Qatar University, Sports Science Program, College of Arts and Sciences, Doha, Qatar; Inter-university Laboratory of Human Movement Biology (EA 7424), Claude Bernard University Lyon 1, Lyon, France.
Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
J Sci Med Sport. 2019 Dec;22(12):1361-1366. doi: 10.1016/j.jsams.2019.07.008. Epub 2019 Jul 24.
To determine the effects of heat stress on ankle proprioception and running gait pattern.
Counterbalanced repeated measures.
12 trained runners performed a proprioception test (active movement discrimination) before and immediately after a 30min, self-paced treadmill run in HOT (39°C) and COOL (22°C) ambient conditions. Velocity was imposed during the first and last minute (70% of maximal aerobic velocity, 13.3±0.8kmh) for determination of running mechanics and spring-mass characteristics.
Rectal (39.7±0.4 vs. 39.4±0.4°C), skin (36.3±1.1 vs. 31.8±1.1°C) and average body (38.3±0.2 vs. 36.4±0.4°C) temperatures together with heart rate (178±8 vs. 174±6bpm) and thermal discomfort (6.5±0.5 vs. 4.3±1.3) were all higher at the end of the HOT compared to COOL run (all p<0.05). Distance covered was lower in HOT than COOL (-5.1±3.6%, p<0.001). Average error during the proprioception test increased after running in HOT (+11%, p<0.05) but not in COOL (-2%). There was no significant difference for most segmental and joint angles at heel contact, except for a global increase in pelvis retroversion and decrease in ankle dorsi-flexion angles with time (p<0.05). Step frequency decreased (-2.5±3.6%) and step length increased (+2.6±3.8%) over time (p<0.05), independently of condition. Spring-mass characteristics remained unchanged (all p>0.05).
Heat stress exacerbates thermal, cardiovascular and perceptual responses, while running velocity was slower during a 30min self-paced treadmill run. Heat stress also impairs ankle proprioception during an active movement discrimination task, but it has no influence on gait pattern assessed at a constant, sub-maximal velocity.
确定热应激对踝关节本体感觉和跑步步态模式的影响。
平衡重复测量。
12 名训练有素的跑步者在 HOT（39°C）和 COOL（22°C）环境条件下分别在 30 分钟、自我调节跑步机跑步前后进行本体感觉测试（主动运动辨别）。在第一分钟和最后一分钟施加速度（最大有氧速度的 70%，13.3±0.8kmh）以确定跑步力学和弹簧质量特性。
直肠（39.7±0.4 与 39.4±0.4°C）、皮肤（36.3±1.1 与 31.8±1.1°C）和平均体（38.3±0.2 与 36.4±0.4°C）温度以及心率（178±8 与 174±6bpm）和热不适（6.5±0.5 与 4.3±1.3）在 HOT 结束时均高于 COOL 运行（均 p<0.05）。在 HOT 中比在 COOL 中覆盖的距离更低（-5.1±3.6%，p<0.001）。在 HOT 中跑步后本体感觉测试的平均误差增加（+11%，p<0.05），但在 COOL 中没有增加（-2%）。除骨盆后倾增加和踝关节背屈角度随时间降低外（p<0.05），脚跟接触时大多数节段和关节角度没有显着差异。随着时间的推移，步频降低（-2.5±3.6%），步长增加（+2.6±3.8%）（p<0.05），与条件无关。弹簧质量特性保持不变（均 p>0.05）。
热应激会加剧热、心血管和感知反应，而在 30 分钟的自我调节跑步机跑步过程中，跑步速度较慢。热应激还会在主动运动辨别任务中损害踝关节本体感觉，但对以恒定、次最大速度评估的步态模式没有影响。
