Resumen de The Effectiveness of 3 Stretching Tecniques on Hamstring Flexibility Using Consistent Stretching Parameters

Scott Davis, Paul E. Ashby, Kristi L. McCale, Jerry A. McQuain, Jaime M. Wine

• This study compares the effects of 3 common stretching techniques on the length of the hamstring muscle group during a 4-week training program.

  Subjects were 19 young adults between the ages of 21 and 35.

  The criterion for subject inclusion was tight hamstrings as defined by a knee extension angle greater than 208 while supine with the hip flexed 908. The participants were randomly assigned to 1 of 4 groups. Group 1 (n = 5) was self-stretching, group 2 (n = 5) was static stretching, group 3 (n = 5) was proprioceptive neuromuscular facilitation incorporating the theory of reciprocal inhibition (PNF-R), and group 4 (n = 4) was control.

  Each group received the same stretching dose of a single 30- second stretch 3 days per week for 4 weeks. Knee extension angle was measured before the start of the stretching program, at 2 weeks, and at 4 weeks. Statistical analysis (p <= 0.05) revealed a significant interaction of stretching technique and duration of stretch. Post hoc analysis showed that all 3 stretching techniques increase hamstring length from the baseline value during a 4-week training program; however, only group 2 (static stretching) was found to be significantly greater than the control at 4 weeks. These data indicate that static stretching 1 repetition for 30 seconds 3 days per week increased hamstring length in young healthy subjects. These data also suggest that active self-stretching and PNF-R stretching 1 repetition for 30 seconds 3 days per week is not sufficient to significantly increase hamstring length in this population.