If you jump from a table and land with your knees locked, why are you more likely to be hurt than if you land with your legs relaxed?
What has happened is the pressure which is applied during the fall
Actually, when you force the nip of the pen into your hand, you get more pain than when you force the head of the pen into your hand.
During the case of falling, knees which are locked, have a more area than the relaxed legs,
You apply the same force, but on different area. When the area is large, then the pressure the less. When there is small area, the pressure is much higher.....