Selective recruitment of the thoracic erector spinae during prone trunk-extension exercise.
OBJECTIVE
This study examined the effect of modified prone trunk-extension (PTE) exercises on selective activity of the thoracic erector spinae.


METHODS
Thirty-nine healthy subjects performed four modified PTE exercises, involving location of the edge of the table (iliac crests [IC] vs. xiphoid process [XP]) and the degree of trunk extension (horizontal vs. hyperextension). Electromyography signals were collected bilaterally from the longissimus thoracis (LT), iliocostalis thoracis (ICT), and iliocostalis lumborum (ICL). Normalized LT:ICL and ICT:ICL ratios were calculated. The data were analyzed using a repeated measures two-way analysis of variance.


RESULTS
The LT:ICL and ICT:ICL ratios were significantly higher under the XP than the IC condition (p < 0.05); however, the degree of trunk extension did not affect the ratio (p > 0.05). Activity in the lumbar erector spinae and left ICT muscles was greater when subjects were in the hyperextended position than in the horizontal position. Moreover, activity in the thoracic erector spinae was greater when the table edge was aligned with the IC compared with the XP (p < 0.05).


CONCLUSIONS
Our findings suggest that PTE exercise with the XP aligned with the table edge increased the selective activation of the thoracic erector spinae muscles.
Department of Physical Therapy, Inje University, Gimhae, Korea.
Kyung-Hee
KH
Park
Department of Rehabilitation Science, Graduate School, Inje University, Gimhae, Korea.
Min-Hyeok
MH
Kang
Department of Occupational Therapy, Dongseo University, Busan, Korea.
Tae-Hoon
TH
Kim
Department of Rehabilitation Science, Graduate School, Inje University, Gimhae, Korea.
Duk-Hyun
DH
An
Department of Rehabilitation Science, Graduate School, Inje University, Gimhae, Korea.
Jae-Seop
JS
Oh
D000328:Adult; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D017116:Low Back Pain / Q000534:rehabilitation*; D008297:Male; D016684:Prone Position / Q000502:physiology*; D060726:Torso / Q000502:physiology*
Electromyography; thoracic extensor muscles; thoracic spine