This study aims to investigate the effects and influencing mechanisms of regular physical activity (RPA) on the COVID-19 pandemic. Daily data from 279 prefecture-level cities in mainland China were collected from 1 January to 17 March 2020. A two-way fixed-effects model was used to identify the causal relationship between physical activity and COVID-19, while also considering factors such as patterns of human behavior and socioeconomic conditions. The instrumental variable (IV) approach was applied to address potential endogeneity issues for a more accurate causal identification, and the mediating effect model was applied to examine the mechanisms of the influence of physical activity on the epidemic. We found that regular physical activity significantly improves individual immunity, which, in turn, leads to a reduction in the probability of being infected with COVID-19. Furthermore, we investigated the heterogeneity of the influence, finding that the negative impact of physical activity on the pandemic is more pronounced in the absence of adequate medical resources, strong awareness of prevention among residents, and fully implemented public health measures. Our results provide empirical evidence for the mechanisms of influence of physical activity on the pandemic. We would suggest that not only should physical activity be actively practiced during the pandemic, but also long-term regular exercise habits should be consciously cultivated to improve the ability of the individual immune system to better cope with sudden outbreaks of emerging infectious diseases.

What kind of role do sports champions play in the COVID-19 epidemic? Do they contribute to the mitigation of the epidemic by some pathway? In this paper, we empirically explore the influence and mechanism of the demonstration effect of sports champions upon the COVID-19 epidemic using COVID-19-related dataset of prefecture-level cities in China from 1 January 2020 to 17 March 2020. The two-way fixed effect model of econometrics is applied to estimate the result, the instrumental variable approach is adopted to address potential endogeneity issues, and socio-economic factors including public health measures, residents’ self-protection awareness, effective distance from Wuhan are also taken into consideration. The results show that the demonstration effect of champions in major sporting events increases the participation in physical exercise, which in turn reduces the possibility of being infected with the epidemic. An increase of one gold medal results in a 0.93% increase in the sports population, then leads to a 3.58% decrease in the cumulative case growth rate (p < 0.01). Further, we find that the effect is greater in regions with developed economies and abundant sports resources. Interestingly, it is greater in regions with less attention to sports, which again confirms the role of the demonstration effect.

Rural depopulation is an inevitable trend due to urbanization and industrial development, and it is a common phenomenon in industrialized countries. The classic theory of induced technological innovation proposed by HAYAMI & RUTTAN (1971) explains the change in agricultural technology during the process of rural depopulation. This paper tests the Hayami-Ruttan induced technological innovation theory from the perspective of agricultural technology choice in the process of rural depopulation. We sort out the influence mechanism of rural depopulation on the choice of agricultural technology from four aspects, namely, factor substitution effect, demand scale effect, conditional bottleneck effect, and agricultural comparative benefit. Using the difference between the rural registered population and the permanent population, we comprehensively compiled the data on the net outflow rate of the rural population from 2005 to 2018 in 313 prefecture-level cities, and reach conclusions through panel regression. The results showed that rural depopulation is not necessarily conducive to labor-saving technological choices, but is conducive to the land-saving technological choice. However, rural depopulation promotes labor-saving technological choices when the population reaches a certain level. The conclusion is not completely consistent with the theory of Hayami-Ruttan, it reflects an idiographic feature of the Chinese environment.

Highway construction reduces the production costs of enterprises, which is conducive to their increased investment in environmental management and the adoption of green production technologies, thereby promoting regional green economic growth. Traditional research mainly focuses on the pollution problem in the transportation infrastructure and transportation process, and it is difficult to explain the spatial spillover problem of the green economy brought by transportation. We measured the shortest passage time and market access of the Yangtze River Economic Belt highway from 2005 to 2019. Meanwhile, we measured the green total factor productivity based on the Malmquist-Luenberger index. The empirical results show that highway construction has a significant role in promoting green economic growth in the Yangtze River Economic Belt. However, there is obvious regional heterogeneity in the degree of effect. Market access has the largest effect in large cities, followed by medium cities, and has the smallest effect on small cities. This suggests that there is an environmental “bottoming-out effect” in highway-induced industrial transfer. Further, we find that green technology innovation is the mechanism by which highways affect green economic growth.