More trail running can be found adjacent to Metropolitan Natural Park in the Camino de Cruces and Soberanía national parks. Between the two parks, there are numerous trails to choose from, but the most popular route is the famous Camino de Cruces. It’s ~11 km one-way from Avenida Madden to the ruins of Venta de Cruces. This is a more challenging trail run owing to the various surface conditions. Though the trail is mostly flat and dry (from Jan-March), the remnant cobblestones from this historic road linking Old Panama City to the port of Venta de Cruces pose some ankle-busting hazards. Use extra caution through these sections! See this link for more detailed information about the trail, directions, etc.
Shorter Option: Run to the Canopy Tower.