We have a female bullterrier, Patrys, at home. We got her as a puppy and grew up to be quite a strong and healthy dog.
The day Hiccup, a tiny Staffordshire pup showed up we did not know what kind of reaction to expect from her. She showed us, however, that she had a very caring attitude about her and took to gently playing with the little one.
As Hiccup grew bigger and bolder the games the dogs played became rougher up to the point I began to worry. Both dogs, however, showed that they are strong enough to handle each other.
The next pup to be raised and trained by her was Bruno. His tackles can put an ITM Cup player to shame. :D
Observing these dogs gave me my philosophy on sparring. If one uses discretion, sensitivity and patience one shall have no need for body armour, mitts, shinguards and-my least favourite- a mouthguard.
As one gets stronger blows can become harder and attacks more forceful. Two styles which seem to share this phikosophy, or that unwittingly demontrate it, are Kyokushinkai and Muay Thai. Exponents of these styles appear to try to kill each other, but if one bears in mind that these are fighters with bodies that were conditioned to take these blows. Resilience is one of the gifts the martial arts have for us.