Sam Ransom, who plays Jonny Z, was training for and competed in the National Gymnastic finals whilst training for the film.
While several older actors were considered for the role of Jonny Z, including champion martial artists and dancers, Sam Ransom was not only the most in character, but also the most experienced athlete, having trained in Gymnstics with his father, a former member of the Great Moscow Circus, since he was 1 and a half, and additionally experienced in basic wire work from the age of 3.
Samppa Von Cyborg who plays Jax, was an initial reference point for the character and the film prior to being cast. He is one of the leaders in the craft of Body modification, his metal Mohawk, metal teeth and multiple trans-dermal and sub-dermal implants are all real.
Frame 137 features debut actor, 10 year old Sam Ransom, doing all his own stunts. For this he had to train intensively for 6 weeks with a team of martial artists, professional stunt men and a former member of the Australian SAS, to master the form, multiple styles and specific action sequences required for the role. By the end of the six weeks Sam was able not only able to perform the required sequences but could also fight, throw and disable opponents several times his own size and weight.
Sam was taught fire breathing by Tim Black, long time holder (2005-2009) of the World Guinness Record for Highest Flame blown by a Fire-breather.