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背景:已有研究证明昏暗光线照射18 h可能导致抓握耐力下降,但短期昏暗光线照射对肌肉耐力是否有相似影响尚不明确。本研究比较了微光或强光照射1 h后抗阻伸膝的完成次数。方法:受试者(5位女性,1 1位男性,19-26岁的大学生)以约40%体重的阻力进行力竭性伸膝。伸膝测试在3种灯光照射条件后立即进行,包括黑暗(DL)、室内灯光(RL)和室内灯光加5 mg褪黑激素(RLM)。每种情形至少间隔48 h,所有受试者测试时身体状态良好。结果:RL照射后伸膝平均次数(62.0±22.0)显著多于DL(51.4±14.7)和RLM(57.8±22.9)照射后(p<0.05)。RLM照射后伸膝次数和DL照射后无显著区别。在运动前即刻进行1 h的昏暗光线照射可能导致大腿肌肉耐力下降。短期昏暗光线照射后运动表现的下降与已有研究所报道的长期照射相似。结论:光的强度可影响肌肉耐力,但这种影响与内生的褪黑激素产量没有直接关系。
BACKGROUND: Previous studies have shown that exposure to dim light for 18 h may result in decreased grip endurance, but it is unclear whether short-term dim light exposure has similar effects on muscle endurance. This study compared the number of completed resistance knees after 1 h light or light exposure. METHODS: Subjects (5 women, 11 males, 19-26 year-old college students) developed an exhaustive knee extension with a resistance of approximately 40% of body weight. The knee extension test was performed immediately after 3 lighting conditions, including darkness (DL), room lighting (RL) and room lighting plus 5 mg of melatonin (RLM). In each case at least 48 h apart, all subjects tested in good physical condition. Results: The average number of knee extensors after RL irradiation was significantly higher (62.0 ± 22.0) than that of DL (51.4 ± 14.7) and RLM (57.8 ± 22.9) (p <0.05). There was no significant difference in the number of knee extensors after RLM irradiation and DL irradiation. Dim light exposure 1 h immediately before exercise may result in decreased thigh muscle endurance. Short-term dim light after exercise decreased the performance of previous studies have reported long-term exposure similar. Conclusion: The intensity of light affects muscle endurance, but this effect is not directly related to endogenous melatonin production.