Objective: The aim of this cross-sectional study was to evaluate a variety of isometric plank exercises.
Design: Twenty university students performed the following eight different variants of plank exercises in random order and with 1-min rest intervals: stable prone plank, suspended prone plank, stable roll-out plank, suspended roll-out plank, unilateral stable prone plank, unilateral suspended prone plank, stable lateral plank, and suspended lateral plank. Surface electromyography signals were recorded for the upper rectus abdominis, lower rectus abdominis, external oblique, lumbar erector spinae, and normalized to the maximum voluntary isometric contraction.
Results: The suspended prone plank and the suspended roll-out plank provided the greatest upper rectus abdominis activity. The greatest lower rectus abdominis activity was induced by the suspended roll-out plank. The highest lumbar erector spinae activity was provided by the suspended and stable lateral planks. The suspended prone plank and the suspended roll-out plank provided the greatest external oblique activity, although not significantly different from the suspended lateral plank.
Conclusions: Muscle activity could be progressed using the different exercises. Although suspended prone plank and the suspended roll-out plank were most efficient for the abdominal muscles, suspended and stable lateral planks were most efficient for the lumbar muscles.