Should you stretch before a workout? What the evidence says
The stretching your PE teacher made you do before running may have quietly made you a little weaker for the next few minutes. The fix is not to skip the warm-up. It is to warm up differently.
Do not do long static stretches, the hold-and-reach kind, right before strength or power training. The evidence shows they can briefly reduce your strength, power, and speed for the minutes that follow. Instead, do a dynamic warm-up: light movement that raises your heart rate and moves your joints through their range.
This is not an argument against warming up. It is an argument for warming up the right way. A good dynamic warm-up genuinely prepares you. A long static stretch beforehand can quietly work against you.
Save static stretching for after your session or a separate flexibility slot, where it belongs.
Why can static stretching before hurt performance?
Because holding a long stretch temporarily reduces a muscle’s ability to produce force.
A large body of research shows that holding static stretches, particularly longer holds beyond about 30 to 60 seconds, immediately before an activity can cause a small, short-lived reduction in strength, power, and sprint speed. It is sometimes called stretch-induced strength loss.
The effect is temporary and modest, and it fades within minutes, but it points the wrong way if your session needs force or speed. Why start a workout having just made your muscles slightly less powerful?
This finding is why warm-up guidance shifted away from the old sit-and-stretch routine. It was not wrong to warm up. It was the type of stretching that was the problem.
What should you do instead?
A dynamic warm-up that rehearses the movement you are about to do.
A dynamic warm-up means active, moving preparation: a few minutes of light cardio to raise your temperature and heart rate, then controlled movements that take your joints and muscles through their range, leg swings, lunges, arm circles, bodyweight squats, gradually building toward the intensity of your session.
The goal is to arrive at your first working set warm, mobile, and primed, not stretched slack. Done well, it can even slightly improve performance, the opposite of a long static stretch.
For runners, that means a gradual build and some dynamic drills. For lifters, ramp-up sets of the actual lift. Rehearse the thing you are about to do, lighter and looser first.
Does stretching before exercise prevent injury?
No, and this is the claim that most needs retiring.
The belief that pre-exercise stretching prevents injury has been tested repeatedly and has not held up. A well-known review by Lauersen and colleagues (British Journal of Sports Medicine, 2014) found that stretching programmes did not meaningfully reduce injury rates, while strength training clearly did.
So if injury prevention is your reason for stretching before a run, the evidence does not support it. What reduces injury risk is being strong, well-conditioned, and progressing your training sensibly, plus a proper warm-up. Our assisted stretching guide covers the same collapsed claim in the paid-studio context.
Warming up matters for readiness and comfort. Stretching specifically is not the injury insurance it was sold as.
Is there ever a case for stretching first?
Yes, for a few activities and for feeling ready.
Some activities that demand a large range of motion under control, gymnastics, dance, certain martial arts, do benefit from targeted mobility work in the warm-up, and there dynamic and shorter, gentler stretches earn their place. If a specific tight area limits your movement, a brief, gentle stretch to access range can help.
And if a light stretch simply makes you feel ready and comfortable, a short one will not ruin your session. The evidence is against long, deep, held stretches before force and speed, not against all movement.
The rule of thumb: dynamic and short before, longer and static after or separately.
When should you do the static stretching then?
After training, or in its own session.
Static stretching still has value for building and maintaining flexibility over time. The best time for it is when force production no longer matters: at the end of a workout as you cool down, or in a dedicated flexibility or yoga session on another day. Our yoga versus stretching guide covers building flexibility as its own goal.
A weekly recovery routine can hold both: dynamic warm-ups around training, and static stretching or a yoga class separately. Our weekly recovery routine guide covers fitting it together.
That way you get the flexibility benefits without paying the performance tax during your session.
The bottom line
Skip long static stretches right before strength or power work, because they briefly sap force, and they do not prevent injury anyway. Do a dynamic warm-up that rehearses your session instead, and save static stretching for after or a separate slot.
Warm up, yes. Just move to warm up, rather than sitting and reaching.
To find a yoga or movement studio for the flexibility side, start with our city wellness maps.