Limited passive hamstring flexibility might affect kinematics, performance, and injury risk during running. Pre-activity static straight-leg raise stretching often is used to gain passive hamstring flexibility.
To investigate the acute effects of a single session of passive hamstring stretching on pelvic, hip, and knee kinematics during the swing phase of running.
Randomized controlled clinical trial.
Biomechanics research laboratory.
Patients or Other Participants:
Thirty-four male (age = 21.2 ± 1.4 years) and female (age = 21.3±2.0 years) recreational athletes.
Participants performed treadmill running pretests and posttests at 70% of their age-predicted maximum heart rate. Pelvis, hip, and knee joint angles during the swing phase of 5 consecutive gait cycles were collected using a motion analysis system. Right and left hamstrings of the intervention group participants were passively stretched 3 times for 30 seconds in random order immediately after the pretest. Control group participants performed no stretching or movement between running sessions.
Main Outcome Measure(s):
Six 2-way analyses of variance to determine joint angle differences between groups at maximum hip flexion and maximum knee extension with an α level of .008.
Flexibility increased between pretest and post-test in all participants (F1,30 = 80.61, P<.001). Anterior pelvic tilt (F1,30 = 0.73, P=.40), hip flexion (F1,30 = 2.44, P=.13), and knee extension (F1,30 = 0.06, P=.80) at maximum hip flexion were similar between groups throughout testing. Anterior pelvic tilt (F1,30 = 0.69, P=.41), hip flexion (F1,30 = 0.23, P=.64), and knee extension (F1,30 = 3.38, P=.62) at maximum knee extension were similar between groups throughout testing. Men demonstrated greater anterior pelvic tilt than women at maximum knee extension (F1,30 = 13.62, P=.001).
A single session of 3 straight-leg raise hamstring stretches did not change pelvis, hip, or knee running kinematics.