Stretching techniques are one of the most used devices in rehabilitation practice. However, some parameters such as frequency have not been studied when proprioceptive neuromuscular facilitation (PNF) techniques are used. The purpose of this study was to analyze in the short and middle-terms the optimal frequency to increase hamstring muscle flexibility, measured by knee extension range of motion (ROM). Thirty-six female subjects were selected, (mean (SD) age 21.7 (1.9) years) with limited hamstring muscle flexibility. The subjects were randomly assigned to four groups (n = 9). The three stretching groups received the intervention five days a week for two consecutive weeks. The three PNF stretching groups alternated concerning frequency with one, three, and six maneuvers per session. Analysis of variance (ANOVA) was used for the first and final measures (< 0.05). A post hoc analysis using the Tukey test (< 0.05) was performed. Data indicated that the PNF stretching groups had a statistically significant ROM gain in relation to the control group, but not among themselves. Concerning gain velocity, the groups that used three and six maneuvers had faster stretching gains (p < 0.05) than the one that used only one maneuver. The results showed that there was no difference in relation to delayed gains when one, three or six stretching maneuvers were used with the hold-relax technique on hamstring muscles.
Flexibility; Proprioceptive Neuromuscular Facilitation; Hamstrings muscles; Movement breadth
