What is repeated in a repetition? Effects of practice conditions on motor skill acquisition.

The nature of repetition and its contribution to the acquisition of motor skills in neurologically healthy subjects are examined in this article. We argue that cognitive processing is a key component of practice, which is undermined by repetitive performances. The effects on motor learning of contextual interference, knowledge-of-results delivery schedules, and observation of models are examined, with particular reference to the nature of practice. The role of repetition in learning with respect to physical therapy is also discussed.