Relations Between Trunk Muscle Endurance, Stability, Balance Function, and Head Position in Adolescents with Idiopathic Scoliosis

Background. Correct head position, torso endurance, stability, and balance are essential factors that ensure proper body posture and functional mobility. In the case of idiopathic scoliosis, the interaction of these factors can influence the progression of scoliosis and the effectiveness of rehabilitation. Aim. To determine the correlations between the static endurance of trunk muscles, trunk stability, balance, and head position in adolescents with idiopathic scoliosis. Methods. Study participants were 22 teenagers (10–17 yrs., mean age 13.5 ± 2.09 yrs.) diagnosed with idiopathic scoliosis. This cross-sectional study measured subjects’ trunk muscle static endurance, head position, trunk stability, and balance. Results. The static endurance of the abdominal muscles (51.6 ± 27.43 s) was significantly worse than the static endurance of the back muscles (93.0 ± 46.05 s). A total of 95.5 % of subjects failed the functional torso stability test. Additionally, 86.36 % of the subjects exhibited a forward-shifted head position with a craniovertebral angle equal to 42.93 ± 5.15°. Moderately strong indirect significant correlations were found between the size of the craniovertebral angle and balance (r = -0.675, p = 0.001), and strong direct relationships between trunk stability and balance (r = 0.803; p = 0.001), dynamic stability and balance (r = 0.824; p = 0.001), static stability and balance (r = 0.778; p = 0.001). Conclusions. Adolescents with idiopathic scoliosis are characterized by a forward head position. Moderate and strong relationships between balance, head position, functional torso stability, and postural stability were determined. No significant correlations were found between trunk muscle static endurance ratios and balance. Keywords: adolescents, idiopathic scoliosis, head position, stability, balance.