Adding meaning to physical fitness test results in individuals with intellectual disabilities.

Evaluating physical fitness in individuals with intellectual disabilities (ID) is challenging, and a multitude of different versions of tests exist. However, psychometric properties of these tests are mostly unknown, and both researchers as clinical practitioners struggle with selecting appropriate tests for individuals with ID. We aim to present a selection of field tests with satisfactory feasibility, reliability, and validity, and of which reference data are available. Tests were selected based on (1) literature review on psychometric properties, (2) expert meetings with physiotherapists and movement experts, (3) studies on population specific psychometric properties, and (3) availability of reference data. Tests were selected if they had demonstrated sufficient feasibility, reliability, validity, and possibilities for interpretation of results. We present a basic set of physical fitness tests, the ID-fitscan, to be used in (older) adults with mild to moderate ID and some walking ability. The ID-fitscan includes tests for body composition (BMI, waist circumference), muscular strength (grip strength), muscular endurance (30 second and five times chair stand), and balance (static balance stances, comfortable gait speed). The ID-fitscan can be used by researchers, physiotherapists, and other clinical practitioners to evaluate physical fitness in adults with ID. Recommendations for future research include expansion of research into psychometric properties of more fitness tests and combining physical fitness data on this population in larger datasets. Implications for rehabilitationIndividuals with intellectual disabilities have low physical fitness levels, and a high risk for unnecessary functional decline and unhealthy aging.Physical fitness testing could help improve, adapt and evaluate exercise interventions, but is challenging in this population.This paper proposes a selection of tests (ID-fitscan) with sufficient feasibility, reliability, and validity in this population, and provides reference values to aid interpretation of physical fitness test outcomes in individuals with intellectual disabilities.The ID-fitscan can be used by researchers, physiotherapists, and other clinical practitioners to evaluate physical fitness, and thereby allowing for a better interpretation of results by using the same tests, and an increasing knowledge of the physical fitness levels of this population.