Moderate evidence
Warming up improves performance in the large majority of studies that measured it.
In practice
A few progressively heavier sets before your working weight isn't a formality — it's a measurable performance gain and it costs five minutes.
What it doesn't say
The review found most warm-ups helped and few hurt, but warm-up protocols vary so much that no single recipe is established.
Source
- Fradkin AJ, Zazryn TR, Smoliga JM (2010). Effects of warming-up on physical performance: a systematic review with meta-analysis. Journal of Strength and Conditioning Research, 24(1):140–148. doi.org/10.1519/JSC.0b013e3181c643a0