Jarosz Jakub, Drozd Milosz, Gawel Dawid, Wilk Michal, Helbin Jonatan, Krzysztofik Michal
Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland.
Department of Sports Games, Faculty of Physical Education and Sport, Charles University, Prague, Czech Republic.
Sci Rep. 2025 May 15;15(1):16960. doi: 10.1038/s41598-025-02126-4.
The aim of this study was to compare the effects of 3 sets of isometric conditioning activity (ICA), each with an equal total duration (9 s per set) but with different distributions contractions, on force production during ICA and subsequent countermovement jump (CMJ) performance. Fifteen resistance-trained males participated in this study (age: 22.1 ± 2.4 years; body mass: 85.1 ± 9.7 kg; height: 181.3 ± 6.5 cm; relative one-repetition maximum (1RM) in back squat: 1.59 ± 0.32 kg/kg of body mass). Participants completed 3 conditions, each consisting of ICA in the half-back squat with a pushing isometric muscle action (PIMA) position at a 120-degree knee angle against an immovable barbell, differing in repetition distribution: 3 sets of 9 repetitions lasting 1 s each (SUST-1), 3 sets of 3 repetitions lasting 3 s each (SUST-3), 3 sets of single repetitions lasting 9 s (SUST-9), and a control condition (CTRL) without ICA. A 1-minute rest was allowed between sets. Approximately 3 min pre-ICA and at 15 s, 3-, 6-, 9-, and 12-minutes post-ICA, the CMJ performance was assessed. Moreover, peak force (PF) production, and force generated at 100 (Force100) and 200 ms (Force200) during each ICA were evaluated. A two-way repeated measures ANOVA indicated a main effect of time on CMJ height (F = 2.674; p = 0.029; ηp²=0.171) but did not show significant differences between conditions (F = 0.934; p = 0.434; ηp²=0.067) or interactions (F = 0.826; p = 0.648; ηp²=0.060). Post-hoc comparisons indicated a significant decrease in CMJ height at the 9th minute compared to the 3rd minute (35.7 ± 5.6 cm vs. 36.8 ± 5.5 cm post-CA; d = 0.161; p = 0.048). In addition, no significant interactions or main effects were found for CMJ contraction time, PF and Force100 during ICA. However, a main effect of condition was demonstrated on Force200 (F = 19.181; p < 0.001; ηp²= 0.013). Post-hoc comparisons revealed higher Force200 values in SUST-1 (mean difference [MD] = 549 ± 137 N; d = 1.049; p < 0.001) and SUST-3 (MD = 348 ± 112 N; d = 0.665; p = 0.002) compared to the SUST-9 condition. None of the ICAs used in the present study had any effect on the CMJ performance. However, the significantly higher Force200 values noted in the SUST-1, and SUST-3 conditions compared to the SUST-9 condition suggest that the specific distributions of isometric contraction influence the force generated during their execution.
本研究的目的是比较3组等长调节活动（ICA）的效果，每组总时长相等（每组9秒），但收缩分布不同，观察其对ICA期间的力量产生以及随后的反向运动跳跃（CMJ）表现的影响。15名经过抗阻训练的男性参与了本研究（年龄：22.1±2.4岁；体重：85.1±9.7千克；身高：181.3±6.5厘米；后深蹲相对单次最大重复重量（1RM）：1.59±0.32千克/千克体重）。参与者完成3种条件测试，每种条件均包括在120度膝关节角度下，于半后深蹲中针对固定杠铃进行推的等长肌肉动作（PIMA）姿势的ICA，重复分布不同：3组，每组9次重复，每次持续1秒（SUST - 1）；3组，每组3次重复，每次持续3秒（SUST - 3）；3组，每组单次重复，每次持续9秒（SUST - 9），以及无ICA的对照条件（CTRL）。组间允许休息1分钟。在ICA前约3分钟以及ICA后15秒、3分钟、6分钟、9分钟和12分钟时评估CMJ表现。此外，评估了每次ICA期间的峰值力量（PF）产生，以及在100毫秒（Force100）和200毫秒（Force200）时产生的力量。双向重复测量方差分析表明，时间对CMJ高度有主效应（F = 2.674；p = 0.029；ηp² = 0.171），但各条件之间无显著差异（F = 0.934；p = 0.434；ηp² = 0.067）或交互作用（F = 0.826；p = 0.648；ηp² = 0.060）。事后比较表明，与第3分钟相比，第9分钟时CMJ高度显著降低（CA后35.7±5.6厘米对36.8±5.5厘米；d = 0.161；p = 0.048）。此外，在ICA期间，CMJ收缩时间、PF和Force100未发现显著的交互作用或主效应。然而，条件对Force200有主效应（F = 19.181；p < 0.001；ηp² = 0.013）。事后比较显示，与SUST - 9条件相比，SUST - 1（平均差[MD] = 549±137牛；d = 1.049；p < 0.001）和SUST - 3（MD = 348±112牛；d = 0.665；p = 0.002）的Force200值更高。本研究中使用的任何ICA对CMJ表现均无影响。然而，与SUST - 9条件相比，SUST - 1和SUST - 3条件下显著更高的Force200值表明，等长收缩的特定分布会影响其执行过程中产生的力量。
