Reaching beyond limits: Motor development and adaptive strategies in children with congenital upper limb differences

Motor development can be defined as the process of learning to control the movements of the body (Haywood & Getchell, 2019). Emerging motor skills foster independence and support broader cognitive and social growth by creating new opportunities for exploration, interaction, and learning. Contemporary theories conceptualise motor development as flexible and experience-driven, shaped by dynamic interactions between the body, cognition, and environment. Children with congenital upper limb differences, born with a partial or missing hand, offer a powerful test case for exploring the limits of this theory. Specifically, how motor skills emerge when typical anatomical structures are altered or absent. This thesis employs a multi-method approach across four empirical studies to investigate (1) the emergence of early gross motor milestones, (2) the development of compensatory motor strategies in childhood, (3) the roles of imitation and self-guided exploration in innovative problem-solving, and (4) the flexibility of internal motor models in adapting to new sensorimotor mappings. We test the overarching hypothesis that motor development is shaped by the dynamic interplay between sensorimotor experience, cognition, and environmental interaction. By examining how children with anatomical constraints develop flexible and creative motor behaviours, this thesis reveals how alternative developmental pathways can support adaptation and demonstrate the fundamental flexibility of the developing motor system. Our findings show that children with upper limb differences follow distinct yet functional motor trajectories, characterised by adaptive use of alternative effectors and exploratory problem-solving. These adaptations go beyond compensation, to reflect creative and embodied learning shaped by individual anatomy and experience. Together, these findings support a dynamic, experience-driven model of motor development and offer novel insights into how structural variation influences both functional outcomes and cognitive processes. Beyond theoretical advances, this work offers practical implications for clinical assessment and parental reassurance, highlighting alternative developmental pathways as valid, adaptive routes to functional success.