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The degrees of freedom problem or motor equivalence problem in motor control states that there are multiple ways for humans or animals to perform a movement in order to achieve the same goal. In other words, under normal circumstances, no simple one-to-one correspondence exists between a motor problem and a motor solution to the problem. The motor equivalence problem was first formulated by the Russian neurophysiologist Nikolai Bernstein: "It is clear that the basic difficulties for co-ordination consist precisely in the extreme abundance of degrees of freedom, with which the centre is not at first in a position to deal."
Although the question of how the nervous system selects which particular degrees of freedom to use in a movement may be a problem to scientists, the abundance of DOFs is almost certainly an advantage to the mammalian and the invertebrate nervous systems. The human body has redundant anatomical DOFs , redundant kinematic DOFs , and redundant neurophysiological DOFs. How the nervous system "chooses" a subset of these near-infinite DOFs is an overarching difficulty in understanding motor control and motor learning.