Worrying over this can be fun, but not necessarily productive. If we were to break down relevant, inherent human abilities into stats, we're almost certain to get more than six. E.g:
Muscle speed: essentially a measure of fast-twitch muscle fiber percentage. Prime determinant of how fast you can run or perform gross motor activities like dodging, but nowhere near as correlated with reaction time as is typically supposed. Also involves other explosive tasks, like jumping.
Reaction time: how fast an impulse is carried by your nervous system up to your brain, the data is processed, and then carried back down your nervous system to trigger your reaction. Perhaps counter-intuitively from some perspectives, this is actually substantially correlated with IQ.
Agility: inherent ability at gross motor skills like dancing, tumbling, etc. Coordination, I guess.
Manual Dexterity: probably substantially correlated with IQ, and in some circumstances, reaction time. Think competitive twitch video gamers.
Strength: muscle power. Actually somewhat less correlated with striking damage than many assume. "Power" is more relevant; the strongest boxers don't hit the hardest, because speed contributes to power, too.
Stamina: conditioning, very much a matter of training, age, health, etc.
Power: how much energy you can generate in a very short interval (e.g., in a strike or push); function of strength and speed.
Health: immune system, etc.
Comeliness: beauty, youth, physical symmetry, proportion, etc.
Intelligence: problem solving ability and speed, memory
Charisma: quick wits, confidence, etc.
Willpower: determination, resolve, etc.
Those are the ones that jump out at me. I could see maybe breaking Memory out as its own stat. Also, not sure how to derive abilities like throwing a football. It doesn't seem all that correlated with agility - the best passers are often not "athletic", and people with good manual dexterity often can't throw worth a damn. There are probably lots of skills that are "their own thing" like this. On the other hand, maybe "aim" should be its own stat; I'm sure good passers have good inherent ability at stuff like archery, shooting a basketball, etc. "Hand-eye coordination" seems to be the parlance.
Then there's balance, which could be considered part of Agility, or its own skill.
Realism requires a computer to simulate, really. Any pen and paper system is going to have to do a lot of fudging, much of which is going to feel arbitrary, abstract, or both.