Bart Bolsterlee

Abstract Longitudinal data on skeletal muscle growth in children are scarce, so little is known about developmental trajectories of skeletal muscle size, the relative timing of muscle and skeletal growth and how cerebral palsy (CP) affects growth. We conducted a mixed longitudinal study of 252 children aged 5–18 years, including 66 children with CP.

1 INTRODUCTION The force-generating capacity of a muscle is largely determined by its architecture (muscle volume, fascicle length, pennation angle, and physiological cross-sectional area (PCSA)) and moment arm (Gans, 1982; Lieber & Fridén, 2000). The muscle fibre length (proportional to maximum muscle excursion) and PCSA (proportional to maximum muscle force) are the primary determinants of the functional capacity of a muscle (Lieber & Fridén, 2000).

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