THE EFFECT OF ASYMMETRICAL EXTREMITIES EXERCISES ON THE CO-CONTRACTION OF THE ERECTOR SPINAE MUSCLE COMPARED TO THE SYMMETRICAL EXTREMITIES EXERCISES IN HEALTHY SUBJECTS: PILOT STUDY

Abstract

Abstract Introduction: Scoliosis is a disorder which results in abnormal curvature of the spine. One type of scoliosis, known as idiopathic scoliosis (IS), may manifest due to left and right erector spinae (ES) muscle imbalance. Physiotherapy, in the form of a physical exercise programme, comprises one widely adopted treatment intervention, particularly for presentations within the mild to moderate severity range, associated with a Cobb angle of between 10°–40°, a global measure of the level of scoliosis. Lifting exercises are generally recommended in order to build strength. However, one specific research gap identified relates to the performance of lifting exercises at particular vertebral levels so as to strengthen the ES muscle in the back area. In addition, few studies had undertaken a comparative analysis of the impact and effectiveness of asymmetrical and symmetrical upper limb (UL) and lower limb (LL) exercises on ES muscle co-contraction. Therefore, the current research aims to address this gap by examining and comparing the effectiveness of asymmetrical extremity exercises on the ES muscle as compared to their symmetrical equivalents. Methods: A total of 21 participants (16 males, 5 females) took part in a trial, comprising one single session, where a surface electromyography (sEMG) device was attached to levels T7, T12 and L3 vertebrae of the spinal column. They were then required to undertake four exercises in all. Results: A statistically significant difference was found to occur between the symmetrical UL exercises as compared to their asymmetrical equivalents in the case of the right ES muscle (p=0.001), thus indicating that symmetrical exercises display greater effectiveness. In addition, differences reaching statistical significance occurred between the symmetrical LL exercises as compared to their asymmetrical equivalents in the right ES muscle (p=0.001). This was particularly evident at vertebral levels T7 and T12, thus indicating that symmetrical exercises are more effective. No significant differences were recorded between asymmetrical and symmetrical exercises in the case of the left ES muscle. Nevertheless, higher muscular activation levels were noted following the undertaking of symmetrical as opposed to asymmetrical extremity exercises. Conclusion: Current research findings show that symmetrical as opposed to asymmetrical extremity exercises exert a greater effect on the ES muscle. This has clinical implications in terms of the design and implementation of physical exercise intervention programmes.