Málaga has several outdoor gyms, some of them are located at the beach, some in parks. One of my favourite things about these gyms is, that you can meet there people at all age, from 15 years to 80 years.
Training is always better with a sea view, especially when you go with a friend or trainer.
These gyms are free, you just have to bring a bottle for water, a towel and you are ready for the workout.