free runner       
noun [ C ] (also freerunner) uk/ˈfriː ˌrʌn.ər/ us/ˈfriː ˌrʌn.ɚ/
 自由跑者(跑酷者)
someone who takes part in an activity in which they move quickly around buildings and objects in a city while performing jumps and other skilful movements
  London's South Bank is full of skateboarders, BMX riders, breakdancers and free runners.
 He is a freerunner — a practitioner of parkour, a supercool mixture of street sports and acrobatics. 他是一名自由跑者,也就是跑酷运动的练习者。跑酷是一种融合了街头运动和杂技的超酷的运动形式。 
 Synonym: traceur
 - More examples
 - The stage includes railings, walls and giant steps that recreate the landscapes used by free runners in cities.
 - Free runners have been carrying out a series of stunts in the city.
 - The image shows a freerunner jumping down from a ledge.