A confirmatory factor analysis of the fitness of adults with intellectual disabilities

Abstract

Purpose: To test whether a new model including nine variables can be used to test the fitness of adults with intellectual disabilities. Methods: This is a cross-sectional study involving 445 adults aged 18–42 recruited during the Spanish Special Olympics. Confirmatory factor analysis (CFA) was used to test the goodness-of-fit of four latent variables: flexibility, strength, balance and cardiorespiratory endurance. The standardized scores of the nine variables in the model were used to develop a fitness index for adults with intellectual disabilities. Simultaneous multigroup analyses were also conducted in order to test the stability of the proposed model across gender and across active and sedentary participants. Results: The findings demonstrated that the proposed structure was well supported (comparative fit index = 0.97, standardized root mean square error of approximation = 0.05) and stable across subgroups. Conclusions: A model with four underlying factors has been shown to have acceptable validity to represent the fitness of adults with intellectual disabilities.

Implications for Rehabilitation

• Our results suggest that a fitness index for adults with ID can be identified based on the components of a four-factor model obtained through CFA

• The fitness index for adults with ID offers a standard frame of reference.

• In order to help practising physical therapists data, we have developed a software application (see http://www.salud.uma.es/calculaFID).

Keywords::

• Confirmatory factor analysis
• fitness index
• intellectual disabilities
• physical fitness

Acknowledgments

The authors would like to thank all of the participants, the collaborating physiotherapists and volunteers and especially Prof. FJ Baron for his help in developing the web calculator. Professor Nicola Adams contributed to the manuscript review from a native English speaker.

Declaration of Interest: This research was partially funded by grants from the OTRI-UMA (ref 806/423505 code 00334) and grants from the Spanish Ministry of Education (EX-2008-0641) and the Swedish Heart-Lung Foundation (20090635).