One of the questions I find myself being asked most often as a trainer/coach is "should stretching be done before weight training as a warm up, or during a workout? Or should it wait until after you are finished? Not only can stretching the wrong muscles at the wrong time hinder your progress, but it may also cause muscle pulls and strains.
When To Stretch:
Stretching a cold muscle can cause injuries ranging from minor strains to actual tears. Research shows that stretching the muscle you’re about to train can cause a significant loss of strength during your lifts. In other words, you may be getting less out of your workout, simply because you stretched the wrong muscles beforehand. The same goes for stretching during the workout. Yes, it may feel good and help to increase blood flow, but you would be better off giving the muscle you are training a light massage between sets instead.
Stretching correctly however during training could actually increase strength and improve recovery between sets. What you want to do is stretch the antagonistic or opposite muscle to the one you are working. For instance, stretch the hamstrings after some leg presses, or the lats after each set of bench presses.
The Ultimate Stretching Technique for Bodybuilders
One of the best and under utilized secrets in the world of bodybuilding is the use of intense stretching of the trained muscle immediately after completing your workout for it. Intense stretching means that it should hurt (although you must know your body well enough to realize if you are going too far), with each extreme stretch lasting for 30-60 seconds before slowly being released.
Some examples of intense stretching would be holding the bottom of a chest flye with moderately heavy dumbbells in your hands, hanging with a close grip from a chinning bar while having your partner pull down on your waist, or sitting in the deepest position of a sissy squat. In other words, you have to go beyond the light stretching you normally perform to make this effective. And what is the benefit of this?
Research has demonstrated that this form of stretching can actually increase the rate of hypertrophy through the increased activation of satellite cells and the enhanced release of growth factors (hepatocyte growth factor, myogenin, IGF-1) within muscle tissue.
In summary, don’t stretch a cold muscle before training, and don’t stretch the muscle you are in the middle of training. However, DO stretch the antagonistic muscle to the one you are training, and once the session for the body part is complete, finish it off with two or three intense 30-60 second deep stretches.
Train hard...train smart...train to grow!