Effect of conventional gait model II variants on gait kinematics and kinetics

The Conventional Gait Model II (CGM2) aims to address the limitations of the Conventional Gait Model (CGM) in a standardised way. Evidence supporting the use of CGM2 has come from independent studies within adult populations, which has hindered the uptake of the model by paediatric centres.

What is the effect of CGM2 model variants on gait kinematics and kinetics in a cohort of typically developing children?

Secondary analysis of three-dimensional gait analysis data of thirty-two typically developing children. Gait kinematics and kinetics were reprocessed for each of the CGM2 model variants. These variants include the introduction of new hip joint centre equations, inverse kinematics, and marker clusters. Differences between kinematics and kinetics were compared using statistical parametric mapping 1D, and root mean squared difference (RMSD).

Differences were seen in kinematics and kinetics across all models, with the largest changes seen in the transverse plane for the hip, knee and ankle, with an average RMSD relative to CGM1.0 of 6.1°, 22.7°, and 9.9° respectively. All other gait variables had an average RMSD of less than 5° for kinematics, 0.1 Nm for moments, and 0.19 W for powers. Changes to the Gait Profile Score were less than 0.14° on average.

The CGM2 model has addressed several known limitations by improving the hip joint centre locations, reducing the number of required anthropometric measures, and introducing inverse kinematics and cluster-based segment tracking. Our results highlight the importance of consistency in model variants and processing methods when comparing data.