Tough Guy

 is a perk in Fallout: New Vegas. Repeatedly breaking bones has led them to become stronger.

Effects
(Speculation) According to the description your limbs get more resistant to damage the more often you get crippled. Theory is that your Limb HP increases by 1% (rounded up) each time you cripple that particular limb. Note that this calculation is made for each limb separately. (needs confirmation)