Experience with jumping mechanography in children with cerebral palsy

OBJECTIVES: Jumping mechanography provides robust motor function indicators among healthy children. The aim of the study was to assess the reproducibility and validity of jumping mechanography conducted as single two-legged jump (S2LJ) in children with cerebral palsy (CP). METHODS: 215 S2LJ investigations from a sample of 75 children with CP were eligible for evaluation. For the estimation of the reproducibility, only the baseline set of data per patient were used. Gross motor function was evaluated by the Gross Motor Function Measure (GMFM-66). In 135 S2LJ investigations, GMFM-66 was assessed within a week in the same child. This data was used for validity assessment. RESULTS: Coefficients of variation for the main outcome parameters ranged between 6.15-9.71%, except for jump height (CV%=27.3%). The intraclass correlation coefficients for peak velocity (V(max)) and peak power relative to body weight (P(max)/mass) was 0.927 and 0.931. V(max) and P(max)/mass were also the test parameters with the strongest correlation to the GMFM-66 score (>0.7). CONCLUSIONS: S2LJ assessed in the present study provided reproducible outcome measures particularly for V(max) and P(max)/mass in children with CP. Further, V(max) and P(max)/mass showed the strongest correlation with the GMFM-66 score and seem to be the most relevant evaluation criteria.