Research vs Bro-science

Should You Never Static Stretch Before Training? Myth vs Research

Published: 2026-07-06

Written by: Hirotsugu YoshimuraReviewed by: Tomonobu Someda

'Static stretching before training kills your strength, so don't do it' vs 'you should stretch to prevent injury' — opinions on warm-up stretching are split. Should you really avoid static stretching (slow, held stretches without bouncing) before exercise? We look at the research from three angles: injury prevention, strength, and flexibility. This topic includes a round where the common belief is partly right.

Let the data settle it.

Round1

Do you need to stretch before exercise to prevent injury?

What's said

学校体育・一般的な運動指導

Stretch well before exercise and you'll be less likely to hurt a muscle or joint. It's injury-prevention basics.

What research says

Stretching alone hasn't been shown to prevent injury.
A large meta-analysis by Lauersen et al.
(2014; 25 RCTs, ~26,600 people) found a risk ratio of 0.963 for stretching — no significant protective effect.
Strength training, by contrast, had a risk ratio of 0.315, substantially reducing injuries.
In other words, current evidence says 'to prevent injury, build strength rather than stretch.'

Verdict

Stretching for injury prevention isn't supported as a way to reduce injuries. If prevention is the goal, strength training and an active warm-up are more effective. This doesn't mean stretching is useless — just don't mistake its purpose.

Confidence:Strong evidence

Round2

Does pre-exercise static stretching reduce strength and power?

What's said

フィットネス系YouTube・SNS

Static stretching before exercise leaves the muscle 'over-lengthened' so you can't produce force. So you should never do it before lifting or sports.

What research says

This belief is partly right.
A meta-analysis by Simic et al.
(2013; 104 studies) reported that pre-exercise static stretching reduced maximal strength by about 5.4% and power by 1.9%.
But the drop depends on how long you hold.
A review by Kay & Blazevich (2012; 106 studies) found no significant impairment at under 30 seconds (-1.1%) or 30–45 seconds (-1.9%); the strength loss mainly appears with holds of 60 seconds or more.
Short stretches typical of a warm-up cause essentially no real performance harm.

Verdict

'Long, intense stretching reduces strength and power right afterward' is true. But a blanket ban overstates it — short static stretches up to about 30 seconds are fine. Holding a single muscle for over a minute is best avoided only right before heavy lifting or power work.

Confidence:Strong evidence

Round3

Do you still need stretching to improve flexibility?

What's said

一般的な柔軟性の常識

If you want to get more flexible, stretching is the only way. Lifting won't improve your flexibility.

What research says

Full-range strength training improves flexibility just as much as stretching.
A meta-analysis by Afonso et al.
(2021; 11 RCTs, 452 participants) found no statistical difference between strength training and stretching for range-of-motion gains (ES -0.22, p=0.206).
So stretching isn't strictly required to get more flexible — training through a large range of motion (deep squats, big movements) can improve range too.

Verdict

Flexibility isn't the exclusive domain of stretching — full-range strength training can improve it just as well. If you enjoy stretching, keep at it, but 'lifting makes you stiff' is a misconception. Note, though, that the meta-analysis is modest in size, so read it with some caution.

Confidence:Mixed evidence