Perceptions on activity behavior during the COVID-19 pandemic "second wave" among US adults: results of a short online survey.

Our findings suggest that PA behavior was negatively affected in US adults during the COVID-19 pandemic, and that "closed gym" (i.e., barrier), and "more time" (i.e., facilitator), were the main factors reported affecting PA participation. Given the well-known public health importance of PA, it is paramount that public health initiatives focus on providing not only educational but also environmental opportunities and support for PA during this period.