So just any activity will do, as long as you like it enough to do it regularly.
The rest is refinement.
Strength training and controlled cardio is much better for continuous health.
> Key Points
> - Improvements in joint position sense can be attained via standard strength-training exercises.
> - Performing resistance exercises at consistent intensity rather than varying intensity resulted in better proprioception performance.
Systemic and muscular vitality is optimized when you get cardio, resistance, and bounding/dynamic movement. Heart, slow twitch, and fast twitch.
Ordinary running doesn't do that, though there is a practice called "fartlek" (literally, speed-play) where you do random bursts of speed. It used to be considered excellent cross training, though I haven't heard the term in a while. (Perhaps because the name is unintentionally hilarious.)