… what would be the optimal position to minimize injury? What would be the areas you cover with your hands/arms?
I would guess feet first, and cover your face.
I’d throw something through it first
Second for that but if I had to take a running leap and bust through I would go head down slightly, arms crossed over face, and lead with the elbows and knees. And praying I don’t slash a major vessel on the way through.
I can’t think of anything outside of a suit of armor, but I think that would preclude the ‘jumping’ part being heavier than shit.
Like a… Jackknife Juggernaut?
I witnessed a guy crash through one on purpose. He was a shoplifter that we just cornered and had back in the office. He was a repeat offender and decided not to stay. Tucked his head down and crashed through plate glass with his left shoulder leading the way. Ran away and left a dribble of blood. We were all stunned that it even happened.
He turned himself into the hospital about a mile away, bleeding horribly.
I had a friend who had to do this naked after her husband shot her lover; jumped right threw the picture window in the living room. She said she didn’t have time to think and just threw her hands in front of her face and just bolted. Apparently that worked out pretty good because she hit the ground and kept running before the glass had a change to fall to the ground. A few minor cuts but not too bad. Adrenaline, what a drug.
As a kid I was playing around on the linoleum basement floor sitting on a shipping dolly. I managed to get myself moving backwards at a good clip and went right thought a plate glass window. I think the bottom of the dolly hit the window first, but my back hit it as well. I saw sheets of glass drop in front of my face as I flew backwards onto the patio but didn’t get a scratch on me.
That’s how I’d go through a window. 
Throw something through it first is a good idea.
It depends on what kind of glass the window is made of. If it is tempered glass it is about 7 times stronger than regular glass and you might not be able to break the glass at all. You might throw your body against it and just bounce off. You can hit tempered glass with a baseball bat and not break it, you need something sharp to break the skin and then it will easily crumble into 1/4 inch bits.
Here is a Snopes verified story about a lawyer in Toronto who used to demonstrate the strength of the office windows in a high rise office building by throwing himself against the glass and just bouncing off. Of course, one time he did this and the whole tempered glass window popped out of the frame and he plummeted to his death.
Do not try this at home.
Be warned…
I had a friend bash through a window with both hands when I was a kid. The glass broke along lines radiating out from the centers, which turned the edges into razor-sharp knives that inflicted long gashes along his forearms – just like the recommended way to slash yourself if you’re serious about committing suicide.
He bled profusely, and needed lots of stitches. He healed up, though.
The memory has stayed with me. If I had to go through a window (instead of breaking it beforehand), I’d prefer to go through back first, curled up in a ball, with my head inside and well-protected.
Not gonna put this to a test…but I’d vote for going through backwards.
I’d rather have my back ripped up than my tummy. The shoulderblades, spine, and ribs offer some protection. In front, the ribs offer some protection also, but there are more vital organs in front than in back. In back, kidneys. In front, all the good goopy stuff: intestines, liver, stomach, pancreas, and all those other little pieces that are missing from my “Visible Woman” model.
The old wedding tackle, too.
There is no other answer than this one.
What you do is turn around and kick near a corner with your boot. Once the glass is broken, you can then easily remove the rest of the glass and then jump through the empty frame.
Hey, no one said you were in a hurry!
(Does the OP need an answer fast?)
Back First, arms tightly at my sides - those things are loaded with lots of veins VERY close to the surface.
Keep in mind - your blood supply in on the front and on the inward sides. the last thing you want is for your neck (arteries AND veins on surface) to be among the parts enlarging the hole.
The idea of the stunt in the movies of jumping through with your arms extended is a real good way of leaving a really big trail of blood.
I’ve actually personally done this. I went through hands first. Got a few small cuts on my hands as a result. Don’t try this if the glass is too thick - this was a large window with thin glass, probably not tempered.
I put a hand through a glass storm door when I was almost six. There was a lot of blood. I vote for trying it backwards next time.
Don’t let your dog try it either.
All those old shows where Rin Tin Tin crashes through windows are faked. The windows were actually made of carefully prepared sheets of sugar. Rin Tin Tin got to eat them afterward.
(BTW, the article suggests that the legend of Rin Tin Tin eating steaks served on a silver platter by a majordomo, and drinking milk from champagne glasses, were all basically just tall tales.)
And wearing a thick, padded leather jacket.
Also, a hat. I don’t want to be picking glass out of my scalp for the rest of my life.