Kaminsky, Leonard A.

Inconsistency in the calculation of time spent in moderate to vigorous physical activity (MVPA) limits interstudy comparability and interpretation of surveillance data. This study assesses whether combining multiple individual methods results in a more accurate estimate of MVPA, while considering the influence of device brand and wear location. Participants (n = 30, age = 49.2 ± 19.5 years) wore two accelerometers (GENEActiv, ActiGraph) on each wrist during two laboratory visits. Individual classification methods (11 for left wrist, eight for right wrist) estimated minutes of MVPA using three approaches (cut-point, two-regression, and machine learning), two types of input (count and raw), and five epoch lengths (1, 5, 15, 30, and 60 s). The consensus estimate was calculated as the mean or median (due to skew) across all individual estimates. No individual or consensus estimates were statistically equivalent to direct observation (mean 38.2 min), with 81%–95% of individual methods overestimating MVPA. The best-performing individual methods were raw acceleration cut-points, with a bias of −3.2 to 2.4 min across devices and wrists. Correlation coefficients between individual methods and the criterion were .35–.71 for the left and .12–.67 for the right wrist, compared to .65–.70 and .58–.66 for consensus methods, respectively. Correlations between device brands were .23–.99 for individual methods and .70–.86 for consensus methods, while correlations between locations were .55–.86 and .73–.87, respectively. Better methods are required for estimating MVPA from wrist-worn accelerometers given the consistent overestimation of MVPA observed. While a consensus method for wrist-worn data was not able to fully resolve these issues, it improves interwrist or interbrand comparability.

ABSTRACT Introduction Peak rating of perceived exertion (RPE) is measured during clinical cardiopulmonary exercise testing (CPX) and is commonly used as a subjective indicator of maximal effort. However, no study to date has reported reference standards or the distribution of peak RPE across a large cohort of apparently healthy individuals. Purpose This study aimed to determine reference standards for peak RPE when using the 6–20 Borg scale for both treadmill and cycle tests. Methods The analysis included 9551 tests (8821 treadmill, 730 cycle ergometer) from 13 laboratories within the Fitness Registry and Importance of Exercise National Database (FRIEND). Using data from tests conducted January 1, 1980, to January 1, 2021, percentiles of peak RPE for men and women were determined for each decade from 20 to 89 yr of age for treadmill and cycle exercise modes. Two-way ANOVA was used to compare differences in peak RPE values between sexes and across age groups. Results There were statistically significant differences in RPE between age groups whether the test was performed on a treadmill or cycle ergometer ( P < 0.05). However, the mean and median RPE for each sex, age group, and test mode were between 18 and 19. In addition, 83% of participants met the traditional RPE criteria of ≥18 for indicating sufficient maximal effort. Conclusions This report provides the first normative reference standards for peak RPE in both male and female individuals performing CPX on a treadmill or cycle ergometer. Furthermore, these reference standards highlight the general consistency of peak RPE responses during CPX.