Article

This study investigates the in vivo function of the medial gastrocnemius and
soleus muscle-tendon units (MTU), fascicles, and tendons during walking in
children with cerebral palsy (CP) and an equinus gait pattern. METHOD: Fourteen
children with CP (9 males, 5 females; mean age 10y 6mo, standard deviation [SD]
2y 11mo; GMFCS level I=8, II=6), and 10 typically developing (6 males, 4 females;
mean age 10y, SD 2y 1mo) undertook full body 3D gait analysis and simultaneous
B-mode ultrasound images of the medial gastrocnemius and soleus fascicles during
level walking. Fascicle lengths were analysed using a semi-automated tracking
algorithm and MTUs using OpenSim. Statistical parametric mapping (two-sample
t-test) was used to compare differences between groups (p<0.05). RESULTS: In the
CP group medial gastrocnemius fascicles lengthened during mid-stance gait and
remained longer into late-stance compared to the typically developing group
(p<0.001). CP medial gastrocnemius fascicles shortened less during stance (1.16mm
[SD 1.47mm]) compared to the typically developing group (4.48mm [SD 1.94mm],
p<0.001). In the CP group the medial gastrocnemius and soleus MTU and tendon were
longer during early- and mid-stance (p<0.001). Ankle power during push-off
(p=0.015) and positive work (p<0.002) and net work (p<0.001) were significantly
lower in the CP group. INTERPRETATION: Eccentric action of the CP medial
gastrocnemius muscle fascicles during mid-stance walking is consistent with
reduced volume and neuromuscular control of impaired muscle. Reduced ankle
push-off power and positive work in the children with CP may be attributed to
reduced active medial gastrocnemius fascicle shortening. These findings suggest a
reliance on passive force generation for forward propulsion during equinus gait.
CI - (c) 2017 Mac Keith Press.

Langue : ANGLAIS