Core strengthening and stability exercises are fundamental for any conditioning training program. Although surface electromyography (sEMG) is used to quantify muscle activity there is a lack of research using this method to investigate the core musculature and core stability. Two types of data reduction are commonly used for sEMG; peak and average rectified EMG methods.
Hibbs, A., THOMPSON, K., French, D., Hodgson, D., & Spears, I. (2011). Peak and average rectified EMG measures: Which method of data reduction should be used for assessing core training exercises? Journal of Electromyography and Kinesiology, 21(1), 102-111. https://doi.org/10.1016/j.jelekin.2010.06.001