Pre-match warm-up routines are very important. They get your players ready to play, both physically and mentally, and they need to be planned as carefully as a training session.
If you don’t plan an effective pre-match warm-up, you will be putting your players’ health and safety at risk. Recent studies have shown that warming up properly reduces the incidence of injuries in young football players by 30% .
Failure to have an effective warm-up before matches will also result in your players starting the game slowly because they are not in the right frame of mind to play.
So if you allow your players to “warm up” by blasting a few shots at your goalkeeper or your pre-match routine consists of making your team run a few laps five minutes before kick off, don’t be surprised if your team is 1-0 down after two minutes and one player down after 10!
Give yourself enough time
Pre-teen players need between 20 and 30 minutes to warm up properly.
If you allocate less time than that, you won’t be able to get in all the essential elements (see below) and if you make young players warm up for too long, they will get bored.
But it’s not sufficient to just tell your parents to get their children to the ground by 9.30am if the game kicks off at 10am. You need to explain why they have to be on time, give them directions to away grounds (or arrange to leave together from one central location) and discourage lateness by making it a rule that if a player doesn’t turn up on time, she won’t be in the starting line-up.
Repetition is good
Don’t introduce new activities into your pre-match routine every week.
Before the match, your players will be (or should be) focused on the game to come so don’t distract them by asking to learn new drills and activities in the 30 minutes or so before kick off.
Try out your warm-up ideas at training sessions – not matches – and when you’ve found a routine that works, stick to it.
Your players will then come to know exactly what they have to do as soon as they arrive at the ground and they should be able to get on with the first activity without any input from you.
Tip: Give your captain the job of getting players ready for the first stage of the warm-up while you shake hands with the match officials and complete all the other little pre-match jobs you have to do.
To stretch or not to stretch?
Very young football players – up to the age of about 10 – do not need to stretch before a game.
From the age of 10, however, a child’s body begins to lose it’s natural elasticity and it’s important that they stretch their muscles in a controlled and progressive way prior to playing football.
What type of stretching is best?
The most recent research has shown that traditional static stretching in a pre-match warm-up can actually decrease a young athlete’s performance and it doesn’t help them avoid injury. 
Dynamic stretching – gentle, repeated and controlled stretching of muscles during whole body movement – is recommended instead as it increases body and muscle temperature, improves elasticity and has been shown to greatly reduce the risk of injury. 
Making circles with the arms while jogging, for example, loosens the shoulder muscles and pulling one leg up behind you while walking effectively stretches the quadriceps (thigh) muscle.
More about dynamic stretching
Warning: Dynamic stretching should not be confused with ballistic stretching. That’s where parts of the body are made to stretch beyond their normal range of motion, i.e. repeatedly touching your toes from a standing position. This type of stretching can be beneficial when used properly but the dangers far outweigh the possible benefits. So don’t use ballistic stretching with young football players.
Essential elements of a pre-match routine
Pre-match warm-up routines should start slowly and gradually increase to match tempo. For example:
Five minutes jogging, preferably with a ball.
Ten minutes dynamic stretching exercises with or without a ball.
Ten minutes playing a keepaway style game in a small grid.
Don’t forget the warm-down
Many (in fact, most) youth football coaches don’t warm their players down after matches.
But the warm-down is very important. Done properly, it will help your players’ heart rate and body temperature to return to normal and also dissipate the by-products of exercise from the muscles thus helping avoid muscle soreness after the game.
It’s also a good opportunity to chat with your players about the game, check if objectives were achieved and think about how you can play even better in the next match.
And it only takes 10 minutes. My warm-down consists of five minutes slow jogging/walking followed by five minutes of gentle static stretching.
 Kirkendall DT, D. J. (2010), Effective injury prevention in soccer, Phys Sportsmed. , Apr;38(1):147-57.
 Rod Pope, Skip the warm-up, New Scientist, 164 (2214), p. 23
 Rick Meana, New Jersey Youth Soccer Director of Coaching, Soccer Specific Warm Up