Effects of carbohydrate combined with caffeine on repeated sprint cycling and agility performance in female athletes

Abstract

BackgroundCaffeine (CAF) has been shown to improve performance during early phase of repeated sprint exercise; however some studies show that CAF also increases the magnitude of physical stress represented by augmented blood lactate, glucose, and cortisol concentrations during latter phase of repeated sprint exercise. No studies have investigated the efficacy of combined carbohydrate (CHO) and CAF consumption during repeated sprint exercise (RSE) in female athletes. Thus, the purpose of this study was to investigate the effects of CAF with CHO supplementation on RSE and agility.MethodsEleven female athletes completed four experimental trials performed 7 d apart in a double-blind, randomized, and counter-balanced crossover design. Treatments included CAF + PLA (placebo), CAF + CHO, PLA + CHO, and PLA + PLA. Participants ingested capsules containing 6 mg · kg−1 of CAF or PLA 60-min prior to RSE, and 0.8 g · kg−1 of CHO solution or PLA immediately before the RSE, which consisted of ten sets of 5 × 4-s sprints on the cycle ergometer with 20-s active recovery. The agility T-test (AT-test) was performed before and after the RSE. Blood samples were acquired to assess glucose, lactate, testosterone, and cortisol.ResultsDuring Set 6 of RSE, peak power and mean power were significantly higher in PLA + CHO than those in CAF + PLA and PLA + PLA, respectively (p < .05). Total work was significantly increased by 4.8% and 5.9% with PLA + CHO than those of CAF + CHO and CAF + PLA during Set 3. PLA + CHO also increased total work more than CAF + PLA and PLA + PLA did during Set 6 (p < .05). No significant differences in AT-test performance either before or after the RSE were occurred among treatments (p > .05). Blood lactate and glucose concentrations were significantly higher under CAF + CHO, CAF + PLA, and PLA + CHO versus PLA + PLA (p < .05), but no differences in testosterone or cortisol levels were found (p > .05).ConclusionsFindings indicate that CAF + PLA or CAF + CHO ingestion did not improve repeated sprint performance with short rest intervals or agility. However, CHO ingested immediately prior to exercise provided a small but significant benefit on RSE performance in female athletes.

The effect of diet components on the level of cortisol

“…A reduction in cortisol levels by 16 % and increased level of testosterone by 37 % was noted. Authors suggest that the observed improvement may support sports performance [82,83].…”

“…The studies concerning consumption of drinks containing carbohydrates and caffeine during workout have shown that the highest increase in cortisol levels were achieved in the group that supplemented caffeine without carbohydrates [81,82].…”

Performance-Enhancing Substances in Sports: A Review of the Literature

“…However, other studies have not shown significant improvement with caffeine. In a study with 11 female athletes performing repeated sprint cycling, neither ingestion of caffeine plus placebo nor caffeine plus carbohydrate improved repeated sprint performance with short rest intervals [71]. Many athletes use caffeine to counter sleep deprivation, but a study on semiprofessional tennis players showed that caffeine did not make up for lost sleep with regard to serving accuracy [72].…”

The Ergogenic Effects of Supplemental Nutritional Aids on Anaerobic Performance in Female Athletes

“…This hypothesis has been tested and is well supported in studies using male subjects (6); however, the data among female participants are sparse. To date, there are limited investigations evaluating the effects of caffeine supplementation on changes in muscular parameters among women (47,76,80,85,90). Of those studies, beneficial results from caffeine supplementation are equivocal.…”

“…When observing changes in highintensity cycling performance, caffeine has been ineffective when supplemented in women (76,80,90). Early evidence investigating the effects of caffeine on high-intensity cycling time to exhaustion revealed no differences with small (4 mg/kg), medium (7 mg/kg), or high (10 mg/kg) dosing protocols (90).…”