Ehlers-Danlos syndrome (EDS) is a group of genetic disorders affecting connective tissue. Symptoms include joint and ligament laxity. The objectives of this study were to compare muscle activation, joint angles, and spatiotemporal parameters during gait, and to compare isometric strength between participants with EDS (hypermobility and classical subtypes) and healthy adults.
Participants with EDS (n = 14) and healthy adults (n = 14) were recruited for this cross-sectional study. Lower extremity muscle activation, sagittal joint angles, and spatiotemporal parameters during gait were measured using surface electromyography (EMG), motion capture, and force plates. Isometric strength of the lower extremity joints was measured with an isokinetic dynamometer. Important characteristics (principal components [PCs]) were determined from EMG and angle waveforms using PC analysis; relationships between PC scores and groups were examined using multilevel linear models after accounting for gait speed. Spatiotemporal parameters and strength were compared using independent t-tests and effect sizes (Cohen's d coefficient).
The EDS group was associated with delayed vastus lateralis (b = 16.69) and medialis activation (b = 11.33), higher rectus femoris (b = 28.34) and tensor fascia latae activation (b = -11.06), prolonged gluteus medius activation (b = -32.78), and lower medial gastrocnemius activation (b = -27.18). Joint angles were similar between the EDS and healthy groups. The EDS group had slower gait speeds, shorter stride lengths, and a greater percentage of time in stance (d = -1.05 to 0.96). The EDS group had weaker hip and ankle muscles (d = -0.83 to -0.97).
Alterations in muscle activation and spatiotemporal parameters during gait in patients with EDS may be a result of impaired proprioception and balance and muscle weakness. Interventions should target these deficits.