What I find fascinating (!) is the way you can tune yourself to be better at different sports.
Not enough strength? Do some weights and swim.
Not enough cardio fitness? Run and cycle.
I've gained and lost weight "to order" a number of times and find it amazing how much is affects performance at different things.
Was a bit slight at 9.25 stone so slogged at the gym and gained 3 stone.
Found this a bit OTT for surfing and martial arts so trimmed off a stone by running and cycling a lot more.
Hard to find a balance that suits but it's pointless being massively bulky if you want to do triathlons or XC racing. But also daft being a super light whippet if you want to swim/surf/do martial arts.
You can't control what you look like (!) but you can control your physical strengths with a bit of dedication.
This is why I have no time for those that moan about not being able to lose/gain weight.
As for fitness – Boxers and triathletes are some of the best allrounders – cardio fitness with strength.