A good warm-up does three things: it raises your heart rate and muscle temperature, takes your joints through the range of motion you are about to use, and rehearses the movement itself. For most people that means five to ten minutes of easy movement, some dynamic mobility, and a few lighter versions of the first thing you plan to do. It is not a stretching session and it should not leave you tired. NHS guidance suggests a routine of at least six minutes before exercise, built from marching, heel digs, knee lifts, shoulder rolls and shallow knee bends (nhs.uk).
What a warm-up is actually for
Cold muscle is stiffer muscle. Easy movement lifts muscle temperature and increases blood flow to the working tissue, and it gives the nervous system a chance to switch on before you ask for speed or load. NHS guidance describes the same logic in practice: raise the heart rate gradually, then move joints through dynamic ranges, then add strength, balance and sport specific movement that resembles what comes next.
That order matters more than the exact exercises. A warm-up that never gets past slow arm circles does not raise temperature much, and one that starts with hard intervals just borrows energy from the session ahead. The useful middle ground is light but continuous work that ends close to the intensity you are about to use.
A warm-up template you can scale
| Phase | Rough time | What it looks like |
|---|---|---|
| Raise | 3 to 5 minutes | Brisk walk, easy jog, stationary bike or marching on the spot |
| Mobilise | 2 to 3 minutes | Leg swings, hip circles, arm circles, walking lunges, trunk rotations |
| Rehearse | 2 to 4 minutes | Skips, a few short accelerations, or one or two light sets of your first exercise |
For a gym session the rehearse phase is simply the first lift at a lighter weight. For a run it is a couple of relaxed strides. For a class or a sport it is the skill you are about to perform at half speed. If you are short on time, cut the middle phase rather than the last one, because the specific part is what prepares you for the actual demand.
What the evidence says about injuries
The strongest evidence for warm-ups is not about comfort, it is about structured programmes. A 2022 systematic review of 15 controlled trials in children and adolescents found that warm-up intervention programmes were associated with a 36 per cent lower injury rate, a pooled injury rate ratio of 0.64 (ncbi.nlm.nih.gov). Those programmes were not simple stretches. They combined aerobic work, strength, balance, jumping and landing practice, and they were repeated at every session for months.
The same review flagged compliance as the factor that mattered most: teams that actually did the programme most weeks saw the benefit, and teams that did it occasionally did not. A warm-up is therefore closer to a habit than a ritual. Ten minutes done every time beats twenty minutes done once a week.
Where static stretching fits
Long static stretches held immediately before explosive work are the one part of the traditional warm-up that research treats with caution. Reviews of the stretching literature report small but measurable drops in strength and power after prolonged static holds, and recommend that static stretching is not used as the whole warm-up (ncbi.nlm.nih.gov).
That does not make stretching useless. If a joint feels restricted, a few short holds of 10 to 15 seconds, or gentle movement into the available range, is a reasonable way to feel ready. Save the long holds for after training, when muscles are warm and the goal is range rather than performance.
Common mistakes
- Turning it into a workout. If you finish the warm-up out of breath and heavy legged, you have spent the session before it started.
- Skipping it in the cold. Low temperatures make the raise phase take longer, not shorter, so add a layer and give it a few extra minutes.
- Stretching instead of preparing. A stretching block alone does not raise temperature or rehearse the movement.
- Warming up too early. The effect fades while you stand around, so keep the gap between the last warm-up set and the first real effort short.
Bottom line
Five to ten minutes of easy movement, a few dynamic drills and a lighter version of your first exercise is enough for most sessions. Do it consistently, keep the hard work out of it, and treat long static stretches as recovery work rather than preparation.
This article is general information, not medical advice. If you have an injury, a heart condition or another health concern, speak to a qualified clinician before starting a new exercise routine.