Purpose The purpose of this study was to examine the relationship between objectively measured sitting time, posture, and low back pain (LBP) in adults with full-time (≥ 40 h/week) sedentary “desk” jobs. Physical activity (PA) and sedentary behavior (SB) between work environments (home vs. office) were also compared during COVID-19. Methods Participants ( N = 53; M age = 41 ± 12years) were full-time employees in sedentary jobs during COVID-19. A survey with demographic, work environment, and LBP questions was completed; Thomas Test assessed poor hip posture. ActivPAL devices were worn for ≥ 4 valid days (≥ 10 h/d) to assess waking sitting time (min/d). Binomial logistic regressions examined sitting as a predictor of poor posture and LBP; ANOVAs compared PA and SB between work environments. Results Objectively measured sitting (min/day) predicted poor hip posture ( β = − 0.01, p < 0.046) but was not significant for LBP ( β = 0.002, p < 0.43). Participants who worked from home had significantly higher sitting time (569 ± 111 vs. 477 ± 46 min/d; p < 0.04), higher muscle strengthening PA (2.2 ± 2 vs. 0.5 ± 1.2d/week p < 0.02), but no difference in aerobic PA ( p < 0.15), than those who worked from an office. Conclusion Given the shift to remote work during COVID-19, employees are at high risk for postural compensations that lead to LBP due to high SB and poor work ergonomics at home. There is a need to develop home-based behavioral and exercise interventions to reduce sitting, help improve posture, and invest in proper ergonomic homework equipment.

The purpose of circulation control for fixed wing aircrafts is to increase the lifting force when large lifting forces and/or slow speeds are required, such as at takeoff and landing. Wing flaps and slats are used on almost all fixed-wing aircraft. While effective in increasing lift, they do so with penalty of increasing drag, weight, and control complexity. The goal of this research was to find an alternative way of pumping pressurized air to the trailing edge slot on a UAV propeller. This design called for rerouting stagnation pressure from the frontal propeller area through the inside of the propeller blades to ejection slots on the trailing edge. This allows for the forward velocity of the aircraft to drive the pressurization of the circulation control plenum passively, without additional hardware. For this study, a Clark-Y airfoil section propeller with an overall diameter of 0.609 meters was designed and tested. The comparison of the augmented to unaugmented propeller showed a 5.12 percent increase in efficiency, which is shown to act over the entire range of flight envelopes of the aircraft and is shown to be particularly beneficial at advance ratios above 0.30, normal operating conditions of propeller-driven UAVs.

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