Faculty of Sport, Centre of Research, Education, Innovation and Intervention in Sport, University of Porto, Portugal.
Int J Sports Med. 2011 Jul;32(7):546-51. doi: 10.1055/s-0031-1273688. Epub 2011 May 11.
The relationships between the start time and kinematic, kinetic and electromyographic data were examined in order to establish the common features of an effective backstroke swimming start. Complementarily, different starting positions were analysed to identify the parameters that account for the fastest backstroke start time under different constraints. 6 high-level swimmers performed 4×15 m maximal trials of each start variants with different feet position: parallel and entirely submerged (BSFI) and above water surface (BSFE), being monitored with synchronized dual-media image, underwater platform plus handgrip with a load cell, and eletromyographic signal of RECTUS FEMORIS and GASTROCNEMIUS MEDIALIS. Mean and SD values of start time for BSFI and BSFE were 2.03 ± 0.19 and 2.14 ± 0.36 s, respectively. In both starts, high associations (r > =0.75, p < 0.001) were observed between start time and centre of mass resultant average velocity at glide phase and horizontal impulse at take-off for BSFI, and centre of mass horizontal position at the start signal for BSFE. It was concluded that the greater impulse during the take-off and its transformation into a fast underwater movement are determinant to decrease the start time at BSFI. Regarding BSFE, a greater centre of mass pool-wall approximation might imply a flatter take-off angle, compromising underwater velocity and starting performance.
为了确定有效的仰泳出发的共同特征，研究了出发时间与运动学、动力学和肌电图数据之间的关系。此外，还分析了不同的出发姿势，以确定在不同约束条件下，哪些参数可以实现最快的仰泳出发时间。6 名高水平游泳运动员分别以不同的脚位（平行和完全浸入水下 BSFI 和水面上 BSFE）进行了 4 次 15 米最大试验，使用同步双媒体图像、水下平台加带有负载单元的手握器以及股直肌和腓肠肌内侧的肌电图信号进行监测。BSFI 和 BSFE 的平均出发时间分别为 2.03 ± 0.19 和 2.14 ± 0.36 秒。在这两种出发方式中，滑行阶段的质心总速度和起飞阶段的水平冲量与 BSFI 的出发时间高度相关（r≥0.75，p<0.001），而 BSFE 的出发时间与质心水平位置与出发信号高度相关。这表明起飞时的冲量越大，并且能够快速转化为水下运动，是减少 BSFI 出发时间的决定因素。对于 BSFE，质心更接近池壁可能意味着更平坦的起飞角度，从而影响水下速度和出发性能。
