I've ripped my shins open too many times on picnic tables and brick walls to use anything that isn't softer. I like to do muay thai and stuff so when you've scraped all the flesh off shins and/or swollen and sore you can't practice on heavy bag for weeks it pisses one off majorly. I mean I've went into full blown crying break downs because of being set back from not being able to even do my normal workout because of the pain. Unfortunately box jumps are too good of a work out not to do and I couldn't imagine not doing them but that doesn't mean one has to unnecessarily hurt or potentially hurt ones self just to practice them.