Silva A J, Machado Reis V, Guidetti L, Bessone Alves F, Mota P, Freitas J, Baldari C
Department of Sport/CIFOP, University of Trás-os-Montes e Alto Douro UTAD, Vila Real, Portugal.
J Sports Med Phys Fitness. 2007 Mar;47(1):58-64.
Creatine supplementation (CS) has been reported to increase body weight and improve performance during high intensity, short duration, exercise tasks. However, none of the published studies has investigated the influence of CS on performance related hydrodynamic variables during swimming. To investigate the effect of oral CS on swimming velocity, body composition and hydrodynamic variables during the period of final preparation of competitive junior female swimmers.
In a double blind and randomized manner, 16 female swimmers, were supplemented with 20 g day(-1) of creatine monohydrate (CS group), or a maltodextrin placebo (PL group) for 21 days. Just pre- and post-21 days of supplementation, subjects performed 2x25 swimming bouts at maximum velocity with a 3 min recovery between bouts. The variables measured were 25 m swimming velocity (MSV(25)); active drag force (D(f)); hydrodynamic coefficient (C(x)); power output (P(o)). Body measures were also analysed: body weight (kg), fat-mass (% FAT), body water (% H(2)O), and fat free mass (FFM).
Significant differences were observed in hydrodynamic values: the CS group showed a significant reduction (approximately =25%), in D(f), C(x) and P(o) values, when comparing pretest with post-test. No differences were found in variables related to body composition and performance between CS group and PL group, as well as for CS group during the experimental period.
These data suggest that 21 days of CS produced significant effects on gross and/or propelling efficiency during swimming in female athletes. However, CS did not influence performance, body weight and body composition.
据报道，补充肌酸（CS）可增加体重，并在高强度、短时间的运动任务中提高运动表现。然而，已发表的研究均未探讨CS对游泳过程中与运动表现相关的流体动力学变量的影响。本研究旨在探讨口服CS对青少年女子游泳运动员赛前最后准备阶段的游泳速度、身体成分和流体动力学变量的影响。
16名女子游泳运动员被随机分为两组，采用双盲法，一组每天补充20克一水肌酸（CS组），另一组补充麦芽糊精安慰剂（PL组），为期21天。在补充的前21天和后21天，受试者以最大速度进行2组25米的游泳测试，每组之间休息3分钟。测量的变量包括25米游泳速度（MSV(25)）、有效阻力（D(f)）、流体动力学系数（C(x)）、功率输出（P(o)）。同时还分析身体指标：体重（kg）、体脂率（%FAT）、身体水分率（%H(2)O）和去脂体重（FFM）。
流体动力学值存在显著差异：与测试前相比，CS组的D(f)、C(x)和P(o)值显著降低（约25%）。CS组与PL组之间以及CS组在实验期间，与身体成分和运动表现相关的变量均无差异。
这些数据表明，21天的CS补充对女性运动员游泳时的总效率和/或推进效率产生了显著影响。然而，CS并未影响运动表现、体重和身体成分。
