I wouldn't say "Kraft" is analogous to skill in German. In fact I'd be willing to say it's never used in that sense. "Fähigkeit", "Fertigkeit", "Kompetenz" and

I wouldn't say "Kraft" is analogous to skill in German. In fact I'd be willing to say it's never used in that sense. "Fähigkeit", "Fertigkeit", "Kompetenz" and a few others are usually used for "skill". "Kraft" can have a spiritual meaning of sorts (vitalize) though. "Kraft schöpfen" is often used to sort of mean gather your thoughts and get revitalized. That's how it's used in KdF. I guess "mental strength" fits most closely in the KdF example. There's also an old-ish word "Geisteskraft" which means something like mental strength. However it does have a different connotation than skill.