递增强度运动时肌氧的变化

Changes of muscle oxygen content during incremental exercises

背景:近红外光谱技术的发展,使连续、实时、快捷及无损检测运动骨骼肌氧含量的变化已成为现实。目的:分析近红外光谱技术检测递增强度运动时肌氧的变化特征及其与个体乳酸阈之间的关系。设计、时间及地点:对比观察,实验于2005年在武汉体育学院健康科学学院实验中心完成。对象:以武汉体育学院23名青年男子中长跑运动员作为实验组,以该校无正规运动训练史的23名男大学生作为对照组,两组平均年龄基本相似[(21±2),(20±1)岁,P=0.215],受试对象对实验知情同意。方法:受试者在功率自行车上做递增负荷运动,逐级递增,直至力竭。利用近红外光谱技术连续检测受试者右侧股外侧肌氧的变化,同时作呼出气体分析,运动全程遥测心率,分别测定安静时、每级负荷运动后即刻和恢复期第2,5,10min手指末梢血乳酸浓度测定,采用在血乳酸动力学变化曲线上标定个体乳酸阈的方法寻找受试者个体乳酸阈。主要观察指标:两组递增负荷运动过程中肌氧的变化及其与个体乳酸阈的相关性。结果:①在递增负荷运动时,肌氧的变化在一定运动强度范围(对照组50～150W,实验组50～200W)只出现轻微改变;运动强度超过一定数值时(对照组为150W,实验组为200W)其变化幅度明显加大。实验组受试者的肌氧平均下降幅度较对照组受试者大(P<0.05)。②肌氧的变化灵敏反映了运动强度的变化,与血乳酸浓度的变化曲线呈高度负相关(r=-0.960,P<0.01),突然出现大幅度下降的拐点时所对应的运动强度与个体乳酸阈基本一致。结论:递增负荷运动中,肌氧的变化信号灵敏地反映了运动强度的变化,其突然出现的大幅度下降的拐点所对应的运动强度与个体乳酸阈显著相关。

BACKGROUND： The development of near infrared spectroscopy realizes the continuous, real time, rapid and non-traumatic detection of skeletal muscle oxygen content changes. OBJECTIVE： To analyze change characteristics of muscle oxygen content during incremental exercises detected by near infrared spectroscopy and the relationship between it and the individual lactate threshold. DESIGN, TIME AND SETTING： Contrast observation was conducted in 2005 at the Experimental Center, Wuhan Institute of Physical Education College of Health Sciences. PARTICIPANTS： The trial group included 23 young male mid-long athletes from Wuhan Institute of Physical Education College of Health Sciences, and the control group included 23 male undergraduates from the same school without normal exercise training, the ages of the students in the two groups were similar [（21± 2）, （20± 1） years, P =0.215]. Participants were informed and agreed to the trial. METHODS： Participants did incremental exercises on bicycle ergometer, load increased gradually until they exhausted. We detected the muscle oxygen content changes of participant light vastus lateralis with continuous-wave near infrared spectroscopy, at the same time; exhaled air was analyzed, remote monitoring of heart rate was done during the whole course, and finger peripheral blood lactate concentrations were measured at rest, immediately and 2, 5, 10 minutes after each grade of load exercise. We used the method labeled individual lactate threshold on the blood lactate clarve to find participant individual lactate threshold. MAIN OUTCOME MEASURES： The muscle oxygen content changes of two groups during incremental exercises and the relationship between the changes and the individual lactate threshold. RESULTS： During the incremental exercises, the muscle oxygen content changed slightly within certain exercise intensity range （control group 50-150 W, trial group 50-200 W）, the muscle oxygen content changed obviously when the exercise intensity exceeded a certain value （control group 150 W, trial group 200 W）. The mean decrease amplitude of muscle oxygen content of participants in the trial group was larger than that of participants in the control group （P 〈 0.05）. The changes of muscle oxygen content sensitively reflected the changes of exercise intensity, and was negatively correlated with blood lactate concentration change curve （correlation coefficient r=-0.960, P 〈 0.01）, when the turning point of sharp decrease abruptly appeared, the corresponding exercise intensity was basically consistent with individual lactate threshold. CONCLUSION： The changes of muscle oxygen content sensitively reflected the changes of exercise intensity, and when the turning point of sharp decrease abruptly appeared, the corresponding exercise intensity was significantly correlated with individual lactate threshold.