Tests to measure core stability in laboratory and field settings: reliability and correlation analyses

Abstract

Although core stability (CS) has been assessed through many different tests, the relationships among them are currently unknown. The main objective was to analyse the relationship between five representative tests used to assess CS in: i) laboratory settings: Sudden Loading Test (SLT) and Stable and Unstable Sitting Test (SUST); ii) field settings: Biering-Sorensen Test (BST), Three-Plane Core Strength Test (TPCT) and Double-leg Lowering Test (DLLT). The reliability of these tests was also examined. Thirty-three recreationally active males performed the tests twice. The relationship between all variables was examined using Pearson-correlation coefficient in those variables with a good reliability. Only stiffness and angular displacement in the SLT, dynamic unstable tasks in the SUST and the holding-time in the BST showed good reliability (ICC: 0.63-0.91; typical error: 9.8%-21.0%). Few and low correlations were observed between the SLT, SUST and BST. Despite finding several significant correlations among the dynamic unstable tasks of the SUST (r≥0.807; p<0.01), no correlations were found between the loading directions of the SLT. The absence of correlations between these tests suggests that CS measurements are not generalisable, as they probably assess different dimensions of CS, or in the case of the BST, a different capacity (i.e. trunk extensor endurance).