SHR # 2432 :: If Blood Flow Restriction Works Why Aren't You Using It - Dr. Jim Stray-Gunderson - I did my first interview about KAATSU, or also known as Blood Flow Restriction Training in 2006. Dr. Stray-Gunderson first appeared on SHR in 2015 to further the discussion. The body of work on blood flow restriction training has grown further. The cumulative take-away is it works at building muscle faster. So why aren't you using it?