Abstract

Context: 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. Objective: 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. Design: Randomized controlled clinical trial. Setting: Biomechanics research laboratory. Patients or Other Participants: Thirty-four male (age= 21.2 [+ or -] 1.4 years) and female (age=21.3 [+ or -] 2.0 years) recreational athletes. Intervention(s): 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 [alpha] level of .008. Results: Flexibility increased between pretest and posttest in all participants ([F.sub.1,30] =80.61, P<.001). Anterior pelvic tilt ([F.sub.1,30]=0.73, P=.40), hip flexion ([F.sub.1,30]=2.44, P=.13), and knee extension ([F.sub.1,30]=0.06, P=.80) at maximum hip flexion were similar between groups throughout testing. Anterior pelvic tilt ([F.sub.1,30]=0.69, P=.41), hip flexion ([F.sub.1,30]=0.23, P=.64), and knee extension ([F.sub.1,30]=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 ([F.sub.1,30]=13.62, P=.001). Conclusions: A single session of 3 straight-leg raise hamstring stretches did not change pelvis, hip, or knee running kinematics. Verf.-Referat