Quadriceps
Calves, Glutes, Hamstrings
Sit on bench facing box few feet away.
Hold one dumbbell securely against chest.
Feet flat on floor, shoulder-width.
Lean slightly forward.
Explosively extend hips/knees, jumping from seated position onto box.
Keep DB close to chest.
Land softly on box, knees bent.
Step down carefully.
Return to seated position. Repeat.