However, 4 months ago I fell while doing box jumps and hurt my back very bad. (coachcalorie.com)
At some point you will be advanced and consider box jumps with the additional load, so make sure the material of the boxes is solid enough to support the weight. (christianbosse.com)
Repeat steps 1 through 4 until you have completed the desired number of box jump repetitions before resting. (shapesense.com)