This present study investigated the effects of the abdominal drawing-in maneuver (ADIM) and chin tuck (CT) on middle thoracic erector spinae, lower thoracic erector spinae, and lumbar erector spinae muscle activity during three prone thoracic extension (PTE) exercises. Twelve healthy subjects performed preferred PTE, ADIM PTE, and ADIM-CT PTE. Surface electromyography was used to collect data on the muscle activity of dominant middle and lower thoracic erector spinae muscles and the lumbar erector spinae. Middle and lower thoracic erector spinae muscle activity significantly increased when ADIM and CT was performed (p<.05). However, lumbar erector spinae muscle activity significantly decreased in ADIM PTE compared to preferred PTE (p=.017) and significantly increased in ADIM-CT PTE compared to ADIM PTE (p=.004). In conclusion, ADIM-CT PTE effectively increased middle and lower thoracic erector spinae muscle activity, and ADIM PTE decreased lumbar erector spinae muscle activity. Hence, ADIM PTE could be a recommended exercise maneuver to strengthen thoracic erector spinae without over activation of lumbar erector spinae.

• Ki-song Kim(Dept. of Physical Therapy, Gangnam Severance Hospital Yonsei University, College of Medicine)
• Gyu-wan Lee(Dept. of Physical Therapy, Gangnam Severance Hospital Yonsei University, College of Medicine)
• Dong-joon Choi(Dept. of Ergonomic Therapy, The Graduate School of Health Science, Yonsei University)
• Heon-seock Cynn(Dept. of Physical Therapy, College of Health Science, Yonsei University, Dept. of Ergonomic Therapy, The Graduate School of Health Science, Yonsei University)
• Oh-yun Kwon(Dept. of Physical Therapy, College of Health Science, Yonsei University, Dept. of Ergonomic Therapy, The Graduate School of Health Science, Yonsei University) Corresponding author