Mindfulness in the gym

Do you have ADHD and find it difficult to do a formal mindfulness practice, even a short one?
Try to observe for a few minutes how your muscles feel during your exercise session in the gym. Observe the changes between tensing and relaxing, feel if there are differences between your left and right arms or legs, observe where and how do you feel the difference between challenging a certain muscle in a healthy way and pushing it too far. This is mindfulness too.