关键词: Duchenne型肌营养不良, 肌力, 下肢, 儿童

Abstract: Objective To compare the difference on the lower-limb muscle strength between 6 to 11-year-old children with Duchenne muscular dystrophy (DMD) and typical children, so as to provide more evidence for muscle strength training of DMD children.Methods Totally 20 DMD children and 20 typical children were enrolled from April 2015 to April 2017, including 19 males and 1 female in the DMD group and 18 males and 2 females in the typical group, both with an average age of (9.0±1.7) years old. Hand-held dynamometry (HHD) was used to measure the muscle strength of hip, knee, ankle and other parts of lower extremity. The differences on muscle strength between DMD and typical children were compared. Results The lower extremity muscle strength of DMD group was significantly weaker than that of typical group except flexor plantaris(all P<0.05), and there was no significant difference on muscle strength between children over 6-year-old and 9 to 11-year-old children in DMD group. Also, the difference on the bilateral hip abduction and toe flexion was not significant between children over 6-year-old in DMD group and typical group (P>0.05), and the toe flexion muscle strength in DMD group was even higher than that in typical group. Hip flexion, hip extension, hip abduction, knee flexion, knee extension and ankle dorsiflexion muscle strength except toe flexion in 9 to 11-year-old children in DMD group had been significantly weaker than typical children with the same age(all P<0.05). Conclusions The lower limb muscles of DMD children are significantly weaker than those of typical children except flexor plantaris. All muscle groups should be taken into consideration when carrying out lower limb strength training for DMD children. In addition, extra attention should be paid to extensor muscles of hip and knee in older children with DMD.

Key words: Duchenne muscular dystrophy, muscle strength, lower extremity, children