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Founded in 1969 by professional dancer Judi Sheppard Missett, Jazzercise remains the original group fitness class for women.

All got started late and have stayed with it. All three work out with Dr. Irv Rubenstein, an exercise scientist who runs STEPS Fitness in Nashville, Tennessee. Kathryn Dettwiller, 77, got pushed ...

From fitness gurus to lifestyle ... some of whom are in their 80s, have been sharing tips, imparting wisdom to younger viewers or just hopping on the latest dance trends. With millions of views ...