It is not a matter of the force, so much as it is about what was affected by the force. Boxer getting hit, or anyone falling down 5 feet, it depends on what happens in the head. A slight force in the wrong area, that bursts one of the blood vessels on the outer surface of the brain,(like they showed on the news), can cause the bleeding. OR, since a huge percentage of the world is walking around with aneurysms, and don't even know it, she could have had one, (an aneurysm is a bulging, ballooned part of any blood vessel, vein, artery, whatever), and if just the right force made it burst, this would also cause subdural bleeding.
The whole deal is, that until your head hurts, you don't know anything is wrong, and even after it does, if you don't go to the ER right away, your friends and family might not even realize that anything is wrong with you, because you seem lucid to them.
Believe me, I have researched this for years, ever since I had a brain aneurysm that burst. If I had not realized that the headache was "weird", and called the ambulance, I would have died. I called my family to meet me at the ER, and that's the last thing I remember for 3 days. However, my sis said that I talked clearly for hours, and I wouldn't even let a nurse take me to the bathroom......and I guess they hadn't done the Cat Scan yet, because they let me walk around by myself, that was how normal I seemed to the world.
After the Cat Scan showed the blood pooling in my brain, they transported me to another hospital with better neurosurgeons. From what I gather, it was a miracle that I made it there in time for the surgery. Afterwards, the doctor said I had had a 10 percent chance of living through the surgery,,,,,,,but I did,,,,,,many others never have time for all the moving from hospital to hospital, thank goodness I called the ER right away, and also my bleed must have been slow.
Anyway, researching all this jazz for the next year, trying to understand how they fixed my aneurysm with a "coil", a platinum wire, threaded up my leg artery, all the way to my brain, since it wasn't reachable from the skull, (thankfully someone invented this about 12 years ago)---I was amazed to find out that something like 30 percent of the world has aneurysms waiting to burst,,,,,,OK, I can't remember the exact percentage, but I just remembered it was freaky.
Basically, I'm just so saddened by Natasha's death. I have followed her grandfather's, mother's, aunt's, sister's,husband's, and her careers, all my life. I feel so sorry for her sons. God Bless them all.