All right, welcome back to the largest study on climbing falls. In the first episode we looked how does extra slack affect the fall, or more precisely does falling more reduce the pendulum into the wall and how hard the climber is going to hit the wall. And then I showed you the importance of soft catch and what a massive difference that makes. And also that hard catches are not only the problem for heavier belayers. Lighter belayers often lack practice to give soft catches since most of the time they don't need, they fly up anyway but in exceptional cases with enough friction... - My foot - What happened to your foot? - Well it was a hard fall. - Heavy belayer? - Eh... Light belayer. Yeah. Yeah. And I also asked you guys - I'm curious, did you ever got unexpectedly hard catch from a light belayer? And turns out this happens more often than I thought. So yeah, light or heavy, you're going to love this episode because we're going to investigate which method of giving soft catch is the best. We're going to compare stepping forward versus jumping up, and as a bonus the tube slide method where the belayer lets the rope slide through the device, which is more common in trad climbing. So let's begin. Now in the previous episode I showed you this beautiful horizontal velocity graphs and I explained that the peak of horizontal velocity is at the bottom of the pendulum, and that is a good indicator how hard the climber would meet the wall if the wall would not be overhanging. And in this test I wanted to go a step further and see what happens when the climber meets the wall. [Climber] - One, two, three And my idea this time was to measure deceleration during the impact. And in many of our test cases this idea was working really well. If we compare the soft catches to the hard one you can see a huge spike in deceleration. However, after doing lots and lots of more falls and analyzing the data, I realized that the peak deceleration is not always a good metric to look. For example, take a look at this hard catch. You can visually see that it was much harder for the climber, but the peak deceleration was nearly identical to the soft catches before. So, turns out our soft bodies are incredible at absorbing impacts, but the problem is that it's very difficult to measure what's happening in our muscles during this impact. So while peak deceleration was interesting to look in some cases, horizontal velocity at the moment of impact was a much better indicator. After all, all of this velocity that we are about to hit the wall, will need to be absorbed by our soft bodies. Okay, so let's see which method to give a soft catch is the best. To not kill me on the very first test we started with smaller falls and "jumping up" technique. And these falls were extremely nice and soft. [Climber] - A soft ride! So let's see how stepping forward will compare. [Climber] - One, two, three - This is harder. And the fall this time felt a little bit harder and we can also see that in the graphs. However overall it was still a very soft catch. And the second fall was very similar. Also a quick note: I was not sure how much stiffer the rope gets over multiple falls, and even though in this video I'm presenting you all the data grouped by method, meaning at first I show you all the soft catches with "jumping up" method, then I show you all the soft catches with stepping forward, in reality we did alternate between the methods between every fall. So we did a jumping up and then stepping forward, etc. Pointless information for most of you, but I know that a lot of geeks are watching my videos and they like to write nitpicky comments. So this is for you, nitpicky geek. All right, now let's see how the tube slide method compares. And while I was expecting a lot from this method, the first fall wasn't any better. The second fall had a very low momentum into the wall but a lot of vertical momentum, which made me almost run across the wall, which was slightly uncomfortable. So we tried again and this time the fall was much nicer and I know that people like to try all the crazy things they see on the internet so that's why I have to stress that this tube slide method is really advanced, so if you don't know what you're doing, make sure that you have an expert guiding you. Now if we would compare all the best attempts of all the methods, we can see that the jumping up was slightly better, but overall all the methods were very similar. [Climber] - So all of these falls felt quite soft, except the one where he does nothing. Then I fell to the wall. Yeah we actually forgot to film hard catches where the belayer does nothing on this test, but no worries this was just a small warm-up. And let's see some bigger falls. So this time we started with a tube slide method, which at least in theory lets the belayer achieve any fall arc. And here is one more attempt this time with even bigger arc or longer braking distance, and the fall was just a tiny bit softer for the climber. For now I'm just gonna keep the softest attempt in the charts and let's see how does that compare to the jumping up technique. And we can see that the first fall was slightly smaller, however it had nearly identical horizontal acceleration and velocity. However it also had lower absolute velocity, which is actually better for the climber. Now the second fall was slightly smaller but had a tiny bit more horizontal velocity towards the wall and again let's keep the best attempts of each method and see how does that compare to the stepping forward technique. And we can see that the fall was smallest, however it had the greatest impact to the wall. Now on the second attempt the belayer did a much better job and the fall was significantly softer. And if we compare all the best attempts of all the methods, we can see that the horizontal speed at the moment of impact was nearly identical. Which means that at least in this test case scenario, a skilled belayer can achieve almost the same results with any method. But since consistency in catches also matters, if we compare the worst attempts, tube slide method was the best, followed by jumping up, and then the stepping forward was the worst. However even the worst cases of any of these methods were much much better compared to the passive belay. So the first arising takeaway was that no matter which method you choose to give a soft catch, it's going to be much better than passively standing and doing nothing. And as always one test is no test, so I wanted to repeat these tests in a different location with another belayer. Ricky who has also a lot of experience using this tube slide method, and he told me that it's actually his preferred method. So, high expectations. [Climber] - Two, three... Falling! - Aw, that was super soft! So we did three attempts, and all of them had very similar horizontal velocity. Nice, for consistency. Next we tested the stepping forward method, and we can see that the fall was much shorter and had a much greater swing into the wall. It seemed that the belayer was pulled towards the wall way too much, and did not have enough control to make the fall smooth. All right next the jumping up method, where Ricky actually did a very bad job on the first attempt. And the same happened on the second attempt where his jump was very minimal, only initiated a little bit from his right calf. So that's not how you jump and that's why I decided to ignore these two attempts for the poor technique, and after he adjusted his technique on the third jump, he jumped with both legs and it was much much better. And finally we did one passive catch where the belayer does nothing and same as before, it causes significantly higher swing into the wall. So at least in this test case scenario, tube slide was the best, followed by jumping up, and stepping forward was again the worst. [Belayer] - So stepping forward versus uh jumping up [Climber] - Yes stepping forward was not in a controlled way. I was just pulled to the wall. I tried to lean backwards to brake, to catch the fall but it was not in a controlled way, and jumping up I can choose how much I want to jump and at what timing. So overall which method is the best will heavily depend on your experience using this methods, however stepping forward seemed to be the worst, and gave the least control, and also worth mentioning is that standing too far in many situations can drag the belayer into the wall completely uncontrollably. And that would make the catch even harder. All right but what if the belayer is significantly heavier. In that case if you try the jumping method there is not much pull up by the rope, and jumping is much more difficult. So maybe stepping forward is better in this case. To test that, Krushu suggested to introduce extra friction which basically makes the belayer heavier. [Climber] - Can we try like this? [Belayer] - He wants to kill me! So that's what we got: a little zigzag in the beginning and then a straight line all the way to the climber. So the rope actually is not going over the edge, it's just very sharp angled. - He says you have to fall! - One, two, three The swing into the wall is... ...okay-ish. So we started with jumping method, which felt slightly harder with increased friction, but still plenty soft enough. Just take a look at this belayer running up the wall and even avoiding his arm being squished into the first quick draw. So let's see if with increased friction stepping forward will be better. This time he was not pulled into the wall uncontrollably anymore. It also looks like he got the perfect timing and even started running forward just before the impact, however the swing into the wall for the climber was still harder compared to the jumping method. Okay, next we did a series of tube slide catches. The first felt very nice and soft. Now the second fall had even softer impact with the wall however I still had a lot of momentum downwards which forced me almost to run down the wall which is a little bit awkward. And the last fall had a very similar effect. And if we look into the best cases for each method, we can see that jumping up and tube slide were very very similar, and the stepping forward was slightly worse. And this bar chart plots all the falls. So we can see that on average, tube slide method performed the best, followed by jumping up, and then stepping forward was the worst. Now from pure feeling standpoint for me as a climber, both jumping up and tube slide methods felt very nice and soft. Maybe if I would be nitpicking this extra momentum downwards sometimes on the tube slide method was slightly uncomfortable, although in theory the belayer should be able to give almost any kind of catch with this method and the stepping forward method was maybe slightly harder, had slightly bigger impact to the wall, however it was still plenty soft enough. And what is not soft enough is passive belays. So once again, no matter which soft catch method we tried it was significantly better than passive belay. And with added friction the belayer wasn't even lifted off the ground this time. Previously when we had no friction, passive belay looked like this: the belayer was still pulled up but now with extra friction, that is not the case anymore and you can see how the climber is being pulled up and into the wall even harder. [Climber] - Okay that was... ... that was the way it was. So yeah don't forget to subscribe, I might need advertisement money to fix my broken body at old age. [Climber] - So what's your favorite method? [Belayer] - Yeah jumping up, yes. Okay so we were leaning towards jumping as our favorite method, but what if the belayer is really really heavy, or there is so much friction in the system that the rope almost doesn't pull the belayer up? In that case, you can jump... I don't know what 30, 40 cm maybe 50 if you're a crazy athlete... but is that enough for the soft catch? And this brings us to this experiment. Here we did a series of falls, alternating between stepping forward and jumping up, and we measured the forces to the climber. And same as before, jumping up was consistently better than stepping forward, and doing nothing was significantly worse. And then we decided to introduce this zigzag in the route, and although it doesn't look like much, it actually added a ton of friction, basically imitating a very heavy belayer. [Belayer] - Wow! I couldn't jump at all! And, as I was expecting, jumping up was not working at all in this case, so let's see if stepping forward is gonna be better. [Climber] - Wow that was solid! [Climber] - 2.5, oh sh*t! And it actually was even worse. [Belayer] - Man I cannot give you a soft catch this way! So yeah no matter how much I tried to jump, I was not able to give a truly soft catch, and stepping forward was even worse. [Belayer] - It's impossible to give a soft catch like this! [Belayer] - To time well the stepping forward on such a short fall is nearly impossible. Now while it seemed that heavy belayers are doomed, on this next experiment I actually discovered something that helps. This time I was belaying a light girl, and as before, I was also struggling to give a soft catch. The jumping simply did not work. And neither did the stepping forward method. But then, I discovered something. [Climber] - Better, better. This one was soft! [Climber] - Yeeeesss! It's soft! So yeah, turns out that bending the knees will give you more range of movement and in this test case scenario it made a huge difference. [Climber] - If the fall was Wuuuuuuuuu Just super soft, and the others was Bung! [Belayer] - Like Bung? - Yeah yeah yeah! - So it's Bung versus Wuuuuuuu. [Climber] - And we prefer Wuuu. - You prefer Wuuuu. - Yeah! And although I already mentioned this in the first episode, but it's really important to stress that simply throwing a lot of slack does not mean a soft catch. And in the case of a passive belay, it can end up very badly. And the only reason she was fine in this case, was because she was falling straight down under the quick draw. So all she felt was just a jerk to the harness. In a different situation with a little bit of swing, that kind of catch would probably break her ankles. So, instead of feeding a ton of slack for your climber maybe you should... feed your climber? And as we saw If the fall is small, bending the knees before the fall might help. Now in case of a big whipper the fall naturally is much bigger, so you will have more time to go down and explode up. And from a biomechanical standpoint, since our muscles act as springs, going down and jumping up should result into a higher jump. Now if that doesn't help, I would suggest more food cycles, and if that's not an option, then I've seen a method used by a very heavy belayer, which worked very well for him, where he took a little bit of slack with his lead hand, and during the impact he used his lead hand to soften the catch. It is extremely important to not have too much slack here or you will burn your hand. So be smart and use this at your own risk. This is sketchy but I've seen it working really well. Or alternatively, go old school and learn how to use tube style belaying, then it doesn't matter what's the weight of the climber, you can always make a soft catch. But of course that comes with its own risks of not having an assisted belay device. But for majority of you, jumping up is going to be the best and if for whatever reason you find yourself away from the wall, then just do stepping forward, as we saw. Whatever soft catch method is much better than passive belaying. Now I understand that this video was full of charts and graphs, and chances are if you're still watching you're a little bit nerdy, however I'm gonna make a separate video for my belay Master Class where I will go more on practical details, including those sketchy low-to-the-ground situations. And also during these two years we have measured forces on hundred of falls, so we have a lot of data. But as I explained in previous episodes, peak force to the climber might not be the most important factor for sport climbers. However that might be much more important for trad climbers. [Climber] - Keep a good eye. [Climber] - Sh****t! So I guess this deserves an episode for trad climbers as well, and all of these people and supporters deserve a huge thank you. None of this project would've been possible without all of you. And you deserve some knowledge. For the last 6 months I was warming up my brain in the mornings with brilliant.org which is an awesome online platform for learning math, data science, and computer science interactively. - Good morning Ben how are you? - Ah feeling like quaternion and four dimensional space with emotions twisting like Möbius transformation and my mood transforming like eigenvector. So no only you get deeper connections with your smart friends, you also deepen your scientific understanding of the world. Just imagine how your regular life problems will look when you will be contemplating that we are all just riding a giant rock through constantly expanding space, with supernovas and solar winds. Or maybe before human thinking becomes obsolete... - Write a short math poem in a style of... me. You want to know how ChatGPT works? So whenever you're are a complete beginner or ready to dive into machine learning and beyond, brilliant.org makes it easy to level up fast, with fun bite-sized lessons. And you can try all of this completely for free for 30 days by visiting brilliant.org/HardIsEasy and the first 200 of you can also get 20% off their annual premium subscriptions. So thank you Brilliant for making sure that we still use our brain. And thank you for watching. Enjoy your brain, and climbing, and see you in the next one. - Now it's gonna be fun... - Feeling like quateri... That word!