离心运动伴不同程度的血流限制对外周疲劳及心脏自主神经功能的效应研究

目的:探讨急性离心运动伴4种不同程度的血流限制对年轻女性外周疲劳及心脏自主神经功能的影响,综合评价各方案的安全性,为长期血流限制运动干预提供参考。方法:将40名女大学生随机分为4组,分别进行小强度抗阻(30%1RM)伴0%(CON组)、40%(BFR₄₀组)、60%(BFR₆₀组)和80%(BFR80组)动脉闭塞压(AOP)的血流限制运动。各小组进行4组伸膝离心运动,第1组重复30次,后3组重复15次,组间休息30 s。检测运动前、运动后即刻、15 min、30 min、1 h以及24 h的骨骼肌收缩性能(最大径向位移、收缩速度)、最大等长力量和心脏自主神经功能。结果:1)与CON组相比,BFR₄₀组的副交感神经活性受到轻微抑制(P<0.05),可在运动后30 min内恢复(P>0.05);2)BFR₆₀组的最大等长力量在运动后显著下降(P<0.01),副交感神经活性进一步抑制(P<0.01),交感神经支配增强(P<0.05),运动后30 min内恢复交感—副交感神经的平衡性(P>0.05);3)BFR80组运动后诱发显著的外周疲劳(P<0.01),使副交感恢复显著延迟,交感活性大幅增强(P<0.05),需更长时间恢复交感—副交感神经的平衡性(24 h内);4)相关性分析显示,副交感神经活性分别与最大径向位移(r=0.65)、收缩速度(r=0.62)和最大等长力量(r=0.55)呈正相关(P<0.05),交感神经活性与上述3个指标呈负相关(P<0.05)。结论:血流限制运动中,40%AOP会抑制迷走神经活性;60%AOP可明显影响交感神经活性和交感—副交感调控的平衡性;80%AOP可诱发显著的外周疲劳,且与心脏自主神经调控密切相关。综上所述,不建议心血管风险高的患者使用80%AOP训练。

Effects of Eccentric Exercise under Different Levels of Blood-flow Restriction on Peripheral Fatigue and Cardiac Autonomic Function

Objective:To explore the acute effects of exercise under different levels of blood-flow restriction on peripheral fatigue and cardiac autonomic function in young women and to evaluate the safety of each condition.The results will provide basis for chronic training.Methods:40 female college students were randomly divided into 4 groups:low load(30%1 RM)combined with0%(CON),40%(BFR₄₀),60%(BFR₆₀)and 80%(BFR80)of arterial occlusion pressure(AOP).Each group performed 4 sets of knee extension eccentric exercise(1 set of 30 repetitions followed by 3 sets of 15 repetitions)with 30 s between each set.The skeletal muscle contractile properties(maximal displacement and contraction velocity),maximum voluntary isometric contraction(MVIC)and cardiac autonomic function were measured at baseline and immediately,15 min,30 min,1 h and 24 h post exercise.Results:1)In BFR₄₀,there was a slight reduce in vagal control when compared with CON(P<0.05),and it could recover within 30 min post exercise(P>0.05);2)In BFR₆₀,MVIC and parasympathetic activity was significantly decreased(P<0.01)while sympathetic outflow was enhanced post exercise(P<0.05),and sympathetic/parasympathetic balance could recover within 30 min post exercise(P>0.05);3)In BFR80,peripheral fatigue and sympathetic activity were dramatically increased(P<0.05)while the withdrawal of vagal activity post exercise was significantly delayed(P<0.05),so it took longer time to restore sympathetic/parasympathetic balance(within 24 hours);4)Correlation analysis showed that parasympathetic activity was positively correlated with maximal displacement(r=0.65),contraction velocity(r=0.62)and MVIC(r=0.55),respectively(P<0.05).While sympathetic activity was negatively correlated with these three parameters(P<0.05).Conclusion:During blood flow restriction exercise,40%AOP reduces vagal activity when 60%AOP significantly changes sympathetic activity and sympathetic/parasympathetic balance.As the restriction increases to 80%AOP,it can evoke clear peripheral fatigue,which is highly related to the adaptation of cardiac autonomic function.So 80%AOP is not recommended for patients with high cardiovascular risk.