Optimal duration of stretching of the hamstring muscle group in older adults: a randomized controlled trial.

Background: "Flexibility" is defined as "the range of movement or motion of a single or multiple joints." Its limits decline significantly with age, reaching maximum flexibility in the mid-to-late twenties for males and females, respectively. Conclusions regarding appropriate stretching time duration are mainly based on mechanical factors such as range of motion (ROM) and flexibility and tend to ignore the adverse neural mechanical tension that may be created during stretching exercises.