BLOCK SLOPE IS THE MAIN DETERMINANT OF BLOCK PHASE PERFORMANCE IN SWIMMING

ABSTRACT Introduction Swimming starts are an important component for decreasing the total race time, especially in short events. In this phase of swimming, the aim is to increase performance using many different techniques and starting platforms. Objectives The effects of height and slope of the starting block on kick-start performance were assessed in this study. Methods Six male competitive swimmers performed 24 kick-starts using four block settings: 65 cm & 75 cm flat and 65 cm & 75 cm sloped. Two-dimensional kinetic and three-dimensional kinematic data were analyzed, including average and maximum horizontal/vertical forces and impulses; reaction times; movement and block times; and take-off vertical/horizontal velocities. Two-way within-subject design ANOVAs were implemented to test the effects of block height and slope on the kinetic and kinematic variables. Results Block slope was the main factor affecting most of the dependent variables. Shorter block and movement times, greater average and maximum vertical forces, vertical impulse, and maximum horizontal force were found for the sloped settings. An inverse relationship was found between block height and 0-5 m times. Conclusion Based on the results, blocks with height of 75 cm and slope of 10° provided better results in swimmers’ performance in the block phase. Level of evidence II, Therapeutic Studies -Investigating the Results of Treatment

摘要
引言 游泳出发是缩短总比赛时长的关键环节，尤其在短距离赛事中。在该游泳出发环节中，选手需通过多种不同技术与出发台（starting block）来提升竞技表现。
研究目的 本研究旨在评估出发台的高度与倾斜角度对蹬壁出发表现的影响。
研究方法 6名男子竞技游泳运动员完成了24次蹬壁出发测试，共采用4种出发台设置：65cm平置、75cm平置、65cm倾斜及75cm倾斜。本研究分析了二维动力学与三维运动学数据，涵盖平均与最大水平/垂直力、冲量；反应时；动作时长与出发台驻留时长；起跳时的垂直与水平速度。本研究采用双因素被试内设计方差分析（ANOVA），以检验出发台高度与倾斜角度对动力学及运动学变量的影响。
研究结果 出发台倾斜角度是影响多数因变量的核心因素。相较于平置设置，倾斜出发台可缩短出发台驻留时长与动作总时长，并提升平均与最大垂直力、垂直冲量及最大水平力。同时发现出发台高度与0-5米分段用时呈负相关关系。
研究结论 基于上述研究结果，高度为75cm、倾斜角度为10°的出发台可提升游泳运动员出发阶段的竞技表现。证据等级：II级，治疗学研究——探究治疗效果