Stretching Exercise

Introduction: According to the American College of Sports Medicine 1,flexibility is an important component of good physical fitness and health. Therefore, for physical activity programs, muscles stretching exercise is an important component. Sedentary or less flexible subjects may perform the VM during stretching exercises due to difficulty in reaching and sustaining extreme ranges of motion.

Methodology: 40 participants of age group 18-25 years having either hamstrings or pectorals tightness were included in quasi experimental study by convenient sampling technique. 20 subjects were included in each group: group A hamstrings tightness and group B pectorals tightness. 3 reps of stretching were given with 15 secs rest after each rep. Heart rate

They were made familiarized with the techniques to be performed. Each subject has to perform a set PNF stretching exercise. It consists of 3 repetitions of stretching exercise, each with 6 sec of isometric contraction followed by 24 sec of sustained stretching. VM was performed in last second of each repetition and 15 seconds rest was given between each repetition.9

On second day, prior to stretching session subjects rested for 10 mins. Baseline HR and BP were measured after that. PNF stretching of hamstrings was performed with subject in supine with hip flexion and knee extension. So for that base line data was measured in supine position. PNF stretching of pectorals was given in high sitting position with horizontal flexion of shoulders forming 90° angle with the trunk and elbows flexed such that the hands touches the back of head. Base line data for pectorals was taken in high sitting position.

Immediately after completion of a set of stretching exercises, HR and BP were measured. To maintain the ecological validity of the results, the measurements were conducted within 30 sec after stretching. Measurements were measured again after 1 min and 3

In the present study, the maximal range of motion was reached and held passively, and the stretched muscle was certainly contracted because of the muscle spindle reflex. The sustained muscle tension may have favored the HR and SBP increases due to the activation of muscle and tendon mechanoreceptors.26,27 The sustained static contraction combined with stretching to the maximal range of motion may also have occluded muscle vessels, leading to an increase in the SBP.28,29. In simultaneous muscle stretching and contraction, type III fibers and metaboreceptor activation may induce vagal inhibition and baroreflex stimulation and contribute to an increase in the overall cardiovascular response.30,31

In the present study, the HR was assessed during exercise sessions performed with a static component sustained for 30 s, with four repetitions. Because the subjects had low flexibility levels, the contraction intensity can be considered as at least moderate, representing a non-negligible muscle workload. Additionally, the HR and BP in each set increased proportionally to the duration of the muscle contraction. This issue evokes the importance of controlling the stimulation duration to prevent undesirable cardiac