The majority of the students used their smartphone at
home (58.4%) and most preferred sitting (40.0%) or lying
on their back (34.9%) when using a smartphone. As shown
earlier, many of the subjects used smartphones in poor
working environments, as indicated by their sitting and lying
positions. Therefore, there is a high likelihood that they
will suffer from musculoskeletal disorders10). Regarding the
average daily use, 42.1% used smartphones for more than
4 hours, and 21.6% use them for between 3 and 4 hours. In
short, 80% of the students used smartphones for more than
2 hours every day11)