Warming up

Warming up gently takes your body from “resting” to “ready”: your pulse rises, blood flow to your muscles increases and they actually get warmer, joint fluid spreads out, and your nervous system switches into movement mode. Five to ten minutes is almost always enough.

A good warm-up has two parts. First, something easy that gets your circulation going: brisk walking, slow jogging, skipping, star jumps. Then movements that resemble the sport you're about to do – light squats before strength training, arm circles before swimming, a few short accelerating runs before football. This “dynamic” warm-up prepares your muscles for exactly the job ahead.

Long static stretches (holding one position for 30 seconds), on the other hand, don't belong in a warm-up: they can slightly reduce jumping power and explosive strength for a short time. Stretching is valuable – but after exercise or as a session of its own.

The “FIFA 11+” programme shows how much warming up can achieve: in a large study of young female players (Soligard et al., 2008, BMJ), a 20-minute warm-up programme for football teams reduced the number of injuries by around a third. Knees and ankles benefit most of all.

Children love to warm up through play: tag, animal walks (like a bear, like a frog), throwing a ball to each other. Moving around a bit sillily before sport is exactly the right thing to do. And if you're sweating slightly and a little out of breath after warming up, you're ready.