The Relationships During Hamstring Flexibility, The Strength Of The Thigh Muscle And The Optimum Hamstrings Muscle Length

Hamstring strains are common injuries, the majority of which occur whilst sprinting. Research shows optimum muscle length is the key factor of hamstring injury. The aim of this article is finding the relationship between flexibility and hamstring injury and the influence of relative thigh strength and providing basis for making training plans for preventing hamstring injury.Methods:We choose BIODEX for isokinetic test to get the muscle torque of knee joint. Using the data of captured by Qualisys, we computed optimum muscle length of biceps femoris(BF) longhead, biceps femoris short head, semitendinosus(ST) and semimembranpsus(SM) through modeling a three-dimensional biomechanics model.We assumed that (1) the subjects' optimum hamstring length that have better flexibility is longer than the ones that have worse hamstring flexibility (2) the subjects' optimum hamstring length that have more balance thigh strength is longer than the ones that have more imbalance.Conclusions:(1) The subjects that have loose hamstring exist the trend of imbalance of thigh strength.(2)The impact of flexibility on the rate of hamstring/quadriceps (H/Q) is not significant.(3) The knee flexion angle of maxim knee flexion torque is impacted by flexibility. Subjects that have loose hamstring have the smaller knee flexion angle.(4)Hamstring optimum length cannot be represented by knee flexion angle.(5)The hamstring flexibility cannot impact its optimum muscle length.