One of the most basic premises that we teach our trainers has to do with the Principle of Overload.  It’s simplest definition says that if you want your body to experience adaptation and change, you constantly have to be pushing your limits and testing your body to do more than it is used to doing.  If you remain inside your comfort zone forever, you’ll never get anywhere (not very far, anyway).  For example, the person who walks on the treadmill and complains that they don’t get any results.  They walk for 20 minutes 4 or 5 times a week at about 3 mph on the treadmill and wonder why nothing changes.  Well, what do you do all day long?  You walk around to do stuff.  Around your house, your office and your errands.  And, I’d be willing to bet that it’s at about that pace, too.  Your body is telling you “I’ve got this.”  The problem is that you’re only doing more of what  you normally do in the first place.  Instead, walk up a hill.  Walk faster.  Climb stairs, jump rope, bike.  Do something different!  Something more!  It’s the same in the weight room.  If you start lifting a 5lb dumbell, you will get results….for a while.  If you’re still lifting that same weight 6 months or a year later, then you’re really not getting anything new out of that.  Your body is already past that.  Pick up the 10’s.  Do more reps.  Something.  So push your limits.  Every day.  Get better.  Every day.  Don’t be afraid to challenge your body.  It just might surprise you.