Repeatability of net mechanical efficiency during stair climbing in children with cerebral palsy

Purpose: To determine the smallest significant change in mechanical efficiency (MEnet) measured by a stair-climbing test. Methods: Duplicate stair-climbing tests (T1 and T2), with more than a 30-minute rest between, were performed by 51 children with diplegic cerebral palsy (CP) at levels II and III of Gross Motor Function Classification System (GMFCS) and 9 children with typical development, aged 5.5 to 13.0 years. Results: The T2 versus T1 slope values of MEnet for CP and typical development did not significantly differ from 1.00. MEnet was significantly higher for GMFCS level II (7.0%) than level III (1.2%). The mean percentage of difference was 7.8% (T2 > T1) for the children with CP, with a 95% confidence interval of -39% to +54%. The 95% confidence interval for MEnet scores computed from the standard error of the mean (SEM) of the percentage of differences was 4.0 to 4.5 for CP. Conclusions: An increase of >13.4% in MEnet score (eg, mean increase from 4.0% to 4.5%) can indicate improved motor status resulting from interventions.