Zep's How-To Mythbusters: Body Position for Descending and Corners

Feb 9, 2016
by Paul Howard  
In this fourth instalment of our ZEPtechniques Mythbuster Series, we’ll be taking a look at one of the classic and most common myths in modern day mountain bike technique - the rider’s body position when descending. But before we get into it, take a look at our previous articles in the links at the bottom of this page to get a feel for what this series is about and why it’s important in helping rider’s not only improve their skills, but also improve their approach to learning through a 'pro’s and con’s' ethos, rather than 'right and wrong.' These articles also go into a bit more detail than usual, helping any instructors or riders with a taste for detail, get more out of them.

The Myth:

After teaching mountain bike technique for nearly twenty years, it amazes me just how many people still think that to ride downhill, you need to put your weight back. This might sound crazy to some of the more up-to-date riders amongst you, but we still see and hear this regularly in the industry today; be it from the public, out-dated instructors, magazines articles or videos. I even saw a recent video on YouTube featuring a pro-rider explaining this very technique, even though he wasn’t doing it himself. In short, this madness needs to stop! This being said, I think it’s important to look at why this myth exists in the first place…

THE BIKES:

In the good ol' days of the 90’s, mountain biking was in a very different place than it is today. The bikes, trails and riding styles were all very different. This produced a downhill riding technique that involved moving the hips back, behind the seat, so the rider could also get lower on the bike. Since, much like modern XC bikes, the only way to get lower (for more stability) on a bike with its seat all the way up, is to move the hips behind the seat, this technique became the staple of the time. In the context of steep head angles, short wheelbases and seats all the way up, this technique actually makes sense. The problem occurs if a rider uses this same technique on a downhill bike or on any bike where the seat is lowered; which constitutes a large proportion of the mountain bike community today.

THE UNDERSTANDING:

The other reason this myth exists is simply from the misunderstanding of the physics that are involved with riding a bike downhill. This myth has then been regurgitated over the years by different magazine articles, videos and coaches who have never really questioned what it is they are teaching, and why they are teaching it that way. Simply put, people are just explaining something based on what they’ve been told before, rather than from truly understanding it themselves. This happens in every sport and this is why it’s important for any instructor or coach to make sure the training they’ve received is the best possible, and to update their knowledge and skills every few seasons.

ZEP s How To
Professional coaching is key in making sure your skills are up to date; making your riding safer, more fun and a whole lot easier. Instructors need to stay up to date, too - a lot of these myths are being regurgitated far too often!


The Solution:

In simple terms, rather than moving back on a descent, the best bet is to stand up in a centred position on the bike. This is key to ensuring you are stable and in a good position to balance from. But what does this really mean when we say words like "stability" and "balance"?

STABILITY: The ability to resist forces

- The more stable the rider, the 'stronger' they are - they are harder to 'push over.'
- More stability means more resistance to forces from the trail - more like a picnic table, less like a lamp.
- The lower and more centered an object's centre of mass, the more stable it will be.

On a bike, this means having your weight centred between the two wheels. This not only makes the rider more stable but also improves traction (since both wheels are evenly weighted) and greatly helps balance.

BALANCE: The movements you make to manage instability

- If a rider were 100% stable they would be balanced - but this never really happens on a bike.
- The less stable the rider the more balancing is required to stay in control.
- Balancing helps riders manage instability, or recover and regain their stability.
- Balancing is easier if a rider has a better range of movement.

Stability and Balance are two sides of the same coin. You can't have one without the other. A rider will never be perfectly stable, so there will always be the need to balance; moving the bike and body to adjust to changes in the terrain and react to the forces acting on the rider. In other words, good riding requires a strong position from which to move and adapt from meaning your position is just as important as being relaxed and mobile.

photo credit www.timhailwoodphotography.com
Being low and centred provides the best position for stability and range of movement, allowing the bike to adjust to the terrain underneath the rider. It's also critical in helping keep both wheels evenly weighted, ensuring good traction front and rear.

So, being centred is already making sense, but riders with bad habits who have been riding for a long time (and watching too many YouTube videos) can still have a hard time trusting this centred, neutral and relaxed position. This logic is sometimes argued against because of what happens when we climb. But I can kind of understand this. To the lay person, moving forward on the bike when you climb, must mean you move back when you descend... it's a fairly rational train of thought. However, the reality is entirely different and can be quite easily explained using the following examples.

- Find a short bank with a decent gradient, a smooth surface and a flat, safe run-out.
- Stand still on the slope (facing the bottom) and you should notice you are standing upright - your body is vertical.
- You do this because you are used to a world where the surface has friction, and the slope provides this.

- Next, walk slowly down the slope.
- Again, your body will be vertical as you 'resist' gravity from pulling you down the slope, faster than walking pace.
- Walking up the slope you will notice the same upright position because, again, you are resisting gravity.

- Next, from a standing start, allow gravity to pull you down the slope as fast as you feel comfortable with.
- You should end up running down the slope.
- You'll notice your body is no longer vertical but more perpendicular to the slope, as you 'let it go.'
- If you stayed upright, you would likely slip over backwards or at the very least find it very difficult to run!

Zep s How-To Mythbusters - Climbing Technical Terrain
Moving forward on the bike when you climb does not mean you move back descending. Understanding the physics behind this is key to improving your position on the bike or your coaching if you're an instructor

Technically speaking, resisting gravity involves very different forces acting on the rider when compared to going with gravity. Similarly, the physics of when the rider is stationary compared to moving, are also different. Furthermore, the physics when moving along a flat surface and going up a slope, are also different when compared to moving down a slope.

In short, just because you stay upright when stationary or walking up the slope, does not mean you do the same when you let it go and run down the slope. In biking terms, just because you move forward on the bike when you climb, does not mean you move back when you descend. If you want to learn more about the physics behind this, feel free to check out this short, simple blog which explains some of this further; Balance Axis... tipping down the hill to stay centred. Otherwise, let's move on to some real world examples.

BODY POSITIONS FOR CORNERING... "DRIVE DON'T SURVIVE"

On groomed snow, do good skiers have their weight backwards? Nope, they tip downhill to keep their weight in the middle of the ski. Skiing with the weight over the back of the skis is unstable, makes it difficult for the skier to turn and they also lose edge grip since the front of the ski has less weight on it.

It’s the same for mountain biking. Leaning back greatly reduces stability, range of movement and front end traction, which makes cornering safely or consistently, very difficult. Improving your speed into, through and out of the corners, therefore, starts with a better position. To keep it simple, I'd like to highlight two key positions for descending and cornering; The 'Neutral' and 'Ready' Positions.

NEUTRAL POSITION: Riding taller to save energy, when the trail is mellow.

- Pedals level, standing up
- Chin over stem
- Taller and relaxed.

In a nutshell, many riders get low and stay low for too much of the time. Their legs get tired and they lose a lot of efficiency in their riding (especially on long descents or through a lot of berms) as their muscles are supporting their weight, the more flexed their joints are. So how do you find a better neutral position?

- Coast along a smooth flat surface.
- Stand on the bike, pedals level. Keep your chin over the stem (centred between the wheels)
- Now lock out your arms and legs. You should find yourself tall.
- Let your elbows and knees relax just slightly.
- You should feel relaxed, balanced, with a loose grip.


ZEP Mountain Bike Camps
The Neutral Position - chin over stem, pedals level, taller and relaxed. This helps save energy which ultimately makes you stronger and more stable.

For many riders, it may feel a little too tall at first (especially if their habit is to keep low all the time), but as long as it feels different (for better or worse), this is good, as it's you trying something new. If your riding is always feeling the same, you know it's not progressing because you're not doing anything different.

PROS & CONS

In the neutral position as you coast along, move the bike around underneath you. You may notice the range of movement you have isn't very large, but the movement you do have, is very easy and 'loose.' On mellow trails (or sections of trail) where the terrain and speed are not as demanding, a large range of movement isn't needed anyway, so this position is ideal in that it keeps you centred and mobile but prevents you from getting fatigued. Tired riders are often unstable as their legs and body are now too weak to properly deal with the trail and the various forces acting on them.

It is, however, a taller position, so in theory, it's slightly less stable. Also, because of the lower range of movement (especially in your arms) then it's not ideal for using when the trail gets rowdy, especially if it's steep. However, it can be advantageous when there is a lot of pressure exerted on a rider like in a high speed berm, or under heavy braking. If you do a 'push up,' you will notice you are stronger nearer the end of your extension. The same biomechanics apply on the bike. If you are trying to resist your body from being squashed into the bike (like a berm), then a slightly taller position can help give you better strength, to do this.


ZEP Mountain Bike Camps
Applying more of a neutral position in berms can save a lot of energy, improve consistency and maintain your speed. With straighter legs, you don't have to push or work as hard to prevent your body from being pushed around, as you get compressed in the berm. Good riders constantly adjust between neutral ready based on speed, terrain and energy; faster/rougher = lower and wider. Slower/more mellow = taller, more relaxed.


READY POSITION: Lower and wider for more stability and range of movement, when the going gets tough.

- Chin over stem
- Low & Wide
- Hinge at the waist & bend elbows to lower chest.

A common error in corners comes from riders having their weight too far back. This is often a result of their knees being too flexed in an effort to 'get low.' Instead of bending the knees to lower the hips, try hinging at the waist to lower the chest, keeping your chin over the stem so as not to let your position get too forward. This keeps you low and strong, preventing your legs from getting tired and 'collapsing' - the all too common reason why so many riders get pushed into the 'back seat' as the bike accelerates away from them in the corner. If this is new to you, it may take a while for it to feel normal but keep practicing and it will become second nature.

ZEP Mountain Bike Camps
The ready position. Bending the elbows and hinging at the waist, help bring the upper body towards the bars. Keeping your chin over the stem will ensure you stay centred, as you get lower. Low and wide.

ZEP Mountain Bike Camps
Here you can see the rider using a ready position. Notice he is hinged at the waist; the back is quite flat, with chin over stem and elbows out. He's low, without bending his knees excessively.

Do the same thing as before... ride along in the ready position and move the bike around underneath you. Front to back and left to right. Your 'sweet spot' should be where you can relax your grip on the bars. This is important to feel as soon as your weight is too far back or too forward, you'll notice you'll have to grip much harder. This is a great indicator of your body position when you're on the bike. If you have a lot of arm pump, it's very often because of your riding position and not the braking bumps.

PROS & CONS:

Lower means more stable. It also means you've bent your elbows to lower your chest. This means you should have more range of movement to move the bike underneath you and let it adjust and flow with the terrain. Flow is key. Being dynamic and loose really helps you make all the subtle adjustments and balancing movements you need, to maintain balance and control. This being said, how you get low is important... you can obviously bend your knees a little bit more, but just be careful of only bending your knees. Steep trails or rough trails where there are a lot of ruts, bumps, steps, roll downs or drops, the ready position is your guy. If it's mellow, though, stand up taller, relax and save some energy.

ZEP Mountain Bike Camps
The ready position: Centered (chin over stem), low and wide. This position can really benefit your cornering... helping keep the rider low and stable, while providing more range of movement in the arms, to help adjust and lean the bike through the corners. This separation (moving the bike underneath the rider) is key for linking corners and holding your speed better.

COMBINING THEM: Being fluid and constantly adapting as needed.

Good riding isn't about being in neutral or ready. It's actually about seeing these two positions as simple reference points, from which you can move between. The idea is to be dynamic and fluid in your movements, allow the bike to move, and allow yourself to adjust between neutral and ready as much or as often as you need. If it's super mellow, ride as tall as you like. If it gets a bit quicker, but it's still quite smooth, perhaps just get a little lower. You get the point. Try not to be fixed in your positioning and you'll gain the best of both worlds... stable, but efficient and adaptable. This is key if you want to boost your confidence, gain some consistency and maybe even go faster or tackle some harder terrain.

ZEP Mountain Bike Camps
Here the rider is somewhere between neutral and ready. For his skill, speed and the terrain, he's decided to get a little lower for some extra stability and range of movement, but not so low that he can't pump, unweight the bike or stay reactive.

It's all about viewing techniques not so much as right or wrong, but more like tools. Tools that you can choose to use based on your situation, skill level, terrain, and even body type. Obviously, some tools work much better more of the time (there are times when riding off the back of the bike is beneficial, like steep, sandy chutes) but the key is to try and maximize your riding by understanding that riding the same way all the time, is unlikely to help you progress. Be open to trying different techniques and keep working on building the number and quality of tools in your 'tool belt.'

Take the pictures in this article, for example, try not to take them too literally. The neutral and ready positions can look a little different from one person to the next. People have different bodies and different bikes. Experiment and find what works best for you, just as long as you remember what doesn't feel great in one situation, may be the perfect tool in another. And remember, all this info applies equally to whether you are riding your xc/trail/all mountain bike or riding your downhill bike - as long as you can lower the seat, the techniques are the same.

To wrap this all up I try to keep two simple things in mind when I'm riding and focusing on my position and balance;

1. "Are my wheels evenly weighted-ish?!"
2. "Am I driving (can I make adjustments if I want to) or surviving?"

Most of all, progress with small steps, have fun and enjoy your riding! In the next blog, we'll take this further and have a look at your position and balance when it comes to riding steeps, rock rolls and for heavy braking.

Happy Trails,

Paul

About the Author

Paul Howard is the Owner-Director and Head Coach of ZEPtechniques, Technical Director of the Professional Mountain Bike Instructor Association, Head Snowboard Trainer for Whistler Blackcomb SnowSchool, Technical Education Committee and 2015 Interski Team Member for the Canadian Association of Snowboard Instructors, and has been teaching mountain biking and training mountain bike instructors around the world, since the late 90's.

About ZEP

ZEPtechniques is a Whistler-based mountain bike camps and instructor training company. Established in 2006, ZEP offers single and multi-week, adult specific rider improvement camps, as well as weekly clinics, private lessons and tours. ZEP's Instructor Training services include the industry's original, multi-week mountain bike instructor training camps; training riders four days per week with evening seminars on suspension set up, bike mechanics, nutrition, as well as strength and conditioning sessions, all with industry experts. As developers of the internationally available Professional Mountain Bike Instructor (PMBI) Certifications and Directors of the PMBI Association, ZEP has long played a key role in establishing and improving the finest teaching practices and instructor certifications, within mountain biking.

ZEP is proudly supported by

Transition Bikes
ANVL Components
Fox Racing Shox
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Photos
Bike Park Photos
Tim Hailwood Photography

Previous articles

Climbing in Technical Terrain
Braking in Downhill Corners
How to Learn (featuring a discussion on pedal positions in corners)

Upcoming articles

Position and balance for steeps and heavy braking.
Techniques for flats vs. bermed corners.
Jumping: The myths and reality.


MENTIONS: @TransitionBikeCompany / @foxracingshox / @troyleedesigns / @FiveTen / @evocsports / @zeptechniques



Must Read This Week

99 Comments

  • + 61
 Awesome Post you guys!! Thanks for doing these articles, very helpful..
  • + 17
 I don't know, just do what it takes to feel good. Leaning forward is nice and dandy in berms etc., but when bombing some rough stuff going back a tiny bit will make it easier to ride it out on the rear wheel without any danger of collapsing over the bars. Landing bigger jumps with rough landing zones with the rear wheel first can give you some extra travel... Just don't always go full back, and be prepared to pull on the handlebars into such a landing - just like trials riders do. Moving your body back also makes it much easier to surf washboards etc. So, forwards isn't necessarily always the right answer.
  • + 3
 The thing they missed in this article is bar height and suspension setup to combine with these New techniques. If someone was previously riding off the back and takes up this New riding style, surely the shock would seem too stiff, and fork too soft giving that otb, unbalanced feel.
  • + 1
 I've never gone over the bars, I just manual trough everything technical. Rock gardens are my favourite
  • + 1
 The article doesn't suggest going full forward all the time, they could have elaborated more on when and how exactly to go further back. Anyways, a good read!
  • - 8
flag wipz07 (Feb 10, 2016 at 7:08) (Below Threshold)
 Just go out and figure it out yourself. On the trail you won´t have any time to think about all of this, it has to become second nature. Don´t try to get better by attending skill centers, it won´t help a lot, just find a riding buddy that is as good as or even better than you and push yourself at your rides. Thats how you will really get the confidence and the riding style that suits you.
  • + 3
 Sorry, this looks like a missed opportunity. They're trying to in the referenced/linked blog, but there's not really a good, clear explanation of the whole concept of keeping your body in the same position relative to the bottom bracket (i.e., weight centered over that) while the bike moves (pitches up/down) below you to conform to terrain. No, you don't get behind your bike - you stay centered over the BB, and then you let the bike pitch forward. Just like in skiing.
  • + 15
 As a highly qualified coach I agree with the message or safety, control, comfort then speed. However it'd be great if the writer didn't tar all coaches with the ethos of regurgitating what they've been told! Especially when there isn't really a one size fits all in any sports coaching!
  • + 3
 Pretty sure there was no point in that article having a go at all other coaches. Peoples level of understanding is as varied as rider skill and ability. What often holds people back from progression is a lack of understanding of the nuances found within every aspect of the skills of in this case riding a bike. This article just challenges a common misconception amount an alarming number of riders out there, whilst offering them a few insights to think a little deeper about a sport they love.
  • + 2
 Second paragraph?
It's not new info if you understand. If you don't, well then it's an amazing read!
It's great that traditional ideas are challenged and articles like this do make a topic for further discussion.
  • + 13
 it's also worth noting, todays longer travel slacked out bikes allow for much more forward centered riding. back in the day when front ends were low and steep, ass out was the only way to avoid an OTB.
  • + 2
 I went from a short TT 26er Reign to a much longer XL Enduro last year. The Reign was a very different ride from its slack seat tube to short TT. The Enduro allows a far more neutral position and descending is a far more over the bars affair as a result. It was a little scary at first but it works just great.
  • + 8
 "rather than moving back on a descent, the best bet is to stand up in a centered position on the bike."
www.pinkbike.com/photo/11471738
www.pinkbike.com/photo/11467007
www.pinkbike.com/photo/11420084

www.pinkbike.com/photo/12117476

Zep you should tell them they're doing it all wrong!
  • + 27
 Some nice pics there @fwp39... I see what you're saying and you're not the only one to draw this kind of conclusion. These guys are all masters of Position & Balance. Their bodies are quiet and they make the bike do most of the work. However, each picture you've found is a "moment in time". A freeze frame. It is not necessarily the position they're in the whole way down the track. Watch some videos and you'll see this. I'll highlight this part of the article again...

"Good riding isn't about being in neutral or ready. It's actually about seeing these two positions as simple reference points, from which you can move between. The idea is to be dynamic and fluid in your movements, allow the bike to move..."

Take a look at Gwin's recent YT video, and you'll hopefully see this.https://www.youtube.com/watch?v=JL_3xbXL3jY

Cheers
  • + 7
 Zep already nailed it, but to reiterate. Images you see of pros sitting all the way back on the bike are able to do so "because" of good body position. Standing more central gives you that reserve if your nose drops (or what have you). You're a human shock and you don't want to ride down "bottomed out" !!! Quickest way to end up over the handlebars, while you get up 'thinking' it was because you weren't far back enough.
  • + 2
 It's hard to say in that last photo of Gwin you posted, but I'd say with the photos of Sam, he is not moved back at all but centered over the bottom bracket in relation to the fall of the hill and terrain beneath him. That is to say, that if the bike were to disappear beneath him, he would probably land on his feet (and maybe roll forward from the momentum), not flat on his back.

Even if that's not the case with these particular photos, sometimes you've got to do what you've got to do in the blink of an eye to survive. It's more the exception than the general rule.
  • + 7
 If you look at each picture and imagine the bike "POOF" disappears, each rider in those pictures would land perfectly balanced on their feet. Its because they are all driving their weight through their bottom bracket, not pushing the bike in front of them.

Watch any world cup rider and you can see that their their bike is going crazy underneath them, but their entire body is neutral and stable to the point that their head doesn't even move. And they would all agree with Zep.
  • + 3
 There will be times where a rider needs to get back to brace for impact. I think when some people teach get your weight back they are really saying get your centre balanced between the wheels. In the olden times we had steep short bikes with along stem and you had to fight between weight back to keep from going over the bars and trying to get weight on the front for traction. Long slack bikes with short stems help that immensely. Even today I think certain World Cup cross country stars could learn a thing or three about bike fit.
  • + 7
 @fwp39, the1st three pics are of Samuel Hill. Normal rules do not apply. :-)
  • + 12
 @fwp, there's a reason for all those pics of Hill looking the way they do, and none of them is an "average" body position, it's just a moment in time where he's sucked the back wheel up because he's either in the air (two of the pics) and is trying to keep it low, or is absorbing a large rock in the rock garden - or in Gwin's case, braced himself as he's braking - check the levers.

Here's a good example of keeping centred, on average, whilst letting the bike move fluidly underneath you: youtu.be/q3PhmP9QuDM?t=49

And a few pics of Hill to prove the point:
www.pinkbike.com/photo/12576771
www.pinkbike.com/photo/12591185
www.pinkbike.com/photo/12523008
  • + 2
 I think its very much a function of terrain and speed - the first set of pics are of riders on steep rock gardens and as Paul says, you are using the two positions as reference points not the be all and end all. Come across a drop off half way down a new trail and you may have to get over the back to manual off the lip but if you know the trail, maybe you'd be riding it at speed in a more neutral position....
  • + 9
 Was going to weigh in here, but see it's pretty well been done to death. All I'll add is that Sam Hill is renowned for riding "over the front of the bike". All those pics of him over the rear are just moments in time. You have to move around on the bike, but "fairly central" is a good position to move from.

Excellent article by the way. I love the Pro's vs Con's technique, rather than:
"you're all doing it all wrong, even the professionals. Do my wierd techniques that feel all wrong and seem to make you slower against the clock or you suck."

naming no names....
  • + 9
 Watch a pro down hill race. Different styles of body english depending on the rider. Do what feels right.
  • + 14
 big difference between being a professional who has had tons of coaching and experience on the bike to dictate and understand their position versus a beginner who is going off youtube videos to build their skill set. to a beginner sitting down with one pedal lower and locking the brakes "feels right"

this is a great article and should be helpful to those who dont knwo and a good refresher for all those that do know.
  • + 8
 Agreed it gives a beginner a starting point for how to use body english. There is no definitive right or wrong style for smashing berms or negotiating steeps. Listen to advice and figure out what works for you. Want a fast learning curve. Follow somone faster than you. Watch thiere moves.
  • + 7
 I've seen moto guys totally new to DH sit down in a berm with their inside foot out and get around it at mach 10. Not sayin' you should, but you can!
  • + 6
 @crankrollwahoo12 If this is truley your opinion and you aren't just trolling; I'd recommend getting an instructor/coach for the day and actually opening your ears.


If you still come to this conclusion afterwards then - unfortunately - " you are an arrogant retard with an inferiority complex " end quote.
  • + 6
 It's ok to get way back when you're trying to show that it's really really steep in pictures:

www.pinkbike.com/photo/13082217

www.pinkbike.com/photo/12841855
  • + 8
 The difference is that the bike has moved forward relative to the body, not the body moving backwards in preparation for something steep.
  • + 2
 Nice comment!
  • + 0
 I would say "relative" is the correct word there.
  • + 4
 Great article and explanation of body mechanics. I think its also worth noting that when riding berms you can generate exit speed by pushing down on the pedals, similar to how you generate speed by pumping in a half pipe or on the landing of a jump.
  • + 3
 @zeptechniques Really interesting read and love the Pros and Cons. The only thing that's slightly confusing is the cornering section. You mention cornering with pedals level but the last but one photo shows the rider cornering with the outside pedal down but this isn't mentioned? (www.pinkbike.com/photo/13107449)
  • + 8
 Excellent article!
  • + 5
 Way to go Paul! We need more of these articles on PB to help everyone understand some fundamentals... even high end trainers/riders could learn a thing or two!
  • + 7
 Some of my favorite articles on PB. Thanks!
  • + 4
 I actually bought the TR500 in these pictures from Paul. Super nice dude. Sad that this will be the last time she sees the PB front page... haha
  • + 2
 LOL I learned this the hard way when I transitioned from my old XC (which I used for AM) to a modern downhill rig. SCETCHY!!! Now I just need to remember not to ride my old XC in the same style as my DH!!! Better yet time to buy a modern Enduro and repurpose the XC into a city commuter.
  • + 2
 Really helpful tips, thanks so much! I have a question about bending the elbows. I notice in the pictures the elbows are bent in such a way that they're sticking up and out. But when I'm riding and trying to stay relaxed I notice that sometimes my arms relax to a point where the elbows "fall" down to the sides, not tucked under but not sticking up and out either. I constantly have to remind myself to stick my elbows out! Does anybody else have this issue as well??
  • + 2
 I now know where to send those people who say : "Don't brake that hard with your front wheel while you're that much forward !" or "You're way too much over your front wheel, push you weight forward or you're buying a ticket for a nasty OTB !".

Needless to say I hardly ever did an OTB. I was wondering why.

Thanks and keep up the good job !
  • + 3
 It's easy to go OTB with an 90s geometry. Much more difficult with long and slack current geo, even when hitting hard a rock.
  • + 1
 Paul

Let me whine a bit since I read countless articles by Lee McCorcmack, Gene Hamiltion and Andy Vinohradsky, analyzing plenty of pictures and did countless drawings for Ryan Leech. I also did a day of one handed riding in the bike park last year, including a bit of jumping, unwillingly due to torn ligament. Hips don't lie aye?

Belly button is the approximate center of mass of your body when you stand up. When you get on the bike in neutral or attack position your COM moves only slightly above/ahead of belly button and a bit more downwards. Proper riding stance, either relaxed or attack (regardless of pitch of the slope -uphilling/descending) is having belly button aligned with the bottom bracket of your bike, paralell to the vector of gravity. Off course more or less. That's how letting go off the bars slightly works. Now your graphic in "Balance Axis" articles is completely wrong and does not even correspond to pictures in this article where your belly button in both positions is clearly above the BB. In that drawing you would be putting pressure on bars, which is ok if you are doing a particular thing, but is definitely not neutral. IT's not about leaning back, it's about keeping your COM over BB and moving out of that balance zone to deliberately perform certain actions.

www.pinkbike.com/photo/12284883
  • + 9
 Hi WAKI. I like that you bought this up as your conclusion can be quite a common misconception. Without going vastly into detailed physics of different components of gravity on a slope and how this affects an object on a slope when it's moving rather than stationary, I'll highlight another brief example to hopefully explain further. You say, "in that drawing you would be putting pressure on bars...". If the rider was stationary, this would be true. However, and again I'll highlight the article:

"Technically speaking, resisting gravity involves very different forces acting on the rider when compared to going with gravity. Similarly, the physics of when the rider is stationary compared to moving, are also different."

To relate to your specific comment you can discover the answer to this yourself... as can anyone reading this. Neither the Neutral or Ready positions will make the rider put pressure on the bars, when they are coasting (little to no brakes), down a slope. Why? Try this:

Find a slope with a level surface that transitions down, into a short slope.
Ride along, relaxed in a Neutral or Ready position from the top to the bottom.
If you coast all the way, the only additional pressures you may feel is at the very bottom of the slope, as the terrain flattens out (this is mostly due to the natural "compression" you would feel, rather like in a berm).
You should notice that on the slope itself, as long as you are keeping your chin over the stem, your hands didn't suddenly get heavy.

You can also try this:
Ride slowly onto the slope and stop halfway down.
As you brake and as you are stationary, you will notice more pressure on your hands*.
Stop only for a brief moment, let the brakes off and roll down the rest of the slope.**
You'll notice the pressure in your hands when you are stopped, should disappear as soon as you let the brakes off.

I like your drawings (wish I could draw like that!) and the idea of keeping the COM vertically aligned over the BB when you are stationary, does makes sense. However, the physics change when you are moving. As the article explains... what is true when stationary is not necessarily true when moving. If you're keen to learn more about the physics, here's one of our many references that I would recommend. I like it because it does a great job of explaining the physics clearly, in a way most of us can understand (physics papers and articles have a habit of completely making things way too complicated!). It's obviously tailored to skiing, but the research and underlying physics in this book are fantastic, and remain true to any downhill sport.

Ultimate Skiing - Master the Techniques of Great Skiing: Ron LeMaster, 2010, BlueSky Inc.

*Because if you still have your chin over the stem, you COM will be slightly forward - horizontally speaking - of the BB. If you were to remain stationary on the slope and wanted to be more stable, you would indeed need to align you COM vertically over the BB. Rather like standing still and "upright" on a slope.

**As you let the brakes off, if you did have your COM aligned vertically over the BB (your chin would be a little behind the stem, most likely) you would end up even further "in the back seat", as the bike would accelerate away from you. Instead, keeping your chin over the stem and your COM aligned perpendicularly over the BB (when compared to the surface of the slope), would result in you staying centred and balanced as the bike accelerates.

Hope that helps.

Cheers,

Paul
  • + 3
 I was with Waki on this one, but now I'm with you! It makes sense. To use Wakis "take the bike away" situation; if your COM is over the BB when the bike disappears you would land on your feet he is right, but if you are moving at any speed before disappearing the bike, your horizontal momentum would have you falling over on your butt immediately. If on the other hand your COM is centered between the wheels, when the bike disappears you would end up on your feet and in the correct position (committed to the hill) to run it out and so not fall over. Of course if you are stationary or moving very slowly then COM over the bb is where you would need to be. (because the horizontal element of the movement would be at or near to zero)

books.google.cl/books?id=nWWgjJfFT0wC&pg=PA77&source=gbs_toc_r&cad=3#v=onepage&q&f=false

Page 84

So Paul, how would you feel about coming to Chile to give some classes and ride some trails? I could be your translator Wink !!
  • - 1
 I understand everything you are saying Paul, but the matter of a fact is that he basic neutral position, the point of departure for all movements on the bike is having your COM above the BB regardless of terrain pitch (in reasonable range off course like 45 degrees, either up or down). Off ourse you adjust your position depending on what is happening, off course putting your weight behind the bike on downhill is what effectively happens but is still the result of having that COM above BB, but jjst as you say, telling somoene to get behind the bike because there's a descent coming is just wrong. As to your drawing, yes there can be a tiny moment when it is advised to move your COM ahead of BB and move that chin ahead of the bars (like approaching a step down at low speed to load the gun, to then shift the wight back), but neutral position is still ALWAYS above the BB with light hands.

Then off course, terrain acts at you, so you may need to shift that weight to counteract the force to stay balanced. Let's take the lip of a jump, or leveling terrain. As the bike rolls on to the lip, you need to make sure your body will follow that movement with it, so you lean back a bit, or rather push with hips like with proper bunny hopping or manualing. IN this way force will come at you through BB, in this way you will direct your body upwards, instead of contuning to go paralell to the ground for a brief moment to get compressed into the bike, which will eventually result in a dead sailor or regular OTB. WHat is fscinating is that it has to be a dynamic movement to generate additional counterforce, because coming at the jump static regardless of where COM is, will try to throw us over the bars (I argued with Lee mcCormack about it, when he showed a graph of the rider staying centered above BB all the way through the jump - you must have that slight bunnyhop tilt at the lip to counterbalance force of lip coming at you) In that way we are able to send a pretty big jump almost no handed. Same with shifting weight into the berm. We always aim at managing those forces through the BB using mostly hips. Still, between obstacles and other things we try to keep that COM above BB. Preferably having that chest low. Last year I noticed how riding high, even with COM over BB causes trouble. Your hands get straighter and you lack the range of movement to allow the bike to freely tip forward. If drop off comes along, and you alck the skill, riding at it in a static manner, the dropping front wheel will pull you ahead. Also, you will lack the power to push the bike forward off a slow drop off since nearly straightened arms are not as effective as eblows bent at 90 degrees - costed me a slight concussion... braking is another can of worms. According to Hamilton and Minnaar you want to get pushed onto the bars, to increase pressure on front wheel (standing for most of braking force), thus maximize grip, but more importantly, to remain balanced as soon as you let go off the brake. Holy cow, Alan McNish talked about it in one interview when referring to setting up and driving a LeMans racing car.

Also you write about having weight centered between the wheels, in such situation you would be putting pressure on bars since BB is moved further back and weight distribution on a modern bike is usually up to 70% on the rear wheel (on flat ground). Theoretically at certain, rather steep pitch of terrain, the vector of the force going from your COM to BB, can accidentally end up crossing the ground right between both wheels. It is still a side product of COM above BB.

I enjoyed the article, but I found that bit about COM and BB a bit misguiding.

Cheers!
  • - 3
 skiing is a great comparison, but in skiing we don't have handlebar that helps us to put the bike in position that will allow us to counter act the force. Braking is a great example because it gets more effective if you DO put pressure on bars. WHen you jump,and while in the air, you should put your COM a bit back and tense the arms to absorb the landing or you will get too much weight ahead. If you approach a drop off slowly , you want to pull on bars slightly to bring your torso forward to be able to push the bike ahead SO that finally you either land rear wheel first ooor you are far back enough fro the bike to come into you, not under you, sending you eover the bars as it touches the ground. Turning bars to dismount from berms, while simultaneously pushing with hips? ? Manuals, wheelies, bunny-hops as means to stay balanced in certain situations? - Comparison to skiing is great for explanation of hip action but has it's limitations.

www.pinkbike.com/photo/11280962
www.pinkbike.com/photo/7677516 - belly button on line with BB ( in fore-aft plane) and force acting perpendicular to the ground.Closer to the rear wheel. Please take note of phenomenon of optical perspective, aaand phase of taking the berm
www.pinkbike.com/photo/5427919/ here belly but, aligned with BB, and accidentally with center of wheelbase
www.pinkbike.com/photo/8332520 - belly buttun over BB, closer to the rear wheel when crossing the ground

www.pinkbike.com/photo/5924660
www.pinkbike.com/photo/5626815

Here:
www.pinkbike.com/photo/5422295 - best tech riders out there, steep and SLOW enough for the COm to bea ahead of BB, and ahead of wheelbase center. Probably some increase of pressure on front tyre for grip.

Whoopsie: he stays balanced isn't he?
www.pinkbike.com/photo/5010779
  • + 4
 I like the passion and interest here WAKI, but can I ask you to please try to be careful. There's some pretty misleading information in your comments that is potentially dangerous for people learning... especially with the jumps and drops. I get where you are coming from but it all stems from a slight misunderstanding of the physics, and how things work when moving vs being stationary. It's also worth mentioning again that each picture you highlight is a moment in time... and photographers naturally like taking pictures when something cool is happening, like rolling over a drop. They don't tell the whole story. In the case of a drop, riders often need to absorb the pressure on the rear wheel to avoid being pushed OTB, and this naturally results in the bike moving ahead underneath them and their hips moving vertically over the BB. But again, they were able to do this because they were most likely centred, and from this "default" position on the bike, they were then able to make the adjustments they need. This is key... as the article explains, the neutral and ready positions are places to move and react from, not where you should stay all the time.

For example, rocks and roots often act to "slow" the bike down, so moving the hips slightly back (so they are vertically above the BB, on a downhill slope), can put the rider in a stronger position to "brace" against the forces from the bumps, that are trying to slow the bike down and through the rider OTB (over the bars). The rider is in this position because of the rough terrain, not because it's a downhill slope. Using one of your examples...

www.pinkbike.com/photo/5626815

... Sam's COM is pretty much vertically aligned over the bottom bracket, in this rock garden. However, if this was smooth, his chin would be more over his stem and his COM would be more aligned over the BB at a perpendicular angle. Here's a couple of examples of this

www.pinkbike.com/photo/13105612
www.pinkbike.com/photo/12487643

Another good analogy or example is skateboarders dropping into a half pipe. It's a steep slope that's smooth. And you can bet their COM is not vertically above their skateboard. They are "tipped" into the pipe, with their body more perpendicular to the slope. Look at some BMX'ers in a halfpipe and you'll see the same thing.

Keep studying and it will make more sense. By the way, this idea is a little newer in mountain biking, but's it's been around in the ski and snowboard teaching world for literally decades. The physics on this are solid. As for now, I appreciate the discussion as I can geek out on this stuff quite easily! As the article also mentions, we'll talk more about this in the next blog and hopefully this will answer some more of your questions... if I put everything in one blog, it would have been way too long!

Cheers,

Paul
  • - 3
 Ok There is a quite high chance I am just unable to translate it right with my poor use of language and communication, because what you wrote now seems like what I was trying to say. I mean the bit about neutral position being a momentary setting from which we go out to do stuff (I wrote about it as point of departure), I haven't meant anywhere that we should ride statically. Apart from skateboarder rolling into the pipe, how can we analyze any form of neutral position based on what the guy is doing on the edge? He is leaning in because as soon as that board is going to roll down the pipe, they will come into balanced position, he makes room for balanced position to happen. If he wouldn't board would slide from under him.

Finally I am not sure comment board is any dangerous, skills clinics + practice is what makes people tick. There are plenty of people hurting themselves jumping and no article can stop them from doing it wrong. I was fortunate to be poor enough to spend one summer on a crappy small table top jump on a crappy bike. Some are not as fortunate - they afford a DH bike and hit A-Line in first year of their riding, being at the mercy of genetics and upbringing conditions Smile The whole concept of location COM somewhere is worthless unless someone shows you that.

Also I was not selectively chosing pictures just to support my argument, I was selective in finding a picture of a top rider in quite neutral moment, neutral at least according to my judgement. As far as laws of physics are the same for everybody I do find what seems as inconsistencies between your top coach preachings though Smile I read lots and apply as much as small kids allow me to. Fortunately those inconsistencies are much smaller than what bike engineers talk about properties of a wheel size or chainstay length...

I'd kill for a drill for learning to manual... I cannot sense well enough the moment when the wheel starts dropping, I am usually too late with it. Straight arms, and hips are quite dialed, but I am just keepin on missing the right moment for reaction for the wheel dropping!

Cheers!
  • + 1
 @zeptechniques: I think this should clear up the confusion somewhat as to body position on the bike. The default person's COM should be over the BB along the line normal to the slope as you propose. This would be similar to the position used in skiing. However, in skiing, there is little chance of an endo due to the longitudinal stability of the skis and the fact that one brakes by turning the skis perpendicular to the slope and there are (hopefully) no objects such as rocks, vertical snow walls to act as a force to go head over heels.
However, as you mention, the position on the bike fore and aft and up and down varies considerably dependent on the terrain. The possibility of OTB's is quite real in technical steep conditions and the best way from a purely physics perspective is to both move the COM lower and rearwards from the default position to prevent this. But you are right in that the slope itself will not cause an endo. An endo ocurrs if the bike and rider are subject to a sudden stopping force as from a log or rock. I myself experienced an OTB on flat ground at a relatively slow speed when I hit a tree stump that was hidden by leaves. So it is the sudden stopping force that is responsible for OTB's, not the steepness of the terrain in and of itself. However, the steeper the terrain, the less the stopping force that is required to go over the bars.
Hopefully this helps.
  • + 1
 @zeptechniques:
Thought I would add another comment.

On the diagram in your 'Balance axis' link article, you indicate that gravity (red arrow) acts in a direction perpendicular to the slope. This is incorrect: Gravity always acts in a downward direction. However the components of the gravity Vector (a vector has both direction and magnitude) can be resolved in the direction of the slope (which provides a force in that direction) and in a direction normal (or perpendicular, i.e. your Balance Axis) to the slope. The normal component of gravity is offset by an equal but opposite normal force by the ground (Newton's law) so there is no net force in the direction perpendicular to the ground. You may want to consider modifying the diagram or description to avoid confusion.

Overall, I feel you give sound advice on mountain bike riding techniques in the article above.
Perhaps you can give me mtb lessons in exchange for physics lessons which is my area of 'expertise'.
  • + 4
 Another great article - better get out and ride while it's fresh in my mind Wink
  • + 1
 Also when we learned in 'the olden days' there wasn't really the option of skills courses or tuition other than finding a big hill with your crappy old bike and trying not fall off. All fair points however ... old dog will try new tricks.
  • + 1
 Some good points in there for sure and some good debate following. A couple of things that are often left out in a feature like this is the explanation that we (bike and rider) are never static, everything is constantly moving and the appearance or relationship between bike and rider can be captured in a still image showing either end of the spectrum. I've viewed many hours of slo-mo video and looked at tens of thousands of sequence images. There just simply isn't enough space in web and print features to use the amount of text required to truly unravel the intricacies and complexities of the physics and applied techniques in this sport. I can spend a whole day with a rider teaching them and I feel I've only scratched the surface of what I've discovered through riding different bikes in different disciplines over the last 30 years. The other missing nugget of gold is the difference in technique for different bikes (brushed on here with 90's geometry reference) and different physiology types. Geometry, suspension travel, rider strength, agility and ability, speed 'vs' Gradient. severity of trail surface (loose, compact, size / scale of feature). At every opportunity you can learn something, it just may just be that your learning how not to do it.
  • + 3
 There's some good thoughts on this thread. Our next article will have some more info to answer/explain some of the questions and comments. Cheers everyone.
  • + 3
 Thanks Paul. These articles are super helpful as a reminder from the PMBI and to share with people as another resource. Keep 'em coming!
  • + 1
 Study the attack position from motocross. Enduro and Downhill are moving toward the same neutral with chin forward and elbows out form. It is about being able to put the front tire where you need it to be, and being to far back in cockpit reduces feel and grip at turn in.
  • + 1
 So I recently learned this chin over stem thing. I'm 6,3" with L evil insurgent, in my ready position my chin hangs WAY over in front of the stem, to bring back even close to step I'd have to shift my hips way over the back tire. I still "feel" centered on the bike with my chin way over, it's just a metric I've never heard of considering and wondering if anyone else is pretty far in front of the stem naturally.

I actually always ride in X-Low mode for some more front in stability since I do feel I get to the front too easily. Joys of being an in between sizes guy I guess. (I had heard the XL was a monster or a bike and that some even taller than me preferred the L)
  • + 1
 @zeptechniques you speak about hinging at the waist a few times in your article, please can your clarify what you mean by this? Is the waist at the height of the belly button or where the hip joints are? Does this movement come from bending the lower thoracic spine or by rotating the torso forward at the hip? Thank you!
  • + 1
 I employed the recommendations in this article and noticed a few very beneficial things:

My hands were far less fatigued from not having to hold on my bars tightly
More control in the rough stuff
I maintained grip in virtually every berm that I had blown through in the past due to lack of grip on the front tire and in return I used my brakes less and therefore faster entry and exit speed with more control.......win, win, win and win.
And last but not least faster Strava times.

These tips work.
- Pedals level, standing up
- Chin over stem
- Taller and relaxed.

The biggest difference was the grip on the front tire with my chin over the stem. It so simple to move forward and has a huge benefit to riding in control at speed.

Thanks ZEP
  • + 1
 Quick observation: The "ready" position is inherently a weight back position with respect to the "neutral" position. If you're hinging at the hips without arching your back in order to get lower on the bike and at the same time trying to keep your chin over the stem then you must move your butt back. There is no way around that as the distance from your chin to your hips is fixed. So by moving to that position from the neutral position you are indeed moving your weight back. This can be seen in the pictures and is easily proven by trigonometry. That said, I totally agree that your baseline position on descents should be as centered as possible but with the caveats that you need to move the bike forward and back (or your weight the opposite) based on variations in the terrain and on how much braking you're doing. Clearly, if you're braking you need to get your weight further back than you would if you were riding the same section without braking in order to maintain balance. Similarly, you wouldn't want to remain fixed in a centered position when transitioning from the relatively flat approach to the near vertical part of Drop In Clinic, unless you want to do a spectacular pile driver.
  • + 1
 This is so true, I remember having a nasty OTB just because I WAS too far on the back. This is very true on rolling drops, because if you are too far, you cannot let the bike ride down first keeping you body in the same level as before untill the fron wheel touches the round. If you fail to do that you compress the fork much more initially and this is a strait path to the OTB.
  • + 6
 post really helpful
  • + 1
 I think I ride like this. However. Old habits die hard. Some times I ride my bike like the hardtail I rode in the early 90's. Especially when tired! I love tea baging my rear tyre. Thats the great thing about current bikes. Some days you just have to hold on. Its a shit ride but a ride all the same.
  • + 1
 Zeb, I am feeling sort of thick now. I read this and the physics article and still don't quite understand what you're saying. I am having trouble admitting your explanation into my model. I'm especially confused about what was different with xc bikes in the olden days (other than scary non-dropper seat getting in the way of your motion.)

Is it fair to explain balance in terms of how much weight isn't on your feet? Standing on pedals with crank perpendicular to ground the weight on feet is balanced across bottom bracket. The rest of the force that holds you up is through your hands. One could argue that a rider is balanced when the hands impose no force on the bars.

Are you saying that I should move from neutral to having more weight on bars when descending? Or just that I shouldn't be moving too far back so that I'm pulling on the bars?
  • + 5
 Paul is the man. Awesome article!
  • + 0
 So...no mention of dropping heels and wrists to have weight behind contact points and push bike, as opposed to on top of them?
That is the best way to avoid going OTB...IMHO.
Agree with centered and chin over stem (which I heard Wade Simmons preach ages ago).
  • + 1
 Dropping the wrists causes an active insufficiency, mean grip strength / endurance gets worse, keep the wrists in a straight or neutral position. The whole hand / grip position will change depending on what your riding. We drop wrist on moto's for throttle control.
  • + 0
 I can easily see your point when you compare with skiing. I come from old school when everyone rode hardtails or fully rigid bikes with skinny tires, steep angles and high saddles and long stems. In those days you did indeed need to get the weight back a bit more if for no other reason than any small obstacle that your back tire hit would launch you over the bars.
These days with full suspension, dropper posts, slack angles, loads of travel and big grippy tires, the game has changed and riding more centered and lower is easy and stable.
However, as you mentioned in your article the example of standing downhill, then walking and eventually running how the body goes from vertical to a more balanced position with speed increases, I put to you that in some situations it is indeed better to have your weight slightly back. Case in point would be creeping down a steep vertical granite slab with a not so smooth transition at the bottom. At slow speed you need to keep both tires at optimal braking to control the speed. The front will have more grip on a steep slab than the rear, so weight must be shifted to compensate. Not to the point of the front losing grip though. At the bottom weight must also be back at the moment of transition.
So, with speed, a centered position going downhill is most stable, but does that position not move a little back with slower speeds?
  • + 2
 Being centred you can adjust as you need.
  • + 2
 Presumably if the speed is slower that implies you are braking more which naturally shifts weight to the front. So it's right to have weight back not because the speed is slow but because you're on the brakes.
  • + 0
 You also have to compensate the fork spring rate by making it stiffer because there is more weight on it, especially when it gets steep. Sorry if this was mentioned in the article.
  • + 4
 Thanks again Paul!
  • - 1
 Most of the confusion is about what "moving back" means and that article misses it.

The image above of the guy going down shows him almost sitting over his rear wheel. To many, that will look far back. It is far back relative to the middle of your frame, when level, but in fact it is just behind the bike's centered of gravity when the bike is pointing down.

Brian Lopes book Mastering Mountain Bike Skills and Technique explains the body position when going up, down or flat in a few sentences and 3 snapshots. It is by far clearer than this long article.
It is all related to the rider's center of gravity relative to the bike's center of gravity. Put the rider in front and you'll risk an over the bar. Put it too far back and you loose direction.
  • + 1
 Lol ... All those otb's weren't from having my weight too far forward ... OK
  • + 2
 Excellent I feel like a dinosaur.
  • + 2
 More like this please PB!
  • + 1
 Α video would be much better.
  • + 1
 Zep have videos on youtube. So sites Fabien Barel and gmbn
  • + 1
 That should say so does ( not site)
  • + 3
 I really liked reading this in article form actually. Saves the effort of trying to freeze frame videos to figure out exactly what's going on!
  • + 1
 Any modifications on these techniques for hard tail riders?
  • + 1
 Do you have a book i can buy?
  • + 1
 no video?
  • + 1
 uhhhhhhhhhhhhhhhhhhh
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