Most of us are spending majority of day sitting (work, car, etc.) so when we go to the gym we shouldn’t do the same.

The human body is designed to move in 3D, not in one plane the way machines are making you move. Your stabilizing muscles are not getting any work because machine is doing that work for you. So when you get back to the real life where you have to control your weights you will expose yourself to injury in a plane of movement where you haven’t strengthened. Stop training your body as a collection of body parts with isolating muscles on machines.

When you push your car out of a ditch you are not trying isolate your quads -you will use all your leg muscles from the toe up. When you do, for example, a leg extension you are just becoming better at using leg extension machine, you are not developing any real life strength and you will not have any carryovers to the sport you might be doing or life tasks.

Doing full body movements will also make you burn much more calories than when you are doing isolation exercises.

So next time why don’t you try to do squat instead of a leg press machine, dumbbell press instead of a press machine, chin-ups instead of a biceps curl, pull-ups instead of a lateral pulldown machine?