Research shows that dynamic stretching, where you actively take a joint through its full range of motion (e.g., stretching while moving—think of a leg swing), is A-OK for improving flexibility before a lifting session. But static stretching—where you get into the stretched position and hold it—may not be.
A study in the Journal of Strength & Conditioning Research found that subjects who static-stretched before lifting still made strength gains, but not as dramatically as those who did no stretching at all. Since stretching relaxes and elongates muscles, it seems to temporarily reduce their ability to produce force; so to maximize your lifting, you should do it after training or at another time entirely.
However, in my opinion, there’s one notable exception: If your muscles are too tight to let you perform certain exercises properly, you’ll need to stretch beforehand—both dynamically and statically—to improve your mobility. Yes, you may compromise strength, but you’ll increase safety, which is far more important.
Research suggests that stretching before exercise is unlikely to reduce your risk of injury, improve your performance or prevent sore muscles.
However, there’s no evidence that stretching before or after exercise will do you any harm, either.
The upshot is if you enjoy stretching, or it is a staple in your exercise routine, there’s no reason to stop. Try this 5-minute post-exercise stretch routine.
Read on to get a deeper understanding of the mechanics of stretching and work out just how much stretching you really need in your life.
What’s the point of stretching?
Stretching for sport and exercise improves flexibility, which increases the ability of a joint to move through its full range of motion; in other words, how far it can bend, twist and reach. Some activities, such as gymnastics, require more flexibility than others, such as running.
Different types of stretches
Static stretch: stretching a muscle to the point of mild discomfort and holding that position, typically for at least 30 seconds or longer.
Proprioceptive neuromuscular facilitation (PNF): methods vary, but typically PNF involves holding a stretch while contracting and relaxing the muscle.
Dynamic stretch: performing gentle repetitive movements, such as arm swings, where one gradually increases the range of motion of the movement, but always remains within the normal range of motion.
Ballistic or bouncing stretches: involves going into a stretch and performing bouncing or jerking movements to increase range of motion.
Most of the research on stretching has focussed on static stretching; there is less evidence on other forms.