Nelson, Gail A Electromyographic activity of the rectus abdominis during a traditional crunch and the basic jackknife exercise with the Ab Loungeā¢. [electronic resource] - Journal of strength and conditioning research Jun 2012 - 1584-8 p. digital Publication Type: Comparative Study; Journal Article ISSN: 1533-4287 Standard No.: 10.1519/JSC.0b013e318234e886 doi Subjects--Topical Terms: Biomechanical PhenomenaElectromyographyExercise--physiologyFemaleHumansMaleModels, TheoreticalMuscle Contraction--physiologyRectus Abdominis--physiologyTask Performance and AnalysisYoung Adult