Date of Award
Doctor of Philosophy (PhD)
Exercise and Rehabilitation Science
Generalized Joint Hypermobility (GJH), in lay terms being “double-jointed”, affects 5 to 43 percent of the general population. In severe forms, GJH impacts systems across the body, with cardiovascular, ocular, and musculoskeletal effects that can be quite debilitating. Most of the literature examining GJH is in this severely impacted group of people. However less severe forms of GJH are present in the athlete population in the same proportions, and athletes with GJH are more likely to be injured while participating in activities. They also experience greater time-loss injuries while participating in athletic activities. The movement biomechanics of those with severe forms of GJH have been studied, but studies investigating athletes and athletic-like movements are sparce with varying results. Therefore, the purpose of this dissertation was to investigate the movement characteristics of those with GJH and identify patterns of movement that may put this group of athletes at risk for injury. Seven collegiate Division 1 women’s Lacrosse athletes from the same team were identified with GJH and evaluated during athletic-like task compared to control participants from the same collegiate team. In the first study, participants performed a maximal countermovement jump while force data were collected to evaluate performance variables between groups. The second study involved both groups of participants performing a bilateral drop jump and a more demanding single-leg land and cut task while kinematic and kinetic data were collected. Finally, the third study used the land and cut task data to create a musculoskeletal model to evaluate ACL strain during the task in each group. The primary findings of this dissertation were that female division 1 Lacrosse athletes with GJH 1) demonstrated equal performance characteristics with their non-hypermobile teammates, 2) demonstrated similar biomechanics during athletic-like tasks until the task became more challenging on their dominant leg, where they adopted a pattern of less hip and knee flexion and a greater plantarflexor moment, and 3) the pattern of motion adopted during the strenuous land and cut task was not largely an attempt to minimize ACL strain.