Energy cost during walking in association with age and body height in children and young adults with cerebral palsy

•Similar declines in gross, net and NN EC can be expected with growth for children and adolescents with CP compared to TD peers.•Net EC and NN EC showed a more gradual decline during growth than gross EC.•The net EC and NN EC reveal similar declines over time. This cross-sectional study into children and young adults with cerebral palsy (CP) aimed to assess the association of gross energy cost (EC), net EC and net nondimensional (NN) EC during walking with age and body height, compared to typically developing (TD) peers. Data was collected in 128 participants with CP (mean age 11y9mo; GMFCS I,n=48; II,n=56; III, n=24) and in 63 TD peers (mean age 12y5mo). Energy cost was assessed by measuring the oxygen consumption during over-ground walking at comfortable speed. Outcome measures derived from the assessment included the gross and net EC, and NN EC. Differences between the groups in the association between gross, net and NN EC with age and body height, were investigated with regression analyses and interaction effects (p