Electromyographic investigation of the upper and lower rectus abdominis, external abdominal oblique, and rectus femoris muscles in seven traditional abdominal exercises

Handa, T., Kato, H., Hasegawa, S., Okada, J., & Kato, K. (2009). Electromyographic investigation of the upper and lower rectus abdominis, external abdominal oblique, and rectus femoris muscles in seven traditional abdominal exercises. Taiikugaku Kenkyu (Japan Journal of Physical Education, Health and Sport Sciences), 54(1), 43–54. https://doi.org/10.5432/jjpehss.a540108