The effect of the Fédération Internationale de Football Association (FIFA ) 11+ Kids injury prevention program on reducing injury rates in children’s soccer.

The intervention group will be instructed to perform the “11+ Kids” injury prevention program during one season (6 months) at least twice a week. ‘11+ Kids’ consists of seven different exercises and can be performed in about 15–20 min. Three exercises focus on unilateral, dynamic stability of the lower extremities (hopping, jumping and landing), three exercises on whole body and trunk strength/stability, and one exercise on falling technique. The difficulty of each exercise is progressively increased in five levels to account for the varying age- and maturity-related performance levels, as well as for general differences in motor skills of children aged 7–13 years. EXERCISE 1: “ALERTNESS” RUNNING GAME LEVEL 1: LISTEN FOR THE STOP COMMAND LISTEN TO THE COACH 3 SETS WITH 5 STOP COMMANDS PER SET STARTING POSITION: the players stand on the goal line, about 2 metres apart. The coach stands just outside the penalty area (distance depends on the players’ age). ACTION: at the coach’s command, the players run straight ahead towards the coach. If the coach calls “right” or “left”, the players must stand on the right or left leg and maintain their balance for around 3 seconds. They can hop until they find their balance. The knee of the supporting leg should not be fully extended, and the arms can be used for balance. If the player does not stand on one leg at the stop command or the other foot touches the ground within 3 seconds, he/she must jog back to the goal line. The coach then gives the command to run and stop (five times in total per set). All players then jog back to the goal line. LEVEL 2: WATCH FOR THE STOP COMMAND STARTING POSITION AND ACTION: as level 1, except that the players watch the coach for the stop command. The coach indicates the leg on which they should stop. WATCH THE COACH 3 SETS WITH 5 STOP COMMANDS PER SET LEVEL 3: BALL IN THE HANDS AND LISTEN FOR THE STOP COMMAND STARTING POSITION AND ACTION: as level 1, except that the players hold a ball with both hands. LISTEN TO THE COACH 3 SETS WITH 5 STOP COMMANDS PER SET LEVEL 4: BALL IN THE HANDS AND WATCH FOR THE STOP COMMAND STARTING POSITION AND ACTION: as level 2, except that the players hold a ball with both hands. WATCH THE COACH 3 SETS WITH 5 STOP COMMANDS PER SET LEVEL 5: DRIBBLE WITH THE BALL AND LISTEN FOR THE STOP COMMAND STARTING POSITION AND ACTION: as level 1, except that the players dribble with the ball. At the stop command, the players stop the ball with the foot and stand on one leg without touching the ball with the free foot. LISTEN TO THE COACH 3 SETS WITH 5 STOP COMMANDS PER SET EXERCISE 2: SKATING JUMPS LEVEL 1: LEARNING HOW TO LAND STARTING POSITION: the players stand on the goal line, about 2 metres apart. The coach tells the players which leg to stand on and makes sure that every player is standing on the correct leg. ACTION: at the coach’s command (“jump!”), the players jump forward on one leg and land on the other leg. The coach indicates the direction in order to avoid collisions. Example: when jumping from the left foot, the player should jump forwards to the right, finding their balance on landing and standing on one leg for 3 seconds. While balancing, the knee of the supporting leg is slightly bent. Balancing with the arms is permitted. The coach then gives the command for the next jump in the other direction. The player should make a clear sideways movement with each jump in order to move forwards in a zigzag. After 5 jumps on each leg, the player returns slowly to the goal line. LISTEN TO THE COACH 2 SETS OF 10 JUMPS (5 PER LEG) LEVEL 2: BALL IN BOTH HANDS STARTING POSITION AND ACTION: as level 1, except that the players hold a ball with both hands. LISTEN TO THE COACH 2 SETS OF 10 JUMPS (5 PER LEG) LEVEL 3: BALANCING WITH THE BALL IN ONE HAND STARTING POSITION AND ACTION: as level 1, except that the players balance with the ball on an outstretched hand (one set with the right hand and one with the left). LISTEN TO THE COACH 2 SETS OF 10 JUMPS (5 PER LEG) LEVEL 4: DROPPING THE BALL ONTO THE GROUND STARTING POSITION AND ACTION: as level 2, except that on landing, the players stretch while standing on one leg and, with the ball above their heads, bend over forwards, drop the ball gently onto the ground and then assume the upright position again. This should be done slowly and in a controlled manner. LISTEN TO THE COACH 2 SETS OF 10 JUMPS (5 PER LEG) LEVEL 5: DYNAMIC BALANCING WITH BALL STARTING POSITION AND ACTION: as level 4, except that the players stretch their free leg behind them upwards and both arms forwards and then return to the usual one-leg position. This is followed by the next jump. The players make as long a stretch as possible, the idea being for the ball, head, torso and raised leg to be in one straight line. LISTEN TO THE COACH 2 SETS OF 10 JUMPS (5 PER LEG) EXERCISE 3: SINGLE-LEG STANCE LEVEL 1: THROWING THE BALL STARTING POSITION: 2 players stand on one leg at 3-5 metres opposite each other. ACTION: the players take it in turns to throw a ball to each other. The distance between them should be reduced to begin with and a simple throwing technique used. 1 SET ON EACH LEG 5 THROWS PER PLAYER LEVEL 2: THROWING THE BALL AND MOVING IT AROUND THE FREE LEG STARTING POSITION AND ACTION: as level 1, except that after it the ball is thrown, the player moves it around the raised free leg. 1 SET ON EACH LEG 5 THROWS PER PLAYER LEVEL 3: PASSING GAME STARTING POSITION: 2 players stand on one leg at 2-5 metres opposite each other. ACTION: the players pass the ball to each other along the ground with the instep, stopping the ball before returning the pass. Passes should be as accurate as possible so that the players can stay in position. 1 SET ON EACH LEG 5 PASSES PER PLAYER LEVEL 4: THROWING THE BALL AND PASSING BACK WITHOUT TOUCHING THE GROUND STARTING POSITION: as level 3. ACTION: the player throws the ball to their partner so that the latter can pass back with the foot. The pass should be volleyed (i.e. without the ball touching the ground first) and be played as accurately as possible so that the player who threw the ball can catch it. The partner must also throw the ball accurately for the volleyed pass to be accurate. Hopping is permitted to find balance. 1 SET ON EACH LEG 5 THROWS PER PLAYER LEVEL 5: TESTING THE PARTNER’S BALANCE STARTING POSITION: two players stand on one leg opposite each other, within arm’s reach. Both hold a ball in both hands in front of each other. ACTION: they push the balls against each other at chest height and try to push each other off balance. When one player touches the ground with the raised foot, the game begins again. The players can hop to regain balance. No hitting movements should be made: the balls must always be touching each other. The coach chooses the exercise partners according to size and dexterity. The exercise can be turned into a competition by awarding a point to the player who sends their partner off balance. 1 SET ON EACH LEG FOR 20 SECONDS EACH EXERCISE 4: PRESS-UPS LEVEL 1: TUNNEL STARTING POSITION: one player stands while the other players are in press-up position close to each other to form a tunnel, hands and feet hip-width apart. ACTION: The standing player rolls a ball down the tunnel and then goes to the start of the tunnel and assumes the press-up position. After the ball has rolled through, the last player in the tunnel takes it and runs to the start of the tunnel, rolls the ball through and goes to the start of the tunnel in the press-up position. The tunnel meanders on in this way. The exercise can be turned into a competition between two groups. 2 SETS, WITH EACH CHILD ROLLING THE BALL ONCE (MAXIMUM 8 PLAYERS PER GROUP) LEVEL 2: FOREARM SUPPORT; SHIN RESTING ON BALL STARTING POSITION: The players lie with their forearms flat on the ground and the ball under the middle of their shins, head facing the ground. The body should be in a straight line from head to foot. ACTION: the players move themselves forward until the ball lightly touches the feet and then back until the ball is almost under the knees. The movements should be slow and deliberate. The forearms stay in the same place and the legs should always be on the ball. 3 SETS OF 15 SECONDS EACH LEVEL 3: ROLLING THE BALL AROUND THE HANDS STARTING POSITION: the players are in the press-up position, with a ball in front of each player. ACTION: the players lift a hand from the ground and roll the ball around the other hand that is still on the ground. They then swap hands to repeat the exercise, thus making a figure eight with the ball. 3 SETS OF 15 SECONDS EACH LEVEL 4: ROLLING THE BALL BETWEEN HANDS AND FEET STARTING POSITION: as level 3. ACTION: the players roll the ball with the left hand under the body to the left foot and then pass the ball with the same foot to the right hand. Repeat the exercise starting with the right hand (to the right foot and then up to the left hand), thus switching sides. 3 SETS OF 15 SECONDS EACH LEVEL 5: HANDS ON THE BALL STARTING POSITION: as level 3, except that the players support themselves by placing both hands on the ball. ACTION: the players move slowly backwards with the feet in small stages and then back to the starting position. The movements must be made calmly and in a controlled manner. Note: if the grass is damp, switch to level 4. 3 SETS OF 10 SECONDS EACH EXERCISE 5: SINGLE-LEG JUMPS LEVEL 1: FORWARDS STARTING POSITION: the players stand on one leg on the goal line with clear space between them, i.e. about 2 metres apart. ACTION: at the coach’s command, the players jump forward on one leg, landing on the same leg. The jumps should be as long as possible. Players should stand still for around 3 seconds after landing. After a complete set (10 jumps in total), the players walk slowly back to the goal line. LISTEN TO THE COACH 2 SETS OF 5 JUMPS ON ONE LEG AND 5 ON THE OTHER LEVEL 2: BACK AND FORTH STARTING POSITION: the players stand on one leg about 2 metres in front of the goal line with clear space between them, i.e. about 2 metres apart. ACTION: as level 1, except that the coach indicates whether to jump forwards or backwards. WATCH THE COACH 2 SETS OF 5 JUMPS ON ONE LEG AND 5 ON THE OTHER LEVEL 3: SIDEWAYS STARTING POSITION AND ACTION: as level 2, except that the players jump sideways. The coach indicates the direction, and constantly watches to ensure that no collisions occur due to players being too close to each other. LISTEN TO THE COACH 2 SETS OF 5 JUMPS ON ONE LEG AND 5 ON THE OTHER LEVEL 4: THE COACH INDICATES THE DIRECTION STARTING POSITION AND ACTION: as level 2, except that the players jump in the direction indicated by the coach (forwards, backwards, left and right). The coach gives the command (“Jump!”) while indicating the direction, to avoid collisions. Ensure that there is sufficient space between the players! LISTEN TO THE COACH 2 SETS OF 5 JUMPS ON ONE LEG AND 5 ON THE OTHER LEVEL 5: THE COACH INDICATES THE DIRECTION; BALL IN BOTH HANDS STARTING POSITION AND ACTION: as level 4, except that the players hold a ball in both hands. LISTEN TO THE COACH 2 SETS OF 5 JUMPS ON ONE LEG AND 5 ON THE OTHER EXERCISE 6: SPIDERMAN LEVEL 1: STROKING THE BALL STARTING POSITION: the players support themselves on their hands and feet, hip-width apart, the back pointing towards the ground. The body should be in as straight a line as possible from the head to the knees. The ball is directly in front of the feet. ACTION: the players lift one leg, touch the ball with one foot and roll it gently forwards and then backwards. They repeat the exercise with the other leg and then alternate the movement with each leg. The movement should be slow and deliberate. 3 SETS OF 15 SECONDS EACH LEVEL 2: A PROPER STRETCH STARTING POSITION: as level 1. ACTION: the players move backwards with their hands extended and then return to the starting position and then move with their feet forwards until the body is fully stretched and back again. The players perform the exercise slowly and in a controlled manner, alternating the movements. 3 SETS OF 15 SECONDS EACH LEVEL 3: THE CRAB STARTING POSITION: as level 1. ACTION: the players move forward on all fours (feet at the front) towards the coach. 3 SETS (5-10 METRES, DEPENDING ON ABILITY) LEVEL 4: DRIBBLING STARTING POSITION AND ACTION: as level 3, except that the players “dribble” with a ball, which is guided in a controlled manner. 3 SETS (5-10 METRES, DEPENDING ON ABILITY) LEVEL 5: BALL BEARING STARTING POSITION: as level 1, except that the players support themselves by placing their feet on the ball. ACTION: the players roll the ball under their feet and move forwards slowly and in a controlled manner. 3 SETS (3-7 METRES, DEPENDING ON ABILITY) EXERCISE 7: SIDEWAYS ROLL LEVEL 1: SQUATTING POSITION STARTING POSITION: the players squat, about 2 metres apart. ACTION: the players put both hands on the ground in front of their knees. They then lower their heads so that the chin is nearly touching the chest and roll over diagonally on their arm, shoulder and back. Example: if rolling to the right, the right arm should be bent and in front of the body. The players then roll over on the outside of their right arm and right shoulder and then diagonally over their back onto their feet. After every roll, the coach must wait for at least 5 seconds before giving the next command. The players concentrate on every roll, and the coach tells the players in which direction they should roll every time. 5 ROLLS PER SIDE LEVEL 2: SLOWLY FROM A STANDING POSITION STARTING POSITION: the players are standing straight, about 2 metres apart. ACTION: the rolls learned in level 1 are now performed from a standing position. The players squat by bending their knees, looking downwards and moving the chin towards the chest. The hand movement should be slow and deliberate, so that the players can master the process. The roll movement is the same as for level 1. 5 ROLLS PER SIDE LEVEL 3: DYNAMICALLY FROM A STANDING POSITION STARTING POSITION: as level 2. ACTION: the squatting posture adopted in level 2 is now performed more quickly and dynamically and the roll learned in level 1 is introduced dynamically. 5 ROLLS PER SIDE LEVEL 4: FROM A SLOW WALK STARTING POSITION: It is important that the players are able to safely execute the fast rolls that they learned in level 3 from a standing position. ACTION: the squatting and rolling actions learned in level 3 are now introduced from a slow walk. LEVEL 5: FROM A FASTER FORWARD MOVEMENT STARTING POSITION: It is important that the players are able to safely execute the movement that they learned in level 4 in both directions. Only then can level 5 be attempted. ACTION: as level 4, except from a faster forward movement (quick walking/jogging). 5 ROLLS PER SIDE Program compliance will be evaluated according to the players’ rate of participation using an attendance log. The investigator will randomly visit one team selected from each group each week throughout the study period to motivate the teams and to ensure that the program is being followed conscientiously and correctly.