Increase in Maximal Cycling Power With Acute Dietary Nitrate Supplementation.

UNLABELLED

Muscle-shortening velocity and hence power have been shown to increase in the presence of nitric oxide (NO). NO availability increases after consuming nitrate (NO). Ingestion of NOrich beetroot juice (BRJ) has increased muscle power in untrained adults.

PURPOSE

This study determined whether NO supplementation could acutely enhance maximal power in trained athletes.

METHODS

In this double-blind, crossover study, 13 trained athletes performed maximal inertial-load cycling trials (3-4 s) immediately before (PRE) and after (POST) consuming either NOrich (NO3) or NOdepleted (PLA) BRJ to assess acute changes (ie, within the same day) in maximal power (P) and optimal pedaling rate (RPM). Participants also performed maximal isokinetic cycling (30 s) to assess performance differences after supplementation.

RESULTS

2 x 2 repeated-measures ANOVA indicated a greater increase in P from PRE to POST NO3 (PRE 1160 ± 301 W to POST 1229 ± 317 W) than with PLA (PRE 1191 ± 298 W to POST 1213 ± 300 W) (P = .009; η = 0.45). A paired t-test verified a greater relative change in P after NO3 (6.0% ± 2.6%) than with PLA (2.0% ± 3.8%) (P = .014; d = 1.21). RPM remained unchanged from PRE (123 ± 14 rpm) to POST PLA (122 ± 14 rpm) but increased from PRE (120 ± 14 rpm) to POST NO3 (127 ± 13 rpm) (P = .043; η = 0.30). There was no relative change in RPM after PLA (-0.3% ± 4.1%), but there was an increase after NO3 (6.5% ± 11.4%) (P = .049; d = 0.79). No differences were observed between the 30-s isokinetic trials.

CONCLUSIONS

Acute NO supplementation can enhance maximal muscle power in trained athletes. These findings may particularly benefit power-sport athletes who perform brief explosive actions.