Effects of trunk stability exercise on muscle activities of rectus abdominalis, external oblique, and internal oblique while performing exercise in a modified crook-lying posture
Affiliations: Department of Physical Therapy, College of Medical Sciences, Jeonju University, 303 Cheonjam-ro, Wansan-gu, Jeonju, Jeonbuk-do, 560-759, Korea | Tel.: +82 63 220 3261; Fax: +82 63 220 2054; E-mail: [email protected]
Correspondence:
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Corresponding author: Department of Physical Therapy, College of Medical Sciences, Jeonju University, 303 Cheonjam-ro, Wansan-gu, Jeonju, Jeonbuk-do, 560-759, Korea. Tel.: +82 63 220 3261; Fax: +82 63 220 2054; E-mail: [email protected].
Abstract: BACKGROUND: Few studies have reported contribution of isometric specific training of abdominal muscles to low back and pelvic stability using a modified crook-lying (C-L) posture with and without a labile surface. OBJECTIVE: To investigate activation amplitude of rectus abdominis (RA), external oblique (EO), and internal oblique (IO) in C-L posture based on various foot and trunk supporting surfaces. METHODS: Participants were 32 healthy adults. Abdominal muscles activities were measured using surface electromyography while performing an exercise with a straight one-leg hold in C-L posture with four different exercise conditions. Two-way repeated measures analysis of variance (ANOVA) with Bonferroni’s correction was used to determine effects of exercise tasks of different conditions on the activation of RA, EO, and IO. RESULTS: Significant differences in abdominal muscle activities were found between supporting surface conditions for all muscles (p< 0.05). RA showed significantly higher muscle activity on more unstable supporting conditions (p< 0.05). EO and IO showed significantly higher muscle activities on trunk support and trunk plus foot support conditions than those with other conditions (p< 0.05). However, there were no significant differences in muscle activities between trunk support and trunk plus foot support conditions in C-L posture (p> 0.05). CONCLUSIONS: Application of unstable trunk and foot support surface while performing straight one-leg hold exercise in C-L posture could be useful for improving the endurance and strength of each abdominal muscle.
Keywords: Abdominal muscles, leg raising exercise, support surface
