Mtibaa Khouloud, Thomson Athol, Nichols David, Hautier Christophe, Racinais Sebastien
1Sport Science Program, College of Arts and Sciences, Qatar University, Doha, QATAR; 2Inter-university Laboratory of Human Movement Biology, University Claude Bernard Lyon 1, Villeurbanne, FRANCE; and 3Aspetar Orthopaedic and Sports Medicine Hospital, Doha, QATAR.
Med Sci Sports Exerc. 2018 Jan;50(1):46-53. doi: 10.1249/MSS.0000000000001418.
Hyperthermia has been shown to affect both central and peripheral nervous systems. However, the consequences of these alterations on the proprioceptive mechanisms underlying human movement control remain unclear. The aim of this study was to investigate the effect of passive hyperthermia on various measures of proprioception and balance, two key components of injury prevention and movement efficiency.
After a familiarization session, 14 volunteers (8 males, 6 females) completed two experimental sessions in temperate (CON, 24°C) and hot (HOT, 44°C-50°C) conditions, in a counterbalanced order. Participants were tested for neural function (electrically evoked M-wave and Hoffman reflex, Soleus), active movement discrimination (five positions, 50 trials, dorsiflexion), dynamic balance (Star Excursion Balance Test, three directions), and static balance (single-leg stance).
Both rectal (39.0°C ± 0.3°C vs 36.9°C ± 0.6°C) and mean skin (37.9°C ± 1.0°C vs 32.0°C ± 2.7°C) temperatures were significantly higher in HOT than CON (P < 0.05). Hyperthermia significantly reduced the Hoffman reflex (P < 0.05) but not the M-wave (P > 0.05) amplitudes, increased the mean error for active movement discrimination (0.58°± 0.13° vs 0.50° ± 0.11°, +17%, P < 0.05), decreased the average distance reached in the posteromedial direction during dynamic balance (88.6 ± 7.9 cm vs 90.9 ± 6.1 cm, P < 0.05), and increased the contact area of the foot (126 ± 14 cm vs 122 ± 13 cm, +2.7%, P < 0.05) and the center of pressure excursion (64 ± 14 vs 57 ± 9 cm, +11.1%, P < 0.10) during single-leg stance.
The current study suggests that hyperthermia impairs the proprioception and balance parameters measured. These observations might be due to heat-induced alterations in efferent and afferent signals to and from the muscle.
已有研究表明，热疗会影响中枢和外周神经系统。然而，这些改变对人体运动控制的本体感觉机制的影响尚不清楚。本研究旨在探讨被动热疗对本体感觉和平衡的各项指标的影响，这是预防损伤和提高运动效率的两个关键因素。
在进行一次熟悉环节后，14名志愿者（8名男性，6名女性）以平衡顺序在温和（CON，24°C）和炎热（HOT，44°C - 50°C）条件下完成了两个实验环节。对参与者进行神经功能测试（电诱发M波和霍夫曼反射，比目鱼肌）、主动运动辨别测试（五个位置，50次试验，背屈）、动态平衡测试（星形偏移平衡测试，三个方向）和静态平衡测试（单腿站立）。
HOT组的直肠温度（39.0°C ± 0.3°C vs 36.9°C ± 0.6°C）和平均皮肤温度（37.9°C ± 1.0°C vs 32.0°C ± 2.7°C）均显著高于CON组（P < 0.05）。热疗显著降低了霍夫曼反射（P < 0.05）但未降低M波（P > 0.05）的振幅，增加了主动运动辨别测试的平均误差（0.58°± 0.13° vs 0.50° ± 0.11°，增加17%，P < 0.05），在动态平衡测试中，降低了向后内侧方向达到的平均距离（88.6 ± 7.9 cm vs 90.9 ± 6.1 cm，P < 0.05），并在单腿站立时增加了足部的接触面积（126 ± 14 cm vs 122 ± 13 cm，增加2.7%，P < 0.05）和压力中心偏移（64 ± 14 vs 57 ± 9 cm，增加11.1%，P < 0.10）。
当前研究表明，热疗会损害所测量的本体感觉和平衡参数。这些观察结果可能是由于热诱导的进出肌肉的传出和传入信号的改变所致。
