This paper takes a theoretical approach to movement computing education for young learners, with a focus on middle grades (grades 6-8, ages 11-14). This age group is targeted as a lower bound because, while some elements of computational thinking may be available to still younger learners, there are abstractions involved in movement computation that pre-require a certain amount of formal operation, in the Piagetian sense. We outline a parallel foundation of key ideas in movement (specifically dance) and key ideas in computing (specifically data representations) at this age-appropriate level. We describe how these foundations might be laid down together early on so that they can later be integrated via the introduction of sensing and feedback technology. Concepts in movement and choreography are studied using words and bodies, as in traditional dance education, and later using computer simulations and motion capture. Data concepts are introduced first by appeal to general questions and later by specification to the movement of individual and collective joints and bodies.