Day 9 is the high-knee grid at 20 a slot, with the power moves moving around it. The circuit is 20 high knees, 10 jumping lunges, 20 high knees, 10 jumping jacks, 20 high knees, 10 jumping jacks, 20 high knees, 10 jumping lunges, 20 high knees - a single pass per set, 2 minutes rest, 3, 5 or 7 sets. Five rounds of high knees per set, 100 in total, with a ten between each.
Compare it with Day 1 and the design shows. There the jacks were the filler and the power moves were the punctuation; here high knees are the filler and jumping lunges take the top and bottom corners while jumping jacks hold the middle. The middle row is the lighter one - jacks are easier than lunges - which means the circuit peaks at the start and the end and eases in the centre. That lets the legs recover a little before the final round of jumping lunges, which arrive after 80 high knees.
High knees: quick feet, knees up, arms driving. Jumping lunges are 10 total, five switches each side - land in a true lunge with the back knee low and spring straight back up, no shuffling between reps. Jumping jacks at 10 are a breather; take them as one, but keep them full. The final 20 high knees should match the first 20 in height.
High knees carry the card, jumping lunges light it up, and the jumping jacks in the middle are the only soft spot on the page.
Make it Harder: Replace the two rounds of jumping jacks with 10 jump squats each.
Make it Easier: Take the jumping lunges as alternating reverse lunges and march the high knees instead of running them.
