What drives Emily to squeeze herself through a tennis racket?

Emily Prior-Willeard, a circus performer and student on UCL's Performing Arts Medicine MSc, explains why she and her friends push themselves to their limits. Read more in The show must go on - in UCL Antenna: https://medium.com/ucl-antenna/https-medium-com-ucl-the-show-must-go-on-f2b463c0e857#.odlo6gnph