INTRODUCTION AND OBJECTIVE: Stretching exercises are largely used in rehabilitation programs, but the ideal duration and the number of sets have not been determined yet. The purpose of this study was to evaluate the effects of 10 sets-30 seconds and 3 sets-3 minutes of static stretch on flexibility of hamstring muscles, comparing different volumes within 10 minutes. Moreover, to verify the difference between the two stretching programs. METHOD: 25 women (17 to 25 years old) were randomly assigned to one of 3 groups: group GC (control), G30 and G3. G30 stretched 10 X 30 seconds and G3 3 X 3 minutes. In all volunteers the stretching was performed by a pulley system, using weight corresponding to 10% of their body weight. This protocol took 6 weeks. Measurements were taken at the beginning of the protocol (Av1), after 6 weeks (Av2), and after 5 months (Av3). Flexibility of the hamstring was determined by measuring knee extension range of movement (ROM) with 90º of hip flexion. A two-way repeated measures Analysis of Variance (Anova) was used and significance level was set at 5% (p < 0.05). RESULTS: There was no statistically significant difference between 30 seconds (G30) and 3 minutes (G3) in knee extension ROM after 6 weeks (Av2) (p >0.05) and neither after 5 months (Av3) (p>0.05). Both the G30 as the G3 showed increasing flexibility at the end of protocol (Av1xAv2) (p<0.05) and after 5 months (Av1xAv3) (p<0.05). CONCLUSION: Stretching sets of 30 seconds and 3 minutes can increase the hamstrings flexibility and keep the flexibility obtained after 5 months from the end of intervention. There was no difference on the flexibility obtained with sets of 30 seconds or 3 minutes.
physical therapy techniques; passive stretching; range of motion; training
