>>715848057 (OP)1: most anti-personnel grenades are FRAGMENTATION grenade. They release a large amount of shrapnel that tears though people at incredibly high speeds. A frag grenade can blow off an entire limb with a combination of explosive force and materiel.
2: high-explosive grenades release shockwaves that are powerful enough to collapse your lungs, gives you concussions, rupture other air-filled organs such as intestines and even cause blood vessels in your brain to burst. At close range, the combination of heat and force will simply rip your body to pieces.
tldr: the air moves so fast your body can't withstand it and instead of the air moving around your flesh, it simply goes through it. Sometimes there are also metal fragments in this air.