"Every movement we make is slightly different from the last one even if we try really hard to make it exactly the same there will always be variability within our movements and therefore within our follow-through as well," said David Franklin from Cambridge University.
"However, this research suggests that this variability has another very important point that it reduces the speed of learning of the skill that is being practiced," Franklin added. If a new task, whether that is serving a tennis ball or learning a passage on a musical instrument, is repeated enough times, a motor memory of that task is developed.
The brain is able to store, protect and reactivate this memory, quickly instructing the muscles to perform the task so that it can be performed seemingly without thinking. The problem with learning similar but distinct tasks is that they can 'interfere' with each other in the brain.
The research may also have implications for rehabilitation, such as re-learning skills after a stroke, the researchers noted. The study was published in the journal Current Biology.