Box Jumps are an excellent exercise for developing explosive strength as they require you to develop your jumping force from a dead stop. The addition of the medicine ball helps add some resistance to your jumps and takes away much of the power generated by your arms which forces your legs and core to do more of the work.
Technique Tips
Select a medium sized box, stand in front of it (not too close that you will hits your knees or shins onthe way up), and then as quick as you can jump up onto it. Try and land as softly as possible. This is a good exercise to use for extra volume due to its low impact landings.
Alternative Exercises
Some good alternatives to Box Jumps with a Medicine Ball are
