I just finished taping PS SLA, and that looks tough!! I plan on doing it later this morning for part of my workout. I do have a question though, how high were those toppers? And what's the lowest height we could do to get results? I have a cooler that I believe is 15-16", would that be ok? I'm only 5'1" and I heard somewhere that the knee shouldn't go past 90 degrees with your foot on it. Is that right? Anyway, just had to tell you that SLA looks so tough, that this will be another "must have" for me!! Thanks!