Bulgarian split squats are a modified split squat or stationary lunge
in which your rear foot is elevated. By elevating your rear foot on a bench,
chair, etc. you will not only increase the resistance which the front leg must
lift, but you will also increase the demand for balance. The Bulgarian split
squat is primarily used as a glutes and quads exercise although it works the
entire lower body muscle mass from the soleus to hip flexors.