Since its invention in the late 1950s, the skateboard has become a standard item of sports equipment for teenage boys. By the early 1970s, bicycle manufacturers started producing quality skateboards which broke less (1) ... and had more (2) ... wheels that would not come off and cause injury. The (3) ... of the sport declined in the 1980s when some critics argued it was still too risky and (4) ... . However, skateboarding has made a comeback and is likely to remain a symbol of youthful energy for many years.