“Core” muscle activation with a stable versus unstable base

Traditional approaches to core stability training utilize stable bases of support; however, little is known regarding the efficacy of unstable supports for core muscle activation. The authors of the current study sought to determine the surface electromyographic (sEMG) difference of torso musculature when comparing athletes under conditions of isometric bracing on a stable versus unstable surface. In general, it was shown that suspension based abdominal bracing noticeably improved anterior core muscles when compared to stable bracing however showed little different in lateral and posterior core musculature.

Eighteen “elite” level male athletes were recruited for inclusion in the study. Surface EMG was utilized to determine the rate of muscle contraction in the core stability muscles of the torso: rectus abdominus (RA), external obliques (EO), and erector spinae (ES).

The findings of the current study show clearly that there is a discrepancy between stable and unstable surface core activation. The use of an unstable surface such as a swiss ball or suspension system clearly demonstrated that anterior core musculature is more active then on a stable surface. Interestingly the authors noted that despite their predictions, unstable exercise failed to activate lateral and posterior musculature which could have implications for postural stabililty and training methodology. With the increase in popularity of suspension based training methods (such as TRX) this paper provides tangible validation as to the efficacy of these alternative training approaches.

> From: Atkins et al., J Strength Cond Res 29 (2015) 1609-1615. All rights reserved to National Strength and Conditioning Association.