UKC

"It's well known from DAV studies that you will probably deck if you blow the clip up to the 5th bolt with indoor spacing of bolts."

How many people here didn't know this?  I fully admit that I didn't.

(From this thread https://www.ukclimbing.com/forums/rocktalk/real-world_fall_forces-693768 )

In reply to Offwidth:

What's the solution. More bolts per route? A wall I use has only 4 on some, excluding the lower off, on the shorter ones. 

In reply to Offwidth:

I was considering replying to that statement and saying I don't believe it, but thought I was just being stupid. Does this mean that most falls below the 4th or 5th bolt on an indoor wall end up on the ground? Obviously if one falls from a foot above any bolt one would expect to be held, but perhaps not nearer the bolt above. Surely it depends on the distance between the bolts and whether one pulls out slack to clip above the head or clips at waist level. Wouldn't there be far more accidents if the statement was generally true? Am I completely misunderstanding?
Incidentally I hardly ever use climbing walls or sport climb but the same principles apply to trad.

In reply to Offwidth:

You won't "probably deck" if you fall below the fifth bolt (that's roughly half way up most indoor walls). If you clip from a sensible position (i.e. not from really far below, taking unnecessary slack out and lobbing off with that slack in your hand) and your belayer doesn't get massively displaced (because the first bolt is clipped/they aren't far lighter than you/you're using a Petal Ohm, etc) then you'll fall x2 the distance above your last bolt plus stretch, which won't be enough for a ground fall if you're at the 5th bolt.

The thread you link to links to a discussion where there is severe belayer displacement and significant slack in the system. These things are not "probably" going to be true for most falls between bolts 4 and 5 in the gym. Ergo most falls won't "probably" result in decking.

Otherwise, you'd see people hitting the deck at the gym all the time. But you don't. And loads of people fall off before the 5th bolt. I do it regularly. If your belayer knows what they are doing, and you aren't needlessly pulling out slack, you're not going to hit the deck.

In reply to oldie:

I read it the same as you and it just isn’t true. I fell last year indoors  just before I clipped the second bolt when the hold I was on snapped in half. My belayer held me even though she is 10 kilos lighter than me. The main issue was people thinking a gun had gone off and a flying hold which could have hurt someone had it hit them.

If you fall below the 5th bolt a competent belayer will hold you. That study appears to be completely misleading in my opinion.

In reply to Offwidth:

I've not read the report in detail but I have to say I was amazed by the length of the falls in the videos, which seem quite excessive unless the belayer is deliberately giving a soft catch - which you would not do on a  low bolt precisely because you don't have the air time to play with. In my personal experience I have never been dropped that far, especially indoors where bolts are close together.  I fall  reasonably often on sport climbs both indoors and out and at 85kg I am heavier than most, if not all, my belayers, sometimes by quite a bit, especially when climbing with women. I've been held on first and second bolt falls without decking it and I have held leaders in that situation myself. Belayers have been using various ATC-type devices,   the Click Up and the Smart  as well as a Gri Gri and it has never been a problem with an attentive belayer.

In reply to Offwidth:

I'm guessing I'm probably the only person here who has actually attended a DAV belaying course? 

"Probably" is overstating the case. They do demonstrate that coming surprisingly close to the ground from clipping the fourth or fifth bolt is *possible*, and emphasise that up to that point the belayer needs to be close in, pay attention to minimal slack, and be more concerned about actually stopping the climber than exaggeratedly soft catches. All basic sensible stuff that I would expect any competent belayer to be aware of.

In reply to AlanLittle:

I mean, the statement as quoted in the OP simply isn't true.  A fall practice routine I have used and demonstrated many many times at my local wall (Brookes) is clip 4th - climb level with 5th - pull up just enough slack to make the clip - drop.  With a climber and belayer of roughly equal weight, and belayer positioned sensibly but not overly wary, the climber does not end up below the belayer.  And this is usually done with an ATC, not a gri-gri.

 

I think a far more reasonable statement would be that it is possible to deck as high as the 5th clip.

Mind you, all this has reminded me how easy it is to hit the floor around the 3rd and 4th clips, a region in which I imagine a fair proportion of people assume they are 100% safe.

It's bollocks.  Let's assume "probably" means a reasonable chance of decking out (as in without much doubt) and give this a value of P_deck>=0.5.  Well experience tells us that significantly less than 1/2 of all falls up to the 5th bolt result in a ground fall.

"possibly" is more like it - especially with crap or novice belaying, poor clipping and with badly designed bolting.  I've once touched the ground from a 4th bolt "fall" and once from a 5th bolt "fall" and both were belaying mistakes and neither of which were falls and in both cases a better belayer would have resulted in no problem. I've been held and held falls from bolts 1-5 with no ground contact and this I think is the norm.

The most likely scenario for ground contact is being 1-2 up height on a top rope on a long climb (because of rope stretch).

It is certainly worth highlighting that a ground fall is perfectly possible with a combination of clipping really high, slack in the system and poor belaying but this isn't the same as "probably".

 

In reply to Offwidth:

I didn't know about the study, but had worked out for myself that clipping above your head is dangerous. 

I see very few people try hard enough to fall off which is probably why we don't see many accidents indoors at the 5th bolt. I mostly observe people screaming take and down climbing and slumping onto the last clip rather than taking a fall from above a bolt.

In reply to Jon Greengrass:

Me too in the UK. In my experience significantly less so outside of the UK.  In my opinion Brits mostly don't "get" sport climbing, and tend to approach sports routes as if trad routes.  It's always surprised me how unwilling Brit trad climbers are to take short safe falls on bolts, especially when the same individuals tend to like to emphasize how they are "slumming it" (as one guy told me) because they are on holiday.

I await a deluge of dislikes from the Ron Hill wearers with bated breath. 

In reply to Offwidth:

T

The perceived wisdom was always that you deck if you pull up slack to clip from below the third bolt.  Can be demonstrated on an easy route: pull up the rope to clip and then down-climb without clipping and the belayer not taking in the rope at all. you can stand on the floor. 

5th? surely you'd be fine.

In reply to Offwidth:

My GF fell off at the third  bolt recently, outside, and didn't deck or come close to it, we use a click up, but it's good to have threads like this to make you think. I see huge amounts of slack sometimes when watching others climb, which would worry me if I was leading.

In reply to Jon Greengrass:

I'm with you on this one. I rarely see people take falls (as opposed to slumps on the rope) indoors in the UK and I quite honestly can't remember the last time I actually saw someone "blow the clip" resulting in a fall.

Whether consciously or unconsciously people tend to avoid really precarious clips. As such, the specific safety advice that messing up a clip low down on a route is potentially dangerous is rather stating the obvious and probably doesn't add too much to the debate.

 

In reply to Offwidth:

You will hit the deck with a poor innatentive belayer stood 15ft out from the wall scratching their arse looking at the floor , the whole "soft catch" thing has a lot to answer for as well.

In reply to The Ex-Engineer:

I managed this last week. First time ever.

In reply to The Ex-Engineer:

I wonder if, at least in part, this is a result of route setters getting better at providing decent positions from which to make the clip?

 

 

In reply to Offwidth:

I've taught that you can deck if you blow though any clips indoors (all walls round here are about 10m high) to everyone I've taught to lead (100s of people). Is this really not common knowledge?

An additional danger is trying to clip high, missing the clip and falling with rope out. It's possible to deck from similar heights. 

In reply to Offwidth

Taken thousands of falls! Never hit the floor! 

In reply to Offwidth:

A deliberate lob taken whilst tying to clip the sixth bolt from well below with an indordinate amount of slack*.

youtube.com/watch?v=FLilKfDBWxc&

So, no, you wont necessarily deck from the fifth bolt.  Or the fourth.  Unless you are trying to clip from well below.  Its counter-intuitive but when clipping level with the bolt is better.

 

*Phil Thomas - balls of steel.....

In reply to Offwidth:

I agree with everyone else that that statement is a load of rubbish.

In reply to Offwidth:

I think loads of climbers at UK walls will never of had any formal training so wont have been taught this.

In my experience its not true anyway. With correct belaying you shouldn't hit the deck from any height at a wall,(except before clipping the first bolt when your belayer can spot you if necessary). The exception to this is poorly set routes.

 

In reply to Offwidth:

If you have a poor belayer.  There are a lot of poor belayers out there, though.

In my experience a missed second is very dangerous and is likely to result in a ground fall.  Third and above won't *if* the belayer is doing their job properly.

 

In reply to muppetfilter:

There's nothing wrong with a soft catch in the right setting.  Missing third with slack out (to clip) is not that setting; it's the time to get all the slack in by taking in and running backwards at the same time for as hard a catch as possible.  It's perfectly possible to catch someone from a missed third with slack out, I've both caught and been caught in that position.

In reply to Offwidth:

My own recent experience is pertinent. I was climbing at a wall with 1m bolt spacing. My leader that day is tall (about 1.2m from waist to fingertip) He attempted to clip bolt 5 at full stretch and fell just before clipping. So his waist was then around 0.2m below bolt 4 and there was around 2.2 m of slack out. So his fall started to be arrested when his waist was already well below bolt 2 and his feet well below bolt 1. He kicked me in the head as he came to a stop.

We were both surprised - my first thought was that my belaying must have been wanting - but doing the maths this outcome was pretty much inevitable. If he had fallen in the same way clipping bolt 4 and the belaying had been only slightly less attentive, he would have grazed the ground.

Just one trial, but this would suggest a ground fall on the rope stretch is quite likely from bolt 4 with a tall climber clipping at full reach. OK, we shouldn't clip at full reach, but I think many of us do when we're in a solid position and the next move looks tough.

Martin

 

 

In reply to Michael Gordon:I don't agree it's rubbish at all. I think a lot of people get a ride surprise if the get to bolt 3 at circa 4m and pop off trying to clip bolt 4 high on a bouncy rope.  Bodging Clipping 5 early , less likely but youll still end up with your feet lower than you think

 

In reply to Offwidth:

I've done deliberate fall practice indoors on a number of occasions, working up from short slumps to the "worst case scenario" where I pull up a loop of slack, touch it to the clip, and let go.  The height of bolt 5 has always seemed ample: I've always hit rope tension well above the floor. Had it been even slightly borderline, I'd have used a higher clip after the first time.

 

In reply to Martin Hore:

Interesting, but isn't a 1m bolt spacing a bit bizarre and unusual? I haven't climbed indoor routes for several years...

In reply to Neil Williams:

s = ut + 1/2 at^2  here u = 0 before the fall and a = g = 10ms^-2 so

s = 5 x t^2

If your belayer has a reaction time of 0.2s then you fall 5 x (0.2)^2 = 0.2m before they do anything

If your belayer has a reaction time of 0.5s then you fall 5 x (0.5)^2 = 1.25m before they do anything

If your belayer has a reaction time of 1s then you fall 5 x (1)^2 = 5m before they do anything

As you get older your reaction time gets worse and your reaction time in cases where you need to make a decision about how to react (e.g.decide between moving with the rope for a soft catch or jump backwards to prevent ground fall) more so than simple reaction time.

Conclusion:  if your belayer is over 50 and the first part of the climb looks hard you better pre-clip the second quickdraw.

 

In reply to Si dH:

About 1.5m is more usual I think.

In reply to wbo:

I agree that you'll often go further than you think. But with good belaying and not pulling up tons of slack you really shouldn't hit the deck after the first 3 clips.

In reply to Michael Gordon: even if you blow the clip and pop off with a metre plus of slack  out? Slack is a poor description here, it's rope for beyond the last bolt.  

Don't forget you have legs extending below your harness as well

 

In reply to Offwidth:

Not hit the floor yet even with novice belayers!

In reply to wbo:

I would say so. But folk should also aim to clip sensibly, if possible.

In reply to Offwidth:

Here's my rede: do not fall clipping the draw, especially at the start of a route.

Unless the start is utterly trivial (for me) I always pre-clip the second bolt with my stick clip, and if I think there is a remote chance to fall clipping the third I pre-clip that as well. This is outdoors. Indoors I just grab a jug on a nearby route if I suspect I might fall clipping any of the first 5 draws.

I'm too old to break my ankles. That's for young people.

In reply to Offwidth:

Off course it´s crap, it´s someone spouting off on the internet. The actual wording from the DAV is "Bis zum fünften Haken droht beim Clippen Bodensturzgefahr!" which translates as "Until the fifth bolt there is (can be) a danger of groundfall when clipping" which is not the same as "probably".

The requirement for the assesor when you are doing your lead belay certificate is that the belayer is alert, ready to react and there is no unescessary slack in the rope, after the fifth bolt some slack is permitted.

The spacing of the bolts in DAV halls is (more or less) standardised and their recommendations can´t really be translated to any other environment, fall off clipping the fifth bolt in the Frankenjura and you are normally 15m off the ground when you stop!

In reply to jimtitt:

There's always going to be some unnecessary slack when someone is pulling up rope to clip a bolt. It's difficult for a belayer to judge exactly how much rope is needed and it's important to err on the generous side since short-roping someone on a hard clip is even more risky.

I think the statement is probably about right. The reason there are not more accidents like this is that it's glaringly obvious to all climbers, even beginners, that they don't want to fall off when they've just pulled a load of slack out above their heads. So they take utmost care to get into a solid position before pulling rope up to clip. Additional factors are a) that climbers are not that pumped by the time they get to the fourth bolt because they haven't climbed very far and b) routesetters generally have relatively easier climbing at the bottom of the route keeping the harder climbing for higher up.

 

In reply to tom_in_edinburgh:

Conclusion:  if your belayer is over 50 and the first part of the climb looks hard you better pre-clip the second quickdraw.

I think that comment is fairly insulting to a lot of people on this forum. To generalise like that is ridiculous.

In reply to Offwidth:

I always think "deck" is a bit of an emotive term in this sort of discussion. There is a world of difference between hitting the ground in freefall and just touching down at the end of rope stretch.

In reply to Si dH:

Perhaps I'm wrong - I'll check - but the wall is only 7.5m high and there are 5 bolts plus the lower-off, first at roughly 2.5m so the maths works OK I think.

Martin

In reply to I like climbing:

I'm over 50.  I wish my reaction time was what it was when I was 20.  It's not.  People's reaction time increases with age and their reaction time in situations where a decision is necessary such as whether to jump backwards even more than the simple reaction time.  Because a falling object accelerates the distance fallen before the person reacts increases with the square of reaction time i.e. a small change in reaction time leads to a big change in distance fallen.  When falling going for the second clip that equates to probability of hitting the floor.

The other week my daughter took a lead fall going for the second clip on a hard route.  She was getting belayed by a very strong competition climber.  With athlete class reaction time and perfect belay technique she came into the wall safely with her foot about 3 inches above the ground.   If I'd been belaying her in that situation I would never have been as fast.   I don't think many climbers my age would be.   

I'm trying to be realistic and keep personal feelings out of it: 50 somethings are not as fast as 20 somethings and there's no margin for extra delay in a fall at the second draw.  

In reply to tom_in_edinburgh:

I appreciate the explanation but don’t agree. Experience plays a big part in this and just because you get to 50 doesn’t mean you can no longer belay in this situation as effectively as you could when you were younger.  Everyone is different. I’m glad your daughter was ok. The route where I had a hold snap on me was 7b so not that hard admittedly and my belayer was 63.

 

I've tried falling at the fifth bolt on an indoor wall with a belayer ~15kg lighter than me, both with and without slack pulled up.

With the slack pulled up I just about deck on rope stretch (at least if they're given no warning, have a normalish amount of rope out for someone clipping, don't take in fast, which would be hard on such a short fall) and the belayer is well off the ground.

I think the biggest danger is kicking your partner in the head. I've since bought an Ohm.

 

In reply to Offwidth:

I hardly ever use indoor walls but the obvious solution would seem to be simply more frequent bolts low down, if its accepted that there should be minimum risk (or bottom rope everything!). 
Jim Titt indicated that the OP translation was misleading: "Until the fifth bolt there is (can be) a danger of groundfall when clipping" which is not the same as "probably". Even so in our safety conscious culture I'm surprised nobody has ever sued a wall's management for negligence for this known risk if it hasn't been addressed.

In reply to oldie:

I'm not. It's all laid out in BS12572.

In reply to oldie:

Methinks you are all reading too much into an already incorrect comment, the note is simply included for both the belayer/leader and the assesor to ensure it is clear to beginner climbers that fumbling a clip AND innatentive belaying low on a route could lead to a groundfall. Which no resonably experienced climber would disagree with.

As to exactly which bolt it is, well they know their walls and their clientele better than anyone who posts on UKC for sure!

Adding more bolts is no solution, for most of the beginners I´m involved in there are already to many and z-clips are commonplace and anyway you can always rely on climbers to screw up something, I´ve seen someone deck falling trying to clip the tenth or eleventh bolt!

In reply to jimtitt:

Got to be a belayer error surely?

In reply to tom_in_edinburgh:

But its not all quite the science you make out. An older person may well with those extra years of experience, be more attentive to body language and contextual information, which could help short circuit a problem before it occurred.

In reply to LeeWood:

That's true, older people compensate for longer reaction times by predicting what will happen based on experience.   But in the specific case of someone going for the second clip the belayer jumping back as soon as their assessment of the climber's body language predicts they're going to fall (rather than waiting until the climber actually falls) would remove any chance of the climber making the clip.

 

 

In reply to tom_in_edinburgh:

Despite all the 'science' being quoted I am still going with the evidence of my own eyes and experience. Having one foot in the grave I tend to climb outside midweek when  the crags seem to be largely populated by other coffin dodgers like me.  I have never seen an oldie drop anyone. I did see one ludicrously long, near ground fall at Stanage  when the leader fell almost the entire height of the crag, despite having gear at his feet. The cause was that his belayer (guesstimated age 22- 24) was not paying attentioon as he was chatting up a rather attractive young lady. Ditto at the wall, I find the oldies seem to be more alert, perhaps because they have seen what happens when you are not.

In reply to Wiley Coyote2:

I agree 'oldies' are generally very safe.  A big part of that is that they are cautious.    All I'm saying is that in the rare situation where you think there is a high chance of the climber falling going for the second clip and you don't have the reflexes of a 20 year old the cautious thing is to pre-clip it.  

In reply to tom_in_edinburgh:

Did I really suggest this ? 

For folk who would mistrust and misread the intentions of all humanity - go tie on to an auto-belay device at your indoor climbing wall, which will just leave you with the the most poignant doubt - yourself

In reply to LeeWood:

 

You said:

"An older person may well with those extra years of experience, be more attentive to body language and contextual information, which could help short circuit a problem before it occurred."

In the context of a discussion about falls at the second clip that implies the experienced/older belayer predicting the climber is going to fall based on 'body language and contextual information' and reacting before the fall occurs.

 

 

In reply to Blanche DuBois:

Actually, I gave that a like because I'm a Ron Hill wearer...

Perverse lot, us Brits!

In reply to brianjcooper:

Is it a problem that actually needs addressing other than by promoting awareness and good practice?

I know from experience I've fallen many times from the middle of an indoor wall including from positions where I would be clipping if I weren't falling but I never once got close to the floor (I've come very close outdoors on a few occasions). That said, I've never pulled out an armful of slack then let go (within my control) or had a hold spin (not!).

How many actually get hurt each year by this? Also for some broader context how does this compare with say indoor bouldering for traumatic injuries/user-hour?

jk

In reply to Offwidth:

Having taken this exact fall in a German wall with DAV bolt spacing spec I can confirm you do come uncomfortably close to the floor - but a good catch means it's around 1m off the deck still, and that's with a belayer 12kg lighter than me. As ever good belaying is the solution. 

In reply to tom_in_edinburgh:

Sadly, the empirical data suggest that we do indeed lose speed as we get older: https://www.ncbi.nlm.nih.gov/pubmed/8014399

However, on the figures given, the change in an individual’s performance over time is likely to be modest: on average 0.5 millisec/year from 20 onwards for simple tasks and 1.6 millisec/year for tasks with an occurrent cognitive load. Variability between individuals also increases with age; however, this may be partially accounted for by the fact that higher means tend to generate higher levels of variability.

 

Given a mean whole-population reaction time of around 250millisecs (https://www.humanbenchmark.com/tests/reactiontime/statistics) we are only losing around  0.2% per year for simple tasks, a differenece of just 10% of the whole-population mean over a fifty year climbing career.

I rather suspect that both differences between individuals, and differences in individuals’ own environmental circumstances over time (how much sleep; physical activity; severity of hangover; etc.) , may be more influential on performance.

 

On a personal note, I turn 46 next week and, allowing for a slow computer, my reaction time was around the whole-population average.

 

In sum, whilst you are quite right to be aware of the issue (indeed I’d be happy to climb with anybody who takes a thoughtful approach, as you seem to) , I think you may be being a little hard on yourself.

 

In reply to tom_in_edinburgh:

 

 

Sorry to say, I found this post really annoying:

I can't see the point of regurgitating equations except to impress people with your knowledge. You could have confined yourself to simply stating that reaction time is a factor when determining fall length. How much of a factor it is - how significant when compared to experience, technique, attentiveness, anticipation - we are no nearer to knowing that after your post than before.

Your examples of reaction times are (apparently) arbitrarily chosen: of course it's possible that they could be typical of belayers from specific age groups (i.e. a lucky guess), but they could be completely different. How do reaction times of belayers actually vary with age? It's an interesting question, but to put any meaningful figures to that you'd need a major study, with high-tech equipment and a large number of repeats with different subjects, to iron out individual variation.

Your "conclusion" is just plain odd: where did this threshold age of 50 come from? It seems designed to insult and alienate members of a specific age group for no good reason.

 

In reply to bpmclimb:

I'm not looking to impress anyone with an equation from O grade physics.

I'm talking specifically about the situation when someone goes for the second clip and falls with rope out.   In that position there will often be enough rope out that they will hit the ground unless the belayer jumps back.  In that case if the distance that comes out of that equation is longer than the distance between the lowest part of the climber's body and the ground then they will hit the ground. 

The reason for plugging some reasonable numbers in was to illustrate that the relationship between time and distance fallen is not linear.   For example, if time goes up by 10% the distance fallen increases by 20%.  

 

In reply to tom_in_edinburgh:

So I have drawn this concluson: You are obviously a bright bloke but you’ve used the wrong example to illustrate that age reduces reaction times.

 

In reply to bpmclimb:

I didn't. I find it easier to read math than verbose text. The reaction time/age thing is a diversion and not worthy of comment. What should be taken away is the power of square laws and how inattention is punished harshly.

In reply to Dom Connaway:

That is a really good point.  There are more things than age which could increase reaction time and some of them could easily be more significant.   

Anything which increases reaction time would be a reason to pre-clip the second quickdraw if there is a serious potential for a fall going for it.

 

In reply to tom_in_edinburgh:

Got to say, I don't agree either (sorry!). When you say the climber doesn't do anything during the reaction time, what exactly are they supposed to be doing? If they're belaying properly the rope is likely already locked off or heading that way so even if they don't realise you're falling (i.e. not reacting at all) they've still caught you. 

I've definitely taken a fall without realising the climber had come off, it certainly wasn't my reaction time that kept them off the deck.

In reply to FreshSlate:

Not if the climber falls with rope out to clip the second draw.   Even if everyone is being careful the rope needed to make the clip could be enough for the climber to hit the ground.  Locking off is not necessarily enough, the belayer might need to jump back to take slack out.

 

 

In reply to tom_in_edinburgh:

Not sure how keen I would be on a belayer overly focused on "jumping backwards" whenever they thought I was about to fall off (even if at the second bolt).  

In reply to Andy Gamisou: Well expect to land on the ground a few times then.  If you're in the situation of possibly falling off clipping to or three then having the belayer just standing around 'trad stylee' is insufficient.

My take away on the 'over 50' thing, as an over 50 is not that age is the problem, but that so many people on here with 'lots of experience' seem convinced their belaying honed on years of trad is super-duper when for this situation it is far from it

 

In reply to wbo:

No-one should be complacent ! But no stress for reaction times. If the stats exist I reckon you'll find accidents bouldering far outnumber those in roped-up situations. 

In reply to wbo:

Hasn't happened (via belaying cockups) so far in around 30 years of climbing, last 10 mostly sport.  Obviously if I'd had belayers focussed on diving backwards at the drop of a hat (and pulling me off the route) then this might be different.

Agree with your point regarding belaying a la the "the leader never falls" method, but still don't particularly want some dipstick pulling me off routes.  

In reply to tom_in_edinburgh:

Taking in rope, let alone jumping back whilst someone is falling, would lead to a higher fall factor and a very hard catch particularly where you are low down and there is little rope out.

To be honest if it's a choice between decking out from 3-4m on rope stretch or being slammed violently into a (hopefully blank) wall I think I'd actually take the deck in most circumstances i.e. unless the ground is particularly broken or hazardous.

If there's an early roof below the bolt you potentially could kill someone by taking in or jumping out. Stopping someone's feet from touching the ground isn't the only consideration.

I agree with your overall point about considering pre-clipping the second bolt wherever necessary but I think you probably get the point by now that there's far more variables in the event of a fall and more desirable characteristics in your belayer than their reaction time.

In reply to nacnud:

Agreed about the important point; However, I would suggest that anyone who has an easy familiarity with equations already knows about square laws, and the way they produce non-linear results; anyone who finds maths difficult or intimidating won't find equations particularly helpful. Either way, I don't think the equations in this context provided a particularly useful illustration, especially given the arbitrary figures which were plugged in, and the strangely arbitrary "conclusion". We seemed to be in a vague middle ground between illustrating square laws and estimating an average reaction time in a 50+ belayer 5 times greater than a younger one.

In reply to bpmclimb:

Which is why I plugged in some reasonable values as well as giving the equations.  All I'm trying to suggest is that unless the belayer has excellent reflexes if there is a high chance of a fall going for the second clip then pre-clipping it is a good idea and older people probably don't have 'excellent' reflexes any more.   I'm deliberately saying 'excellent' because its far from certain that average reflexes will be enough.

Using the equation and guessing that some going for the second clip on an indoor climbing wall will probably have their lowest foot somewhere around 2m above the ground then there is 0.63s between when they start to fall and that foot hitting the ground.  If the foot was 2.5m above the ground they would have 0.7s.

To stop that happening the belayer needs to react and get enough rope out the system so the rope comes tight in time.   At that point the rope will start to stretch and slow the falling climber and the climber will start to swing in towards the wall.   Which means we need the rope to come tight with the climbers foot  sufficiently far above the ground that the climber doesn't hit the ground hard on rope stretch.  If we want the rope to come tight with the climbers foot still 0.5m off the ground  then the time of interest is that taken to fall 2m - 0.5m = 1.5m which comes out to 0.54s.

It's difficult to get a good estimate of human reaction time in a complex scenario like belaying.  A computer reaction test says my reaction time is about 0.22s and varies between about 0.21 and 0.24s.  It then has a caveat that it depends on your computer and whether you are using a wired or wireless mouse and it could be a 50ms overestimate if like me you have a wireless mouse.   The best reaction times on their table are about 0.11s and the median is 0.215s.  So in my mid 50s I'm not far off the median but 2x worse than the best - presumably young people on gaming PCs with wired mice.

But that reaction time number is for staring at a box and waiting for it to turn green then clicking a mouse.  You know the event is going to happen within a few seconds of starting the test and it is a really simple decision and action.   A belayer doesn't know the climber will fall, they need to wait far longer for the event to happen,  other things are happening around them and they have other things to do and determining that a climber is falling and will not be able to recover the situation themselves is far harder than determining whether a box has turned green.  If you go too fast you will pull them off so you need to be sure.    It also takes far longer to jump back and get a meter of rope out the system than to click a mouse.

So for a fall going for the second clip as a belayer you've got about 0.54s to see the climber slip, determine they aren't going to be able to recover it and get maybe a meter of excess rope out the system.   If, like me, as a 50 something reasonably fit person your reaction time in a much simpler scenario (looking for a box to changed from red to green) is about 0.24s it is going to be totally marginal whether this is achievable no matter how much attention you are paying.   

 

 

In reply to tom_in_edinburgh:

Yes it is! Fortunately, it's not particularly useful anyway, not just because there are many other factors, but also because reaction time is way down that list in terms of significance (in my opinion). 

...  btw (in case anyone I might be belaying in the future is reading) I'm not oblivious to the dangers of falling while making the second clip (or the third or fourth for that matter). I might sometimes consider preclipping one or more bolts, for various reasons - but the fact that I'm 50+ is not one of those reasons, sorry

In reply to bpmclimb:

I don't see how it can be way down the list in terms of significance in the case of a fall at the second clip.

The maths says you have around 0.54s to react and get the slack you gave for clipping back out or the climber will hit the ground.

A simple reaction time test on a computer provides a **lower bound** on belay reaction time and in my case it comes out at about 0.24s.    Belay reaction time involves a much more complex decision and is bound to be longer than reacting to a Red/Green colour change with your finger poised over a mouse button.  There's also a significant fraction of a second to actually move back far enough to get the rope tight.   Most of the 0.54s is gone: if there were other factors of comparable magnitude to belay reaction time it would mean that a ground fall is certain.

I think the analysis is actually fairly clear cut.  Unless the belayer has excellent reflexes if there is a significant chance of a fall going for the second clip the safe thing is to pre-clip it.

 

In reply to tom_in_edinburgh:

Sorry, but I think we're going to have to agree to differ. I get it that you think the analysis is clear-cut;  but from my point of view you're so locked in to the idea that it can be completely analysed that you're not seeing all the big assumptions you're making along the way. It's not a general dislike of that approach, by the way - I do actually have something of a maths background - it's just that I believe the belaying scenario to be so full of complexities and variables that a rigorous analysis becomes well-nigh impossible.

.... I would, however, be very interested in real-life, non-anecdotal data, if any is available. How often do climbers actually hit the ground when falling from fumbling the different clips, and is there any detectable correlation with belayer age (I suspect not, but am open to being shown otherwise) - those seem like questions worth asking. It might be difficult finding volunteers for a series of experiments, though!

 

In reply to bpmclimb:

I think the analysis for a fall at the second clip in an indoor climbing scenario with clips at standard heights is clear cut.   I don't think there are any huge assumptions involved because it is a very constrained scenario.  There's no doubt about how long it takes to hit the ground falling from a known height and the lower bound on reaction time is also easily established.

I think it gets a lot more complex for higher clips and I wouldn't claim that reaction time was the most significant factor for higher clips.

In reply to tom_in_edinburgh:

One example of the sort of thing I'm talking about: your model compares small fractions of a second at the belayer end, yet assumes the climber falls completely unexpectedly and instantaneously, like an experimental dead weight being mechanically released. To achieve that a climber would have to hold a completely static, rigid body position, and quit all holds at the same precise moment. That would take quite a bit of doing, even deliberately. 

In reply to bpmclimb:

The belayer can't react to the foot pop or hand-slip immediately because there's a chance the climber will be able to hold on or grab another hold and recover.   So my assumption is they are reacting to the climber being 'in mid air' rather the start of the fall when the first hand or foot slips.

A belayer should predict that a fall will happen based on the climber's body position and get ready to move and this will reduce their reaction time compared with someone that has no warning.  The computer measured reaction times in the calculation in my post above are already for an 'expected event' scenario.  You know the computer is going to turn the box from red to green within a few seconds of the test starting and you are absolutely ready for it to happen.   If the climber falls unexpectedly then the situation is worse than in my calculation.

 

 

In reply to tom_in_edinburgh:

In the real world, belayers can and do hold falls onto the first clip, without the climber decking, including older belayers. How is that possible in your theoretical model? There may be many explanations, but surely one possibility is that the model itself is flawed, that there's a factor or factors which haven't been taken into account.

I'm reminded of some neurological research some time ago which used synaptic transfer speeds to  "prove" that certain manoeuvres performed routinely by skilled musicians were in fact impossible. Wasn't it also once "proved" that a bumblebee can't fly?

My problem with your theoretical model is that it's not rigorous, despite a sprinkling of very precise figures and an equation or two - the only exact measurements are some reaction times with a computer mouse, mixed in with a lot of assumptions, estimates, guesswork about the climbing scenario. It would be no surprise to me at all if such a model had no predictive value in practice.

 

In reply to bpmclimb:

The first clip, after it is clipped is not a problem.  There's no reason to have much rope out, a careful belayer can easily catch a fall. The problem point is a little higher when you give slack so the climber can go for the second clip.   The amount of slack to make the clip can easily be enough to deck.

You could use the 'someone once got it wrong' argument against any theory: it just asserts there could potentially be an error without actually finding it.

I've tried to make the simplifications in the model are in the direction of 'best case'.  For example, you aren't going to get a better reaction time dealing with ropes in a climbing wall than you get with your finger poised above the mouse button looking for a box to change colour.  If the calculation based on the computer reaction time data says it's a really close thing whether a catch is achievable then it's even closer in the real world.

The model does reflect a real problem: the reason I started to think about the issue was watching my daughter take a fall going for the second clip and missing the ground by inches despite excellent belaying by someone I'd class as an athlete.   When you work through the numbers it is obvious there's just no margin in this scenario.

 

 

 

In reply to tom_in_edinburgh:

Actually, that's what I meant by a fall ONTO the first clip; i.e. problems encountered above it, after it is clipped. And I'm not denying (of course) that it's a dodgy area when leading - no experienced climber would!

 

Yes you could. You could also defend any theory by summarily dismissing any objections in the way you just have. Your "theory" has a relatively low proportion of actual measurements in it (none at all taken specifically from the climbing scenario), and a lot of estimate and assumption; however reasonable you think those estimates and assumptions are, the potential for error and lack of applicability is cumulative. I can't state for certain that it's not 100% descriptive of the real world situation, of course: not having done an exhaustive study and series of carefully designed experiments myself, I can't tell you exactly where the problems are, but that doesn't stop me strongly suspecting that they exist - and at the end of the day, where should the burden of proof lie? Propositions which contain mathematics and/or scientific language, but lack rigour because they contain assumption and speculation, are two-a-penny ( it's probably apparent by now that I find this quasi-scientific window-dressing rather tedious): do we really have to adopt an "innocent until proven guilty" approach with all of them? Personally, where scientific rigour is lacking, I'm going to continue to remain sceptical as a default setting.

To be clear, I'm not saying your conclusions are necessarily wrong: there is much in what you say, although I suspect the near-inability of older belayers to stop a fall onto the first clip is a little overestimated: you will do doubt disagree with that, which is fair enough - I just don't believe your "theory" is rigorous enough to prove it one way or another. 

 

 

 

 

 

I’ve caught lead fall clipping the third bolt indoors on an ATC. It was very close, but I was stood against the wall and only got pulled up slightly... By the fifth I would definately expect a catch before the floor!