If you're a runner, the link between training quantity and injury means that total training mileage is an excellent indicator of your injury risk. The more km you accrue per week, the higher your chances of damage. One recent investigation found a marked upswing in injury risk above about 65 km of running per week.
The two best predictors of injury
However, it's important to bear in mind that many injuries are actually NOT new trouble areas; they are recurrences of previous problems. That brings to mind an important point: the absolute-best predictor of injury is a prior history of injury. In other words, if you've been injured before, you're much more likely to get hurt than an athlete who's been trouble-free. Again, this is logical: regular exercise has a way of uncovering the weak areas of your body. If you have slipshod hip muscles, for example, or knees that are put under heavy stress because of your unique biomechanics during exercise ('poor form'), your hips or knees are likely to be hurt when you engage in your sport for prolonged periods of time. After recovery, if you reestablish your desired training load without changing your biomechanics or strengthening your hip muscles, those areas are very likely to be injured again.
Strangely enough, the second-best predictor of injury, after total training time, is probably the number of consecutive days of training you carry out each week. Consecutive days are counted as follows: if you train on Monday, Tuesday, Wednesday, and Friday, you are training on three consecutive days each week (Friday doesn't count because it has a rest day before and after it). Scientific studies strongly suggest that reducing the number of consecutive days of training can lower the risk of injury. For example, instead of working out for one hour from Monday through Friday (five consecutive days), you could probably reduce your risk of injury by completing 75-minute workouts, four days per week (Monday, Wednesday, Friday, and Saturday, for example). Your total training time would be the same in each case, but the second strategy would reduce your consecutive days from five to two, giving you much more average recovery time between sessions and lowering your risk of injury. Recovery time reduces injury rates by giving muscles and connective tissues an opportunity to restore and repair themselves between workouts.
Type A's should take care
Psychological factors seem to play a role in producing injuries, too. Some studies have shown that athletes who are aggressive, tense, and compulsive have a higher risk of injury than their relaxed peers. Such worried, 'Type-A' individuals also have more multiple injuries and lose twice as much training time when an injury actually occurs. So, relax! Tension may make muscles and tendons tauter, increasing the risk that they will be harmed during workouts.
