Table 1 Outcome variables
Outcome variable (unit) | Method used (for activPAL device) | Rationale for inclusion and/or relevance to health |
|---|---|---|
Stepping time (mins / 16Â h day) | Time spent stepping. Standardised to 16Â h awake and wearing the device. | Stepping time includes both dynamic light activity and moderate-vigorous intensity activity, and forms much of total physical activity time during the day. All of these have been associated with health outcomes. |
Mean stepping cadence (steps / min) | Number of steps divided by time spent stepping. | Continuous measure of faster stepping speed (cadence) that has been positively associated with health outcomes and tends to indicate higher activity intensity. |
Moderate-to-vigorous physical activity time (MVPA; mins / 16 h day) | Time stepping with cadence of ≥ 100 steps/min. Standardised to 16 h awake and wearing the device. Validated as a measure of moderate-to-vigorous intensity physical activity [72] | Benefits attained from physical activity may be optimised by increasing the intensity above a certain threshold. Time spent at or above the MVPA threshold are associated with distinct physiological processes and health benefits. |
Mean stepping bout duration (mins) | Total stepping time divided by the number of stepping bouts. | A continuous pattern indicator of how long at a time people step without stopping. Longer versus shorter periods of being active continuously may reflect different behaviours and may have different relationships with health. |
Purposeful walking time (mins / 16 h day) | Time spent stepping continuously for ≥ 2 min. Standardised to 16 h awake and wearing the device. | Purposeful walking time is a subset of total stepping time that may be particularly relevant for walkability, as it refers to time stepping from one place to another. Previous research [59] has tentatively identified a threshold of ≥ 2 min continuous stepping as separating purposeful walking from incidental stepping (where steps occur interspersed among other activities such as standing). |
Standing time (mins / 16Â h day) | Time spent upright without any stepping. Standardised to 16Â h awake and wearing the device. | Standing is stationary light-intensity activity, the least active portion of physical activity. Coupled with sitting and stepping, it forms the complete waking day wearing the activPAL device. Its inclusion is exploratory, and for completeness. |
Sitting time (mins / 16Â h day) | Total minutes per day spent awake and in a sitting or lying position (sitting/lying). Standardised to 16Â h awake and wearing the device. | Excessive sitting time is associated with adverse health outcomes and self-reported sedentary time has previously been linked with walkability. |
Mean sitting bout duration (mins) | Total sitting/lying time divided by the number of sitting/lying bouts. | Continuous pattern indicator of the propensity to accumulate sitting in a prolonged uninterrupted manner. Sitting accumulation patterns have shown associations above and beyond sitting time with health outcomes. |