Masks are an effective tool in combatting the spread of COVID-19, but some people still resist wearing them and mask-wearing behavior has not been experimentally studied in the United States. To understand the demographics of mask wearers and resistors, and the impact of mandates on mask-wearing behavior, we observed shoppers (n = 9935) entering retail stores during periods of June, July, and August 2020. Approximately 41% of the June sample wore a mask. At that time, the odds of an individual wearing a mask increased significantly with age and was also 1.5x greater for females than males. Additionally, the odds of observing a mask on an urban or suburban shopper were~4x that for rural areas. Mask mandates enacted in late July and August increased mask-wearing compliance to over 90% in all groups, but a small percentage of resistors remained. Thus, gender, age, and location factor into whether shoppers in the United States wear a mask or face covering voluntarily. Additionally, mask mandates are necessary to increase mask wearing among the public to a level required to mitigate the spread of COVID-19.

Masks are an effective tool in combatting the spread of COVID-19 but wearing them remains controversial and has not been studied in the United States. To understand the demographics of mask wearers in the US, we observed shoppers (n = 5517) entering retail stores. 41.5% of the observed sample wore a mask. The odds of an individual wearing a mask increased significantly with age, and was also 1.5x greater for females than males. Additionally, the odds of observing a mask on an urban or suburban shopper were ~4x that for rural areas. Thus, gender, age, and location factor into whether American shoppers wear a mask or face covering. Regardless, all demographics wore masks at substantially lesser rates than required to stop the spread of COVID-19.

There is scientific and legal controversy about recent technological advances in performance running shoes that reduce the energetic cost of running and may provide a distinct competitive advantage. To better understand the potential performance-enhancing effects of technological advancements in marathon racing shoes, we examined the finishing times and racing shoes of the top 50 male and 50 female runners from the World Marathon Major series in the 2010s - before and after the introduction of new Nike shoe models (4%, NEXT%, Alphafly, and other prototypes; herein referred to as neoteric Nikes). Data for racing shoes were available for 3,886 of the 3,900 performances recorded at the four annual marathons in Boston, London, Chicago, and New York. In full cohort analyses, marathon finishing times were 2.0% or 2.8 min (138.5±8.1 min vs. 141.3±7.4 min, P<0.001) faster for male runners wearing neoteric Nikes compared to other shoes. For females, marathon finishing times were 2.6% or 4.3 min (159.1±10.0 min vs. 163.4±10.7 min, P<0.001) faster for runners wearing neoteric Nikes. In a subset of within-runner changes in marathon performances (males, n = 138; females, n = 101), marathon finishing times improved by 0.8% or 1.2 min for males wearing neoteric Nikes relative to the most recent marathon in which other shoes were worn, and this performance-enhancing effect was greater among females who demonstrated 1.6% or 3.7 min improvement (P=0.002). Our results demonstrate that marathon performances are substantially when world-class athletes, and particularly females, wear marathon racing shoes with technological advancements.

There is scientific and legal controversy about recent technological advances in performance running shoes that reduce the energetic cost of running and may provide a distinct competitive advantage. To better understand the potential performance-enhancing effects of Nike’s pioneering marathon racing shoes, we examined the finishing times and racing shoes of the top 50 male and 50 female runners from the World Marathon Major series in the 2010s — before and after the introduction of new Nike shoe models (4%, NEXT%, Alphafly, and other prototypes; herein referred to as neoteric Nikes). Data for racing shoes were available for 3,886 of the 3,900 performances recorded at the four annual marathons in Boston, London, Chicago, and New York. In full cohort analyses, marathon finishing times were 2.0% or 2.8 min (138.5 ± 8.1 min vs. 141.3 ± 7.4 min, P<0.001) faster for male runners wearing neoteric Nikes compared to other shoes. For females, marathon finishing times were 2.6% or 4.3 min (159.1 ± 10.0 min vs. 163.4 ± 10.7 min, P<0.001) faster for runners wearing neoteric Nikes. In a subset of within-runner changes in marathon performances (males, n = 138; females, n = 101), marathon finishing times improved by 0.8% or 1.2 min for males wearing neoteric Nikes relative to the most recent marathon in which other shoes were worn, and this performance-enhancing effect was greater among females who demonstrated 1.6% or 3.7 min improvement (P=0.002). Our results demonstrate that marathon performances for world-class athletes are substantially faster wearing neoteric Nikes than other market-leading shoes, particularly among females.

Previous observational work from 2020 demonstrated gender-, age-, and location-related differences in mask-wearing behavior, despite the efficacy and public health messaging that emphasized face coverings in combatting the spread of COVID-19. In 2021, COVID-19 vaccinations and a corresponding change in public health policy became new considerations in deciding personal protective behaviors. To provide an update on mask wearers and resistors approximately one year after our initial study, we observed shoppers (n = 6,118) entering retail stores using the same experimental methodology. Approximately 26% of individuals wore a mask. Mask wearing has decreased across demographic groups compared to 2020. Aligning with previous findings, females were ~1.5x more likely to be observed wearing a mask than males, and the odds of observing a shopper wearing a mask in a suburban or urban area was far greater than at rural stores (~5.7x and ~3.3x, respectively). Gender and location are confirmed to be significant and stable factors that impact mask-wearing behavior in the United States during the COVID-19 pandemic. The impact of age on mask wearing was heavily reduced compared to 2020, potentially due to the availability of COVID-19 vaccines and change in mask guidance for vaccinated individuals.