Background:   The level of disability and endurance of back muscles have been investigated, but there is conflicting evidence following specific exercise interventions for participants with recurrent low back pain (LBP). The purpose of this study was to compare the level of disability and slope of median frequency (MF) of thoracic and lumbar erector spinae (ES) muscles following core stabilization exercise (CSE) and spinal flexibility exercise (SFE).
            Material/Methods:      In total, 46 individuals participated in this study. There were 25 participants in the CSE intervention group (average age of 47.7±8.9 years) and 21 participants in the SFE group (average age of 53.1±9.0 years). Each group participated in the specific exercise intervention program for 4 weeks while maintaining their current activity and/or exercise levels. The Oswestry Disability Index (ODI) was used to measure the level of disability changes. The fatigability of the ES back muscles was measured by the slope of MF, using a modified Sorensen test.
            Results:           The disability level decreased significantly following CSE intervention (t=2.23, p<0.05). However, there was no significant difference in muscle fatigability changes in the 4-week intervention period for either group.
            Conclusions:   The CSE intervention reduced disability level following the 4-week intervention period. Further studies are needed to investigate the effectiveness of specific back muscle exercises in longer intervention periods for back muscle fatigability.

Keywords: Lumbar Vertebrae - physiopathology, Low Back Pain - rehabilitation, Exercise Therapy, Disability Evaluation, Back - physiopathology, Muscle Fatigue - physiology, Pliability, Thoracic Vertebrae - physiopathology