OB hit the nail on the head. As a personal trainer I can pretty much assure you that it is impossible to get maximum results working out on your own. Your brain will tell you to stop long before your muscles are fatiqued. Even using programs such as P90X will not get you the the last three reps that are required for muscle development. Unless you are working to exhaustion you will not get the results you are looking for. In addition, having a set appointment with a trainer will help keep you from finding an excuse not to work out. Even doing cardio without a plan is a waste of time. Your body adapts quickly to the loads you place on it and you need to vary time, intensity and muscle group involvement to keep improving. Find a trainer the is a skier and you will pick up bouys. My 2 cents