There are some good trail running options in and near Tarragona. For the most part, these are sections of the Camí de Ronda, which is the longer distance coastal hiking trail, and also some wooded hiking areas in the hilly areas away from the coast. 

Bassa closa. Hilly hiking area north of the A7, in the Platja Llarga area. Many km of trails. Some are wider forest roads, others are narrower, wooded trails. 

Camí de Ronda. Scenic coastal trail that has some sections on the Tarragona area. Combination of open & wooded. Footing and hilliness can vary by section. One of the best sections is the wooded hiking area east of Platja Llarga: Camí de Ronda/Bosc de la Marquesa (Bosc=Woods). It’s a large area of mainly wooded trails.