Outdoor circuit test: construction and validation of an instrument for the prediction of cardiorespiratory capacity for older adults

Abstract Objective: the present study aimed to construct, validate and verify the reliability of a protocol for assessing the cardiorespiratory capacity of older adults attending the Rio ao Ar Livre (Open Air Rio, or RAL) project entitled the “Outdoor Circuit Test” (OCT). Method: validity and reliability tests were carried out to assess the accuracy of the OCT, with 50 older adults (70.6 ± 6.3 years) of both sexes who regularly attended the RAL. Validity was tested by collecting VO2max data under maximal cardiopulmonary exercise test conditions, and the OCT variables: a) Circuit Execution Time; b) Heart Rate; c) Subjective Perception of Exertion; d) Average Heart Rate (HRméd). Reliability was tested through the reproducibility of the measurements of the OCT variables, expressed by the Intraclass Correlation Coefficient (ICC). The predictive capacity of VO2max was given by multiple linear regression and the final stability of the model by the analysis of the residues and the calculation of Cook’s distances, with a value of P≤ 0.05 adopted for statistical significance. Results: the predictive model based on age, sex, waist circumference, BMI and circuit execution time explained 41% of VO2max variance, with a standard error of estimate of 18.5%. Conclusion: the OCT exhibited satisfactory reproducibility (0.62 to 0.93), and proved to be valid, reliable, and specific for predicting the cardiorespiratory fitness of older adults attending RAL, demonstrating adequate reproducibility and a positive association with the physical fitness of older adults. Resumo Objetivo: Este estudo propôs construir, validar e verificar a confiabilidade de um protocolo de avaliação da capacidade cardiorrespiratória de idosos frequentadores do projeto Rio ao Ar Livre (RAL), denominado “Teste Circuito ao Ar Livre (TCAL) Método: foram realizados testes de validade e confiabilidade para verificar a acurácia do TCAL com 50 idosos (70,6±6,3 anos) de ambos os sexos e frequentadores do RAL. A validade foi testada através de coleta de dados de VO2máx em teste cardiopulmonar de exercício máximo e de variáveis do TCAL: a) Tempo de Execução do Circuito; b) Frequência Cardíaca; c) Percepção Subjetiva de Esforço; d) Frequência Cardíaca Média (FCméd). A confiabilidade foi testada através da reprodutibilidade das medidas das variáveis do TCAL, expressas pelo Coeficiente de Correlação Intraclasse (ICC). A capacidade preditiva do VO2máx deu-se por regressão linear múltipla e a estabilidade final do mo