Department of Sport Sciences, Miguel Hernández University, Elche, Spain.
PLoS One. 2019 Apr 17;14(4):e0214237. doi: 10.1371/journal.pone.0214237. eCollection 2019.
The aim of this experiment was to assess if the previously supported relationship between the structure of motor variability and performance changes when the task or organismic constraints encourage individuals to adjust their movement to achieve a goal. Forty-two healthy volunteers (aged 26.05 ± 5.02 years) performed three sets of cyclic pointing movements, 600 cycles each. Every set was performed under different conditions: 1) without a target; 2) with a target; 3) with a target and a financial reward. The amount of performance variability was analysed using the standard deviation of the medial-lateral (ML) and anterior-posterior (AP) axes and the bivariate variable error. The structure of the variability was assessed by Detrended Fluctuation Analysis (DFA) of the following time series: the coordinate values of the endpoint in ML, AP axes and resultant distance (RD), the hand orientation and the movement time. The performance of the task constrained with a target, or a target and reward, required higher implication to adjust an individual's movements to achieve the task goal, showing a decrease in dispersions and lower autocorrelation. Under the condition without a target, variability dispersion was positively related to autocorrelation of the movement values from ML axis and RD time series, and negatively related to the values from the hand orientation time series. There was a loss of the relationship between variability structure and performance when the task was constrained by the target and the reward. That could indicate different strategies of the participants to achieve the objective. Considering the results and previous studies, the relationship between variability structure and performance could depend on task constraints such as feedback, difficulty or the skill level of participants and it is mediated by individual constraints such as implication or intentionality.
本实验旨在评估在任务或生物体限制鼓励个体调整运动以实现目标时，运动变异性的结构与性能变化之间先前支持的关系。42 名健康志愿者（年龄 26.05±5.02 岁）进行了三组循环指向运动，每组 600 个循环。每组在不同条件下进行：1）无目标；2）有目标；3）有目标和财务奖励。使用中-侧（ML）和前-后（AP）轴的标准偏差以及双变量误差分析了性能变异性的量。通过对以下时间序列的去趋势波动分析（DFA）评估变异性的结构：ML、AP 轴和合成距离（RD）端点坐标值、手的方向和运动时间。受到目标或目标和奖励限制的任务的性能需要更高的投入来调整个体的运动以实现任务目标，表现为分散度降低和自相关性降低。在没有目标的情况下，变异性分散度与 ML 轴和 RD 时间序列中运动值的自相关性呈正相关，与手的方向时间序列中的值呈负相关。当任务受到目标和奖励的限制时，变异性结构与性能之间的关系丧失。这可能表明参与者为实现目标采用了不同的策略。考虑到结果和先前的研究，变异性结构与性能之间的关系可能取决于任务限制，如反馈、难度或参与者的技能水平，并且受个体限制（如投入或意向性）的影响。
