Does joint hypermobility exacerbate altered landing and jumping strategies in adolescents with fibromyalgia syndrome compared to controls?

Background: Joint hypermobility is common in children and persists in various genetic and connective tissue disorders, including conditions characterized by chronic musculoskeletal pain (i.e. Juvenile Fibromyalgia Syndrome), which involves movement dysfunction. It is unclear if joint hypermobility contributes to this dysfunction. This study investigated whether generalized joint hypermobility is associated with altered landing/jumping biomechanics in adolescents with juvenile fibromyalgia syndrome compared to controls.

Methods: Adolescents with juvenile fibromyalgia syndrome and hypermobility (n = 17), juvenile fibromyalgia syndrome without hypermobility (n = 17), and non-hypermobile controls (n = 17) performed a landing/jumping task while 3D-motion capture and ground reaction force data were collected. Timewise data were compared using statistical parametric mapping.

Findings: Both groups with juvenile fibromyalgia syndrome exhibited altered lower extremity biomechanics compared to controls, including increased sagittal hip and ankle kinematics (P < 0.0001), ∼25 % reduced sagittal knee and ankle kinetics (P ≤ 0.038) and ∼ 2.5× greater knee internal rotation (P < 0.0001) during landing/jumping, as well as ∼75 % and ∼ 20 % reduced ground reaction force during initial landing and jumping (P < 0.0001), respectively. Both groups with juvenile fibromyalgia syndrome, demonstrated 17-26 % reduced landing depth (P < 0.0001;d ≤ 1.79) and 26 % reduced jump height (P ≤ 0.01;d ≤ 0.86), indicating inefficient momentum absorption.

Interpretation: Altered biomechanics observed in both groups with juvenile fibromyalgia syndrome may reflect an attempt to avoid pain. While hypermobility did not significantly differentiate the groups with juvenile fibromyalgia syndrome overall, it was associated with more inefficiencies. This study highlights the need for hypermobility-specific movement assessments to understand movement-associated pain, strength, and kinesthetics to improve early identification and treatment of youth with hypermobility at risk for chronic pain and functional limitations.