THE RELATIONSHIP BETWEEN ISOKINETIC STRENGTH OF KNEE FLEXORS EXTENSORS AND JUMPING AND SPRINTING ABILITIES OF U19 ELITE A-LEAGUE PLAYERS- A PILOT STUDY
Abstract
The purpose of this study was to investigate the relationship between knee flexor and extensor
muscle strength and sprint and jump performance in U19 Elite youth A-league football players.
The volunteers of this research were 26 male athletes having at least 5 years of experience and
actively play football in the U19 Elite A-league of a professional football team (age: 19.31±0.73
years; body height: 174.48±6.48 cm; body weight: 68.25±5.96 kg; body fat: 22.00±1.43 percent).
The extensor and flexor muscle strengths of the dominant and nondominant legs of the football
players were measured. Knee flexion and extension peak torque values were measured in both
knees at angular velocities of 60°·s-1 and 180°·s-1 via a Cybex Norm (CSMI, Stoughton,
Massachusetts, the USA) isokinetic dynamometer. In addition, the sprint and jump performances
of these football players were respectively measured with 30-m sprint test and the
Countermovement Jump test (CMJ). It was determined that there was no correlation between
30-m sprint and CMJ performances and isokinetic knee flexion, extension, peak torque strength,
and Hamstring-to-Quadriceps Ratio (H/Q 60°-180°) (p>0.05). As a result, among the factors
affecting the 30-m sprint time and CMJ height in U19 Elite A-league football players, the knee
flexor-extensor values at 60°-180° angular velocity and the H/Q ratio were absent; however,
many other factors such as the maximal strength and cross-sectional area of certain muscles
were thought be effective factors. Furthermore, two different isokinetic angular velocity assessments were performed in our study. It is suggested that to create a general profile, studies
on isokinetic strength at various angular velocities should be conducted in order to correlate 30
m sprint performance with CMJ performance.
Keywords: Elite football league, isokinetic strength, bio motor abilities