Elevated Back Lunge

How to do it

Position a bar onto a rack at shoulder height loaded to an appropriate weight. Place a short, raised platform behind you.
Rack the bar onto your upper back, keeping your back arched and tight. Step onto your raised platform with both feet. This will be your starting position.
Begin by stepping backwards with one leg. Descend by flexing your hips and knees until your knee touches the floor.
Pause, and extend through the hips and knees to rise up, returning all the way to the starting position before alternating.

What muscles does the Elevated Back Lunge work?: Mainly the quads, with help from the glutes, hamstrings.
What equipment do I need?: Barbell.
Is it good for beginners?: It is rated intermediate level.
How do I track progress on it?: Log each set and beat the weight or reps from last time. Liftrung shows your last set beside the next one and estimates your one-rep max from your sets.

Exercise descriptions: free-exercise-db, public domain.