[klibertp]

The same as with every other sport: injury. You don't want to risk injury by extrapolating a faulty training method from magical thinking. In my experience, the arts and systems geared more towards full-contact spars have way, way less Ki/Qi in them.

[soco]

Hmm I definitely cannot say the training is faulty. You cultivate (in Aikido) exactly the harmony of movements which also without spiritual dimension can be understood and practiced in a very physical, efficient and safe way (as safe as martial arts go, duh). Whereas with krav maga for example there's nothing of this, not because ki is missing (it is) but because it seeks efficiency instead of beauty. Or maybe it's only me not able to find the right balanced system...