Doing static stretching exercises before you lift weights can decrease your strength, finds a study published in the January 2009 edition of the Journal of Strength and Conditioning Research. In this study, strength levels of subjects doing static stretches (i.e. stretching a muscle and holding for a set time) before lifting weights decreased the subjects strength by almost 60 pounds. Leg Press strength in women who did ballistic stretches (i.e. ) before lifting did not decrease at all. Muscle flexibility increased after static but not ballistic stretching.
The take home message from this study is that you may not want to perform static stretches when warming up to lift weights or playing your favorite sport unless the flexibility of your muscles is more important than your maximal strength and power. They’re best saved for post-workout or done as a separate workout.
Instead of doing ballistic stretches pre-workout as they can increase your risk of injury you should do dynamic stretching warm-ups. Dynamic stretching involves stretching your muscles by doing different types of movements including: high kicks, skipping, and arm swings. These movements don’t only improve your flexibility. They also increase blood flow to your muscles, lube your joints, and otherwise prepare your body to perform its best. If you are getting ready to lift weights you could also do a few sets of complexes for a complete warm-up.
Proceed slowly with dynamic stretching to reduce any risk of injury. Always remember, if a movement hurts stop. You may also want to find a qualified personal trainer or strength coach for tips on dynamic stretching and warm-up routines.
Below are links to sites that have dynamic and static stretching routines to help you get started.
Here is a dynamic stretching routine video from YouTube.
Bacurau RF, Monteiro GA, Ugrinowitsch C, Tricoli V, Cabral LF, Aoki MS. Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength. J Strength Cond Res. 2009 Jan;23(1):304-8.