The Effect Of Change Of Hamstring And Quadriceps Femoris Strength Of Knee On Balance Ability

Purposes:Through researching effect of change of flexor and extensor muscle on balance ability, reveal internal relationships between change of muscle strength and balance ability and provide theory and practice aid for movement training and Athletic Injuries.Methods:There are twenty-four students come from non-sports professionals, they were randomly divided into four groups, were group of flexion and extension, group of flexion, group of extension and flexion, group of extension, they were going on exercising twelve weeks, for group of flexion and extension exercises flexor for six weeks and exercise extensor for six weeks, for group of flexion exercises flexor for twelve weeks, for group of extension and flexion exercises extensor for six weeks and exercise flexor for six weeks, for group of extension exercises extensor for twelve weeks, after six weeks and after twelve weeks , testing muscle strength,static balance ability and dynamic balance ability of four group; muscle strength was tested by Multi-joint isokinetic muscle strength measurement and training system of Con-trex, static balance ability was tested by Three-dimensional force Platform, dynamic balance ability was tested by SEBT(Star Excursion Balance Test), data Processing was analyzed through Statistical software SPSS11.5, Samples before and after training with analysis of variance.Results:After training twelve weeks , the strength of muscle have increased, the group of flexion and extension, ratio of hamstring to quadriceps femoris strength increases in the first six weeks, decreasing in the second six weeks; the group of flexion, ratio of hamstring to quadriceps femoris strength always increases; the group of extension and flexion, ratio of hamstring to quadriceps femoris strength decreases in the first six weeks, increasing in the second six weeks; the group of always extension, ratio of hamstring to quadriceps femoris strength always decreases. Static balance ability of one leg with eyes open, the group of flexion to extension, compared to the first six weeks, the maximum destabilize path of direction of y increases significantly in the second six weeks; the group of flexion, compared to the first six weeks, general length of path and the general of path in direction of x decrease in the second six weeks; the group of extension to flexion, compared to no training, general length of path in direction of y increases significantly in the first six weeks; the group of extension, compared to the first six weeks, the maximum destabilize path increases significantly. The static ability of one leg with eyes close, the group of flexion and extension, compared to no training ,area decreases significantly after training in the first six weeks; the group of always flexion ,compared to the first six weeks, general length of path decreases significantly after training in the second six weeks. Dynamic balance ability, the group of flexion to extension, compared to training after the first six weeks, length of in the direction of AM and mean of the length of in the direction of AM increase significantly after training in the second six weeks; the group of extension to flexion, compared to no training, length of in the direction of PM and mean of the length of in the direction of PM increase significantly after training in the first six weeks, compared to after training in the first six weeks, length of in the direction of M increases significantly after training in the second six weeks.Conclusion:(1) After training of flexor muscle strength, flexor muscle strength increased, at the same time the strength of extensor muscle increased, ratio of hamstring to quadriceps femoris strength increases, the static balance ability of one leg with eyes open and close increased, dynamic balance ability of one leg increased as increasing of flexor muscle strength, but increasing implicitly over a certain range.(2) After training of extensor muscle strength, extensor muscle strength increased, but flexor muscle strength didn't increased, ratio of hamstring to quadriceps femoris strength decreased, the static balance ability of one leg with eyes open decreased, the static balance ability of one leg with eyes close and dynamic balance ability of one leg changed implicitly.