Affiliations: [a] Department of Rehabilitation Science, The Graduate School, Inje University, Gimhae, Korea | [b] Department of Korean Medicine, Dang Dang Korean Medicine Center, Pusan, Korea | [c] Department of Korean Medicine, Dang Dang Korean Medicine Center, Jinju, Korea | [d] Department of Physical Therapy, Inje University, Gimhae, Korea
Correspondence:
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Corresponding author: Jaeseop Oh, Department of Physical Therapy, College of Biomedical Science and Engineering, Inje University, 607 Obang-Dong, Gimhae-Si, Gyeongsangnam-Do, 50834, Korea. Tel.: +82 55 320 3679; Fax: +82 55 329 1678; E-mail: ysrehab@inje.ac.kr.
Abstract: BACKGROUND: Active straight leg-raise (ASLR) is often performed to strengthen abdominal muscles. The correct execution and maximum benefit of the ASLR can be achieved using abdominal hollowing (AH) and abdominal bracing (AB) exercises. OBJECTIVE: To compare the effects of AH and AB on transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) thicknesses, as well as on the pelvic rotation angle, in healthy women during active ASLR. METHODS: The participants in this study were assigned randomly to either the AH (n= 15) or AB groups (n= 15). During ASLR, abdominal muscle thickness was measured using ultrasound and pelvic rotation was measured using a Smart KEMA device. Each trial was repeated three times for 5 s each. RESULTS: The thickness of the TrA was significantly greater during ASLR with AH than during ASLR with AB (p< 0.001). In contrast, there was no respective significant change in the thickness of the EO (p> 0.311) or IO (p> 0.818). Pelvic rotation angle was significantly reduced during ASLR with AB, compared with ASLR with AH (p< 0.018). CONCLUSIONS: We recommend that AH be performed for the selective contraction of TrA during ASLR, and that AB be performed for the prevention of the pelvic rotation during ASLR. Therefore, AH and AB should be separately done in stabilization exercises.
