Hip-hop dance refers to street dance styles performed to hip-hop music and includes breaking, locking, and popping. Breakdancing originated among Black and Puerto Rican youths in New York City and uses movements where dancers "freeze" from fast motions into positions. Locking involves freezing defined movements and holding a position. Popping uses quick muscle contractions and relaxations to cause jerky motions of the body. These styles were created in the 1970s and made popular by dance crews in the United States.