Stand tall and raise one knee up and across, turning the sole of that foot toward you, and tap the toes with your hands. Switch legs with a small hop and tap the other foot, keeping a light bouncing rhythm going as you alternate. Balance, coordination and cardio all show up to this one - the hop keeps your heart honest while the tap keeps your brain in the game.

Works: hip flexors, quads, calves, obliques

Breathing: Steady and rhythmic, in time with the hops.

Common Mistakes: Hunching forward to meet the foot instead of lifting it higher, landing flat-footed with a stiff knee, and rushing the switches until the taps start missing.

Make Easier: Step between sides instead of hopping, tap the knee instead of the toes, or groove the knee lift with Knee-to-Elbows (Standing) first.

Make Harder: Pick up the pace and lift the foot higher, or alternate rounds with High Knees to keep the heart rate up between tap sets.