RESUMO
STUDY DESIGN: Cross-sectional study. OBJECTIVES: To assess the interrater reliability and validity of the test-table-test (TTT) with which paralympic sports participants involved in Nordic sit-ski sports may be classified. SETTING: Movement laboratory in a rehabilitation centre, The Netherlands. METHODS: Thirty-three persons with a spinal cord injury caudally to Th2, a leg amputation, poliomyelitis affecting the trunk and/or lower extremities, or cerebral palsy participated. Subjects were classified according to a classification system for Nordic skiing (that is, five subclasses between LW10 and LW12) by two raters, involving, among others, a combination of four balance tests called TTT. The validity of the TTT was investigated using a gold standard, involving balance perturbation tests on a force plate and centre of pressure (CoP) displacement measurements. RESULTS: As for the interrater reliability, Spearman's rank-correlation coefficient was 0.95 (P<0.001). As regards the validity of the TTT, correlation coefficients ranging from 0.61 to 0.74 (P<0.001) were found when comparing the data with the gold standard. CONCLUSION: Interrater reliability was high in both scoring and classification. With regard to TTT validity, strong positive correlations between CoP displacement and TTT classification were found. Overall, the results of this study show that the TTT is a reliable and valid test. However, the relations between TTT and CoP displacement in the LW10 and LW10.5 subclasses found in this study are somewhat vague, which could be due to the small number of participants in these subclasses. For the LW10 and LW10.5 subclasses further refinement of the four tests within the TTT is warranted.
