Effect of a semi-rigid backpack type thoracolumbar orthosis on thoracic kyphosis angle and muscle performance in older adults with hyperkyphosis: a randomized controlled trial

Abstract

Purpose: To investigate the effect of a semi-rigid backpack type thoracolumbar orthosis (TLO) on thoracic kyphosis angle (TKA) and potentially contributing factors of hyperkyphosis, including position sense and back muscle strength and endurance. Method: This randomized, controlled trial was conducted on 48 older adults with hyperkyphosis, randomly allocated to an experimental or control group. The experimental group wore a semi-rigid TLO for 3 consecutive months. The control group received no external support or exercise. Thoracic kyphosis angle (TKA), joint position sense, back muscle strength and endurance were evaluated at the baseline and at the end of week 6 and week 12. Results: The two-way (group × time) interactions were significant in terms of TKA (F=37.88, p=<0.001, ηp²=0.45), muscle strength (F=26.005, p=<0.001, ηp²=0.36), muscle endurance measured via load cell (F=3.417, p=0.039, ηp²=0.06), and endurance holding time of Ito test (F=3.629, p=0.045, ηp²= 0.07). A further analysis using one-way repeated measures of ANOVA showed that TKA, muscle strength and endurance were significantly improved in the experimental group. Also, two-way interactions were significant for absolute error and variable error of trunk neutral repositioning test from a trunk flexed and/or extended position for global components and horizontal components trunk repositioning test. Conclusion: Wearing a semi-rigid backpack type TLO even from an unknown brand for short periods during the day (e.g., 2 – 4 hours) over 3 months not only modifies kyphotic posture but also can enhance back muscle performance in older adults with hyperkyphosis.

Effect of a semi-rigid backpack type thoracolumbar orthosis on thoracic kyphosis angle and muscle performance in older adults with hyperkyphosis: a randomized controlled trial