This was news months ago, but:
1. Even professional Olympics volleyball players cannot aim their spikes precisely enough to hit another player's head;
2. Anyone who thinks women volleyball players do not spike just as hard as men has not watched men's and women's volleyball (or are watching, ummm, elsewhere when watching women?).
Before anyone imagines I'm defending a man playing in women's volleyball, no, I'm not and would not. I'm just pointing out that the spiking player's sex was not the cause of the severity of the woman player's injury.