Day 21 is cardio built around hops: 10 hops on the spot, 4 step seal jacks, 10 hops, 4 step Ts, 10 hops. Five items for one set, 2 minutes rest, 3, 5 or 7 sets by level. Three weeks in, and hops are back for their second and last appearance.
Hops on the spot are small two-footed hops in place, hands on hips, feet barely leaving the floor. Between the blocks of hops sit two stepping shoulder movements you know: step seal jacks opening the arms wide from crossed, and step Ts lifting them from the sides to a T. Thirty hops per set, broken into tens by four reps of something slower - the hops lift the heart rate, the steps let it settle a fraction, and the ankles and calves get more work than they have had on any other day.
Land every hop softly on the balls of the feet with the knees bent - the height comes from the ankles, not the knees, and it should be small. Open the arms fully on both step exercises so the shoulders do their share. If hopping is not for you today, step in place for the tens instead.
Thirty hops and eight steps - Day 21 gets your heart rate up with the smallest bounce in the program.
Make it Harder: Do 20 hops in each block instead of 10.
Make it Easier: Cut each block of hops to 6.
