Avoid Overtraining

Overtraining occurs when you exercise beyond your limits - in intensity, frequency or duration - and when you don't give your body enough time between workouts to recover.

The irony is that exercising too much actually leads to a decline in strength, power, speed and endurance - all of those things you wanted to build through exercise. Other symptoms include loss of appetite, sleeplessness, fatigue, and depression.

Another way to protect yourself against overtraining: cross train. By varying your activities and fitness routines regularly, you'll be less likely to stress or injure your muscles.