\chapter{Introduction}

Controlling and learning to control movements of a many degree of freedom system such as the human body is a non-trivial task. This problem is famously known as Bernstein's problem \cite{Bernstein1967}.

Complex movements of humans (and other animals) are thought to develop based on a simple, rudimentary set of building blocks -- commonly called motor primitives -- during ontogenetic development \cite{Flash2005, Hart2010}. Contrary to the hitherto belief that these innate simple reflexes get completely replaced by more complex ones with age, a recent publication by Dominici et al. \cite{Dominici2011} shows that certain basic patterns of muscle activation are instead retained and are being built upon during development in order to achieve a variety of walking movement behaviours.

This project thesis attempts to investigate the role such locomotor primitives play in the development of human biped walking by building a muscoloskeletal simulation model in the OpenSim software \cite{Delp2007} and then applying the basic activation patterns at different stages of human development (neonate, toddlers, preschooler and adults) identified by Dominici et al. \cite{Dominici2011} to it.

\TODO{Describe steps taken and goals of the individual steps.}