When humans move, the active muscles induce tiny magnetic fields. It is possible to decode such so-called magnetomyographic (MMG) signals to reconstruct the commands of the central nervous system that lead to motion. This is a non-invasive methodology to study human physical performance, to investigate neuromuscular disorders, or control prosthetic devices. Using computer simulations, this publication shows that this new approach exceeds the limits of existing methods for studying human motions. In the past, the measurement of muscle-induced magnetic fields was ignored due to technological limitations. Driven by the current development of novel quantum sensors, it is expected that decoding magnetic muscle signals can be a groundbreaking method for clinical neurology and motion science.