Objective

The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD).

Materials/patients and methods

Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analyzed quantitatively and qualitatively.

Results

Overall muscle activity in the children with DMD deviated significantly from that of the control group. Percentage activation amplitude of RF, HS and TA was greater throughout the gait cycle in the children with DMD while the timing of GAS activity differed from the control children. Significantly, greater muscle coactivation was found in the children with DMD. There were no significant differences between sides.

Discussion/Conclusion

Since motor commands are normal in DMD, the hyper-activity and co-contractions are likely to compensate for gait instability and muscle weakness, however, they may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapy or the use of a light ankle foot orthosis may improve stability and thus the pattern of muscle activity.