A thorough warm-up is the critical final component of race preparation, yet many runners approach it rather casually. The shorter the race, the more important the warm-up, because the physiological demands are higher and there isn’t time to ease into race pace. Warming up correctly is also necessary to get the most out of an interval session or tempo run. Let’s look at the benefits of warming up, and how to do an optimal warm-up before a race or workout.

What Are the Benefits of a Warm-up?

The role of the warm-up is to prepare your body to run hard. When you accelerate to race pace after the starting gun fires, the physiological demands on your body increase suddenly and dramatically. For example, the amount of blood pumped by your heart increases 5 to 6 times, and your oxygen consumption increases about 15 times. If you do not warm up thoroughly, you put unnecessary additional strain on your muscles, tendons, ligaments and cardiovascular system. A warm-up provides the following benefits:

Prepare your energy systems: Warming up increases your heart rate, breathing rate, blood flow to your working muscles, and oxygen consumption, and activates the enzymes for aerobic energy production. The result is that your aerobic system is fully primed to handle race pace, and your muscles produce less lactate.

Increase muscle temperature: Over two-thirds of the energy produced by your muscles is lost as heat. Your pre-race run warms up your muscles, making them less stiff and more flexible, thereby enhancing performance and reducing your risk of injury. Since the heat your muscles produce contributes to your body’s heat load, you should reduce the length of your warm-up on a hot day. The opposite is true for cold weather.

Increase confidence: There are also psychological benefits in doing a systematic warm-up. By following a standard warm-up routine before workouts and races, you increase your confidence to handle the challenging task ahead.

The Optimal Warm-up

The components of an optimal warm-up are straightforward:

Run for 15 to 18 minutes, beginning slowly and gradually increasing the pace so you run the last one to two minutes at close to race pace. The shorter the race, the longer this warm-up run should be.

Stretch gently for 10 to 15 minutes. Stretching will help prepare your muscles for the longer stride length you use when running fast. You can also use this time to focus your attention on your race strategy. Recent evidence indicates that prolonged static stretching has a short-term effect of reducing muscle strength, so limit your stretching to two to three repetitions per muscle group and do not hold your stretches for more than 15 seconds. Save your major stretching session for after the workout or race.

Run for another five minutes, followed by several accelerations of 100 to 200 meters up to race pace. Once again, the shorter the race, the faster your accelerations should be, and the more you need to do to be ready to race. For most runners, one to two accelerations before a half marathon or six to eight before a 5K is about right.

You should time your warm-up so that you are prepared to race about 5 minutes before the start. Keep moving during those last few minutes, and if the weather is cold try to keep a hat and sweatshirt on as close to the start as possible. Give yourself enough time to warm up completely but avoid the common error of warming up too early. If you do not warm up enough then you must run the first part of the race more slowly as your body continues to warm up. Starting too quickly for your preparation will cause lactate to accumulate in your muscles early in the race making you slow down later.

Your entire warm-up should take 45 minutes, which can extend to an hour with the obligatory toilet stops. The problem with starting your warm up too early is that you either need to continue warming up longer (using extra energy needlessly) or you complete your warm-up too long before the start of the race and lose some of the physiological benefits of the warm-up.