Box Jump
The box jump is a relatively natural movement—just jump onto any solid surface the specified height above your starting point. To get the best power production, the feet should be directly beneath the hips when jumping. This is usually not a problem since the body will usually do this naturally.
Scaling and Substitution
A person unable to physically jump with both feet at the same time can scale by just stepping up to the surface one leg at a time, similar to climbing stairs. If this scaling is used, you should alternate which leg steps up first to strengthen both legs equally.