Publications by authors named "Brad Humphreys"

Emerging research documents the impact of poor air quality on employee performance in a number of settings, including sport. Unlike other settings, sports teams have limited ability to influence previously scheduled games, making air quality exogenous to unobservable factors affecting game outcomes. We link play-level data from National Football League (NFL) games to data from air quality monitoring stations located near NFL stadiums.

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Airborne transmission of the COVID-19 virus increased the need for health policies to reduce transmission in congregate settings associated with minimal risk before the pandemic. While a large literature estimates tradeoffs between policies designed to reduce negative health outcomes, no empirical research addresses consumer willingness to pay (WTP) for health policies designed to reduce airborne virus transmission. Using survey data from 1381 fans of professional sports, we estimate consumers' WTP for reduced likelihood of coronavirus transmission through mask and social distancing policies using a stated preference approach.

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A Supreme Court decision legalizing sports betting in the US led states to legalize sports betting in order to generate new tax revenues from wagering on sports events. Most states already permit other forms of gambling and receive tax revenues from these sources. The literature analyzing consumer substitution in gambling spending contains some evidence on the impact of expansions in many types of gambling, but no evidence on the impact of expanded sports betting.

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Health production models include participation in physical activity as an input. We investigate the relationship between participation in physical activity and health using a bivariate probit model. Participation is identified with an exclusion restriction on a variable reflecting sense of belonging to the community.

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Background: A major policy goal of many ministries of sport and health is increased participation in sport to promote health. A growing literature is emerging about the benefits of sport participation on happiness. A challenge in establishing a link between sport participation and happiness is controlling for endogeneity of sport participation in the happiness equation.

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Introduction: It has been hypothesized that bone loss arising from long-duration space travel is caused by a reduction in mechanical stimuli to the skeleton. The daily load stimulus (DLS) theory was first proposed to relate daily time histories of mechanical loading from ground reaction forces to bone homeostasis. In this methods paper, an enhanced daily load stimulus (EDLS) is proposed to account for recently developed theories on saturation and recovery of the osteogenic potential of bone with repeated cyclic loading and the potential benefits of standing.

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Background: Spaceflight has been shown to cause atrophy, reduced functional capacity, and increased fatigue in lower-limb skeletal muscles. The mechanisms of these losses are not fully understood but are thought to result, in part, from alteration in muscle usage.

Methods: Knee-joint angles and lower-extremity muscle activity were measured continually, via elecrogoniometry and surface electromyography respectively, from two subjects during entire working days of activity on Earth and onboard the International Space Station (ISS).

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