运动负荷对抗阻训练下皮层神经活动特征的影响:来自fNIRS的证据

Influence of Exercise Load on Cortical Neural Activity Characteristics During Resistance Training:Evidence from fNIRS Study

目的:对不同负荷抗阻训练过程中的大脑皮层神经活动进行监测,探究高负荷训练过程中的皮层神经活动特征。方法:以18名成年男性为实验对象,采用4(运动负荷:20%1RM、40%1RM、60%1RM、80%1RM)*3(兴趣区:初级运动皮层(M1)、运动前区-辅助运动区(PMC-SMA)、背外侧前额叶(DLPFC))的被试内设计,对深蹲训练过程中的大脑皮层含氧血红蛋白浓度(HbO)进行测量,同时使用主观疲劳量表和心率手表监控内部运动负荷。结果:(1)在动作执行阶段,运动负荷越高,HbO mean水平越低,间歇阶段的HbO mean水平在20%1RMK-60%1RM范围内不断升高,但80%1RM下的HbO mean相比60%1RM却出现明显下降;(2)M1和PMC-SMA在动作执行阶段较DLPFC表现出更低的HbO mean水平,在间歇阶段较DLPFC表现出更高的HbO mean水平;(3)运动负荷和兴趣脑区存在交互作用,在动作执行阶段,运动负荷对抗阻训练下皮层HbO mean水平的调节在M1和PMC-SMA区域更明显,但这种调节效应在间歇阶段出现减弱的趋势;(4)随着运动负荷的递增,训练前后的主观疲劳等级差异和平均心率出现明显增加。结论:(1)大脑皮层在抗阻训练动作执行初期有一个能量损耗引发的负激活阶段,并且负激活程度和负荷大小成正相关;(2)运动负荷和大脑皮层激活强度在动作执行后续阶段呈非线性相关,即中低负荷范围内激活强度与负荷同步上升,高负荷条件下出现下降;(3)M1、PMC-SMA较DLPFC在抗阻训练过程中扮演更重要的主动调控角色。

This study aimed to measure the neural activity in the cerebral cortex during different resistance training loads,exploring the impact of high load training on neural activity characteristics.It included 18 males.A two factors within-subjects design was employed:exercise load(20%1RM,40%1RM,60%1RM,80%1RM)and regions of interest(primary motor cortex(M1)),premotor cortex and supplementary motor area(PMC-SMA),dorsolateral prefrontal cortex(DLPFC).Near-infrared functional imaging device was utilized to measure the concentration of oxygenated hemoglobin(HbO)in the cerebral cortex during squatting.Subjective fatigue rating scales and heart rate watch were used to monitor internal exercise load.The results showed that higher loads resulted in lower HbOmean during the execution phase,while HbOmean increased from 20%1RM to 60%1RM range,but dropped at 80%1RM during the rest phase.M1 and PMC-SMA exhibited lower HbOmean than DLPFC during the execution phase,but showed higher HbOmean than DLPFC during the rest phase.There was an interaction between load and regions of interest.Exercise load had a more pronounced effect on HbOmean in the M1 and PMC-SMA compared to DLPFC during the execution phase.However,this regulatory effect tended to weaken during the rest phase.With higher load,there was a significant increase in the difference in subjective fatigue levels before and after training,as well as the average heart rate.It was conclude that the cerebral cortex undergoes an initial phase of negative activation induced by energy consumption during the early stages of resistance training,and the degree of negative activation was correlated with the magnitude of the load.Exercise load and cerebral cortex activation exhibited a non-linear correlation after movement execution,increasing synchronously within the low to moderate load but decreasing under high load.M1 and PMC-SMA played a more crucial regulatory role than DLPFC during resistance training.