Magnitudes of muscle activation of spine stabilizers in healthy adults during prone on elbow planking exercises with and without a fitness ball.

Prone planking exercises have been used by rehabilitation professionals to activate torso muscles in healthy persons and those with low back pain. The aim of this study was to compare the magnitude of electromyographic (EMG) muscle activation from 10 right-sided muscles as demonstrated by the percentage of maximum voluntary isometric contraction (%MVIC) during four planking procedures. Surface EMG activity was acquired from the following muscles: (1) iliocostalis lumborum (IL), (2) longissimus thoracis (LT), (3) lumbar multifidus (LM), (4) rectus abdominis (RA), (5) external oblique (EO), (6) internal oblique (IO), (7) serratus anterior (SA), (8) latissimus dorsi (LD), (9) hamstrings (HS), and (10) gluteus maximus (GM). Thirteen male and 13 females performed prone plank on floor (PPOF), prone plank on ball (PPOB), stir-the-pot on ball (STP), and prone plank on ball with hip extension (PPHE). Previous investigators have not studied the STP and PPHE. During STP, three muscles (RA, EO, and IO) demonstrated very high (>61% MVIC) EMG activation and one muscle (SA) demonstrated high (41-60% MVIC) EMG activation. During PPHE, five muscles (GM, HS, EO, IO, and LM) demonstrated very high EMG activation and two muscles (RA and SA) demonstrated high EMG activation. Clinically, we concluded that STP and PPHE exercises were effective ways to activate RA, EO, IO, and SA at levels conducive to strengthening (> 50% MVIC), with PPHE able to additionally activate GM, HS, and LM at a strengthening level.