Effect of the number of sets on acute cardiovascular responses during stretching exercise

Abstract Few studies have investigated the effects of manipulating variables of stretching exercise prescription on acute cardiovascular responses. The objective of this study was to compare the acute responses of heart rate, blood pressure and double product before, during and after four sets of passive static stretching during unilateral hip flexion. The sample consisted of 16 adult men aged 18 to 27 years (22±2.8 years) with no experience in flexibility training. The cardiovascular variables were measured by photoplethysmography with continuous recording for 5 minutes at rest, during exercise and 10 minutes after stretching. A difference was observed in all variables (p<0.05) when resting and post-exercise values were compared to exercise values. There was only an increase in blood pressure values between sets. Systolic blood pressure was increased in the third set compared to the first [set 1 = 136 mmHg (±9.4); set 3 = 145 mmHg (±9.7)] and diastolic blood pressure was increased in the second set compared to the first [set 1 = 79 mmHg (±6.7); set 2 = 84 mmHg (±9.1)]. Hypotension was not observed post-exercise. It was concluded that the stretching sets have a cumulative effect on systolic and diastolic blood pressure responses, but not on heart rate. However, the stretching protocol produced no hypotensive effect after exercise.

摘要 目前鲜有研究探讨拉伸运动处方变量调控对急性心血管反应的影响。本研究旨在对比单侧髋关节屈曲过程中，四组被动静态拉伸前后及拉伸期间的心率、血压及二重乘积（double product）的急性反应。研究样本为16名年龄18至27岁（平均22±2.8岁）、无柔韧性训练经验的成年男性。心血管指标通过光电容积描记法（photoplethysmography）进行测量，在静息状态、运动过程中及拉伸结束后10分钟内连续记录5分钟。将静息及拉伸后数值与运动中数值进行对比时，所有指标均存在显著差异（p<0.05）。仅在各组拉伸之间观察到血压升高：与第一组相比，第三组的收缩压升高[第1组：136 mmHg（±9.4）；第3组：145 mmHg（±9.7）]；与第一组相比，第二组的舒张压升高[第1组：79 mmHg（±6.7）；第2组：84 mmHg（±9.1）]。拉伸后未观察到低血压反应。研究结论表明，拉伸组数对收缩压与舒张压反应存在累积效应，但对心率无此效应；此外，本次拉伸方案在运动后未产生降压效果。