Physical Fitness In The Danish Cohort ŽDiet, Cancer And Health Ů Next GenerationsŪ Ů A Validation Study

Lene LERCHE, Danish Cancer Society Research Center, Denmark

1 Unit of Diet, Genes and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark

Physical fitness comprises several components, of which, cardiorespiratory fitness (VO2max (ml O2/kg/min)) is of particularly interest due to its strong inverse association with risk of chronic diseases, including cardiovascular disease, diabetes and cancer. Less complicated methods than standard test of cardiorespiratory fitness including submaximal exercise testing and non-exercise questionnaire based methods are mostly used in epidemiological research.
The aim was to evaluate the validity of a submaximal fitness test The Danish Step Test (TDST) and a simple self-reported question (SSRQ) as methods for estimating physical fitness. This was done by comparing these two methods with a VO2maxtest, which is considered the gold standard.
125 participants aged 19-67 years were recruited from the cohort. Participants completed a VO2maxtest, TDST and answered the SSRQ rating their physical fitness level. Pearson product-moment-correlation-coefficients were calculated to assess the relationship between the VO2maxtest and TDST. The VO2maxtest, TDST and the SSRQ were grouped into five categories. The degree of misclassification across categories between TDST and the SSRQ, respectively, in relation to the VO2maxtest were investigated.  
Moderate correlations between the VO2max test and TDST were found (men: r=0.555, n=60, p<0.05, women: r=0.658, n=65, p<0.05).
When comparing the categories of physical fitness from TDST with the VO2maxtest, on average only 6% of the women were classified outside the same (±1) category. However, for men there was a higher degree of misclassification with 38% outside the same (±1) category, where TDST especially seemed to underestimate physical fitness. When comparing the categories from the SSRQ with the results from the VO2maxtest, only 9% of the women were misclassified. Among men, only 13% fell outside the same (±1) category.
The SSRQ was found to be a superior method to TDST when estimating physical fitness in a less cost prohibitive and more practical way than the VO2maxmethod.