Discussion
adiposity, chronic disease [Heart rate recovery
SECONDARY, ADIPOSITY
We found that heart rate recovery after a simple stepping test was positively associated with adiposity in preschool children at 5-years of age. This study also observed significant sex differences in cardiovascular fitness, as boys had a faster heart rate recovery time after the step test than girls. No favourable associations were observed between heart rate recovery and cardiovascular health at rest.Current research recognises the importance of examining fitness and metabolic health in adults due to the gradual manifestation of chronic disease [Heart rate recovery has been described as a simple, non-expensive method of estimating cardiovascular fitness, and its use in clinical studies in adults is well established [While additional efforts are needed to validate the ROLO Kids step test, previous studies that used similar step tests reported consistent associations [This study observed several sex differences in adiposity and cardiovascular fitness. At 5-years of age, boys were significantly taller, and leaner compared to girls, consistent with biological differences in metabolism from early life [A secondary finding of this study is that the ROLO Kids step test may serve as a novel and innovative method of assessing cardiovascular fitness in preschool children. To our knowledge this is the first step-based method of assessing cardiovascular fitness in 5-year-old children. Three-minute step tests are considered simple and practical assessments that can be easily replicated with limited equipment, space and training requirements [This analysis had many strengths including the use of accurate objective anthropometry and body composition measurements that were collected by trained researchers. This analysis considered a wide range of variables and included valuable data related to early years which were used to provide additional context for the relationship between cardiovascular fitness and adiposity. The ROLO Kids step test is an innovative method to assess fitness in this age group and could easily be replicated in a small office space with low financial burden. It is important to acknowledge that the non-standardized approach to the use of the ROLO Kids step test and determination of heart rate recovery is a confounding factor. It is plausible that heart rate recovery levels were clouded by differences in effort due to free cadence. The assessment of perceived effort was used to control for this by including it as a confounder in the multivariate analysis. However, it should be acknowledged that the assessment of perceived effort by two researchers in this study was a subjective measurement. Another limitation may be the use of the 7-point scale to assess effort in this analysis. As the scale was not evenly weighted, it could potentially skew the results and result in very small numbers in the “poor effort” group. Future analyses may use a different scale that is equally weighted so that effort or participation with the step test could be better assessed. The interpretation of our findings from the ROLO Kids step test are limited by a lack of validation. The results of this study should encourage efforts to build stronger evidence to determine the validity of the ROLO Kids step test in larger paediatric cohorts.