It’s amazing how creative you can be with training on low bars.
Sven and Alex showed a variety of workouts in this video, including a good lead-up drill for those trying to achieve their first pull-up (at 0:17), push-ups on a bar (0:34), assisted pistols followed by pistols on a bar (2:20) and many other exercises, most of which require great strength, balance skills and endurance.
They say they only do regular and weighted Calisthenics, without weightlifting.