Correlation between isometric strength in five muscle groups and inclination angles of spine

This study was aimed to identify correlation between maximum isometric strength in five muscle groups determined by dynamometry results of muscle tests and the inclination angles of the spine.

This predictive correlational study included 63 young healthy athletes aged 10-15. (m/f 31/32; 12.73 ± 1.58 years; 162.57 ± 12.94 cm; 52.86 ± 12.17 kg; 3.95 ± 1.70 training years; 4.05 ± 1.31 training h/week).The maximum isometric strength in five muscle groups was measured by a handheld dynamometer with external belt fixation using a portable stabilization device. The inclination angles were measured with a digital inclinometer. The data were analyzed using descriptive statistics, and correlations were estimated by Pearson's correlation coefficient (r).

The isometric muscular strength of the muscle group of the hip extensors was in a significant correlation with the lumbar lordosis angle (LLA), r = 0.714 (p < 0.0001). The isometric muscular strength of the muscle group of the erector spinae was in a significant correlation with the LLA, r = 0.578 (p < 0.0001) and with thoracic kyphosis angle (TKA), r = 0.522 (p < 0.0001).

There is a strong association between isometric strength of the muscle groups of the hip extensors and erector spinae and the inclination angles of the spine. Based on the isometric results, physical therapy can be proposed for increasing the muscular strength of those muscle groups, which can help in the prevention of more severe forms of postural deformities. These slides can be retrieved under Electronic Supplementary Material.