As a result of injuries accrued over many years riding in a fixed regular stance, from 2007 onward Mullen made a conscious effort to “erase” his riding stance, re-learning tricks (and in many cases learning new tricks he was unable to do previously riding regular) goofy and endeavoring to re-learn riding a skateboard neutrally in the absence of any preferential “natural stance.” In an interview with Tony Hawk, Mullen explained that he had developed problems in his right hip joint, with scar tissue having built up in his joint over years as a result of habitually hyper-extending his leg ("e. g.", doing the splits, a danger inherent in practicing riskier tricks such as darkslides) while skating. Mullen stated that through extensive stretching and the use of blunt objects he was able to break up the scar tissue in order to restore range of motion.