Estimation of physical activity intensity cut‐points using accelerometry in breast cancer survivors and age‐matched controls

Abstract

Objective To examine the association between accelerometer activity counts and energy expenditure during walking in breast cancer survivors (BCS) compared with age‐matched healthy controls, and differences in moderate‐to‐vigorous physical activity (MVPA) cut‐points. Methods Using a case–control design, 19 BCS and 19 age‐matched women completed 6 min of resting energy expenditure and 6‐min periods of treadmill walking in Midwestern United States. Accelerometers and an open‐circuit spirometry system were used to measure activity counts and energy expenditure (VO2). A mixed‐factor analysis of variance was conducted on activity counts and VO2. Independent samples t tests compared the magnitude of associations between groups. Results There were group by speed interactions on energy expenditure (p < 0.001) and counts (p < 0.001). The linear association did not differ between BCS and controls for the R2 (p = 0.62) nor the slope (p = 0.43), but there was a difference in the intercept (p = 0.01). This resulted in different MVPA cut‐points between groups: 1,439 ± 761 counts·min−1 in BCS and 1,937 ± 639 counts·min−1 in controls. Conclusion The findings support the use of different cut‐points to quantify time spent in MVPA for BCS. Application of these cut‐points is warranted to accurately assess physical activity (PA) patterns for better prescription and health outcomes in PA programmes for BCS.

Accelerometer output and its association with energy expenditure in persons with mild-to-moderate Parkinson’s disease

“…The Physical Activity Readiness Questionnaire was included for screening and identified contraindications for exercise engagement [20]; persons who answered "yes" to two or more questions were asked to receive physician's clearance prior to participation. The sample consisted of 30 persons with PD, and 30 controls were matched on age and sex; this is consistent with previous studies of MS [19] and other clinical populations (e.g., breast cancer survivors) [21].…”

“…The accelerometer and metabolic data per speed were imported into Microsoft Excel for processing per subject. We based the approach of data processing and analyses with previous research examining the relationship between accelerometer activity counts and energy expenditure in other clinical populations [21,26]. We treated the data within subjects as dependent and data between subjects as independent to generate individual-level regression equations rather than creating a regression equation using all data from all subjects collectively; this approach avoids violating a key assumption of regression (i.e., independence between subjects because data of each subject would be stacked across speed).…”

Development and Evaluation of an Accelerometer-Based Protocol for Measuring Physical Activity Levels in Cancer Survivors: Development and Usability Study

“…For data analysis related to objective physical activity data captured in this protocol, standard cut-off points as well as vector magnitude and total activity counts will be evaluated by the research team. The current literature suggests that vector magnitude may better discriminate between sedentary and light physical activity in women aged older than 60 years [ 48 ], although among breast cancer survivors, total activity counts may provide better estimates of moderate-to-vigorous physical activity [ 49 ]. These population-relevant cut-off points will allow for a more accurate interpretation of accelerometer data for the older female cancer survivor population; however, information remains limited for cut-off points specific to ovarian cancer survivors.…”

Perceived autonomy support from healthcare professionals and physical activity among breast cancer survivors: A propensity score analysis

“…Device-measured PA using an accelerometer limits recall bias associated with self-reported measures. However, the predetermined thresholds for the general population that have been used to identify time spent in light, moderate, and vigorous PA are currently being questioned for their use with women with breast cancer [27,53,54]. The thresholds for moderate-and vigorous-intensity PA would be lower for this population than for the general population [53,54].…”

“…However, the predetermined thresholds for the general population that have been used to identify time spent in light, moderate, and vigorous PA are currently being questioned for their use with women with breast cancer [27,53,54]. The thresholds for moderate-and vigorous-intensity PA would be lower for this population than for the general population [53,54]. Thus, the use of the Freedson thresholds may have underestimated time spent in moderate and vigorous intensity PA, thereby reducing the number of participants identified as having engaged in these activities and the time spent in each.…”