According to Bernstein, the central nervous system solution to the human body’s enormous variation in movement choice and control when directing movement—the problem of degrees of freedom (DF)—is to freeze the number of possibilities at the beginning of motor learning. However, different strategies of freezing DF are observed in literature, and the means of selection of the control strategy during learning is not totally clear. This review investigated the possible effects of the class and objectives of the skill practiced on DF control strategies. The results of this review suggest that freezing or releasing the DF at the beginning of learning does not depend on the class (e.g., discrete skill class: football kick, dart throwing; continuous skill class: athletic march, handwriting) or objective of the skill (e.g., balance, velocity, and accuracy), in isolation. However, an interaction between these two skill elements seems to exist and influences the selection of the DF control strategy.

据伯恩斯坦说，中枢神经系统解决了人体在指导运动时在运动选择和控制方面的巨大差异（自由度（DF）问题），目的是冻结运动学习开始之初的可能性。但是，文献中观察到了不同的冻结DF策略，并且在学习过程中选择控制策略的方法还不十分清楚。这篇综述调查了技能类别和目标对DF控制策略的可能影响。该评价的结果表明，在学习开始时冻结或释放DF并不取决于课程（例如，离散技能课程：踢足球，掷飞镖；连续技能课程：运动进行，手写）或技能目标（例如，平衡，速度和准确性），隔离中。但是，这两个技能要素之间似乎存在相互作用，并且影响了DF控制策略的选择。