Adolescent soccer is correlated with an increase of kyphosis but a reduction of low back pain: a controlled cross-sectional survey

Methods We performed a clinical evaluation on 102 males age 1116 who played competitive soccer two to three times per week. We compared them to a normal sample of 180 boys of the same age range who did not play soccer. In addition, we proposed a validated questionnaire on LBP prevalence and clinical characteristics that were compared to a normal sample of 668 schoolboys. The validated measurements we collected were plumbline distances from kyphosis apex (C7, T12 and L3) and ATR according to the Bunnell method. We calculated the Sagittal Index (SI: sum of the distances of C7 and L3), and the Sagittal Ratio (SR: C7/L3 relationship between kyphosis and lordosis). According to previous studies, we considered the following to be normal references: ATR of less than 5°, Sagittal Index of 1.5-5.5 cm (C7), 2.8-7.0 cm (L3) 5.5-11.0 cm, and Sagittal Ratio of 0.37-1.31. Our analysis used normality tests, ANOVA and chi-square; the Kruskall Wallis test for non parametric data was also applied.