Effects of Alignment of the Thoracic Spine and Ankle Joint on Muscle Activation During Sling Exercise

Abstract

Objective: The purpose of this study was to investigate the effect of thoracic spine and ankle joint alignment on trunk and upper limb muscle activity during trunk forward lean exercise using a sling. Methods: 25 subjects participated in this study. All subjects performed trunk forward lean exercise using a sling under four conditions according to the alignment of the thoracic spine and ankle joints. Trials were performed 3 times in each condition. Muscle activity of the trunk and upper extremity was measured using electromyography. Results: In the dorsiflexion, the thoracic kyphosis condition showed significantly higher muscle activity in the pectoralis major, rectus abdominis, latissimus dorsi, transverse abdominis than dorsiflexion(p＜0.05). In the plantar flexion, thoracic kyphosis condition showed significantly higher muscle activity in pectoralis major, transverse abdominis, latissimus dorsi muscle activity than dorsiflexion(p＜0.05). Conclusions: Regardless of ankle alignment, thoracic kyphosis condition increased the activity of the pectoralis major, transverse abdominis, latissimus dorsi. Therefore, regardless of the alignment of the ankle, it is recommended to perform the trunk forward lean exercise using a sling in thoracic kyphosis.