Leg extension/Leg curl Superset
4 sets
12 leg extensions with 1 second hold on full extension each rep.
12 laying leg curls with dumbbell with 2 second negative (2 second count on descend)

Notes: Use a light medium weight. For the leg extension set up, grab a chair with a back and place some books or anything that can safely raise you, your feet and dumbbell should be off the ground in order to have full range of motion. Make sure to have a chair with a back or use a wall! Get creative but stay safe.
After the 12 leg extensions immediately perform 12 leg curls. Rest 2 minutes between sets.
Repeat 4 times.