Romer Lee M, McConnell Alison K, Jones David A
Sports Medicine and Human Performance Unit, School of Sport and Exercise Sciences, The University of Birmingham, Edgbaston, Birmingham, UK.
Med Sci Sports Exerc. 2002 May;34(5):785-92. doi: 10.1097/00005768-200205000-00010.
This study evaluated the influence of simulated 20- and 40-km time trials upon postexercise inspiratory muscle function of trained competitive cyclists. In addition, we examined the influence of specific inspiratory muscle training (IMT) upon the responses observed.
Using a double-blind placebo-controlled design, 16 male cyclists (mean +/- SEM VO2max 64 +/- 2 mL.kg-1.min-1) were assigned randomly to either an experimental (IMT) or sham-training control (placebo) group. Maximum static and dynamic inspiratory muscle function was assessed immediately pre- and <2, 10, and 30 min post-simulated 20- and 40-km time trials before and after 6-wk of IMT or sham-IMT.
Maximum inspiratory mouth pressure (P0) measured within 2 min of completing the 20- and 40-km time trial rides was reduced by 18% and 13%, respectively, and remained below preexercise values at 30 min. The 20- and 40-km time trials induced a reduction in inspiratory flow rate at 30% P0 by 14% and 6% in the IMT group versus 13% and 7% for the placebo group, and also remained below preexercise values at 30 min. There was also a significant slowing of inspiratory muscle relaxation rate postexercise; these trends were almost completely reversed by 30 min postexercise. Significant improvements in 20- and 40-km time trial performance were seen (3.8 +/- 1.7% and 4.6 +/- 1.9%, respectively; P < 0.05) and postexercise reductions in muscle function were attenuated with IMT.
These data support existing evidence that there is significant global inspiratory muscle fatigue after sustained heavy endurance exercise. Furthermore, the present study provides new evidence that performance enhancements observed after IMT are accompanied by a decrease in inspiratory muscle fatigue.
本研究评估了模拟20公里和40公里计时赛对训练有素的竞技自行车运动员运动后吸气肌功能的影响。此外，我们还研究了特定吸气肌训练（IMT）对所观察到的反应的影响。
采用双盲安慰剂对照设计，将16名男性自行车运动员（平均±标准误最大摄氧量64±2 mL·kg⁻¹·min⁻¹）随机分为实验组（IMT）或假训练对照组（安慰剂）。在进行6周的IMT或假IMT前后，分别在模拟20公里和40公里计时赛之前以及之后<2分钟、10分钟和30分钟时，立即评估最大静态和动态吸气肌功能。
在完成20公里和40公里计时赛骑行后的2分钟内，测得的最大吸气口腔压力（P0）分别降低了18%和13%，并在30分钟时仍低于运动前值。在IMT组中，20公里和40公里计时赛使30%P0时的吸气流量速率分别降低了14%和6%，而安慰剂组分别降低了13%和7%，且在30分钟时也仍低于运动前值。运动后吸气肌放松速率也显著减慢；这些趋势在运动后30分钟时几乎完全逆转。20公里和40公里计时赛的成绩有显著提高（分别为3.8±1.7%和4.6±1.9%；P<0.05），并且IMT减轻了运动后肌肉功能的下降。
这些数据支持了现有证据，即持续的高强度耐力运动后存在明显的全身性吸气肌疲劳。此外，本研究提供了新的证据，即IMT后观察到的成绩提高伴随着吸气肌疲劳的减轻。
