Ogawa Takeshi, Nagao Maiko, Fujii Naoto, Nishiyasu Takeshi
1Division of Art, Music, and Physical Education, Osaka Kyoiku University, Kashiwara, Osaka, Japan.
2Faculty of Health and Sport Sciences in University of Tsukuba, Tsukuba, Japan.
BMC Sports Sci Med Rehabil. 2020 Apr 15;12:25. doi: 10.1186/s13102-020-00172-1. eCollection 2020.
Although numerous studies have reported the effect of inspiratory muscle training for improving exercise performance, the outcome of whether exercise performance is improved by inspiratory muscle training is controversial. Therefore, this study investigated the influence of inspiratory muscle-loaded exercise training (IMLET) on peak oxygen uptake (O), respiratory responses, and exercise performance under normoxic (N) and hypoxic (H) exercise conditions. We hypothesised that IMLET enhances respiratory muscle strength and improves respiratory response, thereby improving O and work capacity under H condition.
Sixteen university track runners (13 men and 3 women) were randomly assigned to the IMLET ( = 8) or exercise training (ET) group ( = 8). All subjects underwent 4 weeks of 20-min 60% O cycling exercise training, thrice per week. IMLET loaded 50% of maximal inspiratory pressure during exercise. At pre- and post-training periods, subjects performed exhaustive incremental cycling under normoxic (N; 20.9 ± 0%) and hypoxic (H; 15.0 ± 0.1%) conditions.
Although maximal inspiratory pressure (PImax) significantly increased after training in both groups, the extent of PImax increase was significantly higher in the IMLET group (from 102 ± 20 to 145 ± 26 cmHO in IMLET; from 111 ± 23 to 127 ± 23 cmHO in ET; < 0.05). In both groups, O and maximal work load (W) similarly increased both under N and H conditions after training ( < 0.05). Further, the extent of W decrease under H condition was lower in the IMLET group at post-training test than at pre-training (from - 14.7 ± 2.2% to - 12.5 ± 1.7%; < 0.05). Maximal minute ventilation in both N and H conditions increased after training than in the pre-training period.
Our IMLET enhanced the respiratory muscle strength, and the decrease in work capacity under hypoxia was reduced regardless of the increase in O.
尽管众多研究报告了吸气肌训练对改善运动表现的作用，但吸气肌训练是否能提高运动表现的结果仍存在争议。因此，本研究调查了吸气肌负荷运动训练（IMLET）在常氧（N）和低氧（H）运动条件下对峰值摄氧量（O₂）、呼吸反应和运动表现的影响。我们假设IMLET可增强呼吸肌力量并改善呼吸反应，从而在低氧条件下提高O₂和工作能力。
16名大学田径运动员（13名男性和3名女性）被随机分配到IMLET组（n = 8）或运动训练（ET）组（n = 8）。所有受试者均接受为期4周、每周三次、每次20分钟、强度为60% O₂的自行车运动训练。IMLET在运动期间加载50%的最大吸气压力。在训练前和训练后，受试者在常氧（N；20.9 ± 0%）和低氧（H；15.0 ± 0.1%）条件下进行力竭性递增自行车运动。
尽管两组训练后最大吸气压力（PImax）均显著增加，但IMLET组PImax增加的幅度显著更高（IMLET组从102 ± 20 cmH₂O增加到145 ± 26 cmH₂O；ET组从111 ± 23 cmH₂O增加到127 ± 23 cmH₂O；P < 0.05）。两组在训练后，常氧和低氧条件下的O₂和最大工作负荷（W）均同样增加（P < 0.05）。此外，训练后测试时，IMLET组在低氧条件下W下降的幅度低于训练前（从 - 14.7 ± 2.2%降至 - 12.5 ± 1.7%；P < 0.05）。常氧和低氧条件下的最大分钟通气量在训练后均比训练前增加。
我们的IMLET增强了呼吸肌力量，且无论O₂是否增加，低氧条件下工作能力的下降均有所减少。
