The relationship between the reflexive contraction in the hamstring muscle group in adolescent football players and explosive power, sprint and eccentric force parameters

Our study is done to determine the relationship between the reflexive contraction parameters of the hamstring muscle group in football players and the explosive power, ability to sprint, concentric and eccentric force and the flexibility of the muscle, thus to be able to offer ways to prevent injuries for football players. In 30 football players (n=30) within the adolescent age group, the reflexive contraction parameters were recorded (Tensiomyograph) before and after the FIFA 11+ warm-up; their explosive power and jumping ability values after the FIFA 11+ warm up (Fusion Sport Smart Jump), their sprint ability values with a camera and photocell system (Seven Electronic SE-164), their eccentric and concentric force values with a isokinetic dynamometer (Humac NORM Cybex), the time to attain maximal force and flexibility values with Sit and Reach test (Sit and Reach Box) were tested on different days. The following values were recorded: the reflexive contraction values (the delay as Td, the relaxation time as Tr, the contraction time as Tc, the time that contraction goes on without relaxation as Ts, maximal displacement as Dm); the flight time acquired with drop jumps, counter-movement jumps and squat jumps, the jumping height values, the peak power values, elastic energy usage ratio values (Stretch-Shortening Cycle), eccentric utilization ratio values; the right and left PK (peak torque) value for the right and left legs in concentric and eccentric contraction at 60°/s angular velocity (with isokinetic system) and the PK/VA value (peak torque relative to body weight); their 10-20-30 mt. sprint time values with muscular photocell system and their hamstring flexibility values with Sit and Reach test. At the end of the analyses there were meaningful changes in Ts and Tr values (p<0.05) and it is found that with regression analysis, the Ts value has a meaningful relationship with the right leg's eccentric peak torque (p<0.01). Thus, since the values we've recorded can't be explained by today's technology, we propose that these muscular values be tested one by one with different variables. Key words: FIFA 11+, tensiomyograph, hamstring muscle, football, eccentric force