I always try to express what I have just learned in my own words or game systems. Its a learning trick that allows me to build up an intuitive understanding of things with the least memory clutter.
Game design has always been my crutch to overcome my mental limits. If I can express it in a game system correctly, then my understanding is pretty good.
Lately, I've been tinkering with my health. I'm trying to lose waistline (not necessarily weight), like many people, and my readings regarding nutrition and fitness seems to go against the understanding and simplification of some game systems.
I know, I know... The standard of reality is never to strict as to be imposed on the fun of games. Still the anti-tweaking attitude is tantamount to argumentum vericundum in a hobby that is supposed to be democratic.
So anyway, other than my other readings I'm trying to lose weight and bring up my endurance. So i read up about calories, basically the energy requirement of the body. I remember the physics I've been trying to relearn in my short sword exercise.
I've begun to wonder: What is Strength and what is Constitution (or Health)? In GURPS strength is related to mass. After reading up about how bone density can be conditioned to be increased and of course the genetic disposition, and considering height in the body's architecture strength seems to be very measurable.
Strength. I don't mean to step on the parade of people who would like to imagine themselves stronger than their mass would give them credit for. Their are limits, and an engineer as much as a physical therapist, or a biologist will tell you that there are costs and trade offs.
of course there is a kinesthetic element in strength. The ability to shift balance quite precisely in lifting a heavy object maximizes mechanical efficiency of the body. So flat out, mass (muscle and bone mass) is not the primary affect on strength there is some Kinesthetics to it.
Strength is the ability to exert a range of power. A professional boxer able to throw 450J is a combination of muscle, dexterity and mass. one can attribute the kinesthetic aspect to the skill of the boxer, allowing him to multiply the mass transfered and attack precision. Still, strength plays a role in generating the basic level of power.
Strength can be compared to Amperes. The amount of Energy that can be commuted by the body in an instant of time. The more muscles, the more "pistons" are able to contribute in that single chemical burst that results to mechanical force. In this method, you can build a system that bench marks the strength in terms of amps
Endurance, the stamina and metabolism aspect of health or constitution as opposed to its other parallel properties, is very tricky. It is both a battery and a generator. One thing to that deserves some attention is the basic calorie requirement of the average 150lb human, 2000 calories. If I were to convert that to a more familiar energy, that would be around 350 watt-hours or 0.1 watt-seconds. taking in the modifiers like low-activity lifestyle and endurance sport (Iron Man, marathon running) and military requirements.
If you look at the iron age professional soldier (at 150lbs; 68kg) marching 24km (15mi; 6 hours) in full kit (60lbs; 27kg) once a week (de re militari) that is roughly 2100 cal. That is roughly a ~3000 day, averaging an energy generation capacity of 517 W*h or 0.14 W*S. About 50% better than a semi-active person.
If you consider the two premises, you might notice that someone who will try to increase their strength will naturally have to improve their Endurance since the person's body begins to consume more energy and you need time to effectively build muscle mass. There seems to be a natural equilibrium and relationship with strength and endurance. I think it would be rare for a 350lb Strong man to have a limited endurance...
Of course in the exceptions, another thing worth noting is how being "overweight" affects calorie consumption. A high BMI, where the person is encumbered with fat tends to burn up more calories because of the mass they are naturally moving around. So It actually "penalizes" efficiency, along with the cardio-vascular conditions inherent with a high fat ratio.
I guess I have to dig into my military handbooks for some more benchmarks. Although ideally, a 20% cumulative increase should suffice. As for stat limitations, extraordinary specialization: where both strength and endurance increase at the expense of the other should be benchmarked. The way you cannot find an Olympic endurance runner with the body a Strongman or vice versa. The optimization cap, basically starts making the economic limitations of the body quite visible because of the diminishing returns.
How about Fantasy?
Dwarves being short but powerful. Height has some problems, if you've read about the Castrata who become giants because of the coincidental timing of their castration suffer poor limb strength. This is due to the proportions of humans, which past a certain height has diminishing returns.
So imagine a human whose bone density has mutated to 20%-40%. Maybe, because of breeding selection by an outside force that required strength without the vertical advantage, you can have dwarves. Of course, remember that there is always an expense in evolution. Diet tends to "buffer" the biological cost. A diet of high in calcium can allow dwarves 20% shorter but 20% more massive. These values are set arbitrarily btw.
where humans have a (2.33*h)^3 = mass, the dwarves have a (3.18*h)^3 = mass. A 1.4m or 4'8" the average dwarf has a mass of 88kg or 194lbs. Depending on the logarithmic advancement of stats at a 20%, he is a point of strength better than humans. Naturally they will have a higher energy demand, so they will be more fat-ready biological design.
It would be interesting to note that I heard of instances people having crushed shells into their food. I personally eat the shrimp shell and all (except the head) when cooked in a way to soften it. A carnivorous diet of Insects: high protein and calcium, would be perfect for dwarves. Especially when they have subdivided these critters into their human equivalent.
Their pork, giant slugs or worms rich in calcium in soft chitin, fats, and a useful waste consuming omnivore. Their chicken would be an omnivorous scavenger, picking on insects too small to eat and their excess starch based basic food unit. Their cows and goats (a smaller version of the cow), which provides a a rich variety of secondary products could be giant amphibious beetles that dwell in nutrient rich underground lakes and rivers fed by volcanic nutrients and energy (2nd law of thermo dynamics). Soft boned frogs and amphibians would also fit as a diet rich in calcium.