Excerpted from "A Year of Health Hints"
365 Practical Ways to Feel Better and Live Longer
Fitness activities that involve steady, rhythmic motions of
your major muscle groups and burn oxygen for more than a brief
spurt are considered aerobic. They force your heart and lungs to
work at anywhere from 60to 85 percent of their capacity. Brisk
walking or bicycling, for ample, are aerobic. So is aerobic
dance--informally choreographed routines that combine
calisthenics and dance.
Aerobic dance classes became the rage in the early 1980s, but
the shock to bones and tendons caused by repeated jumping and
bouncing produced a number of injuries. Now, low-impact and
nonimpact aerobics have replaced many higher-intensity aerobic
workouts. Both are kinder to your skeleton.
Low-impact aerobics are designed so that:
Your feet stay
close to the floor, and only one foot leaves the floor at a time.
Only moderate
jumping is involved.
Jerky movements
are kept to a minimum.
Nonimpact aerobics are designed so that:
No jumping is
involved.
They rely on large
muscles of the thighs (as in knee lifts) rather than muscles in
the feet and
calves (as in jogging
and skipping in place).
They require more
arm movement than high-intensity aerobics.