So I have the low impact series but have been using a different sliding disc I bought at Wal Mart...they are frustrating and I can not use them that well especially with jumping jacks. What do you guys think of Cathe's discs and do you recommend them? If they come highly recommended I will purchase them. Looked at her shopping page for rating on them but the one rating did not apply to the discs. Any input would be greatly appreciated.