1. Exercising Too Much: Top athletes and their trainers minimize the possibility of over- training by manipulating the amount, intensity, and type of exercise. Typically they start the season with a lot of low-intensity work. As the season progresses, they exercise less often but more intensely. During this time the emphasis is on technique. Between seasons the players stay in shape with "active rest," engaging in low-key sports other than the sport they're training for.
You can apply these same principles to your daily routine. If you are a runner, go long distances at a slow pace on some days and short distances faster on others. If you feel you can't afford to take a day off from exercise, do an "active rest" activity such as hiking, bicycling, or swimming. Bodybuilders can achieve the same result by alternating long, gentle workouts with short, intense ones.
2. Not Eating Enough Food: Loss of appetite is a typical sign of overtraining. Just when your muscles need calories and glycogen the most, you don't feel like eating. If you're exercising hard and long, be sure you get plenty of calories and, in particular, plenty of complex carbohydrates. Although the liver can make glycogen out of protein, it prefers to make it out of carbohydrate. While it's true that athletes need more protein if they're exercising intensely, they also need to be sure to eat plenty of fruits, vegetables, and other complex carbohydrates such as pastas and cereals. Otherwise the protein in the diet is used to replace glycogen instead of to repair muscle.
3. Not Getting Enough Rest: Take your rest periods as seriously as you do your exercise. Muscle tissue doesn't grow stronger during exercise, it breaks down. It needs a period of rest to repair and build up. Back-to-back hard workouts mean constant muscle wear without tissue regeneration. When nine ultra-long-distance runners who participated in a seventeen-mile-a-day, ten-day race had their thighs measured before and after the race, the measurement actually decreased. You'd expect the quadriceps to get bigger after such an event, but they were smaller!
Bodybuilders also find that a little rest pays off. A well-known female competitor once wrote an article describing the difficulty she was having trying to develop her biceps. She worked the muscle daily. Nothing happened. She increased the weight. No improvement. In frustration, she cut back on the weight and took every other day off. The poor muscle, finally getting a chance to repair, grew larger.
