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Background: Walking cadence (steps/min) has emerged as a valid proxy of physical activity intensity, with consensus across numerous laboratory‐based treadmill studies that ≥100 steps/min approximates absolutely defined moderate intensity (≥3 metabolic equivalents; METs). We recently reported that this cadence threshold had a classification accuracy of 73.3% for identifying moderate intensity during preferred pace overground walking in young adults. The purpose of this study was to evaluate and compare the performance of a cadence threshold of ≥100 steps/min for correctly classifying moderate intensity during overground walking in middle‐ and older‐aged adults. Methods: Participants (N = 174, 48.3% female, 41–85 years of age) completed laboratory‐based cross‐sectional study involving an indoor 5‐min overground walking trial at their preferred pace. Steps were manually counted and converted to cadence (total steps/5 min). Intensity was measured using indirect calorimetry and expressed as METs. Classification accuracy (sensitivity, specificity, accuracy) of a cadence threshold of ≥100 steps/min to identify individuals walking at ≥3 METs was calculated. Results: The ≥100 steps/min threshold demonstrated accuracy of 74.7% for classifying moderate intensity. When comparing middle‐ vs. older‐aged adults, similar accuracy (73.4% vs. 75.8%, respectively) and specificity (33.3% vs. 34.5%) were observed. Sensitivity was high, but was lower for middle‐ vs. older‐aged adults (85.2% vs. 93.9%, respectively). Conclusion: A cadence threshold of ≥100 steps/min accurately identified moderate‐intensity overground walking. Furthermore, accuracy was similar when comparing middle‐ and older‐aged adults. These findings extend our previous analysis in younger adults and confirm the appropriateness of applying this cadence threshold across the adult lifespan. [ABSTRACT FROM AUTHOR]

To develop and evaluate the validity of the Pregnancy Physical Activity Questionnaire-Short Form (PPAQ-SF). A prospective cohort of participants (N=50) completed the updated PPAQ (long-form) and wore an ActiGraph for 7 days on the nondominant wrist in early, mid, and late pregnancy. The top ten questions with the highest relative contribution to the between-person variance in PPAQ-assessed total MET-hours/day were selected. Internal validity was evaluated using the ActiGraph and the updated PPAQ (long-form) within the current dataset. Validity was also assessed in an external validation dataset of 222 pregnant participants using the updated and original PPAQ (long-forms). Spearman correlations between the PPAQ-SF and ActiGraph estimates of MVPA MET-hours/day were r = 0.34 (95% CI 0.18-0.48) for overall pregnancy and ranged from 0.21 (95% CI -0.07-0.47) in early pregnancy to 0.49 (95% CI 0.23-0.69) in mid-pregnancy. In the external validation dataset, correlations between the PPAQ-SF and the PPAQ (long forms) estimates of MVPA MET-hours/day were statistically significant across pregnancy (r=0.94-0.99). Reproducibility ranged from 0.35 in early pregnancy to 0.77 in mid pregnancy. In summary, the PPAQ-SF can provide a time-efficient measure of MVPA during pregnancy with acceptable validity; reproducibility was reasonable in mid-pregnancy., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)