Joint Hypermobility Syndrome (JHS) is characterised by chronic pain and generalised joint hypermobility (GJH). This thesis set out to improve understanding of the mutisystemic presentation and management of JHS in childhood. Study 1 determined that child- and parent-reported quality of life of children with JHS were strongly correlated. Symptoms of stress incontinence, pain, fatigue and the child’s age accounted for 75% of the variance in child-reported quality of life. Study 2 comprised a systematic review with meta-analysis, revealing that sporting participants with GJH had a 5 times greater risk of knee joint injury playing contact sports, with no increased risk of ankle joint injury. Study 3 showed that proprioceptive acuity in children with JHS was similar in both knee hyperextension and early flexion. Study 4, a randomised controlled trial, demonstrated that physiotherapy exercises performed into knee joint hyperextension improved psychosocial health, while the same exercises performed to neutral knee extension achieved significantly greater improvement in the physical health of the child with JHS, with pain equally reduced between groups. Finally, the factor analysis in study 5 established five distinct phenotypical sub-types of JHS in children, based on their multisystemic symptoms. Overall, the findings support normalising movement in hypermobile range.