Callanetics

The fitness industry has seen its share of fads — step classes, Callanetics, dancercise, Zumba — and failures.

Callanetics' subtitled claim--"10 years younger in 10 hours"--strikes many specialists in the field as a bit too much of a miracle.

Now 76, with arthritis, she does two hours of Callanetics daily and looks as trim as her 46-year-old daughter.