The aim of this study was to investigate the physical factors influencing the change in thoracic kyphosis angle due to walking in 105 elderly subjects by measuring the thoracic kyphosis angle before and after walking.
The study population consisted of older people aged between 65 and 85 years, with a degree of independence in daily living of J1 to J2. Exclusion criteria were those with motor paralysis and a history of orthopaedic surgery. After collecting basic information through interviews, spinal alignment (thoracic kyphosis angle and lumbar kyphosis angle) and joint range of motion (thoracic extension, lumbar extension, and hip extension) were measured. Ten-minute continuous walking was performed, and EMG of erector spinae, and quadriceps muscles was recorded during walking. Spinal alignment was re-measured immediately after walking. Muscle strength measurements were performed on a separate day, considering fatigue. Multiple regression analysis was used to analyse physical factors associated with the amount of change in the thoracic kyphosis angle. IBM SPSS Statistics ver. 27 was used for the statistical analysis with a less than 5% significant level.
Five factors influencing the amount of change in thoracic kyphosis angle with walking were extracted: lumbar kyphosis angle (β = -0.21, p0.05), lumbar extension ROM (β = -0.20, p0.05), hip extension ROM (β = -0.24, p0.05), erector spinae muscle strength (β = -0.22, p0.05), and erector spinae muscle slow wave-ization (β = 0.19, p0.05). The degree-of-freedom-adjusted coefficient of determination R2 was 0.155.
It was suggested that thoracic kyphosis anlge tends to increase less if lumbar kyphosis angle, lumbar spine extension range of motion and hip extension range of motion are larger and erector spinae muscle is stronger. Also, it tends to increase more if erector spinae muscle fatigue occurs. However, the predictive accuracy of the regression equation was low, suggesting that the factors measured in this study did not fully explain the changes in the thoracic kyphosis angle. In future studies, multifaceted evaluation, including measurement of centre of gravity position and movement analysis, is necessary.
Even if there is no abnormality in the thoracic kyphosis angle before walking, the finding that the thoracic kyphosis angle may increase during walking due to the problems of lumbar alignment, range of motion and muscle strength is an important starting point for countermeasures against thoracic kyphosis posture in the older people.
Thoracic kyphosis angle
Gait
