从增强式训练中易损的 II 型肌纤维。
Preferential type II muscle fiber damage from plyometric exercise.
机构信息
Department of Physiological Sciences, Stellenbosch University, South Africa.
出版信息
J Athl Train. 2012 Jul-Aug;47(4):414-20. doi: 10.4085/1062-6050-47.4.13.
CONTEXT
Plyometric training has been successfully used in different sporting contexts. Studies that investigated the effect of plyometric training on muscle morphology are limited, and results are controversial with regard to which muscle fiber type is mainly affected.
OBJECTIVE
To analyze the skeletal muscle structural and ultrastructural change induced by an acute bout of plyometric exercise to determine which type of muscle fibers is predominantly damaged.
DESIGN
Descriptive laboratory study.
SETTING
Research laboratory.
PATIENTS OR OTHER PARTICIPANTS
Eight healthy, untrained individuals (age = 22 ± 1 years, height = 179.2 ± 6.4 cm, weight = 78.9 ± 5.9 kg).
INTERVENTION(S): Participants completed an acute bout of plyometric exercise (10 sets of 10 squat-jumps with a 1-minute rest between sets).
MAIN OUTCOME MEASURE(S): Blood samples were collected 9 days and immediately before and 6 hours and 1, 2, and 3 days after the acute intervention. Muscle samples were collected 9 days before and 3 days after the exercise intervention. Blood samples were analyzed for creatine kinase activity. Muscle biopsies were analyzed for damage using fluorescent and electron transmission microscopy.
RESULTS
Creatine kinase activity peaked 1 day after the exercise bout (529.0 ± 317.8 U/L). Immunofluorescence revealed sarcolemmal damage in 155 of 1616 fibers analyzed. Mainly fast-twitch fibers were damaged. Within subgroups, 7.6% of type I fibers, 10.3% of type IIa fibers, and 14.3% of type IIx fibers were damaged as assessed by losses in dystrophin staining. Similar damage was prevalent in IIx and IIa fibers. Electron microscopy revealed clearly distinguishable moderate and severe sarcomere damage, with damage quantifiably predominant in type II muscle fibers of both the glycolytic and oxidative subtypes (86% and 84%, respectively, versus only 27% of slow-twitch fibers).
CONCLUSIONS
We provide direct evidence that a single bout of plyometric exercise affected mainly type II muscle fibers.
背景
增强式训练已成功应用于不同的运动领域。研究表明，增强式训练对肌肉形态学的影响有限，并且对于哪种肌纤维类型受到主要影响，结果存在争议。
目的
分析急性增强式训练引起的骨骼肌结构和超微结构变化，以确定哪种类型的肌纤维受到主要损伤。
设计
描述性实验室研究。
环境
研究实验室。
患者或其他参与者
8 名健康、未经训练的个体（年龄=22±1 岁，身高=179.2±6.4cm，体重=78.9±5.9kg）。
干预措施
参与者完成了一次急性增强式训练（10 组 10 次深蹲跳，每组之间休息 1 分钟）。
主要观察指标
在急性干预前 9 天和即刻、干预后 6 小时、1 天、2 天和 3 天采集血样。在运动干预前 9 天和后 3 天采集肌肉样本。分析血样中的肌酸激酶活性。使用荧光和电子传输显微镜分析肌肉活检以评估损伤。
结果
肌酸激酶活性在运动后 1 天达到峰值（529.0±317.8U/L）。免疫荧光显示 1616 个纤维中有 155 个出现了肌膜损伤。主要是快肌纤维受损。在亚组中，7.6%的 I 型纤维、10.3%的 IIa 型纤维和 14.3%的 IIx 型纤维的抗肌营养不良蛋白染色丢失，提示存在损伤。IIx 和 IIa 纤维中存在类似的损伤。电子显微镜显示，明显区分了中度和重度的肌节损伤，且在糖酵解和氧化亚型的 II 型肌纤维中，损伤可量化地占主导地位（分别为 86%和 84%，而慢肌纤维仅为 27%）。
结论
我们提供了直接证据表明，单次增强式训练主要影响 II 型肌纤维。
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