Another common form for ODE models of bone remodeling uses mass action kinetics. This fundamental concept is commonly used to model chemical and biological reactions, such as those seen in enzyme kinetics, ecological systems, and disease dynamics . In our classification, mass action kinetics includes Michaelis-Menten and Hill equations for enzyme and ligand binding kinetics. The mass action kinetics model structure for bone remodeling leverages the foundational model by and refinement by (Figure ). The mass action kinetics approach is a major alternative to the power law approach as it better identifies how specific signaling factors affect the balance between osteoblast and osteoclast populations.