Flipped upside down on lead fall (how/why?)

Today while leading a route in the gym, I fell and ended up upside down. I cannot figure out how/why.

Here are some potentially relevant facts:

• I had just done a campus move out from a roof, onto an overhanging face. Right before I fell, I had both hands on a hold, with my feet dangling directly below (i.e., not on anything at all). The fall itself was not mid-movement. I just decided I was too pumped to try the next move and let go.
• The last draw clipped was on the roof, so roughly the same height as my knot and probably 2 feet directly in front of me.
• I'm 99% sure I was not flipped by catching the rope with my leg, because I didn't feel any contact with the rope, and my belayer and two observers both indicated I didn't hit the rope. (Also, given the way the rope was running relative to my body position, it would have been almost impossible to catch it.)
• It was just empty air underneath me, so I did not, for example, hit a hold with my foot on the way down, flipping me over.
• My knot did go through both of my tie-in points. (I've seen some people get tipped before when they missed their top tie-in point.)
• In case it matters, my belayer outweighs me by some, but not a ton. (I'm 140 lbs, and he's maybe 25-30 more than me.)

Any guesses? Of all of the things I've seen/heard of causing a person to flip, none of them seem to apply here. I was right-side up, then I wasn't, and I still don't know why.

Angular momentum of the fall. You were short-roped, in other words and that force just served to tip your balance out, and over? More slack in the belay would likely have prevented? 

What do you think, plausible?

hear to chime in and say this is why you always wear a helmet sport climbing!

Cherokee Nunes wrote:

Angular momentum of the fall. You were short-roped, in other words and that force just served to tip your balance out, and over? More slack in the belay would likely have prevented? 

What do you think, plausible?

Thank you for the reply. Yes, that seems plausible. (But my physics education did not extend to angular momentum.   )

I have a vague sense that it was a pretty hard fall, but it's hard to judge, because this is the one time I've ended up upside down in roughly a decade of climbing, so suffice to say the experience is hard to compare to other falls.

Also, the belayer says that he didn't feel very much force, so perhaps it was rope drag -- which would increase the short-roped effect, regardless of what the belayer was doing.

Was it truly a horizontal roof? Maybe you leaned back to prevent yourself from hitting your chin on the wall. That would have sent your feet forward and up, causing you to spin backwards even more. More rope would've fixed that. 

drew A wrote:

Was it truly a horizontal roof? Maybe you leaned back to prevent yourself from hitting your chin on the wall. That would have sent your feet forward and up, causing you to spin backwards even more. More rope would've fixed that. 

The roof itself is, as near as I can tell, perfectly horizontal. My hands were exactly 1 hold above the roof onto a face that's maybe 30 degrees overhanging.

Given that my face was not really above the roof, I wasn't consciously afraid of hitting my face on the roof, nor was I doing anything intentional to avoid such. But I suppose it's possible that I made such a movement without thinking about it. (The whole thing was super quick and disorienting, so the brief moment between letting go and finding myself upside down is hard to assess.)

Thank you for the hypothesis.

I suspect the poles of the earth shifted at the very same moment  that you let go. Lucky you weren't flung off the planet!

https://www.ukclimbing.com/news/2017/08/mina_leslie-wujastyk_-_harnesses_helmets+head_injury_at_malham-71253

Worth a read. Mina’s conclusion was harness too big. 

Same thing happened to me on an outdoor route a few months back - I like the angular momentum idea to explain the upside down fall.

I definitely didn’t have my leg behind the rope, but as I threw for the hold I peeled off a little sideways and I kind of helicopter fell (spinning and upside down).

One thing to note is when you tie in keep the tie in points as close together as possible as this will minimize the potential for a “spinning fall.”

Maybe you lifted your legs to brace for impact, and that moved your center of mass above the tie-in ?

Your tie-in point may be too low. Is your upper body more massive than your legs relatively speaking ?

jbak x wrote:

Your tie-in point may be too low. Is your upper body more massive than your legs relatively speaking ?

Jonathan Lagoe wrote:

https://www.ukclimbing.com/news/2017/08/mina_leslie-wujastyk_-_harnesses_helmets+head_injury_at_malham-71253

Worth a read. Mina’s conclusion was harness too big. 

Hmm. I did get a new harness very recently. It's the right size, I'm confident. But now I'm starting to wonder if the tie-in points are a smidge lower than on other harnesses I've had. (Prior to this I went through three BD Aspect/Technician harnesses -- love the 5th gear loop!)

As far as my body proportion...maybe? I climb a lot, but I don't think anybody would use the word massive to describe my upper body. But maybe my lower half is even less so.

Thanks again, everybody. Really appreciate having some people think through this with me.

It is possible to raise your tie-in by looping an extra piece of webbing snugly around your waist. I tie my chalkbag with a waterknot and loop the rope thru both that and my harness.

Mike P wrote:

Today while leading a route in the gym, I fell and ended up upside down. I cannot figure out how/why.

Here are some potentially relevant facts:

• I had just done a campus move out from a roof, onto an overhanging face. Right before I fell, I had both hands on a hold, with my feet dangling directly below (i.e., not on anything at all). The fall itself was not mid-movement. I just decided I was too pumped to try the next move and let go.
• The last draw clipped was on the roof, so roughly the same height as my knot and probably 2 feet directly in front of me.
• I'm 99% sure I was not flipped by catching the rope with my leg, because I didn't feel any contact with the rope, and my belayer and two observers both indicated I didn't hit the rope. (Also, given the way the rope was running relative to my body position, it would have been almost impossible to catch it.)
• It was just empty air underneath me, so I did not, for example, hit a hold with my foot on the way down, flipping me over.
• My knot did go through both of my tie-in points. (I've seen some people get tipped before when they missed their top tie-in point.)
• In case it matters, my belayer outweighs me by some, but not a ton. (I'm 140 lbs, and he's maybe 25-30 more than me.)

Any guesses? Of all of the things I've seen/heard of causing a person to flip, none of them seem to apply here. I was right-side up, then I wasn't, and I still don't know why.

I've seen this happen many times in the gym, you probably need to wear your harness higher than you think, tighten the waist first then the leg loops. When people tighten the leg loops first it tends to pull the waist down too low.

If the loop below the tie in knot is too big, it can cause twisting as well

A random web search found this:  "A man's center of gravity is located at the center of his chest at his sternum "   No doubt, this is not applicable to all men.  And, yeah, I'm assuming your a guy.

You indicated the last draw was ~ 2 feet directly in front of you. 

If there is not a lot of slack in the rope, you'll get pulled inward at the back of your harness and your CG pull your upper body away from the draw.

Bill Lawry wrote:

A random web search found this:  "A man's center of gravity is located at the center of his chest at his sternum "   

I think if the human center of gravity was at chest height everyone would tilt backwards when hanging in a climbing harness. 

Astrid Rey wrote:

I think if the human center of gravity was at chest height everyone would tilt backwards when hanging in a climbing harness. 

CG is a malleable thing in a human. Move the legs, arms, …. arch or bend forward the back, etc.. a bit …. and all can be well. We tend to adjust it almost intuitively.  

Edit: And, when you are hanging by your arms and otherwise relaxed, your CG isn’t optimal for a draw inward / under a roof.

Bill Lawry wrote:

CG is a malleable thing in a human. Move the legs, arms, …. arch or bend forward the back, etc.. a bit …. and all can be well. We tend to adjust it almost intuitively.  

Edit: And, when you are hanging by your arms and otherwise relaxed, your CG isn’t optimal for a draw inward / under a roof.

Center of gravity in a normal standing pose is around the belly button. That can change very slightly by moving our arms upward but at no point will it be at chest height unless one is a contortionist with their legs. 

If center of gravity was anywhere near chest level we would tilt backwards constantly when hanging in a harness. It's easy to confirm. Just bend your waist and hang over a railing and your are more or less balanced. Then try balancing with the pivot point at your chest. It's going to be impossible no matter what you do with your arms and legs.  (If you can make your chest the center of gravity by positioning limbs then you should work for Cirque du Solei.) It is also very intuitive since there is clearly much more mass in human anatomy below the chest than above.

How big is your head? 

I can think of a couple reasons why you might have flipped, but the short answer is that you were short-roped on the fall. By my thinking, this makes a flip more likely for two reasons:

1. You have less time to react. Your body will automatically react while falling to control your rotation. One way this happens is by lifting your legs, which crucially extends your center of gravity (CoG) forward beyond the belay loop. You can see how the CoG changes in Fig 2, denoted by the green circle. You will always rotate about your CoG. In Fig 1, the climber falls with straight legs and is immediately caught and flipped backwards by the rope. In Fig 2, the force of rotation would actually be slightly forward towards the wall.
2. Direction of pull. Force in the vertical direction will not cause a rotation--the rotation is caused entirely by the horizontal component of the arresting force. If you're familiar with torque calculations: the line between your CoG and the belay loop is the moment arm, and only force perpendicular to that line will cause rotation. In Fig 1 with a short rope, the horizontal component of force is much greater because the bolt is right in front of the climber. In Fig 2, you can see that the force is mostly vertical and doesn't generate much torque.

This isn't based on any specific climbing knowledge, just over-simplified MS Paint models and some physics education. If anyone can think of an objection to these points I'd be glad to hear it.