In the world of sports and fitness, flexibility and proper biomechanics play a crucial role in performance and injury prevention. Hamstring flexibility is of particular interest, as limited flexibility in this muscle group can affect an individual’s running gait. One common method used to improve hamstring flexibility is preactivity static straight-leg raise stretching. However, the question arises: does this method have any immediate impact on running kinematics? In 2012, Davis Hammonds, et. al., conducted study which aims to answer this question by investigating the acute effects of a single session of passive hamstring stretching on pelvic, hip, and knee kinematics during the swing phase of running.

Methods: This research involved a randomized controlled clinical trial with 34 male and female recreational athletes, with an average age of 21.2 years for males and 21.3 years for females. The participants underwent treadmill running tests before and after an intervention. During these tests, motion analysis systems were used to collect data on pelvis, hip, and knee joint angles during the swing phase of running. The intervention group had their right and left hamstrings passively stretched three times for 30 seconds each immediately after the pretest, while the control group had no stretching or movement between running sessions.

Results: The study found that flexibility increased in all participants between the pretest and posttest, confirming the effectiveness of the hamstring stretching intervention. However, when it came to specific running kinematics, such as anterior pelvic tilt, hip flexion, and knee extension at maximum hip flexion and maximum knee extension, there were no significant differences between the intervention group and the control group throughout testing. Interestingly, it was observed that men displayed greater anterior pelvic tilt than women at maximum knee extension.

Conclusion: In conclusion, the findings of this study suggest that a single session of three straight-leg raise hamstring stretches does not lead to immediate changes in pelvis, hip, or knee running kinematics. This information is valuable for athletes and fitness enthusiasts who use hamstring stretching as a part of their routine, as it indicates that such stretching may not have an immediate impact on their running biomechanics. However, it’s essential to consider the long-term effects and potential benefits of regular hamstring stretching in a broader context of injury prevention and performance enhancement.

This research adds to our understanding of the relationship between hamstring flexibility and running kinematics, highlighting the need for continued exploration of the subject to better inform training and rehabilitation practices.

Reference: Davis Hammonds, A. L., Laudner, K. G., McCaw, S., & McLoda, T. A. (2012). Acute lower extremity running kinematics after a hamstring stretch. Journal of athletic training, 47(1), 5-14.