Stepping Bout Patterns
Although the impact on stepping bout patterns was also variable between active workstation types, both sit-to-stand and treadmill desks had less impact on the overall patterns of stepping as compared with standing. However, categorized stepping bout analyses revealed three key findings as follows: (1) treadmill desk users showed trends of engaging more frequently in prescribed or shorter than prescribed workday stepping bouts relative to controls (approximately 1.5 more bouts/workday) and the sit-to-stand desk group (approximately 1.2 more bouts/workday) in the short-term at M3 but did not sustain these trends after M12; (2) treadmill desk users favored accumulation of both total daily and workday long duration (ie, >30 min) stepping bouts compared with sit-to-stand desk users in the short-term after M3, which ranged from 0.1 to 0.4 more of such bouts per day, but did not sustain these trends after M12; and (3) the sit-to-stand desk group showed trends of accumulating more total daily stepping bouts of shorter than prescribed durations (ie, approximately 6 more bouts/day) relative to controls after M6, which was also not sustained after M12. Correspondingly, neither sit-to-stand nor treadmill desk groups showed short- or long-term trends of change in total daily usual stepping bout duration, and the treadmill desk group had a short-term trend after M3 of longer workday usual stepping bout durations, relative to both controls and the sit-to-stand desk group (ie, approximately 5 more min/stepping bout); this trend was only sustained long-term after M12 relative to the sit-to-stand desk group (ie, approximately 3 more min/stepping bout).A possible explanation for the observed variability in trends of standing and stepping bout patterns between sit-to-stand and treadmill desks may be the impact of desk type on the ability to perform work. For example, when treadmill desk users were provided with feedback after M6 that they reversed positive stepping gains observed after M3, several participants in the treadmill workstation group indicated a heavy work cycle between these 2 time points as a limiting factor in their ability to walk and work on the treadmill. Participants indicated that this particular work cycle required increased multitasking involving reading, writing, and typing. This reluctance to use the treadmill desk when performing office work that likely places a higher demand on cognitive function and involves multitasking, coincides with prior evidence that treadmill desks may result in decreased performance of mouse proficiency, typing, and fine motor movement tasks [