Goods Paul S R, Landers Grant, Fulton Sacha
School of Sport Science, Exercise and Health. The University of Western Australia, Australia; Physiology Department. Western Australian Institute of Sport, Australia.
School of Sport Science, Exercise and Health. The University of Western Australia , Australia.
J Sports Sci Med. 2017 Mar 1;16(1):93-98. eCollection 2017 Mar.
The purpose of this investigation was to determine the efficacy of a moderate dose of caffeine to improve repeat-sprint performance in elite freestyle sprinters. Nine highly trained male swimmers performed 6 x 75 m freestyle sprints on two occasions 1-h after consuming either 3 mg·kg caffeine (CAF), or placebo, in a cross-over manner. Capillary blood samples for the analysis of blood lactate concentration and pH were collected after the 1, 3, and 5 sprint, while heart rate and perceived exertion (RPE) were collected after every sprint. There was a moderate effect for improved mean sprint time in the CAF condition (0.52 s; 1.3%; = 0.50). When assessed individually, there was a large effect for improved performance in sprints 3 (1.00 s; 2.5%; = 1.02) and 4 (0.84 s; 2.1%; = 0.84) in CAF compared to placebo, with worthwhile performance improvement found for each of the first 5 sprints. There was a significant treatment effect for higher blood lactate concentration for CAF (p = 0.029), and a significant treatment*time effect for reduced pH in the CAF condition (p = 0.004). Mean heart rate (167 ± 9 bpm vs 169 ± 7 bpm) and RPE (17 ± 1 vs 17 ± 1) were not different between placebo and CAF trials, respectively. This investigation is the first to demonstrate enhanced repeat-sprint ability in swimmers following acute caffeine ingestion. It appears likely that the combination of a moderate dose of caffeine (3-6 mg·kg) with trained athletes is most likely to enhance repeat-sprint ability in various athletic populations; however, the exact mechanism(s) for an improved repeat-sprint ability following acute caffeine ingestion remain unknown.
本研究的目的是确定中等剂量咖啡因对提高精英自由泳短跑运动员重复冲刺能力的功效。九名训练有素的男性游泳运动员以交叉方式，在摄入3毫克/千克咖啡因（CAF）或安慰剂1小时后，两次进行6组75米自由泳冲刺。在第1、3和5次冲刺后采集毛细血管血样以分析血乳酸浓度和pH值，同时在每次冲刺后采集心率和主观用力程度（RPE）。在CAF条件下，平均冲刺时间有中等程度的改善（0.52秒；1.3%；P = 0.50）。单独评估时，与安慰剂相比，CAF组在第3次（1.00秒；2.5%；P = 1.02）和第4次（0.84秒；2.1%；P = 0.84）冲刺中成绩提高有较大效果，在前5次冲刺中每次都有值得注意的成绩提升。CAF组血乳酸浓度较高有显著的治疗效果（P = 0.029），且在CAF条件下pH值降低有显著的治疗*时间效应（P = 0.004）。安慰剂组和CAF组试验的平均心率（167±9次/分钟对169±7次/分钟）和RPE（17±1对17±1）分别无差异。本研究首次证明了急性摄入咖啡因后游泳运动员重复冲刺能力增强。中等剂量咖啡因（3 - 6毫克/千克）与训练有素的运动员相结合似乎最有可能增强各类运动员群体的重复冲刺能力；然而，急性摄入咖啡因后重复冲刺能力提高的确切机制仍不清楚。
