Mechanical energetics of different sagittal gait patterns in children with bilateral spastic cerebral palsy.

Abstract

Children with cerebral palsy (CP) often exhibit inefficient gait; however, the relationship between their distinct sagittal gait patterns and this inefficiency remains unclear. This study examined the mechanical energy characteristics of gait in a large cohort of children with bilateral spastic CP, classified into four sagittal gait patterns: Crouch, Apparent Equinus, Jump, and True Equinus. Three-dimensional gait data from 148 children with bilateral spastic CP and 19 typically developing (TD) controls were collected using motion capture. An extended inverted pendulum framework was applied to assess deviations of dimensionless kinetic, T, and potential, V, energy waveforms from optimal energy exchange during single support, in order to quantify the Amplitude and Phase Problems. Results indicated that the amplitude-related inefficiency was most pronounced in the Crouch pattern, characterized by elevated V amplitude without proportional increases in T, and least in True Equinus, which showed elevated amplitudes in both V and T; nevertheless, both patterns exhibited significantly higher amplitude ratios than TD (p < 0.05). All CP subgroups had positive time lags, compared with a slightly negative lag in TD, and reduced continuous relative phase values (p < 0.05), indicating impaired phase coordination. These inefficiencies resulted in significantly greater total energy fluctuations, cost of transport, and energy recovery index across all CP subgroups (p < 0.05), with sustained energy injection in early stance and dissipation in late stance, particularly in Crouch and Jump patterns. These findings reveal gait-pattern-specific biomechanical inefficiencies in CP, offering a quantitative foundation for targeted interventions to improve gait efficiency.