Effects on Hamstring Muscle Extensibility,Muscle Activity,and Balance of Different Stretching Techniques

[Purpose] The purpose of this study was to investigate the effects of two differentstretching techniques on range of motion (ROM), muscle activation, and balance. [Subjects]For the present study, 48 adults with hamstring muscle tightness were recruited andrandomly divided into three groups: a static stretching group (n=16), a PNF stretchinggroup (n=16), a control group (n=16). [Methods] Both of the stretching techniques wereapplied to the hamstring once. Active knee extension angle, muscle activation duringmaximum voluntary isometric contraction (MVC), and static balance were measured before andafter the application of each stretching technique. [Results] Both the static stretchingand the PNF stretching groups showed significant increases in knee extension anglecompared to the control group. However, there were no significant differences in muscleactivation or balance between the groups. [Conclusion] Static stretching and PNFstretching techniques improved ROM without decrease in muscle activation, but neither ofthem exerted statistically significant effects on balance.Key words: Balance, Muscle activation, Stretching