Originally posted by P-funk
This statment is not exactley true..
There are two types of warm up that can be done prior to a resistance training workout, a general warm up and a specific warm up.
The specific warm up is what most people opt to do. It consists of performing light movment specific to the movments which are about to be performed in order to get blood in the muscle and prepare it for what is to come (ie light squats, light bench press, shoulder press etc....)
The general warm up is just that.....General. It can be something like calistenics (jumping jack) or stationary bike, tread mill etc.....This type of warm up, all though commonly overlooked is excellent for preparing the body for a workout is several different ways:
a) raising heart rate
b) getting blood flowing
c) improving cardiovascular and respiratory efficiency
etc......
A general warm up does not have to, and should not tire you out. Often time I have done the stationary bike as a warm up on leg day for 10min and still nbever had a problem doing heavy squats.
There are many benfits to both types of wamr up and I encourage you to maybe even try using both of them at the same time. Five minutes of a general warm up to get the blood/oxygen moving to through the body and the heart rate up and then 2-3 light sets of an exercise as a more specific warm up.