The relationship between pelvic girdle flexibility and lumbar stress fractures (spondylolysis) in adolescent baseball players

Abstract

In this study, we investigated the association between lumbar stress fractures (LSF), the acute phase of lumbar spondylolysis, and physical characteristics of adolescent baseball players. Participants were categorized into a fracture group (18 male baseball players aged 12-15 years, diagnosed with magnetic resonance imaging) and a control group (25 asymptomatic baseball players aged 12-16 years). We evaluated the physical examination in both groups using the following tests: finger-floor distance, angle of straight leg raising test, the external and internal range of motion (ER and IR, respectively) of the hip joint, the Duncan-Ely test, the Thomas test, and Oberʼs test. Compared with the control group, the fracture group showed bilateral high positive rates in the Duncan-Ely test, bilateral increase in ER, and bilateral decrease in IR. Tightness of the anterior hip joint may increase the pelvic tilt and a decreased IR may limit pelvic motion during pitching, batting, and dashing, which may exaggerate lumbar load and result in LSF.