Bassa Eleni, Adamopoulos Ilias, Panoutsakopoulos Vassilios, Xenofondos Anthi, Yannakos Athanasios, Galazoulas Christos, Patikas Dimitrios A
Laboratory of Evaluation of Human Biological Performance, Department of Physical Education and Sport Science at Thessaloniki, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Biomechanics Laboratory, School of Physical Education and Sports Sciences at Thessaloniki, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Sports (Basel). 2022 Dec 21;11(1):1. doi: 10.3390/sports11010001.
Drop jump (DJ) performance gain with increasing drop height is well documented in adults, but there is still no clear evidence of such gain in children. This study aimed to examine the differences in DJ performance gain in male adults and prepubescent boys by comparing drop heights tailored to each individual's performance and expressed as a percentage of their squat jump (SJ) performance. Fifteen boys (9-11 y) and 15 men (19-27 y) executed DJs from drop heights that were set at 75%, 100%, 125%, and 150% of their best performance in SJ (DJ, DJ, DJ, and DJ, respectively). Vertical ground reaction force (vGRF), contact time and kinematics of the lower extremities were captured. The results showed that boys jumped significantly lower than adults in DJs, and both age groups presented jumping gain with increasing drop height, up to DJ. Boys demonstrated longer total contact time, lower angular velocity and vGRF during the propulsive phase, as well as smaller knee flexion at touchdown and lower reactive strength index. vGRF in DJ and DJ was lower than in DJ and DJ. The highest value for maximum knee flexion was also presented at DJ. It is concluded that in prepubescent boys, the appropriate drop height for an effective DJ is linked to their performance in SJ and might be between 75% and 125% of their maximum SJ performance.
在成年人中，随着跳落高度增加，下落跳（DJ）表现提升已有充分记录，但在儿童中仍没有此类提升的明确证据。本研究旨在通过比较根据个体表现量身定制的跳落高度（以其深蹲跳（SJ）表现的百分比表示），来检验成年男性和青春期前男孩在DJ表现提升方面的差异。15名男孩（9 - 11岁）和15名男性（19 - 27岁）从设定为其SJ最佳表现的75%、100%、125%和150%的跳落高度执行DJ动作（分别为DJ₁、DJ₂、DJ₃和DJ₄）。记录下肢的垂直地面反作用力（vGRF）、接触时间和运动学数据。结果显示，在DJ动作中男孩跳得明显比成年人低，且两个年龄组都随着跳落高度增加而呈现跳跃表现提升，直至DJ₃。男孩在推进阶段表现出更长的总接触时间、更低的角速度和vGRF，以及触地时更小的膝关节屈曲角度和更低的反应力量指数。DJ₁和DJ₂中的vGRF低于DJ₃和DJ₄。最大膝关节屈曲角度的最高值也出现在DJ₃。研究得出结论，对于青春期前男孩，有效DJ动作的合适跳落高度与其SJ表现相关，可能在其最大SJ表现的75%至125%之间。
