The evaluation of static and dynamic postural balance in children with thoracic hyperkyphosis

Background: To investigate how postural balance is affected by thoracic hyperkyphosis compared to healthy children and elucidate the relationship between balance and strength and tightness.Methods: A cross-sectional analysis using standardized measures to identify balance function in children with thoracic hyperkyphosis (n = 31) and compare age-matched healthy children (n = 31). Primary outcome measurements were performed for the static and dynamic balance with the biodex balance system and limits of stability with the functional reach test. Secondary outcome measurements were strength with a hand-held dynamometry, tightness with the length test of pectoralis minor and hip flexors, and the sit-reach test for hamstrings. Mann-Whitney U test was used to compare the difference between the groups. Spearman's correlation was used to analyze the possible correlations between balance and strength and tightness.Results: A significant difference was found between the groups for static balance with eyes closed (except double-leg stance anteroposterior stability index) and for the forward reach distance (p < 0.05). Strength and tightness were significantly different in children with thoracic hyperkyphosis than in healthy children (p < 0.05). Also, it was found that muscle strength of trunk extension and hip abduction and tightness of hip flexors and hamstring were factors associated with static balance with eyes closed (r > 0.10, p < 0.05). Conclusions: Static balance in children with thoracic hyperkyphosis is affected when visual input is particularly removed, and static balance with eyes closed is correlated with changed strength and tightness in some of the trunk and lower extremity muscles.(c) 2021 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.