Cowley Jeffrey C, Gates Deanna H
School of Kinesiology, University of Michigan, Ann Arbor, MI, 48109, USA.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
Exp Brain Res. 2018 Aug;236(8):2309-2319. doi: 10.1007/s00221-018-5303-6. Epub 2018 Jun 5.
During fatiguing tasks, people adapt their movement strategies to offset effects of muscle fatigue. Painful stimuli may compete for cognitive resources during this process, impairing fatigue adaptation. This study determined how pain affected movement control and muscle endurance during a repetitive task and how pain catastrophizing moderated these effects. Twenty-two healthy young adults performed timed reaching movements until voluntary exhaustion on two separate days. On 1 day, subjects simultaneously experienced ischemic pain in the contralateral arm. Subjective pain, and effort were recorded at regular intervals. Timing errors, distance and speed were calculated for each movement. Detrended fluctuation analysis was used to quantify temporal persistence in each time series. Subjects made shorter, slower movements during the last compared to the first minute of fatigue on both days (p < 0.001). Deviations in movement speed were corrected faster in the no pain condition compared to the pain condition (p = 0.042), but only early during the condition. Time to fatigue was influenced by pain and the order of testing. Subjects performed the task longer on the second day whether the condition was pain or no pain. This effect was larger when the pain condition was first (3.4 compared to 1.1 min. increase). Subjects with high and low pain catastrophizing responded similarly to the painful stimuli. The results suggest that pain causes people to adopt more conservative movement strategies which can affect the fatigue rate, but these effects depend on familiarity with the painful stimulus and the fatiguing task.
在疲劳任务期间，人们会调整他们的运动策略以抵消肌肉疲劳的影响。在此过程中，疼痛刺激可能会争夺认知资源，从而损害疲劳适应能力。本研究确定了疼痛在重复性任务中如何影响运动控制和肌肉耐力，以及疼痛灾难化如何调节这些影响。22名健康的年轻成年人在两天内分别进行定时伸手动作，直至自愿疲劳。在其中一天，受试者同时在对侧手臂体验缺血性疼痛。定期记录主观疼痛和用力程度。计算每个动作的时间误差、距离和速度。去趋势波动分析用于量化每个时间序列中的时间持续性。与疲劳第一天的第一分钟相比，两天中疲劳最后一分钟时受试者的动作更短、更慢（p < 0.001）。与疼痛条件相比，无疼痛条件下运动速度的偏差校正得更快（p = 0.042），但仅在该条件的早期阶段。疲劳时间受疼痛和测试顺序的影响。无论有无疼痛条件，受试者在第二天执行任务的时间更长。当疼痛条件为先时，这种影响更大（增加3.4分钟 compared to 1.1分钟）。疼痛灾难化程度高和低的受试者对疼痛刺激的反应相似。结果表明，疼痛会导致人们采取更保守的运动策略，这可能会影响疲劳率，但这些影响取决于对疼痛刺激和疲劳任务的熟悉程度。
