No.
There are a number of reasons why. I exercise and encourage others to exercise not only to have better health, strength, posture, and so on .. But, for injury prevention and to help make everyday tasks easier on our bodies.
When you go to push open a heavy door you don't have pounds of metal supporting your body to help you do that. All you have is .. You! Your body needs more than just your pecs to open that heavy door. By working out without machines you teach your body how to recruit the muscles necessary to do such everyday tasks. This way your wont hurt yourself. Plus, you are working more muscles at one time meaning more calories are being burned!
