrate levels were determined. Ss also performed an incremental submaximal test (initial speed of 10 km/hour, load increasing by 1 km/hour every four minutes with the test finishing one stage after having achieved the anaerobic threshold). Throughout the test, VO2 and heart rate were monitored, and at the end of each stage a lactate sample was taken.

No significant differences were observed in any of the cardiorespiratory and metabolic parameters between the three treatments, neither in urine nor plasma nitrate levels.

Implication. The oral supplementation of 20 gr/day of L-Arginine during the days before a physical effort does not elicit improvements in the running economy measured by VO2, lactate, and heart rate.

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