原著論文
伸張性収縮における筋線維の動員と筋損傷との関連性
2018 年 23 巻 2 号 p. 89-94
詳細
2018 年 23 巻 2 号 p. 89-94
【Purpose】 This study investigated that the relationship between muscle fiber recruitment and the magnitude of muscle damage by eccentric contractions (ECCs).【Methods】 Nine healthy men (age: 27.2±6.0 y, height: 174. 0±5.3 cm, body mass 70.1±2.1 kg, % body fat: 20.9±2.7%, lean body mass: 55.5±2.0 kg) were recruited in this study. Subjects performed that 5 sets of 6 ECCs of the elbow flexors using a dumbbell adjusted to 80% of each individual’s 1 RM. The dependent variables that maximal voluntary isometric contraction (MVC) torque, range of motion (ROM), delayed onset muscle soreness (DOMS), transverse relaxation time (T2) and cross sectional area (CSA) of magnetic resonance imaging (MRI) were measured immediately before, immediately after and 1, 3, and 5 days after each exercise. 【Results】 MVC torque decreased immediately after (p<0.05) and remained lower than baseline at 1 and 3 days (p<0.05) after exercise. ROM also decreased immediately after (p<0.05) and remained lower than baseline at 1 day after exercise (p<0.05). DOMS developed 1 and 3 days (p<0.05) after ECCs, and CSA increased only 5 days after ECCs (p<0.05). Increased T2 was observed immediately post-exercise and 1 day after exercise (p<0.05). An increased CSA was observed at 5 days after exercise (p<0.05). We found a significant correlation between the change in T2 and MVC at immediately after (r=0.77) . In addition, a significant correlation between the change in T2 at immediately after and change in CSA at 3 days after (r=-0.83) was found.【Conclusion】 We suggest that the muscle fiber recruitment with ECCs is related to the magnitude of muscular dysfunction and swelling.
