Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany.
Olympic Base Center Rhineland, Cologne, Germany.
PLoS One. 2018 Jun 28;13(6):e0199307. doi: 10.1371/journal.pone.0199307. eCollection 2018.
Skeletal muscle fatigue has been shown to be associated with hyperphosphorylation of the ryanodine receptor 1 at serine 2843 (pRyR1Ser2843), due to chronic overloading exercise. We investigated whether pRyR1Ser2843, is a mechanism relevant for muscle fatigue also under acute, in contrast to chronic, muscle loading. 24 male subjects (age: 24,8±3,8; height: 182,8±7,2 cm; weight: 82,5±9,9 kg) were evenly (n = 6) assigned to the following four different resistance exercise (RE) groups: hypertrophy- (HYP), strength endurance- (SE), maximum power- (MAX) at the subjects' 10, 25 and 3 repetition maximum, respectively, and low intensity (LI) RE with 70% of the 10 repetition maximum. Each group completed three different RE volumes (1 set, 5, and 10 sets). Muscle biopsies from the vastus lateralis were taken before and after exercise, analyzed for pRyR1Ser2843 and examined for association with RE-induced muscle fatigue which was determined as reduction in maximum isometric force (isoFmax) in the quadriceps femoris muscle also before and after exercise.The degree of RE-induced muscle fatigue was specific in terms of set volume as well as of RE mode. isoFmax was not reduced in any group after one set of RE. Five sets led to a significant reduction of isoFmax in HYP and SE but not in LI and MAX (p<0,05). Ten sets of RE, as compared to five sets, exclusively induced further muscle fatigue in LI. In terms of RE mode differences, isoFmax reduction was generally higher in HYP and SE than in MAX and Li after five and ten sets of RE (p<0,05). However, pRyR1Ser2843 did not show any significant regulation, regardless of exercise condition. We conclude that despite its relevance in reducing muscle contractility in chronic overloading, pRyR1Ser2843 does not reflect the degree of muscle fatigue exerted by acute hypertrophy-, strength endurance-, maximum power and low intensity-oriented exercise.
骨骼肌疲劳已被证明与肌浆网钙释放通道 1 上丝氨酸 2843 的过度磷酸化（pRyR1Ser2843）有关，这是由于慢性超负荷运动所致。我们研究了在急性而不是慢性肌肉负荷下，pRyR1Ser2843 是否也是肌肉疲劳的相关机制。24 名男性受试者（年龄：24.8±3.8；身高：182.8±7.2cm；体重：82.5±9.9kg）被平均（n=6）分为以下四个不同的抗阻运动（RE）组：肥大-（HYP）、力量耐力-（SE）、最大力量-（MAX），分别在受试者的 10、25 和 3 次重复最大，以及低强度（LI）RE 为 10 次重复最大的 70%。每组完成三种不同的 RE 量（1 组、5 组和 10 组）。股外侧肌的肌肉活检在运动前后进行，分析 pRyR1Ser2843，并检查其与 RE 引起的肌肉疲劳的关系，RE 引起的肌肉疲劳通过股四头肌的最大等长力（isoFmax）的降低来确定，该力在运动前后进行测量。RE 引起的肌肉疲劳的程度在组容量和 RE 模式方面是特异性的。任何一组在进行一组 RE 后，isoFmax 均未降低。五组的 RE 导致 HYP 和 SE 中的 isoFmax 显著降低，但 LI 和 MAX 中则没有（p<0.05）。与五组 RE 相比，十组 RE 仅在 LI 中进一步引起肌肉疲劳。就 RE 模式的差异而言，与五组 RE 相比，HYP 和 SE 中的 isoFmax 降低在十组 RE 后通常高于 MAX 和 Li（p<0.05）。然而，无论运动条件如何，pRyR1Ser2843 的调节均不明显。我们的结论是，尽管 pRyR1Ser2843 在降低慢性超负荷引起的肌肉收缩性方面具有相关性，但它并不能反映急性肥大、力量耐力、最大力量和低强度定向运动所产生的肌肉疲劳程度。
