Full Range of Motion - Yeah, I'ts Important!

I was reading Muscle and Body magazine yesterday and came across an article that screamed "P90X".  The article was about the best way to build thick mass and discussed whether or not to increase weight, reps, or number of exercises.  However, after reading the entire article, a few principles that Tony harps on us everyday were pointed out as most important.

1. Use FULL RANGE OF MOTION to fatigue the maximum number of muscle fibers
   Using full range of motion causes you to recruit (and fatigue) the muscle fibers along the entire length of the muscle, not just in the middle ranges where the muscles are the strongest; more muscle fibers used = bigger muscles.
2. Make sure to achieve a noticable BURN AND MUSCLE PUMP
   We all know Tony says to make sure the last three reps are tough whether you're doing 8-12 reps or 12-15...the last 3 need to be TOUGH!  Remember, being able to contract at the top and stretch completely at the bottom will pump your muscles to their fullest extent.

To quote Muscle and Body
"Interestingly, it's the eccentric portion of the movement (where the muscle is stretching as you resist the weight's return to the starting position) that stimulates the greatest muscle growth" 
This means go all the way up, and control the movement on the way down!

So make sure that when you're doing your curls, pull-ups etc...you listen to Tony when he says "All the way up, All the way down"  You may not be able to do as many reps this way, but trust me, you'll be more fatigued, have a bigger pump, and your muscles will grow more than if you only go 1/2 way down.