Realistic Human DR

[Pursuivant]

Both Martial Arts options are bordering on cinematic, but could have realistic explanations. Tough Skin is more likely than Ablative.

If you want hyper-realism:

Nominally the human skull provides DR 2 for the brain but that's perhaps a bit cinematic as well, since living bone isn't as rigid as dry bone and any injury which hits the head hard enough to inflict HP damage as the potential to inflict Traumatic Brain Injury (TBI). At best, it provides DR 1 vs. kinetic attacks (cr, cut, imp, pi), DR 2 vs. burn and corrosive attacks.

The human rib cage should provide DR 1 (Ablative, Limited (Only vs. crush, cut, burn & corrosive) for the Vitals.

The spine should provide DR 2 to protect itself (Ablative, Limited: Only vs. crush, cut, burn & corrosive).

Fat, thick muscle, scar tissue, or similar might give DR 1 (Tough Skin, Limited: Crushing only, Not for Head or Groin).

Realistically, people who play contact sports do suffer massive bruising, it's just that it doesn't immediately show. The same thing is true of normal people who suffer massive crush trauma. The damaging effects of the injury don't really kick in until after the wound begins to heal, when all the crushed, dead tissues starts to be broken down. At that point, the massive increase in waste products in the blood stream can overload the kidneys.

That suggests a potential modifier for DR:

Delayed Damage Onset (-20%): Your DR doesn't actually protect you, it just prevents damage from affecting you as quickly. If you take this limitation, keep track of all points of damage you suffer. At some point in the future, specified when you take this limitation you suffer all the deferred damage at once. Choose any delay from 1 hour to 1 week (although 24 hours is most common). Deferred damage might be due to supernatural or superscience effects or just the fact that your body doesn't respond to the damage as quickly. This limitation is commonly associated with the Ablative or Tough Skin limitations.