Day 18 is a circuit, 3, 5 or 7 sets, 2 minutes rest, and it is all legs, all standing, all sideways. The top row is 5 side lunges to the left, 10 calf raises, 5 side lunges to the right. The bottom row is 5 squats, 10 side-to-side lunges, 5 squats. Both lunge counts on this card mean what they say: side lunges are 5 per side, side-to-side lunges are 10 in total, alternating.
The two lunges look alike and are not. A side lunge starts from standing: step wide to one side, sit deep into that leg with the other leg straight, reach your hands toward the floor, and push back up to standing before the next rep. Side-to-side lunges never stand up: you stay low and shift your weight from one bent leg to the other, the straight leg swapping each time, 10 shifts in all. The first teaches you to absorb a sideways step; the second keeps the inner thighs and hips under continuous tension. Calf raises and squats around them keep the whole leg working in the plane it knows.
In side lunges, keep the bent knee tracking over the foot and the straight leg's foot flat. In side-to-side lunges, keep your chest up and your hips low the whole way across - the temptation is to rise as you shift, and rising is rest. Squats to parallel or below, heels down. Calf raises full range.
A running program that spends a day going sideways is protecting every stride that goes forward.
Make it Harder: Add a small hop as you shift on every side-to-side lunge, landing soft and staying low.
Make it Easier: Rest your hands on your thighs during the side-to-side lunges and stay a little higher than the picture shows.
