Relationship between Nonspecific Low Back Pain and Physical Function among Japanese High School Long-distance Runners

Abstract

Background: For long-distance runners, low back pain as well as lower extremity disorders are becoming more common. This study analyzed the relationship between regular physical assessment results and nonspecific low back pain among long-distance runners.

Methods: Subjects included 105 high school long-distance runners, who were divided into the low back pain group (n = 20; LP) and non-pain group (n = 85; NP). All subjects underwent regular chronic pain and physical assessments every six months. Differences in each measurement between both groups were analyzed using an unpaired t-test for comparison.

Results: The LP had a shorter history of athletics (LP=3.2 years, NP=4.6 years, 95% confidence interval (95%CI): -2.55, -0.28, r=0.45), a greater hip extension angle (LP=32.7°, NP=28.4°, 95% CI: 2.85, 5.61, r=0.67), a lower hip extension muscle strength (LP=3.1 kgf/kg, NP=4.0 kgf/kg, 95% CI; 0.19, 0.61, r=0.45), and a greater number of times during the stand-up test (LP=11.1, NP=8.1, 95% CI; 0.40, 5.56, r=0.45) than the NP.

Conclusion: An excessive hip extension angle and insufficient hip extension muscle strength were considered as risk factors. It is possible that the excessive movement of the hip joint and the biarticular muscles may have caused the low back pain in the inexperienced runners.