I have no documented, clinical, legal or otherwise proof of this tip, but I thought it would be worth the suggestion.
Here's my fitness tip:
I personally like running. It's exhilerating, going fast; however, it can be hard on the tibia bone (shin bone, in the form of shinsplints), feet, ankles, and sometimes the knees due to the impact. Running provides great cardiovascular exercise, muscular endurance exercise, and after extended exercise (such as track team practice), provides a runner's high.
To get rid of the downsides of the pain from ankle and knee impact, and not deal with shinsplints, I suggest the use of an exercise machine such as the orbitrek (yes, an old machine, but the only example I know of). Such a machine provides a cardiovascular and muscular endurance exercise without the downsides of impact pain and shinsplints. The majority of the body's muscles get a workout on top of the cardiovascular system.