Queensland University of Technology (QUT), Faculty of Health, School of Exercise and Nutrition Sciences. Victoria Park Road, Kelvin Grove, Queensland 4059, Australia; Queensland University of Technology (QUT), School of Exercise and Nutrition Sciences, Institute of Health and Biomedical Innovation. 60 Musk Ave, Kelvin Grove, Queensland 4059, Australia.
Queensland University of Technology (QUT), Faculty of Health, School of Exercise and Nutrition Sciences. Victoria Park Road, Kelvin Grove, Queensland 4059, Australia.
J Sci Med Sport. 2021 Aug;24(8):818-823. doi: 10.1016/j.jsams.2021.01.003. Epub 2021 Jan 19.
To test the effects of hot-water immersion on the rapid force production and parameters of neuromuscular function in healthy adults.
Cross-sectional study.
Fifteen healthy adults (24.9±5.6 years; 178±11.4cm; 72.8±16.2kg) performed neuromuscular assessments before, after and ∼15min after either 90min of 42°C (hot) or 36°C (sham-condition) water immersion (lower body). Knee extensors rate of torque development (RTD) was measured during explosive voluntary contraction in the interval of 0-50ms (RTD) and 0-150ms (RTD) and during electrically-evoked contractions by single twitches (RTD) and low- and high-frequencies doublets (RTD and ). Rate of EMG rise (RER) was calculated for voluntary contractions and half-relaxation time (HRT) and electromechanical delay (EMD) was measured during single twitches.
After the hot-water immersion (when rectal and muscle temperature were elevated [↑1°C and ↑2.4°C, respectively]), RTD, RTD and RTD significantly increased and HRT decreased when compared to baseline and sham-condition (p<0.05). Approximately 15min after the hot-water immersion (when muscle temperature was still higher [↑1.4°C], but rectal temperature at baseline level), RTD remained higher and RTD presented higher values than baseline and sham-condition. The RTD and RTD showed further increases compared to post hot-water immersion trials. HRT showed no changes compared to post water immersion, but the EMD presented lower values than baseline and sham-condition. No changes were observed for RTD and RER at any moment.
Increased muscle temperature provoked by 42°C hot-water immersion increases the early phase of the RTD (<70ms) (voluntary and evoked) and decreases HRT and EMD of the knee extensors.
测试热水浸泡对健康成年人快速力量产生和神经肌肉功能参数的影响。
横断面研究。
15 名健康成年人（24.9±5.6 岁；178±11.4cm；72.8±16.2kg）在接受 42°C（热水）或 36°C（假条件）水浴 90 分钟前后以及约 15 分钟后，分别进行神经肌肉评估。在 0-50ms（RTD）和 0-150ms（RTD）的爆发性自愿收缩期间以及单刺激（RTD）和低、高频双刺激（RTD 和 ）期间测量膝关节伸肌扭矩发展率（RTD）。计算自愿收缩的肌电图上升率（RER）和半松弛时间（HRT），并在单刺激期间测量电机械延迟（EMD）。
热水浸泡后（直肠和肌肉温度升高[↑1°C 和 ↑2.4°C]），与基线和假条件相比，RTD、RTD 和 RTD 显著增加，HRT 降低（p<0.05）。热水浸泡后约 15 分钟（当肌肉温度仍较高[↑1.4°C]，但直肠温度恢复到基线水平）时，RTD 仍然较高，RTD 比基线和假条件显示更高的值。RTD 和 RTD 与热水浸泡后试验相比进一步增加。与水浸泡后相比，HRT 没有变化，但 EMD 低于基线和假条件。RTD 和 RER 没有在任何时候发生变化。
42°C 热水浸泡引起的肌肉温度升高增加了 RTD 的早期阶段（<70ms）（自愿和诱发），并降低了膝关节伸肌的 HRT 和 EMD。
