The Physics of Pumping on a Skateboard - Fully Explained + Easy to Understand!

I have been wanting to make this video for a very long time now, and finally here it is! A full, accurate, explanation of how to pump on a skateboard and exactly why it works, complete with experimental proof (actually showing my explanation from 5 years ago to be incomplete)
This video was a lot of fun to make, and I'm excited to get the ball rolling again on uploading skateboarding videos now that my foot is finally starting to feel good enough to actually go skateboarding.
Thanks for all of the support in the meantime, and just know that all of you guys make the long hours I put into these videos way more than worth it!
...and as promised at the end of the video, here is a link to the video on skating bowls: • How to Skate Bowls - G...
If you're interested in what gear I use to skate and film my videos, here are some links to the equipment I use:
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Never Stop Improving!
#skateboarding #physics #neverstopimproving

[@lancelovecraft5913]

Physics major here. Excellent video. Ppl at the park often talk in terms of speed, not wrong, but I think the conservation of energy is a far more effective conversation. Great use of normal vectors and vector components in ur explanation of forces as well

[@polarproductionsofficial]

This is the best pumping tutorial I’ve ever watched

[@cryptictyga8426]

The legend is back 🙌

[@dwaipayandattaroy9801]

🤟

[@Mistytario]

As an engineer and begginer skater, this was what I needed to understand how to pump. Great video!

[@thesodathief]

bro no way Justin Lauria thE GOAT IS BACK 2020 might not be so shitty after all

[@datukalex]

So cool that you’re back. I’ve learned so much from your older videos. Really hoping this is the start of more. And on this topic-I was just figuring our that the push was as important as the crouch a few days ago. Still working on my pumping, but I think you just handed all of us the keys.

[@maiochka]

This is terrific, especially the experimental part 'No pumping Vs. crouching only Vs. pushing off only'. Thanks Justin!

[@maiochka]

I've got one question: should I push off equally with both feet or should I press more with the back foot? Thanx for your time!

[@edbisdee]

for ages i've been looking for a tutorial that explains pumping properly, i've been thinking to myself 'I don't think i can trust a tutorial that doesn't explain the force vectors'. and this is spot on for it! Also, great hat!

[@ViniciusFortuna]

From what I understand, the physics is about angular momentum. On a circle L = mass * velocity * radius. Because L is constant, you can increase the velocity by reducing the radius. You reduce the radius at the top curve by compressing and at the bottom curve by extending. I think switching between compressed and extended when going straight doesn't affect your momentum, so it's important to change position in the curved parts of the ramp or bowl. More details and math at www.real-world-physics-problems.com/physics-of-skateboarding.html

[@raphaelpoitou8609]

Yes!!! Thanks fellow accurate physicist, you've said it all, this it the correct explanation.

[@hosoiarchives4858]

Yes

[@domingosprudencio3498]

Duude I just learned how to pump today because of your videos. Coming back home after successfully pumping in a ramp at my local skatepark and seeing a new video of yours about how pumping physics works is truly satisfying

[@thelankgod8073]

THE KING RETURNS!!!!

[@lightning3605]

Welcome back Also 1:58 is really satisfying

[@raphaelosorio4388]

The surfing community needs someone like you! Trying to apply what I learned here to surfing

[@matthiasvoigt1380]

Hey Justin, thank you for the video. The explanation is better than the old one, but i think still not accurate. I believe that the key point is that you have do work against the centrifugal force (~v*v/r, where v is speed and r the radius of the transition). That is why it works good on smooth transitions and less good an sharp angles.

[@OMNIPHEAST]

Banks and transitions both require us to do work, so he wasn't wrong, just not as thorough as possible. What I might call "wrong" is saying the total energy of the system increased. Actually, he only looked at gravitational potential energy and not the chemical potential energy which we convert into kinetic energy by pumping.

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@raphaelpoitou8609]

And so since you seem to know a bit more about physics, the exact equation that explains everything is L = I*omega and since I = mr^2 (where r is the radius so the distance between your center of mass and the center of curvature of the ramp) and omega = v/r, L = m*r*v, and m (your mass) is a constant, L stays constant for an isolated system (in this case the you-skateboard system) and since r gets smaller, v (your linear velocity aka your speed) has to get bigger in order to compensate for r getting smaller so that L stays constant.

[@emresongur721]

I am an engineer learning to skate. That was exactly what I needed. Very clear explanation. Onece I know how it works then I do not think but do.

[@noahyenerich9509]

I can’t believe he is back. Let’s goooooooooooooooooooooooooo

[@yooowazzam9782]

yep i totally know a lot of algebra and science🙄

[@OMNIPHEAST]

Good news. This requires zero algebra, just arrows. If you look at an introduction to vectors, it doesn't really require numbers, the visual is pretty intuitive. From there, if you find vectors interesting, you might learn some algebra or science. In fact, a vector is a first order tensor, and Einstein was said to be unsure about his tensor algebra and had it checked by other mathematicians.

[@yooowazzam9782]

@@OMNIPHEAST yup i understood this 😅

[@RamManNo1]

Finally a video that truly explains pumping! I just learned this technique on a 4 ft half pipe. Finally able to go top to top. Slammed hard and got some wicked burn on my elbow and a bruised hip. But damn it was awesome! Hopefully be able to drop in soon.

[@TheMeepitFeepit]

So excited to see this in my notifications!! 😍

[@BadBBilly7]

same here, i was like...oh yeah the GOAT is back online.

[@MrEpic-nr4oi]

i've watched a lot of these tutorials, and this one is best of all. It combines every possibility in one video, thanks for creating this

[@NeverStopImprovingSB]

Thanks man!!

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@garretteverett2613]

Hey Raphael, maybe spend more time making the video and less time copy-pasting your comment into every other reply on these videos. I'm sure you have valuable things to say but I've encountered doomsday evangelists with more reserved and tactful output.

[@ct96]

@@raphaelpoitou8609 I wouldn't be so quick to discount this explanation with statements like "the way it actually works......". What you have described is the Curvilinear motion explanation of movement around a curve which describes forces on an object in a reference frame tangential to the path it is travelling, at any instance of time that motion can also be analysed using Rectilinear methods which use the resultants of forces acting on an object during its motion in a rectangular reference frame. Of course I still can't guarantee this explanation is correct without breaking out my old Dynamics textbook and doing a few problems both ways and then comparing the directions of forces etc to his explanation but these problems can definitely be solved in both ways with both explanations being the way it works, just using different concepts.

[@eqvbohsds8955]

Bro!!!!! You!!!!! You are the one!!!! THEEE ONE!!!!! Pumping finally makes sense to me!!!! Cant wait to try it out after healing from my ankle injury! Bro! Love you man!!!!!! #muchlove #suchappreciates

[@MrZuludemidog]

Thanks 🙏🏽 -always wanted an actual break down of how n why “pumping” works!

[@lucasthompson8765]

This video fixed my inability to tic tac. I wasn't utilizing the friction of the wheels and pumping to generate momentum in the direction I wanted to go. I have never heard it explained like this. Thank you and keep up the great content. +1 sub

[@NeverStopImprovingSB]

Rock and roll sir, thank you for the comment!

[@quandary23]

lmao my physics teacher should show this to his classes to show how physics matters in the real world - love the video, nice job!

[@NeverStopImprovingSB]

Haha that would definitely be epic! Thank you 🙏

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner. So basically if your physics teacher showed this to his classes to illustrate anything else than kinetic energy turning into potential energy and vice versa (which was the correct part of the video) then he would be incorrect as well.

[@Skylarka]

This is the best pumping tutorial on the internet. Great work, thank you!

[@NeverStopImprovingSB]

Thanks very much Sky!

[@DDRaHolic]

Between this and your other video, I finally pumped after a few days of trying. If anyone else is having trouble pumping, my issue was that when I would ride back down fakie, I wasn’t bending my knees enough and sucking my knees into my chest as I started to pump.

[@1tonyjaa]

Nice its great to see you back :D

[@BadBBilly7]

Woohooo!, your back Justin, we missed your awesome tutorials bro, yessss, this is a good day

[@jayduf9054]

This is so awesome , yesterday I did my best pumps ever and after watching this video I’m going to do even better today 😄👊🏻

[@RegularFootisChris]

Great Video! Thank you for speaking slow and clear! Back in the 1990's we Called it Compressing!

[@NeverStopImprovingSB]

Really?! Compressing? That is so cool to learn!

[@morozom91]

Great video! Exactly what I was looking for, with the scientific explanation for pumping.

[@jkou5549]

Great video thank you. I’m 56 and learning to skate a bowl and your tips are awesome!

[@NeverStopImprovingSB]

Nice! and thank you!

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@DeniseNepraunig]

My inner engineer is happy watching this! Really great video and explanation 👍

[@NeverStopImprovingSB]

Thanks a ton! 💪

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@bluetetanus]

wonderful video!

[@vitorstipp3498]

jezzzz you are awesome! Hugs from Brazil!

[@JesusL0vesY0u]

Dude why you no upload in so long.

[@jacksoncarter6352]

Great video I don’t even skateboard I was just wondering this question and surprisingly there aren’t a whole lot of videos that go over the actual physics

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@ProgressSkateboarding]

Nice one, champ!

[@dougkalagian]

really great explanation, thank you!

[@NeverStopImprovingSB]

Aww man I'm glad you enjoyed it, always nice to meet a fellow skate nerd 😝

[@Bahomar]

great video, thanks so much, cheers

[@Remolhunter97]

thanks mate. best video out there

[@thndr_5468]

Thank you for the video, can't wait to give these a shot next time I skate!

[@NeverStopImprovingSB]

I spend a majority of my time skating just pumping around endlessly at the skatepark. It is so dang much fun.

[@raphaelpoitou8609]

Oh and btw I'm adressing this comment directly to you Never Stop Improving, since I know you might end up seing all of my kind of "copy paste" comments : your video was really well done, looked good and you sounded really convincing, I'm just trying to bring the correct explanation to people who want to learn the actual physics behind this incredible phenomenon that is pumping, as you thought you did by correcting yourself from your own older video. I hope you will understand and not delete all of my comments. Kindly, Raphaël

[@termitedidge]

Great video, really enjoying your content.

[@pandacinnamon]

Skateboarding is for nerds! Thank you for this

[@allisonpeet1469]

this video is great!

[@riazkhandvk]

Nice Skate Park Set UP.... Can you send the Design plan

[@jaysahunter256]

"We're just gonna ignore friction and air resistance for now" That's how I really knew this guy was legit

[@jasonnacionales6745]

HOLY CRAP HE UPLOADED

[@estebanlopez5372]

I love your videos SO MUCH ! Thanks a lot for teaching us

[@NeverStopImprovingSB]

Rock on Esteban!!! 🤘

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@ansborromeo7470]

how about for the consecutive humps on the pump track?

[@dontblamepeopleblamethegov559]

Oh so it's basically "apply upward force to reduce the pressure of your weight on the board so it doesn't slow down". Cool, thanks!

[@dead7781]

3:46 I don't think the vectors are accurate. Either that or I'm dumb. Can someone explain? (Edit) I just figured it out. ...I think. You're logic when going down is solid, but when going up the ramp you're not adding more force in the direction you're going, you're decreasing the force that's against you by crouching. As your going up the ramp, your weight is making the ramp push against you perpendicular to the ramp. The is why pushing down on the board while your going up makes you go slower. But if you lighten yourself, by crouching, the less you will be pushing down on the ramp, the less the ramp will be pushing on you and therefore more momentum is conserved. Theoretically you could "jump" the ramp. Imagine you pulled off an ollie just before going up where the board is 1 cm away from the ramp during the entire jump. Now imagine 0.1 cm. Now 0.01 cm. On and on until it looks like your riding up the ramp normally, but none of your weight actually ever pushed it. This would mean the ramp would not slow you down at all. You would literally have the same speed at the bottom of the ramp and after. Obviously you can't pull this off perfectly so some speed would be lost, and you would be limited by how high you can jump as well. TL;DR So basically, you wanna put more force downward on the board when going down a ramp, and decrease that same force when going up.

[@NeverStopImprovingSB]

That was a good thought exercise 👍

[@chongsiu7893]

I like your explanation. Another way to think about this which helped my understanding is that: say you are going up a ramp, without any pumping, then all the potential energy that is gained when you reach the top of the ramp must come from your original horizontal kinetic energy, so you have less horizontal kinetic energy at the top, thus you are slower. Whereas if you stand up from a crouching position just before you hit them ramp, then some of the potential energy can come from vertical kinetic energy that you gained when you stood up, and less horizontal kinetic energy needs to be "consumed", thus you maintain more horizontal speed at the top of the ramp.

[@dead7781]

@@chongsiu7893 yeah I figured out I was completely wrong about the crouching down while you're going up. You, and just like the guy in the video are correct, you need to start crouched and then as you hit the ramp, you stand up. Apparently, this has to do with circles and centrifugal forces. It's related to how an ice skater spins faster when she pulls her arms in while she is spinning. If you want to understand it more intuitively, there was a great article that explained it perfectly. I forget where I found it, but google "physics of pumping skateboarding". The author mentions the pandemic, so it was a relatively recent article.

[@raphaelpoitou8609]

No you were right to doubt it haha The way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@dead7781]

@@raphaelpoitou8609 cool, I'll check it out!

[@SacTimonWild]

gr8t video!

[@VividSkateboarding]

So awesome!

[@alphainfinitum3445]

he has explained it using proper physics.

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@stef84]

Back!

[@aliem0matic]

So that is way I couldn't get the hang of pumping, Thanks!

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@tyizzle80]

What's crazy is I thought it was impossible to gain speed by pumping then as I started riding I notice that I just started to do it on my own. You can't tell when you are doing it right because you Wheels and Board makes a different type of sound as you pump along.

[@OfficialOwenDragon]

Alternate title talking about science with skateboarding

[@NicholasABerk]

Could you explain why learning to pump taught me to Ollie over curbs?

[@NeverStopImprovingSB]

You are an anomaly sir 🤔

[@jstoppa]

great explanation! thanks

[@NeverStopImprovingSB]

You're Welcome!

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@margorwylm]

Thank you so much! This helped me a lot with my pumping strategies

[@mthjsful]

Hi @Never Stop Improving, I often see videos about pupming a longboard on flat surfaces. Does that really give speed, or there is some slight descent on the road in these videos? If it can give you momentum, how does it work where there is no curves like on the pumptrack or ramps on the video?

[@NeverStopImprovingSB]

Ahh yes, that is a different kind of pumping, and yes they can generate speed on flat with that (even up an incline). In that case, they are turning their board to the side slightly and using the fact that the wheels only roll in one direction (thus allowing them to leverage the friction between the wheels and the riding surface) to push off a little each time and slowly increase their speed.

[@mthjsful]

@@NeverStopImprovingSB Appreciate your answer, now I understand it. Thanks a lot !

[@HECKAKYH-ADEKBATEH]

1. This isnt pumping, this is vertical pumping, fraction of pumping. 2. Pumping works by playing with weight versus centrifugal forces. To visualise - hold two skateboards vertically against each other, and match their top wheels and slightly push so there is contact. One skateboard will visualise road. Pumping is using own weight to push rotating(!) wheels slightly sideways. This causes friction, which will attempt to escape, and since the wheels are rotating, they are less resistent in that direction, so the push force will escape into that direction. The movement and principle is also used on swimming boards.

[@rosariopatricialopezmagana316]

Gracias. Estaba muy confundida con las demás explicaciones que solo dicen "empuja". :)

[@glueckstierranch]

Nice vid 💪🏻

[@NeverStopImprovingSB]

Thank you 🤜🤛

[@michaelculhane3058]

Are you pushing straight down at the earth? Or straight towards the wall? Hard to tell where your force is.

[@NeverStopImprovingSB]

I feel more like I'm pushing down towards the center of the earth

[@michaelculhane3058]

@@NeverStopImprovingSB Thanks!

[@fauldurand]

Skating and Science. What a beautiful marriage.

[@NeverStopImprovingSB]

Yes yes my friend! 💪

[@dwaipayandattaroy9801]

1:25, only gravity pull , no reverse push, + towards Slope kinetic motion of wheels... ! else you had to Stomp on the middle deck to mitigate antigravity push, Stomping on front nose base wheels for some other reason

[@OMNIPHEAST]

I think you're referring to the normal vector

[@maxoliver1083]

Finally!!!!!!!!!!!!

[@geromemercado9265]

0;37 I cant lmao

[@chinarello2928]

So How does it work in the bowl? You are supposed to raise up in the middle?

[@NeverStopImprovingSB]

I have a dedicated video that covers exactly that: kzbin.info/www/bejne/epepe6GKmrGXj5Y Hope it helps!

[@chinarello2928]

@@NeverStopImprovingSB Thanks, so basically you compress going up the ramp, straighten in the middle before the curve, then crouch again heading down and stand-up as you exit to flat? I have had trouble distinguishing between the big bowl shape and one with two corners, but your video was the first to mention that there is actually a difference. Now I just need to find a way to read that so I don't keep getting stuck like a fly on a wall on the flat vertical part of the wall.

[@raphaelpoitou8609]

@@chinarello2928 Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@chinarello2928]

@@raphaelpoitou8609 I will check that out. I have practiced a bit and I'm getting better somehow by accident, but I would love to be able to accelerate and not just slow down

[@chinarello2928]

@@raphaelpoitou8609 So what I gather is that to speed up you should crouch when going around a bend and tighter the pocket the more speed you will gain. On the straight part of a wall you should be as extended as practical. The hard part is that when you go into the curvy part the centrifugal force actually makes you push against the board. So if I get this right you should kind of let the centrifugal force pull you down and not really fight it and when you come out of the pocket you can extend your legs again before the next curvy part. Where it gets tricky is that on a straight part of a bowl I can actually gain speed also snaking up and down the wall.

[@padraigharrison6919]

Invert tutorial ?

[@c0nD1337]

The Normal Force has an X component :D

[@Alf_4]

how does this apply to longboard pumping on a consistant gradient or level surface?

[@raphaelpoitou8609]

Hey, the way it actually works is not as shown in this video but really by shortening the distance between your center of mass and the center of curvature of the curved part of the ramp :) I will try to make a video myself to illustrate exactly how this works more clearly but this guy called Garrett Milliron made a video called "The physics of pumping a longboard" which shows the correct explanation in, unfortunately, a less understandable manner.

[@garretteverett2613]

Longboard pumping is more like carving, this only applies in the most general sense of it as you do try to compress into and explode out of turns.

[@ModalSoul]

4:00

[@Balltickler-bb5eq]

I wish he was my physics teacher

[@Stonedtodeath321]

My guy is teaching basic classical mechanics to explain skateboarding

[@zarate1om]

Very interesting! I was watching a video by Steve Mould (kzbin.info/www/bejne/g4atnn6ibLaZerc) where he talked about spring swings and parametric resonance. I’m not versed in physics but the video, specifically 6:35 of the video, made me wonder if it had something to do with pumping on a skateboard. Any thoughts on this?

[@tomasgoncalves555]

came here to see if u could pump on a skateboard, didnt get what i came for

[@NeverStopImprovingSB]

Did you have something different in mind than what was discussed in the video?

[@Jadea420]

Here cause I ate shit

[@ericjorgensen8028]

Since the wheels only roll in one direction.... Nope.

[@marsmachine1156]

Fantastic video. Surprisingly geeky (in a good way) for a skateboarder! 🛹🤓🤙🏻

[@coochiecrumbs3526]

When your physics teacher used to be a skater in the 9th grade

[@danfromzr3289]

I’m a big time big bowl skater and you just changed my life. I know the muscle memory and have the strength to maintain solid speed. However I think understanding this in depth is going to help so much. In my head I see it almost as jumping off of a slanted wall into flat ground. If you can add that factor you will go even faster than just standing up at the bottom.

[@SunriseSessions]

After watching tons of instruction video's and trying to remember all the actions I had to execute.... It took about 10 seconds in this video to actually understand the physics and now I don't have to remember anything because I simply 'get it'. Best tutorial ever. Thnx heaps

[@NeverStopImprovingSB]

Love hearing that! Keep up the good work!

[@dereksilva1523]

Ur back!!! I really missed ur content, ur my favorite skating KZbin channel so keep up the skate content!

[@raphaelpoitou8609]

Okay so I am pretty sure this explanation is wrong. Tl;dr : Pumping is made possible by the conservation of angular momentum, not pushing off of the ground. There is a video called "the physics of pumping a longboard" that explains the actual science that makes pumping possible. The video I am mentioning includes a lot of incorect information and isn't clear at all if you have never heard of the subjects used in the video, but the idea is the correct one : by bending down your knees on flat parts which doesn't affect your linear speed and extending them in the angular or curvy parts which reduces the distance between your center of mass and the center of the circle drawn by the angular part of the ramp, you generate speed every time you pass a curvy section. I think I might do a video myself to try and explain this concept in-depth while keeping it simple so everyone can understand it with everything I have learned about it in the past week I have spent researching the matter.

[@gradies]

What was incorrect?

[@AdrianQuark]

First consider the transition from flat ground to uphill. It should be obvious that if you push down on the board on flat ground, this will not make it to forward at all. Putting a hill in front of you doesn't change that. The force arrows in the video which show a force going up the hill also show a force going away from the hill, which cancels out in the forward direction as you expect. The only way to push the board forward up the hill is to push at an angle, i.e. lean back and push away from you. This will push the board forward, but obviously you would fall off. You can apply the same analysis when you're going downhill; we can ignore gravity to look only at the force you can add yourself. If you push parallel to the ground you're not adding any forward force, because you are pushing the board backward exactly as much as the ground pushes you forward. But if you push straight up, as the video diagram shows, then you're pushing the board away from you and you'll fall back. In the same spirit of experimentation shown in the video, find a long, fairly consistent incline, and push multiple times as you roll down (but before you begin to level out). If pushing works just by pushing off the incline, you should be able to gain more speed each time you stand up. But I'll bet $100 that you'll go no faster than rolling.

[@AdrianQuark]

Oh I realized Garrett was probably asking what's incorrect about the other video mentioned. It makes sense to me, and makes one easily testable prediction: you can't pump a transition with a smaller radius than your center of gravity. So let's get a tall person to pump some 3' radius transitions.

[@raphaelpoitou8609]

@@AdrianQuark I'll start by answering your second comment because I'm struggling to understand the first one rn. So coming from someone who has built his own mini-ramp, a 3 foot radius transition would be ridiculously small, since a 3 foot high transition (what I have built myself) required something close to 8 ft of radius if I recall correctly. and anyway, yes it is indeed harder to pump in a 3 ft mini ramp than on a 9 ft bowl, because you have less time to extend and bend your legs.

[@raphaelpoitou8609]

@@gradies Hey! First of all thanks a lot for making your video and giving me the keys to understand how pumping works! Well the main things I was able to point out were you said at some point that the center of mass was geting closer to the "radius of curvature" instead of center of curvature, so basically the opposite, you said that the angular momentum had to stay constant, which was correct, but then you said it had to stay equal to zero, which was obviously wrong when you're in the middle of the curved transition, since you have positive speed, mass and radius, so it's constant, but not null. Also the reason why I'm saying your video is not very clear is because you didn't developp and simplify the equation from L = Iw to L = mrv. Apart from those things, great video and great explanation!

[@kidzbop38isstraightfire92]

I don't understand any of this but it's cool regardless

[@memorysometimers3067]

Glad to see ya back bro!! You definitely in the best state possible right now.

[@fanbulma8879]

as always good video 😀 ! i need fly out video 🙂

[@OMNIPHEAST]

Same

[@isaachophan5736]

First

[@Skinnyriver]

Wow just wow

[@AN-vs5pb]

YES HE IS BACK LET'S GOOOOOO

[@kennybraverman9719]

I think what you said is right but you are leaving out centripetal force The way a ballet dancer spins faster. By compressing you increase your acceleration and by decompressing at the wrong time you loose that acceleration. I could be wrong but I think this plays a big part in increasing speed.

[@Hotdogwaters]

Tibees, 3brown1blue would be fucking proud. Thank you so much for this

[@RYOkEkEN]

great vids always

[@GeorgeAustria]

Free body diagrams 👀 nice job! They're a great visual

[@guangruli4486]

love the correction you did