Want an easy way to improve your performance and overall results? A meta-analysis of 104 studies found that static stretching before exercise reduces muscle strength by 5.4%, muscle power by 1.9% and explosive performance by 2.0%. Not only is static stretching not beneficial, it appears to be counterproductive.
In contrast to pre-exercise static stretches, dynamic stretches, such as walking lunges and arm circles, has been shown to increase power, speed, agility, endurance, flexibility and strength!
Sources:
http://www.ncbi.nlm.nih.gov/pubmed/22316148
http://journals.lww.com/nsca-jscr/Abstract/2008/07000/Four_Week_Dynamic_Stretching_Warm_up_Intervention.36.aspx