According to Official Guinness Records,
The most backward flips against a wall in one minute is 29 and was achieved by Miguel Marquez (Spain) on the set of Zheng Da Zong Yi - Guinness World Records Special in Beijing, China, on 19 June 2009. Miguel is a four time national champion in the sport of Tumbling and acrobatic discipline used in gymnastics.
For a complete list of 2009 records, please visit 2009 Guinness Records in China.