RESUMEN
OBJECTIVE: This predictive correlational study aimed to investigate the association among low back pain (LBP), dyskinesia of the lumbosacral spine segment (determined by inertial sensors), and inclination angles: the inclination angle of the lumbosacral spine (alpha), the inclination angle of the thoracolumbar spine (beta), and the inclination angle of the upper thoracic section (gamma). Our hypothesis was that young athletes with LBP had a particular dyskinesia: nonphysiological movements of the lumbosacral segment of the spine. METHODS: The study group consisted of 108 young athletes aged 10 to 16 years (male/female 44%/56%; 12.3 ± 1.8 years; 160.1 ± 12.0 cm; 51.1 ± 13.8 kg; 4.3 ± 2.4 training years; 3.7 ± 2.1 training h/wk). The alpha, beta, and gamma angles were measured with a digital inclinometer. The position of the lumbosacral segment at the maximum extension was determined with the inertial sensors, positioned at the 11th thoracic vertebra (T11), the third lumbar spine vertebra (L3), and the second sacral spine vertebra (S2). The data were analyzed using Student's t tests, tetrachoric correlation coefficients, and logistic regression. RESULTS: There was a significant statistical difference in alpha angles (tâ¯=â¯9.4, P < .001) and lumbar positions in extension (tâ¯=â¯6.4, P < .001) between groups with LBP and without LBP. The logistic regression indicated that LBP in young athletes was significantly associated with the increased alpha angle and nonphysiological lumbar position in extension measured by a sensor at the third lumbar spine vertebra. CONCLUSION: There was a strong association among LBP, increased inclination angle of the lumbosacral spine, and dyskinesia of the lumbar spine segment in young athletes.