Motivation to learn is a disposition developed through exposure to learning opportunities. Guided by the expectancy-value theory of Eccles and Wigfield (1995), this study examined the extent to which expectancy belief and task value influenced elementary school students' physical activity and knowledge learning in physical education (PE). Students ("N" = 753) from 15 US public schools contributed student-level and class-level data. With a 2-level design, the data were analyzed using hierarchical linear modeling. Physical activity ("t" = 3.18; p less than 0.01) positively predicted fitness knowledge. Attainment value (i.e. perception of importance) as the only expectancy-value construct, significantly predicted fitness knowledge ("t" = 3.07; p less than 0.01), when physical activity was held constant. As the physical activity intensity increased, the positive prediction of attainment value to knowledge attenuated and then turned negative ("t" = -3.10; p less than 0.01). The study indicated that although a physically-active context helps students to make sense of fitness knowledge, a vigorous context shifts their motivation away from cognitive learning, toward physical participation. To resolve the difficulty of attaining learning objectives both physically and cognitively, PE teachers may want to maintain an active learning context with moderate physical intensity. Future research should address the effect of learner motivation on dual or multiple learning outcomes in PE. (Contains 3 tables.)