If you are a serious soccer player, what are your chances of sustaining a serious injury? What can you do to lower your injury risk?
To find answers to these key questions, researchers from the San Jose Earthquakes professional soccer team and the East Bay Sports Medicine and Orthopaedic Associates in California recently followed 237 Major-League soccer players over the course of a full season (Morgan, B. & Oberlander, M., 'An Examination of Injuries in Major League Soccer,' The American Journal of Sports Medicine, Vol. 29(4), pp. 426-430, 2001). The players ranged in age from 18 to 38.
The researchers defined a minor injury as one that interrupted participation in practice or play for a period of less than one week, a moderate injury as one necessitating absence for more than one week but less than one month, and a major injury as a malady which caused an inability to participate lasting for more than one month.
There were ten professional teams involved in the research, and each team played 32 regular-season games. Each team's practice sessions averaged 105 minutes, and the researchers multiplied the average practice time by the number of practice sessions performed during the season to arrive at a total practice time of 241 hours per athlete. This was eight times greater than the total time per athlete spent in competition (27.7 hours). Overall, the 237 players had a total 'exposure' of about 64,000 hours (57,117 practice hours and 6,567 game hours).
During the season, there were a total of 256 injuries which resulted in time lost from participation. 154 injuries were minor, 67 were moderate, and 35 were classified as serious. No position (midfielder, goalkeeper, defender, or forward) was associated with a higher rate of injury, but games were significantly more risky than practices. Injuries occurred during practices at a rate of about 2.9 injuries per 1000 hours, while the injury rate for games was 35.3 per 1000 hours, about a twelve-fold increase. A higher proportion of severe injuries also occurred during games. Player age had no impact on injury risk, and late season was found to be the time period with the highest rate of injury.
Knee injuries were the worst
As you might expect, the majority of injuries (77%) occurred in the leg, with 21% involving the knee and 18% striking the ankle (many other studies point to the knee and ankle as the most common sites of injury during soccer). Knee injuries resulted in the most time lost from competition and produced the greatest number of cases requiring surgery. At the ankle, lateral sprains were more common than medial ones (ie, damage to the outside ankle ligaments was much more likely than harm to the inside ligaments).
There were also a considerable number of strains of the hip-adductor muscles, the hamstrings, and the quadriceps. The hip adductors, or groin muscles, were the hottest trouble spot, accounting for 53% of muscle strains, with the hams checking in at 42% and the quads adding just 5% to the total mayhem.
This new research supports other studies which have also suggested that games are particularly risky from an injury standpoint, compared with practices. In one study, researchers found that there were 16.9 injuries per 1000 hours in games, versus 7.6 injuries per 1000 hours in practices (Ekstrand, J. et al., 'Incidence of Soccer Injuries and Their Relation to Training and Team Success,' American Journal of Sports Medicine, Vol. 11, pp. 63-67, 1983). In another investigation, the rate of injury during games was pegged at 13 per 1000 hours, while practice logged only three injuries for each 1000 hours of participation (Engstrom et al., 'Soccer Injuries among Elite Female Players,' American Journal of Sports Medicine, Vol. 19, pp. 372-375, 1991).
How does soccer stack up against other sports in terms of injury risk?
Although endurance running is often considered to be a high-injury sport (about 50 to 65% of all endurance runners are injured in an average year), the actual rate of injury in running is comparable with that of soccer. Various studies suggest that the running injury rate is about five injuries per 1000 hours of running, with little difference between training and competition ('Prevention of Running Injuries by Warm-Up, Cool-Down, and Stretching Exercises, The American Journal of Sports Medicine, Vol. 21(5), pp. 711-719, 1993). This is a little higher than the 'practice' rate of injury for soccer but much lower than soccer's competition-related injury rate. Injury rates in other sports have been poorly studied, but it appears that soccer has one of the highest rates of athletic damage (Sportblessures breed Uitgemeten, Haarlem, DeVriesborch, 1990).
What footballers can do about it
How can soccer players reduce their risk of getting hurt? To minimize the risk of hip-adductor strains, they should carry out Indian-hop exercises. To Indian-hop, jog for a few strides and then 'jog diagonally to the right' by taking a step (with your right foot) which has a direction about 45 degrees clockwise from a straight-ahead step (ie, about half-way between a straight-ahead step and a step which is absolutely lateral). To put it another way, step to the 'north-east' with your right foot (assuming you have been jogging in a perfectly 'northern' direction to begin with). When your right foot makes contact with the ground, hop one time in place. When your right foot comes down to earth from this single hop, explosively hop diagonally to the left (to the 'north-west'), landing on your left foot. When your left foot strikes the ground, hop once in place and then explode diagonally to the right (north-east again). Your right foot will then hit, hop, explode diagonally to the left (not literally), and so on. Stay relaxed at all times as you carry out this drill; try to move in a coordinated and rhythmic manner. Indian-hopping is also very good for the ankles.
To strengthen the knees, one-leg squats with lateral hops work very well (see also Exercise two on page ten). To carry these out, stand with your left foot forward and your right foot back, with your feet about one shin-length apart (they should be hip-width apart from side to side). If possible, place the toes of your right foot on a block or step which is six to eight inches high. Most of your weight should be directed through the heel of your left foot. Now, bend your left leg and lower your body until your left knee reaches an angle of 90 degrees between the thigh and lower leg. Once your left knee reaches an angle of 90 degrees between the thigh and lower leg, hop laterally (with your left foot; the right foot stays in place) about six to ten inches, hop back to 'centre', and then hop medially (to the right when your left leg is forward) for six to ten inches, before coming back to the centre position and then returning to the starting position, maintaining upright posture with your trunk and holding your hands at your sides. Start with two sets of 12 reps on each leg, and progress to more sets and reps.
For the ankles, balance-board work is optimal. Try the following routines:
1. Side-to-Side Edge Taps. Place one foot directly in the middle of a balance-board platform, and note that your board is unstable in all directions (planes). Slowly and deliberately touch or 'tap' the lateral edges of the platform to the ground (left edge, right edge, left, right, etc.) for about one minute. Maintain full control at all times, avoiding hasty motions of the balance board. If the exercise is too difficult at first, place the toes of your other foot on the ground behind the wobble board for better balance. Once the minute is up, repeat the exercise on the opposite foot.
2. Front-to-Back Edge Taps. These are just like the side-to-side exercise, except
that you are touching the front edge of the balance board to the floor, then the back edge, etc. Do it for a minute on your left foot and then a minute on your right.
3. Edge Circles. Place your left foot in the centre of the wobble board, and then slowly and deliberately touch the edge of the platform to the floor, rotating this 'edge touch' in a clockwise fashion so that an edge of the platform is in contact with the floor at all times. The actual motion must be very slow and controlled to gain full benefit from the exercise and should be performed for one minute without stopping. As before, place the opposite foot on the ground behind you, if a full one-leg balance proves too challenging. Once you have rotated for one minute on one foot, change to the other.
4. Counter-Clockwise Edge Circles. These are the same as the edge circles, except that you are now rolling the edge along in a counter-clockwise direction.
5. Bicycle leg swings with resistance reduce the risk of hamstring strains. To do these, attach a medium-resistance stretch cord to your right ankle and to a solid object (pole, tree, another human, etc.) in front of you. The attachment point on this object should be roughly at knee height, and the object should be about a metre in front of you (you may have to adjust this distance). Stand with your weight fully supported on your left leg (you may place your right hand on a wall or other support to maintain balance), and begin by flexing your right hip and raising your right knee up to waist height (your right thigh should be parallel with the ground); as you do this, your right knee should be flexed to 90 degrees or more.
Once your thigh is parallel to the ground, begin to extend your right knee (swing the lower part of your right leg forward, unflexing the knee) until your knee is nearly fully extended (eg, your leg is nearly straight), with your right thigh still parallel to the ground. As your right knee nears full extension, allow your right thigh to drop downwards and backwards, 'paw' the ground with your
foot, and keep your leg moving until the entire thigh and leg are extended behind your body (as if following through on a running stride). Your right knee should be near full extension (your leg should be straight) until it reaches the peak of the backswing. As your right hip nears full extension (eg, as you approach the end of the backswing), raise your right heel by bending your right knee; your heel should move closely towards your buttocks as you do this. As this happens, move your right knee forward until it returns to the appropriate position in front of your body, with your right thigh parallel to the ground. Repeat this entire sequence of actions in a smooth manner such that the hip and leg move though a continuous arc without stopping or pausing. Once you are able to coordinate the movement, strive to perform the swings at a cadence of at least 12 swings every ten seconds (slightly faster than one swing per second). Start with two sets of 50 reps on each leg and progress to more sets and reps over time.
Regular use of exercises like these should help decrease the risk of the most common soccer injuries.