Kasser R, Harper L, Hines A, Holyfield M, Young C; The University of Tennessee Health Science Center, Department of Physical Therapy, Memphis, TN USA. Rkasser@utmem.edu.

PURPOSE: The purpose to this study was to determine the time course for increasing hamstring length with a passive stretching program and ascertain how long the increased hamstring length is retained after the stretching is stopped. BACKGROUND: Previous studies have shown that hamstring flexibility increases significantly 6 weeks after starting a stretching program. Willey et al found that when hamstring stretching is stopped, flexibility decreases to baseline levels within 4 weeks. They did not however, measure earlier to determine if the decrease occurred before 4 weeks. SUBJECTS: Thirty healthy college students were recruited for the study. The subjects were informed of the risks and benefits of volunteering before signing an informed consent form. METHODS: The subjects were randomly assigned to 2 groups, control and passive stretch. Baseline measurements were taken. The stretch group was instructed to perform passive stretching of each lower extremity 2 times each day 5 days a week for 6 weeks and return to be measured on week 2, 4, & 6. This group stopped stretching and was measured each week. The control group did no stretching and they were measured as often as the stretch group. ANALYSES: A repeated measures ANOVA combined with a Post-hoc Tukey’s test determined which measurements were significantly different (P £ 0.05). RESULTS: The stretch group measurement at 4 weeks was significantly greater than baseline. After the 6^th week, stretching stopped and measurements were done each week for the next 5 weeks. Measurements did not fall to baseline levels. The control group did not show differences from baseline until week 7 when the measurement value was significantly greater than baseline and the measurements stayed significantly greater until the end of the study. CONCLUSIONS: Unexpectedly, performing weekly passive ROM measurements (average of 3 measurements) was enough of an intervention to increase significantly the control group and maintain the stretch group hamstring length after the stretching program stopped. FUNDING SOURCE: None.

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