This is one of the largest gaps between what everyone does and what the evidence supports, and it has survived decades of research saying otherwise, largely because it was taught in school.
What the research actually found
Static stretching before activity does not produce a meaningful reduction in injury rates. This has been examined repeatedly across sports and populations, and the result has been consistent enough that most sports medicine bodies stopped recommending it years ago.
Worse, holding static stretches immediately before performance temporarily reduces force production and power. The effect is modest and it is in the wrong direction for anyone about to sprint or lift.
And it does not reduce next-day soreness. That belief is nearly universal and essentially unsupported.
What does reduce injury risk
Not spiking your load. The single largest modifiable factor. Injury risk tracks sudden increases relative to what you are conditioned for far better than it tracks absolute volume. This is the idea behind the acute-to-chronic ratio in Apple Watch Training Load.
Being strong in the positions you load. Strength training reduces injury rates substantially across sports, and it is the intervention with the best evidence of anything on this page.
Eccentric strengthening specifically. For hamstring strains in particular, eccentric programmes have among the strongest evidence of any injury prevention intervention in sport.
Sleeping enough. Chronic short sleep is associated with markedly higher injury rates in athletes. Unglamorous, free, and larger in effect than anything you can do in a warm-up.
What to do instead of stretching before training
A dynamic warm-up: five to ten minutes that raises your temperature, moves the joints you are about to use through range, and rehearses the movement at increasing intensity. Ramp-up sets for lifting, strides for running.
That is well supported, takes the same time you were spending on stretching, and does not blunt your first working set.
When stretching is the right answer
When you want more range of motion. It reliably produces that, over weeks, and there are plenty of legitimate reasons to want it: a squat depth you cannot currently reach, an overhead position that limits your press, a sport that demands it.
Do it after training or in a separate session, not before performance. And judge it against flexibility gained rather than injuries avoided, because the second is not what it does.
The related modality with a similarly overstated reputation: do massage guns work.