Merida is very keen on exercise especially marital arts and training in use of various weapons. On top of that she is very active and outgoing, making as much use she can of the day. She often tries to as many varying activities as she can in a day or week. Because of this she is an accomplished fighter and has a great deal of commitment to keeping herself in good physical shape. It does help that she has the memories of several pervious hosts who were very athletic to draw upon, though it is certain that she would be much more active than Tanel in either case.
Kax’s first host, Tanel, on other hand was lethargic, insensitive, cantankerous, vindictive, obnoxious misanthrope though in a good way. Still he would have a hard time to motivate himself to get out of bed in mornings let alone committing himself to regular exercise and was very much of a slacker. When he first set off on his explorations he couldn’t swim or run very far, though one thing he did do well was walking and when he needed to, he could crawl and climb to get out of tight spots.