1. Andersson, EA, Nilsson, J, Ma, Z, and Thorstensson, A. Abdominal and hip flexor muscle activation during training exercises.;Eur J Appl Physiol,1997
2. Axler, CT and McGill, SM. Low back loads over a variety of abdominal exercises: searching for the safest abdominal challenge.;Med Sci Sports Exerc,1998
3. Behm, DG, Leonard, AM, Young, WB, Bonsey, WA, and MacKinnon, SN. Trunk muscle electromyographic activity with unstable and unilateral exercises.;J Strength Cond Res,2005
4. Bird, M, Fletcher, KM, and Koch, AJ. Electromyographic comparison of the ab-slide and crunch exercises.;J Strength Cond Res,2006
5. Clark, KM, Holt, LE, and Sinyard, J. Electromyographic comaprison of the upper and lower rectus abdominis during abdominal exercises.;J Strength Cond Res,2003