The Four-Minute Warm-Up
Short enough that you stop skipping it.
The best warm-up is not the thorough one in the article. It is the one you still do on the evening you nearly did not train at all.
A warm-up needs to raise temperature, move the joints you are about to load through their range, and prime the movement pattern. That takes about four minutes. Everything past that is either mobility work with different goals or a routine long enough that you will eventually skip it and then skip the session with it.
Two minutes to raise the temperature
Anything that makes you slightly warm and slightly out of breath. Rowing, skipping, brisk stairs.
One minute on the joints being loaded
Move them through the range you are about to use, unloaded. Not held stretches.
One minute rehearsing the movement
The first exercise, with the empty bar or very light. Two sets, easy.
Then start, even if you feel unready
Feeling ready is not the goal. The first working set continues the warm-up.
Go deeper
What the paid version adds to this one.
The extended version for heavy days and what each part is for
Warm-ups that are actually rehab in disguise, and when you need one
Why static stretching before lifting is the wrong tool
Filmed warm-ups for each of the main lifts