There are many theoretical models that attempt to accurately and consistently link kinematic and kinetic information to musculoskeletal pain and deformity of the foot. Biomechanical theory of the foot lacks a consensual model: clinicians are enticed to draw from numerous paradigms, each having different levels of supportive evidence and contrasting methods of evaluation, in order to engage in clinical deduction and treatment planning. Contriving to find a link between form and function lies at the heart of most of these competing theories and the physical nature of the discipline has prompted an engineering approach. Physics is of great importance in biology and helps us to model the forces that the foot has to deal with in order for it to work effectively. However, the tissues of the body have complex processes that are in place to protect them and they are variable between individuals. Research is uncovering why these differences exist and how these processes are governed. The emerging explanations for adaptability of foot structure and musculoskeletal homeostasis offer new insights into how clinical variation in outcomes and treatment effects might arise. These biological processes underlie how variation in the performance and use of common traits, even within apparently similar subgroups, make anatomical distinction less meaningful and are likely to undermine the justification of a "foot type." Furthermore, mechanobiology introduces a probabilistic element to morphology based on genetic and epigenetic factors.