Degree of thoracic kyphosis and peak torque of trunk flexors and extensors among healthy women☆☆☆

OBJECTIVE The aim of this study was to analyze the effects of aging on the degree of thoracic kyphosis and peak torque of the trunk flexor and extensor muscles among women without a densitometric diagnosis of osteoporosis. METHODS Thirty women were selected to make up three groups: young women (n = 10; 24.60 ± 2.27 years of age); adults (n = 10; 43.50 ± 2.88); and elderly women (n = 10; 62.40 ± 2.67). Bone mineral density (BMD), degree of thoracic kyphosis and peak torque of the trunk flexors and extensors were evaluated. Differences between the groups were evaluated using the Kruskal-Wallis ANOVA and Mann-Whitney U tests. Pearson's correlation coefficient was used to assess correlations between the variables. The significance level was taken to be 5% (p ≤ 0.05). RESULTS The elderly group presented a greater degree of thoracic kyphosis (p = 0.009) and lower peak torque of the trunk flexors and extensors than the young group. The adult group presented lower peak torque of the trunk than the young group. A negative correlation was observed between age and peak torque of the trunk flexors and extensors (p ≤ 0.001), and a positive correlation between age and the degree of thoracic kyphosis (r = 0.58; p ≤ 0.001). The elderly group presented higher values for the eccentric/concentric ratio of the peak torque for flexors (p = 0.03) and extensors (p = 0.02). CONCLUSION This study suggests that physiological aging may be associated with a greater degree of thoracic kyphosis and lower muscle strength of the trunk flexors and extensors. Moreover, the elderly women showed a relative capacity for preservation of eccentric strength.