Gastrocnemius Medialis Muscle Geometry and Extensibility in Typically Developing Children and Children With Spastic Paresis Aged 6–13 Years

Abstract

Gait of children with spastic paresis (SP) is frequently characterized by a reduced ankle range of motion, presumably due to reduced extensibility of the triceps surae (TS) muscle. Little is known about how morphological muscle characteristics in SP children are affected. The aim of this study was to compare gastrocnemius medialis (GM) muscle geometry and extensibility in children with SP with those of typically developing (TD) children and assess how GM morphology is related to its extensibility. Thirteen children with SP, of which 10 with a diagnosis of spastic cerebral palsy and three with SP of unknown etiology (mean age 9.7 ± 2.1 years; GMFCS: I–III), and 14 TD children (mean age 9.3 ± 1.7 years) took part in this study. GM geometry was assessed using 3D ultrasound imaging at 0 and 4 Nm externally imposed dorsal flexion ankle moments. GM extensibility was defined as its absolute length change between the externally applied 0 and 4 Nm moments. Anthropometric variables and GM extensibility did not differ between the SP and TD groups. While in both groups, GM muscle volume correlated with body mass, the slope of the regression line in TD was substantially higher than that in SP (TD = 3.3 ml/kg; SP = 1.3 ml/kg, p < 0.01). In TD, GM fascicle length increased with age, lower leg length and body mass, whereas in SP children, fascicle length did not correlate with any of these variables. However, the increase in GM physiological cross-sectional area as a function of body mass did not differ between SP and TD children. Increases in lengths of tendinous structures in children with SP exceeded those observed in TD children (TD = 0.85 cm/cm; SP = 1.16 cm/cm, p < 0.01) and even exceeded lower-leg length increases. In addition, only for children with SP, body mass (r = −0.61), height (r = −0.66), muscle volume (r = − 0.66), physiological cross-sectional area (r = − 0.59), and tendon length (r = −0.68) showed a negative association with GM extensibility. Such negative associations were not found for TD children. In conclusion, physiological cross-sectional area and length of the tendinous structures are positively associated with age and negatively associated with extensibility in children with SP.

Muscle morphology and architecture of the medial gastrocnemius between typically developing children with different ancestral backgrounds

“…The contradicting results could have been caused by difference in methods. The current study and Weide et al . (2020) measured the extensibility statically and the other studies defined extensibility during dynamic stretching.…”

“…The contradicting results could have been caused by difference in methods. The current study and Weide et al (2020) measured the extensibility statically and the other studies defined extensibility during dynamic stretching. However, the current study data created a unique norm-database for the extensibility of the muscle belly, muscle tendon and fascicle length that can be used as a reference when investigating the extensibility parameters of SCP children.…”

“…We did not expect to find great differences in extensibility of the tendon between typically developing children with different ancestry. Weide et al . (2020) found no differences in extensibility of the MTU from baseline to 4Nm between TD and SCP children, which was in contrast to other studies that found less muscle belly and more muscle tendon extensibility in SCP compared to TD children (Theis, Mohagheghi and Korff, 2016; Kalkman et al ., 2018; Weide et al ., 2020).…”

Glycine receptor subunit-β-deficiency in a mouse model of spasticity results in attenuated physical performance, growth, and muscle strength

“…Refs. 89 and 93 ). Within the current spastic mouse model, morphological adaptations were homogenous, and muscle morphology was independent of the severity of motor dysfunction (i.e., neurological score and righting reflex) and intervention history.…”

“…Our results are in line with those of ultrasound studies performed on muscles from children with spasticity, as these children in general showed a reduced physiological cross-sectional area compared with typical developing children ( 27 , 94 , 95 ). Moreover, ultrasound studies have shown that at young age, the calf muscle morphology of children with spasticity is only slightly different from that of typical developing children ( 93 ). However from the age of 6 yr there is a slower increase of physiological cross-sectional area ( 87 ).…”