The time course of passive stiffness responses following an acute bout of static stretching in healthy, elderly men

Background The time course of passive stiffness responses following an acute bout of static stretching has received little research attention, particularly in older adults. Objective To determine the time course of the acute effects of static stretching on passive stiffness of the hamstrings in healthy, elderly men. Methods Fifteen elderly men (age = 70 +/- 7 years) underwent two randomized conditions that included a control treatment and an experimental treatment of four, 15-s straight-leg raise static stretches. Passive stiffness was calculated as the slopes of the initial and final phases of the angle-torque curve at pre-treatment (Pre) and post-treatment time points of zero (Post0), five (Post5), and ten (Post10) minutes. Results Passive stiffness collapsed across phase was lower at Post0 (P= .029,d= 0.64) and Post5 (P= .042,d= 0.54) but not Post10 (P> .999,d= 0.15) compared to Pre for the stretching treatment. There were no significant differences in passive stiffness (collapsed across phase) between any of the time points (P> .999,d <= 0.14) for the control. Conclusions An acute bout of static stretching produced significant decreases in the passive stiffness characteristics of elderly men; however, these decreases returned to baseline values within 5 to 10 minutes.

Automated summary

The study found that passive stiffness in the hamstrings of healthy older men significantly decreased after static stretching, but returned to baseline levels within 5 to 10 minutes.