Evaluating optimal height for hamstring activity in maximum-speed single-leg bridge test.

Abstract

Hamstring strain injuries often occur during high-speed movements, yet no functional test reliably induces rapid hamstring contractions. This study aimed to determine the optimal platform height in the maximum-speed single-leg bridge test (MS-SLBT) to maximize hamstring activation. This cross-sectional study included 26 healthy male recreational athletes. Participants performed the MS-SLBT using 20, 40, and 60 cm platforms at maximal speed. The conventional single-leg bridge test (SLBT) was performed on a 60 cm platform at any speed. Measurements included buttock-raising speed; muscle activity of the semitendinosus (ST), biceps femoris (BF), and gluteus maximus (GM) using surface electromyography; and heel-bearing force. MS-SLBT showed significantly faster buttock-raising speeds (0.7-1.0 m/s) than SLBT (0.5 m/s) (p<0.01). ST and BF muscle activities were significantly higher during MS-SLBT on 60 and 40 cm platforms (>90% maximal voluntary isometric contraction) than during SLBT and MS-SLBT on 20 cm platform (p<0.01). GM muscle activity during MS-SLBT was approximately double than that during SLBT(p<0.01). Heel-bearing force was significantly higher during MS-SLBT than during SLBT, MS-SLBT on 40cm platform showing the highest force (p<0.01). MS-SLBT on 40 and 60 platforms required higher hamstring activity, with faster buttock-raising speed and greater heel-bearing force than SLBT and MS-SLBT on 20 platform.