The Effects of Hamstring Stretching on Range of Motion:
A Systematic Literature Review

Study Design: Systematic literature review.  Objective: Investigate the literature regarding the most effective positions, techniques, and durations of stretching to improve hamstring muscle flexibility. Background: Hamstring stretching is popular among physical therapists, athletic trainers, and fitness/coaching professionals, however, numerous stretching methodologies have been proposed in the literature.  This fact establishes a need to systematically summarize available evidence in an attempt to determine the most effective stretching approach. Methods: A list of 28 pertinent manuscripts that included randomized and clinical trials was created according to specific inclusion/exclusion criteria. These manuscripts were critically reviewed for quality according to the PEDro (10-point) scale and descriptive information about the stretching parameters employed in the research. Results: Cumulatively, 1338 healthy subjects were included in the reviewed studies. Methodological quality scores ranged from 2 to 8 (Mean±SD=4.3±1.6).  Several methodological flaws were frequently recognized including failure to conceal group allocation or perform blinded assessment.  All studies reported improvements in range of motion after stretching. Conclusions: Overall, methodological quality was poor with only 21.4% (6/28) of studies achieving a score between 6 and 8, thus it was difficult to confidently identify 1 most effective hamstring stretching method. Instead, the evidence appears to indicate that hamstring stretching increases range of motion with a variety of stretching techniques, positions, and durations. 

2005 Decoster LC, Cleland J, Altieri C, Russell PJ: The Effects of Hamstring Stretching on Range of Motion: A Systematic Literature Review. J Orthopedic and Sport Physical Therapy, 35(6) 377-387.