Joint Hypermobility and Joint Range of Motion in Young Dancers.

Abstract

Joint range of motion (ROM) refers to the extent of movement of the joint, recorded using standard goniometers. Joint hypermobility (JHM) is a condition in which most of the synovial joints move beyond the "normal" limits. Joint hypermobility is recognized as a feature of heritable disorders of the connective tissue and can be identified mostly by the Beighton scale. Data on the possible relationship between JHM and joint ROM are lacking in the literature. The main objective of the present study was to evaluate the relationship between JHM and joint ROM in the different lower-extremity joints in young dancers. Joint hypermobility and ROM were assessed among 240 female dancers, aged 8 to 16 years, and 226 nondancers of similar age. The prevalence of JHM is significantly higher among dancers compared with the control subjects (P < 0.001). Joints' ROM is higher among dancers with JHM compared with dancers without JHM (P < 0.05). This phenomenon, however, is age dependent; as in young dancers (aged 8-10 years), this pertains only to the ankle dorsiflexion ROM. In adolescent dancers (aged 11-13 years), this relationship has been observed in most joints: ankle/foot en pointe, ankle dorsiflexion, hip external rotation, hip abduction, and hip extension. In mature dancers (aged 14-16 years), dancers with JHM had greater ROM in ankle/foot en pointe, hip abduction, and knee flexion (P < 0.05). (1) Joint ROM and JHM are associated one with the other; (2) the relationship between joint ROM and JHM is age dependent; and (3) JHM is common among young nonprofessional dancers compared with control subjects. The main clinical implications of the current study are to try and reduce the risk of injuries among JHM dancers by developing proprioceptive trainings to improve the correct alignment of the hyperextended joints, to increase their muscle strength for better stabilization of the hypermobile joints, and to provide them additional balancing and stabilizing exercises for their supporting muscles.