Association between hip and trunk muscle strength and modified single-leg horizontal jump test performance in elite team handball players

Introduction Assessing unilateral jumping performance and its determinants is important in handball, as it underpins key offensive and defensive actions. This study aimed to evaluate the intra-session reliability of a modified single-leg horizontal jump (SLHJ) test in elite players and its associations with hip and trunk strength. Methods Eighty elite handball players performed three single-leg horizontal jumps (SLHJs) using both their preferred and non-preferred push-off legs. Jump distance, side deviation, and resultant jump angle were measured as dependent variables. Unilateral maximal and explosive isometric strength of the hip abductors, adductors, extensors, flexors, and lateral trunk muscles were assessed as independent variables. Results SLHJ reliability was poor-to-moderate for side deviation and jump angle (ICC 2.k = 0.33–0.70) and good-to-excellent for jump distance (ICC 2.k = 0.87–0.93). Moderate correlations were observed between non-preferred leg SLHJ distance and explosive hip flexion ( r = 0.31), and between SLHJ side deviation and hip extension maximal strength ( r = 0.31). Multiple regression analysis showed that, for the preferred leg, adduction maximal strength predicted distance ( R 2 = 6%), and for the non-preferred leg, explosive hip flexion predicted distance ( R 2 = 10%), extension and abduction maximal strength predicted side deviation ( R 2 = 14.5%), and extension maximal strength predicted jump angle ( R 2 = 8.4%). Discussion Due to lower reliability, directional SLHJ measures should be interpreted with caution. Hip strength was partially supported as a determinant of SLHJ performance in elite handball players. The modified SLHJ better reflects performance differences related to hip strength in the non-preferred leg.