Daneshfar Amin, Petersen Carl J, Koozehchian Majid S, Gahreman Daniel E
University of Canterbury.
Jacksonville State University.
Int J Sport Nutr Exerc Metab. 2020 Sep 17;30(6):427-434. doi: 10.1123/ijsnem.2020-0126. Print 2020 Nov 1.
This study aimed to identify the acute effects of caffeinated chewing gum (CAF) on bicycle motocross (BMX) time-trial (TT) performance. In a randomized, placebo-controlled, double-blind cross-over design, 14 male BMX riders (age = 20.0 ± 3.3 years; height = 1.78 ± 0.04 m; body mass = 72 ± 4 kg), consumed either (300 mg; 4.2 ± 0.2 mg/kg) caffeinated (300 mg caffeine, 6 g sugars) or a placebo (0 mg caffeine, 0 g sugars) gum, and undertook three BMX TTs. Repeated-measure analysis revealed that CAF has a large ergogenic effect on TT time, F(1, 14) = 33.570, p = .001, ηp2=.71; -1.5% ± 0.4 compared with the placebo. Peak power and maximal power to weight ratio also increased significantly compared with the placebo condition, F(1, 14) = 54.666, p = .001, ηp2=.79; +3.5% ± 0.6, and F(1, 14) = 57.399, p = .001, ηp2=.80; +3% ± 0.3, respectively. Rating of perceived exertion was significantly lower F(1, 14) = 25.020, p = .001, ηp2=.64 in CAF (6.6 ± 1.3) compared with the placebo (7.2 ± 1.7). Administering a moderate dose (300 mg) of CAF could improve TT time by enhancing power and reducing the perception of exertion. BMX coaches and riders may consider consuming CAF before a BMX race to improve performance and reduce rating of perceived exertion.
本研究旨在确定含咖啡因口香糖（CAF）对小轮车越野（BMX）计时赛（TT）成绩的急性影响。在一项随机、安慰剂对照、双盲交叉设计中，14名男性BMX车手（年龄 = 20.0 ± 3.3岁；身高 = 1.78 ± 0.04米；体重 = 72 ± 4千克）分别食用含咖啡因（300毫克咖啡因，6克糖）或安慰剂（0毫克咖啡因，0克糖）的口香糖，并进行了三次BMX TT赛。重复测量分析显示，CAF对TT时间有很大的促力作用，F(1, 14) = 33.570，p = .001，ηp2 = .71；与安慰剂相比缩短了1.5% ± 0.4。与安慰剂组相比，峰值功率和最大功率体重比也显著增加，F(1, 14) = 54.666，p = .001，ηp2 = .79；增加了3.5% ± 0.6，以及F(1, 14) = 57.399，p = .001，ηp2 = .80；分别增加了3% ± 0.3。主观用力感觉评分在CAF组（6.6 ± 1.3）显著低于安慰剂组（7.2 ± 1.7），F(1, 14) = 25.020，p = .001，ηp2 = .64。服用中等剂量（300毫克）的CAF可通过增强功率和降低主观用力感觉来改善TT时间。BMX教练和车手可能会考虑在BMX比赛前食用CAF以提高成绩并降低主观用力感觉评分。
