Core stability workout   View More Photos Photograph by Justin
Steele  Stabilizer muscles in your hips, back, and shoulders
have critical jobs, like supporting your spine and joints under
the jolting and jarring of pickup basketball, tennis, trail
running, or just about anything else you might do for fun on the
weekend. That makes a core-focused interval session the single
most time-efficient training and a solid foundation if you're
looking to get back in shape. Note that our routine begins with
a total-body exercise, then moves to a lower-body exercise, then
an upper-body exercise, and, finally, a core exercise, before
repeating the pattern. "That basic sequence is important so that
you can always do the next exercise with good intensity," says
Chris Jordan, who built this routine based on published
scientific research on interval and circuit training. The
complete circuit should take four minutes, and Jordan recommends
doing it for about 20 minutes. "But don't do this routine on
consecutive days," he says.