Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Exeter, United Kingdom.
Peninsula Clinical Research Facility, National Institute for Health Research, College of Medicine and Health, Exeter, United Kingdom.
Am J Physiol Regul Integr Comp Physiol. 2019 Aug 1;317(2):R346-R354. doi: 10.1152/ajpregu.00084.2019. Epub 2019 May 29.
Exhaustive single-leg exercise has been suggested to reduce time to task failure (T) during subsequent exercise in the contralateral leg by exacerbating central fatigue development. We investigated the influence of acetaminophen (ACT), an analgesic that may blunt central fatigue development, on T during single-leg exercise completed with and without prior fatiguing exercise of the contralateral leg. Fourteen recreationally active men performed single-leg severe-intensity knee-extensor exercise to T on the left (Leg) and right (Leg) legs without prior contralateral fatigue and on Leg immediately following Leg (Leg). The tests were completed following ingestion of 1-g ACT or maltodextrin [placebo (PL)] capsules. Intramuscular phosphorus-containing metabolites and substrates and muscle activation were assessed using P-MRS and electromyography, respectively. T was not different between Leg and Leg conditions (402 ± 101 vs. 390 ± 106 s, = 0.11). There was also no difference in T between Leg and Leg (324 ± 85 vs. 311 ± 92 s, = 0.10), but T was shorter in Leg and Leg than in Leg (385 ± 104 s, both < 0.05). There were no differences in intramuscular phosphorus-containing metabolites and substrates or muscle activation between Leg and Leg and between Leg and Leg (all > 0.05). These findings suggest that levels of metabolic perturbation and muscle activation at T are not different during single-leg severe-intensity knee-extensor exercise completed with or without prior fatiguing exercise of the contralateral leg. Despite contralateral fatigue, ACT ingestion did not alter neuromuscular responses, muscle metabolites, or exercise performance.
剧烈的单腿运动已被建议通过加剧中枢疲劳的发展来减少随后对另一侧腿进行运动时的任务失败时间（T）。我们研究了一种可能会削弱中枢疲劳发展的镇痛剂对乙酰氨基酚（ACT）对无先前对侧疲劳和在对侧腿运动后即刻（Leg）单腿运动时 T 的影响。14 名有休闲运动习惯的男性在左腿（Leg）和右腿（Leg）上进行单腿剧烈强度的膝关节伸展运动，直至 T，而不进行先前的对侧疲劳，且在 Leg 后立即进行 Leg（Leg）。测试在服用 1 克 ACT 或麦芽糊精[安慰剂（PL）]胶囊后进行。使用 P-MRS 和肌电图分别评估肌肉内含磷代谢物和底物以及肌肉激活。Leg 和 Leg 之间的 T 没有差异（402±101 对 390±106 s，=0.11）。Leg 和 Leg 之间的 T 也没有差异（324±85 对 311±92 s，=0.10），但 Leg 和 Leg 的 T 比 Leg 的 T 短（385±104 s，均<0.05）。Leg 和 Leg 之间以及 Leg 和 Leg 之间的肌肉内含磷代谢物和底物或肌肉激活没有差异（均>0.05）。这些发现表明，在完成无先前对侧疲劳和在对侧腿运动后即刻进行的剧烈单腿膝关节伸展运动时，T 时的代谢紊乱和肌肉激活水平没有差异。尽管有对侧疲劳，ACT 摄入并未改变神经肌肉反应、肌肉代谢物或运动表现。
