When talking about overtraining there is one test that for me has been fool proof ever since someone showed it to me. Its so obvious yet sneaky at the same time. THE BIGGEST precursor for overtraining your body's load is frankly your GRIP STRENGTH. Put 225-315 on a bar a day you know for a fact you are perfectly rested/no muscle groups are broken down. Grab that bitch like your doing shrugs and just let it hang. Watch the clock to see how long your grip holds out before Whoosh-BANG. Next time (months down the road) you walk into the gym and you wonder damn I've gone hard these past few weeks I wonder if I am overtraining (or can't lift as much as used to), repeat this exact test. If your grip fails by 1/3 or more from previous time you are in a state of degraded muscle and should incorporate more rest days into your routine. If you beat your previous time that means you are getting stronger. The reason I pick 1/3 is there are obviously a few factors that go into the first test ("dude I'm jacked on jack3d, was on dbol cycle, etc.) so the 1/3 differential is a safe bet. A lot of people don't realize the value that overall grip strength can have on determining the balance of your entire nervous system. This is what we are testing here, not the muscles in your wrist or forearm, but the overall quality of your nervous system and if you are growing stronger. For some, the determination to succeed in the gym overrides their ability to listen to their body. I have been there before, but this test has always worked for me..
Cheers