Hüdavendigar Park (Hüdavendigar Kent Parkı) is one of the best green spots for a run in Bursa. This park, in the western part of Bursa features paths around gardens, athletic fields, and on both sides of a river, connected by a pedestrian bridge. One can put together a ~4 km route combining all the paths in the area.
For a longer run, you can cross the main road and head north to the Timsah Arena (Stadium) complex, where there’s a ~1 km path through waterfront Mihraplı Park. In all, this is a ~6 km route. For public transport access, you could take the subway to Acemler istasyonu, which is next to the stadium and start your run there.