Cross-Validation of Predictive Equation for Cardiorespiratory Fitness by Modified Shuttle Walk Test in Adults with Schizophrenia: A Secondary Analysis of the CORTEX-SP Study

Mikel Tous-Espelosin; Sonia Ruiz de Azua; Nagore Iriarte-Yoller; Pedro M Sanchez; Edorta Elizagarate; Agurne Sampedro; Sara Maldonado-Martín

doi:10.3390/ijerph182111390

Cross-Validation of Predictive Equation for Cardiorespiratory Fitness by Modified Shuttle Walk Test in Adults with Schizophrenia: A Secondary Analysis of the CORTEX-SP Study

Int J Environ Res Public Health. 2021 Oct 29;18(21):11390. doi: 10.3390/ijerph182111390.

Authors

Mikel Tous-Espelosin^{1

2}, Sonia Ruiz de Azua³, Nagore Iriarte-Yoller⁴, Pedro M Sanchez^{4

5}, Edorta Elizagarate⁴, Agurne Sampedro⁶, Sara Maldonado-Martín^{1

2}

Affiliations

¹ GIzartea, Kirola eta Ariketa Fisikoa Ikerkuntza Taldea (GIKAFIT), Society, Sports and Physical Exercise Research Group, Department of Physical Education and Sport, Faculty of Education and Sport-Physical Activity and Sport Sciences Section, University of the Basque Country (UPV/EHU), 01007 Vitoria-Gasteiz, Spain.
² Physical Activity, Exercise and Health Group, Bioaraba Health Research Institute, 01009 Vitoria-Gasteiz, Spain.
³ Cibersam, Department of Neuroscience, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain.
⁴ Refractory Psychosis Unit, Psychiatric Hospital of Alava, 01007 Vitoria-Gasteiz, Spain.
⁵ Faculty of Medicine, University of Deusto, 48007 Bilbao, Spain.
⁶ Department of Psychology, Faculty of Health Sciences, University of Deusto, 48007 Bilbao, Spain.

Abstract

Cardiorespiratory fitness (CRF) can be direct or estimated from different field tests. The Modified Shuttle Walk Test (MSWT) is suitable for all levels of function, allowing a peak response to be elicited. Therefore, we aimed (1) to validate the equation presented in the original study by Singh et al. for evaluating the relationship between MSWT with peak oxygen uptake (VO_2peak) in adults with schizophrenia (SZ), (2) to develop a new equation for the MSWT to predict VO_2peak, and (3) to validate the new equation. Participants (N = 144, 41.3 ± 10.2 years old) with SZ performed a direct measurement of VO_2peak through a cardiopulmonary exercise test and the MSWT. A new equation incorporating resting heart rate, body mass index, and distance from MSWT (R² = 0.617; adjusted R² = 0.60; p < 0.001) performs better than the Singh et al. equation (R² = 0.57; adjusted R² = 0.57; p < 0.001) to estimate VO_2peak for the studied population. The posteriori cross-validation method confirmed the model's stability (R² = 0.617 vs. 0.626). The findings of the current study support the validity of the new regression equation incorporating resting heart rate, body mass index, and distance from MSWT to predict VO_2peak for assessment of CRF in people with SZ.

Keywords: assessment; equation for estimation; field test; peak oxygen uptake; validation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Cardiorespiratory Fitness*
Exercise Test
Humans
Middle Aged
Oxygen Consumption
Schizophrenia*
Walk Test
Walking