Beyond the Clinic: Maximum Free-Living Stepping as a Potential Measure of Physical Performance.

Measures of physical performance captured within a clinical setting are commonly used as a surrogate for underlying health or disease risk within an individual. By measuring physical behaviour within a free-living setting, we may be able to better quantify physical performance. In our study, we outline an approach to measure maximum free-living step count using a body-worn sensor as an indicator of physical performance. We then use this approach to characterise the maximum step count over a range of window durations within a population of older adults to identify a preferred duration over which to measure the maximum step count. We found that while almost all individuals (97%) undertook at least one instance of continuous stepping longer than two minutes, a sizeable minority of individuals (31%) had no periods of continuous stepping longer than six minutes. We suggest that the maximum step count measured over a six-minute period may be too sensitive to the adults' lack of opportunity to undertake prolonged periods of stepping, and a two-minute window could provide a more representative measure of physical performance.

Estimating changes in physical behavior during lockdowns using accelerometry-based simulations in a large UK cohort.

To contain the recent COVID-19 outbreak, restrictions have been imposed, which has limited outdoor activity. These physical behavior changes can have serious health implications, but there is little objective information quantifying these changes. This study aimed to estimate the change in physical behavior levels during full lockdown conditions using objective data collected from a thigh-worn activity monitor. Data used were from 6492 individuals in the 1970 British Cohort Study, collected between 2016 and 2018. Using walking bout characteristics, days were classified as either "indoor only" (n = 861), "indoor and exercise" (n = 167), and "outdoor active" (n = 31 934). When compared to "outdoor active" days, "indoor only" days had 6590 fewer steps per day (2320 vs 8876, p < 0.001), a longer sedentary time (1.5 h, p < 0.001), longer lying time (1.4 h, p < 0.001) and shorter standing (1.9 h, p < 0.001) and stepping (1.3 h, p < 0.001) times. The "indoor and exercise" days had a smaller number of steps compared to "outdoor active" (7932 vs 8876, p < 0.05). There is a strong relationship between reduced daily stepping, and increased sedentary time, with a range of poor health outcomes. This has important implications for public health policy and messaging during pandemics.