Relationship between isometric force-time characteristics and dynamic performance pre- and post-training

BACKGROUND: The effect of strength training on the relationship between isometric force-time characteristics with dynamic performances is still unknown. Therefore, the purpose of this study was to investigate if strength training would alter relationship between the force-time characteristics achieved from isometric squat (ISqT) with dynamic performances. METHODS: Six female and 18 male elite floorball athletes (age: 24 +/- 3 years; stature: 1.68 +/- 0.07 m; body mass: 64.4 +/- 10.7 kg) performed a countermovement jump (CMJ), 20-m sprint and ISqT at 90 degrees (ISqT90) and 120 degrees (ISqT120) knee angles during the preliminary test. Subsequently, they underwent 12 strength training sessions over six weeks and repeated the three tests upon completion of training. RESULTS: ISqT and CMJ improved significantly post-training (P<0.01). Before training, all measures of ISqT90 were significantly correlated to CMJ height and sprint times (r=0.56 to 0.63, P<0.01 and r=-0.42 to -0.58, P<0.05, respectively), while only rate of force development (RFD) measures of ISqT120 were significantly correlated to CMJ height and sprint times (r=0.55 to 0.56, P<0.01 and r=-0.51 to -0.53, P<0.05, respectively). After training, all measures of ISqT90 were significantly correlated to CMJ height (r=0.43 to 0.71, P<0.05), while only PF achieved from ISqT120 was significantly correlated to CMJ height (r=0.43, P<0.05). CONCLUSIONS: The relationship between force-time characteristics achieved from ISqT with CMJ and sprint performances changed after a period of strength training.