A Comprehensive Analysis of Assessing Cardiorespiratory Fitness in the Intellectually-Disabled People: A Systematic Review Study

Intellectual disability is associated with many comorbidities, such as epilepsy, cerebral palsy (CP), and anxiety disorders, and can affect the health status of the individual. The physical fitness (PF) of people with intellectual disability is lower than typical developing peers, making them particularly vulnerable to health problems in adulthood. People with intellectual disabilities show lower aerobic capacity in childhood (8–10 years), adolescence (11–14 years), and youth (15–18 years) than healthy counterparts, and this difference gradually increases with age increases. With this in mind, PF assessment is a simple, safe, and low–cost tool that allows several health indicators to be evaluated. Based on the PF level of children, educational and public health strategies and policies can be developed. Accurate evaluation of cardiorespiratory fitness seems necessary to prepare and present training interventions to prevent subsequent diseases. Therefore, this study aims to examine and summarize a set of tests and specific field tests related to cardiorespiratory fitness in people with intellectual disabilities.

The present study was a systematic review. The relevant data were selected, collected, and analyzed from studies on physical fitness and the health of people with mental disabilities. Databases of PubMed, Web of Science, Medline, Google Scholar, and Scopus, as well as Persian databases, Jahad Daneshgahi Scientific Information Center database, MedLib (Comprehensive Database of Medical Articles), IranMedex, Iran Research Institute of Information Science and Technology (IRANDOC) and the country's publications database (MAGIRAN), were searched until 2021. The articles searched should include a set of PF tests. The search was performed in each database based on predefined keywords. The data extraction process and literature results were evaluated according to PRISMA (preferential reporting items for systematic and meta–analysis) guidelines. After collecting studies from databases, duplicate items were removed. Two authors screened the remaining articles, considering their 'Titles' and 'Abstracts' to identify studies that met the inclusion criteria. During the study selection process, one researcher blindly analyzed the 'Titles' and 'Abstracts.' As the 'Titles' and 'Abstracts' did not contain enough information to make an informed decision, a researcher reviewed the full text. Related articles were retrieved for the whole study. Then, two authors reviewed the full text of the potential studies, and consensus made decisions to include or exclude the studies. Disputes were resolved by consensus; if necessary, the third arbitrator, as a judge, assisted in the review and selection.

A total of 1086 articles were identified, and with the removal of duplicates, the number reached 448 articles. The analysis of the articles 'Titles' and 'Abstracts' showed that 332 articles did not meet the required criteria, and led to their deletion. The full text of the remaining 116 articles was studied, and 98 articles were deleted. Finally, 18 articles met the inclusion criteria for the final study. Of these 18 articles, ten studies were related to a set of health–related fitness tests in people with intellectual disability that examined cardiorespiratory fitness with functional tests, and 8 studies were articles that examined cardiorespiratory fitness in people with intellectual disability with functional tests. In addition, the tests of these articles did not exist in the set of physical fitness tests of people with intellectual disability and were not repetitive. About 53 sets of physical fitness tests were found, of which 10 were related to people with disabilities (intellectual disability) according to the study criteria. According to the PF factors evaluated in this set of tests and the large volume of material, the important factor of PF in people with intellectual disability and the cardiorespiratory fitness factor were studied to examine the content more accurately. Through this set of tests and articles, 18 functional tests of cardiorespiratory fitness related to people with intellectual disabilities were identified.

Given the relationship between physical fitness and health and the opportunity provided by the school environment to assess physical fitness in people with intellectual disabilities, we need to standardize and reach a consensus on specific physical fitness assessments for people with intellectual disabilities in this environment