Development of a Comprehensive Tool for Assessing Cardiorespiratory, Muscular Strength and Endurance Function in People with Intellectual Disabilities

Accurate assessment of cardiorespiratory function, muscular strength and endurance seems necessary for awareness and for providing exercise interventions and prevention of subsequent diseases. Therefore, the aim of the current research was to develop a comprehensive tool for assessing cardiorespiratory, muscular strength and endurance function in people with intellectual disabilities.

The current research is fundamental and has practical implications in terms of its purpose. In this study, the psychometrics of 51 specific tests of intellectual disability people were used to develop a tool for measuring cardiorespiratory function, muscular strength and endurance. The face validity of the instrument was examined through a 51-test questionnaire by 15 experts and 15 intellectually disabled educators, the content validity by a 51-test questionnaire by 15 experts, and the construct validity through a 19-test questionnaire by 243 intellectually disabled educators. The reliability of the tool was checked through internal, intra-rater and inter-rater consistency. Internal consistency was estimated with Cronbach's alpha. The intra-rater and inter-rater reliability were also checked through the implementation of the tests by 18 people with intellectual disability in three times and with three raters through the internal correlation index (ICC), confidence interval (CI) and standard error of measurement (SEM). Data analysis was done through exploratory and confirmatory factor analysis with AMOS26 and SPSS22 software.

Based on the results of estimating the content validity ratio (CVR), 19 out of 51 tests had a content validity ratio higher than 0.49 and the rest of the tests were excluded. In terms of construct validity, 10 out of 19 tests were removed and the final 9 tests were approved for evaluating cardiorespiratory function, muscular strength and endurance. Exploratory factor analysis extracted three latent factors that explained 46.21% of the total variance. Confirmatory factor analysis confirmed the final construct model. From the results of factor analysis, KMO=0.829, BT=4706.93 and p<0.0001.

The current study provided a special set of tests for people with intellectual disability in the fields of cardiorespiratory assessment (one test), strength (four tests) and muscular endurance (four tests). after psychometry, 51 specific tests were presented in this field. By using this set of tests, it is possible to make an accurate assessment of the physical fitness related to the health of people with intellectual disability.