渐增负荷对男性运动员水下海豚腿质心速度的影响——基于统计参数映射分析

Effects of Incremental Loading on the Center of Mass Velocity in Male Athletes’Underwater Dolphin Kick--Based on Statistical Parametric Mapping Analysis

目的:评估水下海豚腿(underwater dolphin kick,UDK)的负荷-速度曲线(loadvelocity profiles,LVP),采用统计参数映射(statistical parametric mapping,SPM)方法分析渐增负荷对UDK质心水平速度的影响。方法:招募8名大学生游泳运动员,通过半牵引游泳方法进行7轮渐增负荷的UDK测试(负荷分别为21 N、33 N、45 N、57 N、69 N、81 N、93 N)。采用最小二乘法拟合受试者个性化LVP,并使用混合线性模型或SPM检验不同负荷水平下离散型变量(平均质心水平速度)和连续型变量(质心水平速度)的差异。结果:UDK的LVP表现出显著的线性关系(R2=0.896±0.057,SEE=0.069±0.035)。在渐增负荷影响下,平均质心水平速度呈现线性递减趋势(ES=2.24~7.65,P<0.01)。采用SPM分析发现,渐增负荷对质心水平速度的影响是非线性的,当负荷超过57 N后,负荷对质心水平速度的影响急剧增大(差异时间:11%~63%),其影响主要集中在上打阶段。结论:LVP可作为评估游泳运动员UDK水平的有效手段。在制定水中抗阻训练方案时,应谨慎考虑渐增负荷对运动员游泳技术的持续影响,并结合离散型和连续型变量的分析结果,选择适合运动员的个性化负荷水平。

Objective:To evaluate the load-velocity profile(LVP)of the underwater dolphin kick(UDK),and applies the statistical parameter mapping(SPM)method to analyze the effects of incremental load on the horizontal velocity of the center of mass of the underwater dolphin kick.Methods:Eight college swimmers were recruited to participate in 7 rounds of UDK test by using the semi-tethered swimming method.The loads for each round were 21 N,33 N,45 N,57 N,69 N,81 N,93 N,respectively.The least square method was used to fit subjects’personalized LVP,and a mixed linear model or SPM was used to analyze the differences between discrete variables(average center of mass horizontal velocity)and continuous variables(horizontal velocity of center of mass)across various load levels.Results:The LVP of UDK exhibited a reliable linear relationship(R2=0.896±0.057,SEE=0.069±0.035).As the load increased,there was a linear decrease in average center of mass horizontal velocity(ES=2.24~7.65,P<0.01).The SPM method revealed a non-linear effect of incremental load on horizontal velocity of center of mass.Notably,when the load exceeded 57 N,there was a significant decrease in horizontal velocity of center of mass(difference time range:11%~63%),particularly during the up-kick phase.Conclusions:The LVP is an effective tool for evaluate UDK performance of swimmers.When designing in-water resistance training programs,coaches and athletes should carefully consider the continuous influence of incremental loading on swimming technique,and select the individual load levels suitable for athletes based on the analysis of both discrete and continuous variables.