Over Training
Over training is when you don't give your body enough time to recover.
Athletes will train long and hard to improve their strength and stamina.
Some athletes will train very hard and not give themselves enough time
to let their bodies heal. This will have a negative effect on the athletes
performance. 
Side effects will include:
- Constant soreness and pain throughout the body
Of course you're going to be sore when you first start working out. Especially if it's been several years since you worked out. That's why you should start out slowly then work your way up.
It's okay to take a few days off
Listen to your body: If you're experiencing any of the above symptoms then you might want to take a few days off from training. Try relaxing or getting a massage to help loosen the muscles.
My overtraining story
At my old job me and a several friends decided to start meeting up at the gym to start lifting weights. There was maybe about 6 or 7 of us who decided to start meeting at the gym. A few of the guys were already working out and were used to lifting weights. I haven't lifted weights in over two years.
Well...I let my ego get in the way and decided to pack on the weight they were using instead of starting off from the bottom and working my way up. I didn't want to look like a "wimp" in the gym. I pushed myself to the limit. I wanted to prove to my co-workers that I could lift just as much as they could.
Several days later I was so sore that I barely could lift my arm up to wash my hair while in the shower. I was in so much pain it wasn't even funny. My training was set back by weeks because I had injured myself. Afterwards I got depressed about it so I quit.
Here are some steps to take to prevent overtraining
- If you're new to working out, then start of slowly and work your way up.
- Leave your ego at the door. You don't have anything to prove by working out as hard as someone who's used to working out.
- Listen to your body. Take a few days off if you need to.
- Make sure you get plenty of rest and relax.
- Don't overwork the same muscle more than twice in the same week. In High School I used to bench press 3 times a week and realized I was getting weaker because I wasn't giving my chest enough time to recover. You have other parts of your body to work out as well.
- Drink plenty of water, eat right, get a full nights rest, and take a multivitamin to help your body function at it's full potential!