This routine comes from Vern Gambetta a great strength coach. He is the one who named this complex "Super Legs " and later JC Santana made this popular under the name " Leg Cranks".
Start of by doing the rep range on the far left and then make your goal the highest number on right. Meaning start with 20 reps for the squats........and your goal should be 24. If you can do 3 rounds of 24/24/24/12 then you kick ass!
20-24 reps bodyweight squats ( go fast ! )
20-24 reps alternating lunges or reverse lunges ( go fast ! )
20-24 reps alternating split squat jumps
10-12 reps squat jumps or box jumps ( as high as possible )