Sanders Ross H, Fairweather Malcolm M, Alcock Alison, McCabe Carla B
Exercise and Sport Science, FHS, The University of Sydney , Australia ; Centre of Aquatics Research and Education, SPEHS, The University of Edinburgh , Edinburgh, Scotland.
Sportscotland Institute of Sport , Stirling.
J Sports Sci Med. 2015 May 8;14(2):304-14. eCollection 2015 Jun.
Despite the importance of maintaining good alignment to minimize resistive drag in swimming there is a paucity of literature relating to the effect of technique asymmetries on rotations of the body about a vertical axis (yaw). The purpose of this paper was to present an approach to analyzing the effect of technique asymmetries on rotations in swimming, exemplifying the process with a case study of a breaststroke swimmer. The kinematics and angular kinetics of an elite female international breaststroke swimmer performing a 'fatigue set' of four 100m swims were derived from digitized three-dimensional video data using a 13 segment body model. Personalised anthropometric data required to quantify accurately segment and whole body centres of mass and segmental angular momentum were obtained by the elliptical zone method. Five episodes of torques producing yaw occurred in the stroke cycle sampled for each 100m swim of this swimmer. These torques were linked to bilateral differences in upper limb kinematics during 1) out-sweep; 2) in-sweep; 3) upper limb recovery; and lower limb kinematics during 4) Lower limb recovery and 5) the kick. It has been shown that by quantifying whole body torques, in conjunction with the kinematic movement patterns, the effect of technique asymmetries on body alignment can be assessed. Assessment of individual swimmers in this manner provides a solid foundation for planning interventions in strength, flexibility, and technique to improve alignment and performance. Key pointsA unique (not been attempted previously) study of yaw in breaststroke swimming that yields new knowledge of how technique and strength asymmetries affects body alignment.Establishes an approach to investigation of yaw in swimming using 3D videography and inverse dynamics.Exemplifies the approach with a case study. The case study illustrated the potential of the approach to enable detailed assessment of yaw and to explain how the yaw is produced in terms of the asymmetries in speed and magnitude of the swimming actions.This procedure should be used to identify and quantify asymmetries that might impair performance.
尽管保持良好的身体姿态对于减少游泳时的阻力至关重要，但关于技术不对称对身体绕垂直轴（偏航）旋转的影响的文献却很少。本文的目的是提出一种分析技术不对称对游泳中旋转影响的方法，并以一名蛙泳运动员的案例研究为例说明该过程。使用13节段身体模型，从数字化三维视频数据中得出一名优秀的国际女子蛙泳运动员进行四组100米“疲劳组”游泳时的运动学和角动力学数据。通过椭圆区域法获得准确量化节段和全身质心以及节段角动量所需的个性化人体测量数据。在该运动员每次100米游泳采样的划水周期中，发生了五次产生偏航的扭矩事件。这些扭矩与上肢运动学在1）向外划水；2）向内划水；3）上肢恢复过程中的双侧差异以及下肢运动学在4）下肢恢复和5）蹬腿过程中的双侧差异有关。研究表明，通过量化全身扭矩并结合运动模式，可以评估技术不对称对身体姿态的影响。以这种方式对个体游泳运动员进行评估为规划力量、柔韧性和技术方面的干预措施以改善身体姿态和表现提供了坚实的基础。要点对蛙泳中偏航进行独特的（此前未尝试过的）研究，得出了关于技术和力量不对称如何影响身体姿态的新知识。建立了一种使用三维摄像和逆动力学研究游泳中偏航的方法。以案例研究为例说明该方法。案例研究展示了该方法详细评估偏航并解释偏航如何根据游泳动作的速度和幅度不对称产生的潜力。此程序应用于识别和量化可能损害表现的不对称情况。
