Introduction

Moderate aerobic, high-intensity and sprint running or cycling training can transiently impair postural control. However, the acute effects of modified sprint interval training (mSIT) at different muscle working modes have not yet been examined. Thus, this study aimed at investigating acute effects of time-matched eccentric (ECC) versus concentric mSIT cycling session (CON) on jumping and functional balance performance.

Methods

Twenty-five healthy and active males (30.0 ± 6.0 years; 80.1 ± 9.1 kg; V̇O_2max: 64.2 ± 7.9 mL kg⁻¹ min⁻¹) were enrolled in this acute randomized controlled crossover trial. Counter-Movement-Jump (CMJ) and functional balance testing (Y-Balance-Test composite score [YBT_CS]; Posturomed total distance: Posturomed_TD) were assessed as primary outcomes before, and immediately after cessation of ECC and CON (10 × 10 s maximum sprints and 50 s of active recovery).

Results

A significant mode × time interaction effect for CMJ (F = 9.620, p = 0.005, η_p² = 0.29) was observed. Subsequent post-hoc testing revealed significant moderate reductions in jumping height after CON (0.31 ± 0.06 vs. 0.27 ± 0.06m; p = 0.004, SMD = 0.59), whilst ECC remained unchanged. YBT_CS (mode × time interaction: F = 6.880, p = 0.015, η_p² = 0.22) showed small but significant balance impairments after CON (0.964 ± 0.068 vs. 0.960 ± 0.063 AU; p = 0.009, SMD = 0.28) and did not significantly change after ECC. Although large significant interaction effects (p = 0.029, η_p² = 0.18) were observed for Posturomed_TD, follow up post-hoc testing did not reveal relevant pre-post differences, neither for ECC nor CON.

Conclusion

Both functional balance and jumping performance are deteriorated after acute concentric but not eccentric mSIT cycling. Although higher pedal forces at lower perceived efforts and heart rates during eccentric mSIT were observed, it seems that the cardiocirculatory demanding CON session elicited more pronounced balance and jump performance impairments than eccentric cycling.

中文翻译：

---

向心而非偏心的自行车冲刺间隔严重损害健康活跃的年轻人的平衡和跳跃表现：一项随机对照交叉研究

介绍

适度的有氧、高强度和短跑或骑自行车训练会暂时损害姿势控制。然而，改进的冲刺间歇训练 (mSIT) 在不同肌肉工作模式下的急性影响尚未得到研究。因此，本研究旨在调查时间匹配偏心 (ECC) 与同心 mSIT 骑行训练 (CON) 对跳跃和功能平衡表现的急性影响。

方法

25 名健康活跃的男性（30.0 ± 6.0 岁；80.1 ± 9.1 kg；V̇O _2max：64.2 ± 7.9 mL kg ^-1  min ^-1）参加了这项急性随机对照交叉试验。反运动跳跃 (CMJ) 和功能平衡测试（Y 平衡测试综合评分 [ YBT _CS ]；姿势总距离：姿势_TD）在 ECC 和 CON 停止之前和之后被评估为主要结果（10 × 10 秒的最大冲刺和 50 秒的主动恢复）。

结果

观察到 CMJ 的显着模式 × 时间相互作用效应（F = 9.620，p  = 0.005，η _p ²  = 0.29）。随后的事后测试显示 CON 后跳跃高度显着中度降低（0.31 ± 0.06 对 0.27 ± 0.06m；p = 0.004，SMD = 0.59），而 ECC 保持不变。YBT _CS（模式 × 时间交互作用：F = 6.880，p  = 0.015，η _p ²  = 0.22）在 CON（0.964 ± 0.068 对 0.960 ± 0.063 AU；p  = 0.009，SMD = 0.28）和ECC后没有明显变化。虽然大的显着交互效应 ( p  = 0.029, η _p ² = 0.18) 对于 Posturomed _TD观察到，后续的事后测试没有揭示相关的事后差异，无论是 ECC 还是 CON。

结论

急性同心但不偏心 mSIT 循环后，功能平衡和跳跃性能都会恶化。尽管在离心 mSIT 期间观察到在较低的感知力和心率下更高的踏板力，但似乎与离心循环相比，需要心脏循环的 CON 会话引起了更明显的平衡和跳跃性能损害。