Dept of Human Movement and Sport Sciences, University "Foro Italico", Rome, Italy.
Int J Sports Physiol Perform. 2014 Jan;9(1):151-60. doi: 10.1123/ijspp.2012-0289. Epub 2013 Apr 23.
To investigate the effects of work-to-rest-ratio manipulation on neuromuscular and metabolic responses during 2 high-intensity intermittent training (HIT) protocols to exhaustion. Since different exercise durations were expected, the authors hypothesized that the protocol registering a longer duration would have a more pronounced effect on neuromuscular responses, while the other would challenge the cardiopulmonary system more.
Thirteen competitive cyclists (age 19 ± 2 y) performed a preliminary incremental test to identify their maximal power output and 2 intermittent protocols to exhaustion (40:20s and 30:30s) at a fixed work rate of 135%Pmax interspersed by passive recovery. Surface electromyographic (sEMG) parameters (including muscle-fiber conduction velocity), cardiopulmonary parameters, and blood lactate concentration [La-] were recorded.
Time to exhaustion and total work were significantly higher for the 30:30s (38 ± 13 min, 495 ± 161 kJ) than for the 40:20s (10 ± 3 min, 180 ± 51 kJ). No differences were found in sEMG parameters for the 2 protocols. Mean and peak values of VO2, heart rate, ventilatory parameters (except for the peak value of respiratory frequency), and [La-] were significantly higher in the 40:20s than in the 30:30s.
These results do not support the hypothesis that a longer time spent at high intensity has a more pronounced effect on neuromuscular responses, as no differences in EMG parameters were found in the 2 HIT protocols. Regarding metabolic responses, while the 40:20s led to maximal values of VO2, [La-], and ventilatory parameters within a few minutes, the 30:30s allowed maintenance of moderately high values for a considerably longer period, especially for [La-] and ventilatory parameters.
研究工作与休息比值的改变对 2 种高强度间歇训练（HIT）至力竭的神经肌肉和代谢反应的影响。由于预计运动持续时间不同，作者假设持续时间较长的方案会对神经肌肉反应产生更显著的影响，而另一个方案则会对心肺系统构成更大的挑战。
13 名竞技自行车运动员（年龄 19 ± 2 岁）进行了初步递增测试，以确定他们的最大功率输出，并以 135%的最大力量输出进行 2 种间歇协议至力竭（40:20s 和 30:30s），两次运动之间穿插被动恢复。记录表面肌电图（sEMG）参数（包括肌纤维传导速度）、心肺参数和血乳酸浓度[La-]。
30:30s 的力竭时间和总功（38 ± 13 min，495 ± 161 kJ）明显高于 40:20s（10 ± 3 min，180 ± 51 kJ）。2 种方案的 sEMG 参数无差异。40:20s 的平均和峰值 VO2、心率、通气参数（除了呼吸频率的峰值）和[La-]均显著高于 30:30s。
这些结果不支持这样的假设，即长时间处于高强度状态会对神经肌肉反应产生更显著的影响，因为在 2 种 HIT 方案中，EMG 参数没有差异。关于代谢反应，虽然 40:20s 在几分钟内达到了 VO2、[La-]和通气参数的最大值，但 30:30s 允许在相当长的时间内保持较高的适度值，尤其是对于[La-]和通气参数。
