摘要：The aim of this study was to identify the changes in movement variability and movement velocity during six weeks training period using a resistance horizontal forward-backward task without (NOBALL) or with (BALL) the constraint of catching and throwing a rugby ball in the forward phase, during a six-week period. Eleven elite male rugby union players (mean ± SD: age 25.5 ± 2.0 years, height 1.83 ± 0.06 m, body mass 95 ± 18 kg, rugby practice 14 ± 3 years) performed eight repetitions of NOBALL and BALL conditions once a week in a rotational flywheel device. Velocity was recorded by an attached rotary encoder while acceleration data were used to calculate sample entropy (SampEn), multiscale entropy and the complexity index. SampEn showed no significant decrease for NOBALL (ES -0.64 ± 1.02) and significant decrease for BALL (ES -1.71 ± 1.16; p<0.007) conditions. Additionally, movement velocity showed significant increase for NOBALL (ES 1.02 ± 1.05; p<0.047), and significant increase for BALL (ES 1.25 ± 1.08; p<0.025) between weeks 1 and 6. The complexity index showed higher levels of complexity in BALL condition, specifically in the first three weeks. Movement velocity and complex dynamics were adapted to the constraints of the task after a four-week training period. Entropy measures seem a promising processing signal technique to identify when these exercise tasks should be changed.
关键词：entropy; strength training; Task constraints; team sports; Adaptability
