Weighted Jump Squat

How to do it

Position a lightly loaded barbell across the back of your shoulders. You could also use a weighted vest, sandbag, or other type of resistance for this exercise.
The weight should be light enough that it doesn't slow you down significantly. Your feet should be just outside of shoulder width with your head and chest up. This will be your starting position.
Using a countermovement, squat partially down and immediately reverse your direction to explode off of the ground, extending through your hips, knees, and ankles. Maintain good posture throughout the jump.
As you return to the ground, absorb the impact through your legs.

What muscles does the Weighted Jump Squat work?: Mainly the quads, with help from the calves, glutes, hamstrings, lower back.
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.