"FACT: unless you run 30 miles per week, you may not change your body shape."
Chuck Norris' "Total Gym" infomercials use this statement as a means of promoting their product. There is a basic truth to what is said: aerobic exercise (cycling, running, walking, skiing, skating, swimming, etc.) may not change your body shape, unless you do it enough.
What they don't tell you:
1) Without aerobic exercise, the heart and blood vessels do not get adequate workouts. Cardiovascular fitness cannot be achieved in a few short minutes per day.
2) "Body Shape" can be changed in two ways: by toning the muscles underneath "flabby" areas, and reducing fatty tissue overall. It's a fact that when fat is burned, it is removed from fat stores generally, not in "target areas." Toning underlying muscles is good, but one cannot remove fat from a specific area
(except by liposuction.) Males and Females may reduce fat from different areas, but targeting specific areas is nonsense.
3) Running 30 miles per week might seem improbable, which help their point, but cycling is another aerobic exercise, as is walking, swimming...aerobic exercise is at the "heart" of overall fitness (even Chuck will tell you that.)
4) The "Total Gym" sounds like a great product. Too bad it has to be marketed at the expense of so many other great fitness endeavors, many of which may be more important to overall health.
5) Cycling is a lot more fun (IMHO).