Feasibility and reliability of the Assessing Levels of Physical Activity health-related fitness test battery in adults with intellectual disabilities

Abstract

Background: People with intellectual disabilities (IDs) seem to have a lower physical fitness (PF) than their peers without disabilities, which coincides with reduced autonomy, life expectancy and quality of life. To assess PF in these individuals, it is necessary to use appropriate tools that permit the assessment of their physical capacities taking into account their specific characteristics. The aim of this work is to study the feasibility and reliability of the Assessing Levels of Physical Activity (ALPHA)-Fit test battery for adults in a group of men and women with mild to moderate ID.

Methods: Forty-one adults with ID of both sexes, ranging in age from 20 to 60 years old, participated in the study. To identify the feasibility and reliability of the ALPHA-Fit test battery for adults, two complete assessments were done for each one of the tests included in the battery. The assessments were performed for a period of no more than 2 weeks (test-retest). An intraclass correlation coefficient was used to determinate test-retest reliability, and a mixed analysis of variance factorial was used for each of the dependent variables. Bland-Altman plots were also used to assess consistency between the two measurements. Feasibility was calculated as the percentage of people who were able to perform the tests correctly (not feasible <50%, fairly feasible 50%-75% and feasible >75%). In order to determine other psychometric properties, minimal detectable change and standard error of measurement (SEM) were also calculated.

Results: Of the 10 tests in the ALPHA-Fit test battery, eight were shown to be feasible. High reliability was obtained (>0.90) for the variables related to body composition. In the hand-grip test, reliability was high in the men's group but low in the women's group. Good reliability results were also found (0.80-0.89) in the dynamic sit-up test for women, but not for men. Fair reliability (0.70-0.79) was found in jump-and-reach and neck-shoulder mobility tests. The variables in the 2-km walk and agility tests indicated poor reliability. All tests showed SEM values related to high variability. However, Bland-Altman plots showed results related to lack of consistency.

Conclusions: The feasibility and reliability calculations, as well as the SEM values, confirm that not all the tests of the ALPHA-Fit Test Battery for Adults are suitable for the assessment of PF in adults with ID, probably because of the complexity of the motor fitness tests. The authors emphasise the necessity of making adaptations to the protocols used or of using other tests more appropriate to the characteristics of people with mild to moderate ID.

Keywords: adults; disabilities; feasibility; physical-fitness; reliability.