Fu-Chen Chen, Chien-Yu Pan, Chia-Hua Chu, Chia-Liang Tsai, Yu-Ting Tseng
Physical Education, National Kaohsiung Normal University, , 802 Kaohsiung, Taiwan ROC. E-mail: fcchen@mail.nknu.edu.tw
DOI: 10.2340/16501977-2720

Objective: To determine the joint position sense of the lower extremities and its relationship with motor function in children with developmental coordination disorder (DCD) and typically developing (TD) children.
Methods: A total of 56 participants were recruited; 28 children with DCD (age 10. 86±1. 07 years; 13 females, 15 males) and 28 TD children (age 10. 96±1. 18 years; 12 females, 16 males). Knee and ankle joint position sense were assessed using a Biodex isokinetic dynamometer. Joint position acuity was measured by position error (PE) and position error variability (PEV). Motor function was examined using the 2nd edition of Movement Assessment Battery for children (MABC-2) and quantified via sub-scores from 3 MABC-2 domains.
Results: Both PE and PEV at knee and ankle joints were significantly greater in children with DCD compared with TD children. In addition, both PE and PEV were significantly greater at the ankle joints than the knee joints in children with DCD. For children with DCD only, joint position acuity in the lower extremities significantly and negatively correlated with MABC-2 balance sub-score.
Conclusion: This study verifies that lower limb proprioception is impaired in children with DCD. Also, children with DCD displayed greater proprioceptive deficits at the ankle compared with the knee joint. Children with DCD who had poorer joint position acuity, i. e. greater PE and PEV, in the lower extremities tended to perform less well in balance function.

This is the first study to investigate joint position sense (the awareness of the postion of a joint in space) of the lower limbs and its relationship with motor func-tion in children with developmental coordination disorder and typically developing children, while addressing limitations in previous studies. The results show that children with developmental coordination disorder have: () impaired joint position sense at both knee and ankle joints; () poorer joint position sense at ankle than knee joints; and () decreased balance function with increasing impairment in joint position sense in their lower extremities. These findings suggest that lower limb proprioception is impaired as well as joint position acuity of lower extremities plays a role in balance function in children with developmental coordination disorder.