ABSTRACT Background Effort measurement is essential for adaptation to interactive learning technologies. Most contemporary technologies measure effort through the log data (reaction time and correctness). Some adaptive technologies use facial expressions and attention to adapt. Objectives We present a novel, complementary, and multimodal definition of effort that can be used to adapt not only the content but also the interaction in learning technologies for children. Methods We propose a 3D view of an effort measurement, that is, cognitive, physiological, and physical. We use eye‐tracking, heart rate monitoring, and motion tracking to define these three dimensions. We then apply this measurement within two motion‐based educational games and show how this 3D effort varies across the different phases of the educational games and children's performance. Results and Conclusions The results show an interaction effect of the phase and performance on each of the three effort dimensions. We discuss how these results can inspire the design of multi‐sensory adaptive learning systems for children.