If you know the symptoms of overtraining you can avoid running yourself into the ground. And this will help you tons, short term and long term.
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Overtraining not only injures your body, but drains your mind and saps your enthusiasm as well. Find out what it is, and diagnose it early so that you don't burn out.
"Excessive frequency, volume, or intensity of training that results in extreme fatigue, illness, or injury (which is often due to a lack of sufficient rest, recovery, and perhaps nutrient intake)."
"…[The] accumulation of training and/or non-training stress resulting in long-term decrease in performance capacity with or without related physiological signs and symptoms of overtraining, in which restoration of performance capacity may take several weeks or months."
Overtraining doesn't happen in an instant, or over a few days. Real overtraining means wearing yourself out too much over the course of weeks or even months.
Also, whether overtraining occurs is heavily dependent on who's training. Your individual genetics, history of physical activity, other stressors, and individual response to the exercise all play a role in determining what overtraining is for you.
And you can't reverse its negative effects just by taking a weekend off. You've been digging yourself into the hole for a while, so it'll take weeks or months to recover from it.
Overreaching is the little brother of overtraining. It's what happens to you if you push too hard for just a few days or a week.
Since overreaching is overtraining on a smaller scale, you can recover from it fairly quickly. A weekend or a few days of taking it easy should see you doing fine.
Overreaching is not always a bad thing. Overreaching followed by a recovery period at the end of a workout program can give you substantial gains in strength and power - when you start working out again. Thus, many workout programs culminate with pushing you a bit too hard at the end.
But be careful! The symptoms of overtraining and overreaching are identical; it's just that one goes on longer. As outlined in the handy-dandy diagram below from Essentials of Strength Training And Conditioning, here's the evolution of overtraining…
All right, here are the symptoms of overtraining to watch out for. Try to catch overtraining when it's just starting to kick in. Later, it's a lot more painful to correct.
These are psychological factors that are best diagnosed by athletes themselves. Also, the psychological symptoms of overtraining occur earlier than the physical symptoms do. 
If you feel tired or fatigued for a few days, it probably isn't anything. But if you frequently have the symptoms below, consider taking a rest.
If taking a rest helps, then the problem was probably overtraining. If it doesn't help, then maybe the problem is not just overtraining – and you should look into other causes.
The physical, easily testable, symptoms of overtraining occur later. This is when overtraining has become so serious that you start to regress in your training. The bodily symptoms are…
The declines in performance, despite continued training, are that last part of overtraining to show up. When you've gotten to the point where you can't fake it to yourself anymore and your excessive practice is actually harming you, you need to stop.
Or you will hurt yourself.
Taking a rest sometimes can be hugely beneficial, both physically and psychologically. And when you come back and start training again you'll feel refreshed, rejuvenated, and enjoy getting better at your sport all the more.
Oh, and be sure to sign up for the e-zine Starting Strong to get monthly strength training, exercise, and diet tips e-mailed to you - and access to the free e-book Train Smart, Eat Smart: Exercise Nutrition Hacks!
The Symptoms of Overtraining: Are You Sabotaging Yourself?
1. Baechle, Thomas R., and Roger W. Earle. 2008.Essentials of Strength Training And Conditioning. Champaign, Ill: Human Kinetics. Pp. 114.
2. Garrett, William E., and Donald T. Kirkendall. 2000. Exercise and Sport Science. Philadelphia: Lippincott Williams & Wilkins. Pp. 487.
3. Baechle. Pp. 114.
4. Garrett. Pp. 487.
5. Baechle. Pp. 114.
6. Ibid. Pp. 115.
7. Garrett. Pp. 487.
8. Baechle. Pp. 114.
12. Ibid. Pp. 116.
13. Garrett. Pp. 495.
14. Baechle. Pp. 116.
18. Garrett. Pp. 487.
19. Baechle. Pp. 116.
20. Garrett. Pp. 487.
22. Ibid. Pp. 488.
23. Ibid. Pp. 487.
24. Ibid. Pp. 488.
25. Ibid. Pp. 495.
26. Ibid. Pp. 487.
27. Baechle. Pp. 116.
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