Static and dynamic stretching and its effects on hamstring flexibility, horizontal jump, vertical jump, and a 50 meter sprint

Preactivity stretching is commonly performed by active individuals as part of their warm-up routine.  While both static and dynamic stretching are techniques utilized by the everyday exerciser, it has been questioned as to whether these types of stretching protocols can be harmful or beneficial to anaerobic exercise performance.  The current literature on stretching has also been biased toward athletes.  Therefore, the purpose of this study was to investigate whether 3 weeks of either static or dynamic hamstring stretching affects range of motion (ROM) and anaerobic exercise performance in recreationally active individuals.  Twenty two healthy college-aged students were randomly divided into three groups; static stretching (n=9), dynamic stretching (n=8), or no-stretch control (n=5).  Subjects completed three weeks of the stretching protocol with measurements taken before and after the stretching regimen.  ROM of the hamstrings were measured via the sit and reach test and the active knee extension test (AKET) while three variables of anaerobic performance (horizontal jump, vertical jump, and 50 meter sprint) were analyzed.  Statistical analysis showed no significant differences (P<0.05) between groups for the horizontal jump (P=0.261), vertical jump (P=0.983), or the 50 meter sprint (P=0.899).  Furthermore, three weeks of either static or dynamic hamstring stretching did not improve ROM in our active subjects.  Therefore, based on the current investigation, static stretching does not negatively impact anaerobic exercise performance, while dynamic stretching may not be as beneficial to an exercise routine as previously thought.