Comparison of External Oblique, Internal Oblique, and Erector Spinae Muscle Activation During Core Rotation Exercise Using a Variable Resistance Pole

Objective: The present study examined the influence of posture and contraction characteristics on the activation of the external oblique (EO), internal oblique (IO), and erector spinae (ES) muscles during a combination of right rotation and lateral flexion with a variable resistance pole.Design: Cross-sectional study Methods: Surface electromyography of bilateral EO, IO, and ES was recorded in 18 adults performing combined right rotationlateral flexion using a Variable Resistance Pole in both standing and sitting postures.Analysis of variance (ANOVA) was employed to compare muscle activation across a range of postures and contraction phases.Results: Posture significantly affected left EO, IO, and ES activation (p 0.05), and contraction phase affected bilateral EO, IO, and ES (p 0.01).Left EO activity was higher in sitting during the initial phase but about twice as high in standing during maintenance.Left IO activation was consistently greater in standing, whereas left ES activation was roughly twice as high in sitting in both phases.Overall trunk muscle activation increased significantly from initial to maintenance in most muscles (p 0.05).Conclusions: These exercises have been shown to elicit posture-dependent recruitment of the oblique and erector spinae muscles, as well as greater trunk activation during sustained contraction.This provides valuable insights for the design of core stabilization program for low back-related conditions.