ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2020 April;60(4):520-6

DOI: 10.23736/S0022-4707.19.10293-9

Copyright © 2019 EDIZIONI MINERVA MEDICA

lingua: Inglese

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

Danny LUM ^{1, 2} ✉, Ranald JOSEPH ¹

¹ Sport Science and Sport Medicine, Singapore Sport Institute, Singapore, Singapore; ² Physical Education and Sports Science, National Institute of Education, Nanyang Technological University, Singapore, Singapore

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° (ISqT90) and 120° (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.

KEY WORDS: Isometric contraction; Resistance training; Exercise