Yeah I had pain around the patellar tendon last year and doing this helped. But you don't need to buy that thing for $24, you can do it with a cut-open $5 bicyc

Yeah I had pain around the patellar tendon last year and doing this helped. But you don't need to buy that thing for $24, you can do it with a cut-open $5 bicycle tire tube and it works equally well.