  Owing to the pandemic caused by the coronavirus disease of 2019 (COVID-19),
several universities have closed their campuses for preventing the spread of
infection. Consequently, the university classes are being held over the
Internet, and students attend these classes from their homes. While the
COVID-19 pandemic is expected to be prolonged, the online-centric lifestyle has
raised concerns about secondary health issues caused by reduced physical
activity (PA). However, the actual status of PA among university students has
not yet been examined in Japan. Hence, in this study, we collected daily PA
data (including the data corresponding to the number of steps taken and the
data associated with six types of activities) by employing smartphones and
thereby analyzed the changes in the PA of university students. The PA data were
collected over a period of ten weeks from 305 first-year university students
who were attending a mandatory class of physical education at the university.
The obtained results indicate that compared to the average number of steps
taken before the COVID-19 pandemic (6474.87 steps), the average number of steps
taken after the COVID-19 pandemic (3522.5 steps) has decreased by 45.6%.
Furthermore, the decrease in commuting time (7 AM to 10 AM), classroom time,
and extracurricular activity time (11 AM to 12 AM) has led to a decrease in PA
on weekdays owing to reduced unplanned exercise opportunities and has caused an
increase in the duration of being in the stationary state in the course of
daily life.
