What a warmup is meant to accomplish
A warmup prepares the body for training by raising core and muscle temperature, increasing blood flow, and rehearsing the movement patterns to be performed. A common structure is a few minutes of light general cardio, a short period of dynamic mobility for the joints involved, and then progressively heavier ramp-up sets specific to the day's main lift.
Dynamic movements (leg swings, arm circles, bodyweight squats) are generally preferred before training over prolonged static stretching, which research suggests can briefly reduce peak force output if held too long right before heavy efforts.
Ramp-up sets for the working lift
Specific warmup sets bridge the gap to working weight. A typical approach is three to four sets that climb from a light load toward the target, with falling reps as the weight rises, ending just below the planned working weight. This grooves technique and primes the nervous system without accumulating fatigue.
The right amount varies with the person, the exercise, and the load. Heavier compound lifts usually warrant more ramp-up sets than lighter accessory work. The goal is readiness, not exhaustion.