Ideal Body Type

[Jim Callen]

What-if any- is the ideal body type for alpine snowboarding? Is there one? It's got to affect the physics of how you board, so I was wondering if anyone has a distinct advantage over another person due to the type of body they have.

[AlpentalRider]

your joking right?... please tell me this is a joke... please tell me your not being serious....*looks at calender making sure it's not 4/1*

[Baka Dasai]

Lots of sports have ideal body types. Check out Olympic gymnasts and weightlifters - they're all really short. I've heard that any sport that involves "tumbling" (like gymnastics, or even freestyle snowboarding) favours shorter people. Look at the Olympic wrestlers - massive upper bodies on skinny little legs. The cyclists are the opposite - tree-trunk legs and skinny upper bodies.

Alpine snowboarding? I reckon something approaching the cyclist's proportions would be best - big strong legs to give you strength where it counts and a low centre of gravity. No need for bulk in the top half though.

As a tall skinny guy with long legs and a high centre of gravity I'd like to say that any deficiencies in my riding are solely due to having an unsuitable body type.

[LeeW]

Dont forget the back muscles.

[Vahur]

Cyclists have to fight with gravity, that's why "skinnier" riders have advantage (especially in mountain biking). I checked Athens men mountain biking winners data and their BMI was between 21.3-21.9
Riders don't have to fight gravity, quite opposite, bigger mass has advantage in downhill. E.g. Hermann Maier has BMI 27., C. Klug 27,4.

[nils]

Does that mean I could have won the gold in mountain bike? i've got 22 BMI and a slow pacing heart !
I still need the thick trunks to carve the olympics thu!

[knoch]

i figure you just gotta be real heavy, and you gotta be able to handle your weight real well. in my experience the extra push from gravity helps a lot.

[Neil Gendzwill]

What you need are thighs like tree trunks and core strength to match. Guys like Maier and Klug aren't successful because they're heavy, it's because they're strong. The high BMI comes from lots of muscle mass - I bet if you looked at body fat % it would be relatively low. BMI doesn't mean much for athletes. Weightlifters and wrestlers can get BMI into the 30s while having BF under 10.

[Jack Michaud]

have the ideal body type. Low center of gravity.

[Randy S.]

http://www.expeditionzone.com/Storiefiles/thumb/sabinacoll400.jpg

[kjl]

Alpine snowboarding? I reckon something approaching the cyclist's proportions would be best - big strong legs to give you strength where it counts and a low centre of gravity. No need for bulk in the top half though.

I wonder if these particulars of alpine snowboarding affect this:

1) You move your center of gravity with respect to your edge angle through angulation at the hips. Therefore, a certain amount of angulation at the hip with somebody with a normal or heavy upper body will move the center of gravity much more than somebody with the biker build like me, because my trunk and shoulders weigh so much less in comparison to my legs than others.

2) Most of your legs (the heavy thigh/quad parts) are behind the center of the board (towards the tail), if you are in a highly compressed carve. Again, somebody with a light trunk/shoulders would need to lean forward towards the nose more than a top-heavy guy to recenter their center of gravity in the middle of the board again.


In fact, I wonder if somebody with a very large upper body would have an advantage in being able to move his CoG around much more with relatively small motions compared to a skinny, hollow-chested guy.


In fact, I will use this excuse the next time I wash out my toeside.

Next up: experiments in carving with lead weights on my shoulders.

[Neil Gendzwill]

I'd say that snowboarders need a ton more strength in the legs than bikers do. They also need core and upper body strength to support the motions involved. I was watching the tour and Armstrong's main competition, the German guy (sorry forget his name) was described over and over as a "beast" a veritable Hulk of a man in cycling. He's 6'1" and 161 lbs. That's not a beast, that's the guy that gets sand kicked in his face at the beach. For the record, that's a BMI of a little over 21. Cyclists are about aerobic endurance, racing snowboarders are about muscular endurance and strength. Different types of muscle fibres focused on in training. Different athletes almost entirely.

[BobD]

As I understand it, what makes a good carve is edge pressure. The ability, despite being laid out in a carve, to apply a strong downward pressure to the edge. I think this is done by levering the board with the legs, against the relatively large mass if the upper body. This is why "well built" guys can carve so well, and why you never see a picture of a woman really laid out, ( on a snowboard that is).

BobD

[Jim Callen]

Hey Alpental-nope, this thread wasn't a joke. I was really curious about this, and I've gotten a lot of great responses to ponder. Thanks everyone.

[AlpentalRider]

I find this thread quite comical. Cyclists have big legs because they train on bicycles most of their life! It's not like a tree-trunk legged guy said "hey I should be a cyclist". A person's body adapts to what they are doing. Now it is true that in some sports certain body types offer a slight advantage (short guys for lifting events and gymnastics comes to mind), but with the mechanics of snowboarding involved, I just don't see any one body type having a big difference over another given the riders have the same level of skill.

I say most of the measurable difference between snowboarders is technique. And a guy with treetrunk legs and twigs for arms can learn the technique just as well as a guy with popeye arms and toothpick legs provided both individuals are physically fit. Same goes for tall vs short, and heavy vs light. The variances and competitive edge are negligable if even measurable IMO.

[ncermak]

Spy? any clue?

[Tommy D]

Originally posted by BobD
As I understand it, what makes a good carve is edge pressure. The ability, despite being laid out in a carve, to apply a strong downward pressure to the edge. I think this is done by levering the board with the legs, against the relatively large mass if the upper body. This is why "well built" guys can carve so well, and why you never see a picture of a woman really laid out, ( on a snowboard that is).

BobD

This thread kinda follows an argument my friends and I are having about Karting. I have very little mass compared to the guys I compete against, so my kart accelerates and climbs faster. However, I can't corner as fast, 'cause I don't have the same amount of grip my heavier friends are able to find.

Also, I'm short by comparison (5'8"), so when I lean to the outside of the turn for more grip, I don't transfer as much weight(mass) as my taller, heavier friends.

Interesting note: Even considering the above, I run faster lap times on average than my buds (We are all at the same skill level), so my lack of mass must be an advantage somewhere, but probably in the transitions from right to left, where I can maintain more speed.

[Jack Michaud]

looks like sweet Victoria Jealouse to me.

[kjl]

Originally posted by AlpentalRider
I say most of the measurable difference between snowboarders is technique. And a guy with treetrunk legs and twigs for arms can learn the technique just as well as a guy with popeye arms and toothpick legs provided both individuals are physically fit. Same goes for tall vs short, and heavy vs light. The variances and competitive edge are negligable if even measurable IMO.

Obviously I don't know for sure, but my intuition says otherwise. For a sport where we can feel the difference between 55 and 56 degrees on foot angle, or putting your back hand here rather than there makes such a marked difference in your carve, I would say that the difference of having an extra 10 pounds around your waist or an extra 10 pounds around your chest would make a noticable difference. I would also posit this: People with big upper bodies will tend to carve better in general. Pear shaped people (small shoulders, big waist or butt) will have a harder time carving heelside unless they have very high stance angles. Obviously you can compensate with technique.

[Bob W]

I would say that the female rider is none other than Tara Eberhard. One of the best female alpine riders out there. Victoria came into racing just as Tara was heading out!

[P06781]

Has anyone noticed after a long season of riding that your front , rear leg, hip, and stance develope asymmetrical muscles . Does this happen to everyone or this a result of "bad" or uneven technique ? Should we ride a few days each year opposite to help even the muscles out? Just wondering...

Jim

[Jack Michaud]

Originally posted by Bob W
I would say that the female rider is none other than Tara Eberhard.

Tara is regular-foot. Victoria is goofy.

[mirror70]

Originally posted by Tommy D
This thread kinda follows an argument my friends and I are having about Karting. I have very little mass compared to the guys I compete against, so my kart accelerates and climbs faster. However, I can't corner as fast, 'cause I don't have the same amount of grip my heavier friends are able to find.

Sounds to me like they're just better drivers. While their tires are able to generate greater cornering loads, that is in direct proportion to ho much more load they need to generate (because of the increased mass).

[Jack Michaud]

Originally posted by kjl
I would also posit this: People with big upper bodies will tend to carve better in general.

It's a simple fact of physics, lower center of gravity is better. You want your center of gravity to be as close to your "roll axis" as possible, AND you want your mass to be concentrated there. For cross-over carves, your roll axis is down in the board. For cross-under/through, it's closer to your hips.

[LeeW]

Originally posted by Tommy D
This thread kinda follows an argument my friends and I are having about Karting. I have very little mass compared to the guys I compete against, so my kart accelerates and climbs faster. However, I can't corner as fast, 'cause I don't have the same amount of grip my heavier friends are able to find.

Also, I'm short by comparison (5'8"), so when I lean to the outside of the turn for more grip, I don't transfer as much weight(mass) as my taller, heavier friends.

Interesting note: Even considering the above, I run faster lap times on average than my buds (We are all at the same skill level), so my lack of mass must be an advantage somewhere, but probably in the transitions from right to left, where I can maintain more speed.

This would apply to motorcycle road racing. There's a French man on World Supersports-- Cambon. He's real short, but he rides like hell!

[LeeW]

Originally posted by Jack Michaud
Tara is regular-foot. Victoria is goofy.

Tara Everhard's been a fan of mine for a very very very long time. I wonder where is she these days and what is she doing? The first alpine boarding I was exposed to was the two page Burton commerical promoting alpine board with her trashin' the gates with zebra base burton (or suit?) in 1990 or 1989 TWS issue. She KICK ASS! Is she still married to that dude (forgot his name) who used to run Cross M (and is he still runnin' it?) ? Pool-something was his last name, I think

[Tommy D]

Originally posted by mirror70
While their tires are able to generate greater cornering loads, that is in direct proportion to how much more load they need to generate (because of the increased mass).

I am not sure what you mean?

Are you saying that regardless of mass, we should be able to attain equivalent levels of grip from our tires?

I guess that would make some sense, but would it hold true given a 80 lb weight difference on a greasy track?(F1 Boston)

Keep in mind the differences in lap times are within a tenth or less of each other per lap, and yes, they are phenomenal drivers!

[Kirk]

I do agree with the low cog concept as an ideal - it makes sense. I would also agree with Neil in the muscular strength and endurance argument. Regardless of your height or distribution of mass (within reason), one's strength, endurance and even flexibility is going to be play the biggest role IMHO. I've seen athletes of different sizes and shapes do some amazing things (that you would not have expected given their size/shape) simply because they've coditioned themselves to do it. I truly belive leg strength and endurance (not just quads) is key to initiate and drive a turn, but once you're inclinated, "core" muscles (abs, oblique, lats and other trunk muscles) are going to have an impact on how well you achive body angulation to maintain some mass over that edge. My 0.02.

[jason_watkins]

Originally posted by Tommy D
I am not sure what you mean?

Are you saying that regardless of mass, we should be able to attain equivalent levels of grip from our tires?

I guess that would make some sense, but would it hold true given a 80 lb weight difference on a greasy track?(F1 Boston)

Keep in mind the differences in lap times are within a tenth or less of each other per lap, and yes, they are phenomenal drivers!

In general it's true: a given tire supports a given maximal accelleration. Adding 500lbs to the center of gravity of a car will not affect it's maximum skid pad performance. It's because weight appears on both sides of the equation and cancels out: more weight means more force on the contact patch, but at the same time, more weight means more force required to produce the same acelleration (F=MA) so they cancel.

BUT

If you re-read Tommy's original post, he mentions that the heavier riders can MOVE a larger proportion of their total mass (assuming the carts have equal weight) while cornering. That's a whole different story, since now the COG is moving, and the simple math above doesn't apply. Considering that the average put put cart at cart racing places has no real suspension other than the compliance of the tire, they don't have any roll compensation, and so moving the COG more could equalize forces between tires more, making it less likely you surpass the static friction limit on any particular tire.

It's a lot like something JM has said about snowboard racing: heavy riders have a slight advantage. Even though both have the same accelleration due to gravity, a heavier rider can push back on the snow with a larger absolute force: so chop that would chatter and throw a lightweight like me gets blasted through confidently by someone heavier.

I'm no go-kart race engineer.... but I think the above is all true, so I think Tommy D's statements hold: there's a power-weight advantage to being light, and there's a cornering advantage to being heavy. In the little carting I've done, the 130lb chick always won. But that's because the carts were massively power limited.

[mirror70]

<img src="http://www.cf-cars.com/images/massVSvelocity.jpg">

The two primary assumptions made there are that 1) µ is constant, and 2) r is constant. In the real world, µ varies with mg, but for this example we'll assume it's constant.



As for snowboarding, you want a higher cog and strong legs. This is for two primary reasons:
[list=1]
Your legs are your springs. You want them as light as possible because that way they will move faster. Your legs are considered to be "unsprung mass," and this is the enemy of smooth riding over chop & bumps. This, obviously, needs to be balanced with the fact that you need strong legs
Flexibility. Having a higher cog means that it is above your legs. This enables you to place your cog wherever it needs to be. Why is this important? Because you ride hard boots, your legs are connected to the board and really have only one joint that moves. Given this, with your cog in your legs, you are severely limited in where you can place it. With only one joint, your cog becomes largely tied in to edge angle, and the proper edge angle is going to vary quite a bit depending on the snow, your speed, and various other factors. Moving your cog up gives you far more freedom to relocate it, and begins to remove the ties between edge angle and cog placement.
[/list=1]

Of course, physics and kinematics back this up, while anecdotal evidence does not. Why is this?

It is because technique and talent are what determines how fast a rider is.

[mirror70]

Oh, and regarding your mass while karting, this technique does nothing at best. Recall Newton's Third Law regarding "equal and opposite reactions" for proof.

As for anecdotal proof of this, watch the pros drive their karts - their bodies don't move except when they turn around to see who is behind them.

[jason_watkins]

Oh, and regarding your mass while karting, this technique does nothing at best. Recall Newton's Third Law regarding "equal and opposite reactions" for proof.I'll have to take you at your word since I don't have the ability or inclination to go through the math. But I would point out that, as you said, the grip isn't linear. That math would be valid for a point mass unicycle, but I don't believe for a 4 wheel kart. Because the grip is sub-linear, there's an advantage to equalizing weight distrobution.

see discussion here (http://autozine.kyul.net/technical_school/handling/tech_handling_3.htm) .


As for anecdotal proof of this, watch the pros drive their karts - their bodies don't move except when they turn around to see who is behind them.Not in the vids I've seen playing in the local karting place. They move their body like you wouldn't believe. As do motorcycle racers, but of course, that's about stability. But based on this anicdotal evidence, and my intuition, I'll continue to believe there's an advantage to moving the cg toward the inside of a turn.

[Jack Michaud]

Originally posted by mirror70

As for snowboarding, you want a higher cog and strong legs.

Well, not too high, you want it up in your hips, sure, but not much higher. Women have a better body type because their cog is typically a few inches lower than men's.


This is for two primary reasons:
Your legs are your springs. You want them as light as possible because that way they will move faster. Your legs are considered to be "unsprung mass," and this is the enemy of smooth riding over chop & bumps.
Actually your legs are half sprung. The top coil of a spring is totally sprung, the bottom coil is totally unsprung and there is a gradient in between. The result is that only half of the spring's mass is unsprung (assuming a straight-rate spring).
-Jack

[Neil Gendzwill]

I've always understood heavier skiers/riders to be better gliders, all else being equal. More momentum, less likely to be affected by small variations in drag. Not sure how that works out with the math though.

[Tommy D]

Originally posted by Neil Gendzwill
I've always understood heavier skiers/riders to be better gliders, all else being equal. More momentum, less likely to be affected by small variations in drag. Not sure how that works out with the math though.

Yeah, my friends are always pulling away from me on the flats. Makes good drafting though!

[Jack Michaud]

people are posting scans of physics equations!!! (guilty)

[Fit Fat]

Without getting to far into it the reason that Tommy D has problems getting around the corners is that without the same abiltity to move his mass around he can't get the Kart to turn.

Karts like the ones we are driving have a single "live" axle with no differential action (in a race car this would be what is known as a "spool" inside the rear differential, the Kart obviously does not have a diff.) The rear wheels of the Kart turn at an identical speed, ina straight line this is fine, however when making a corner the radius being negotiated by each rear wheel is diffrerent and therefore the speed of each rear wheel wants to be different. The inside wheel travels a shorter distance at a slower rate of speed compared to the outside wheel. The live axle has them locked at the same speed and so one or both wheels must create some type of drag against the rest of the kart. Shifting mass toward the outside wheels of the kart in a corner takes away some of the drag being induced by the inside tire doing two things simultaneously. #1 it allows the Kart to go faster due to less friction induced drag. #2 it changes the grip behavior of the kart and gives the front end more grip further enhancing the cornering at corner entry. This movement of the mass may need to be modified mid corner to get grip back to the rear of the kart but that is another discussion altogether.

All of this being said however, less mass gives Tommy D a better power to weight ratio. If the Kart had a differential he would also have better lateral acceleration also and us big guys wouldn;t stand a chance.

[slopetool]

Jerry Masterpool used to coach Cross-M
Good eye, Jack! I think its Victoria too.

[Aisling]

Originally posted by Jack Michaud
have the ideal body type. Low center of gravity.


jack, chicks with junk in the trunk? LOL

[FTA2R]

females have a disportionate amount of fat around their thighs, men around the abdomen. I think that's what Jack may have been referring to, Aisling. maybe the big booty helps too, I don't know :


---
Barry

[Aisling]

Barry, i know what jack was talking about but i just find the phrase 'junk in the trunk' hilarious.

PSR was telling me i was going be great as soon as i mastered the technique cause i'm a dancer... strong legs, good core strength. now all i have to do is master that whole... um.... not crashing thing.:p

[Kirk]

Low COG? Big Booty? Junk in the trunk? Don't know, but whatever ya want to call it, it seems to have worked out well for Isabelle Blanc - she took gold at Park City in '02!!;)

http://www.ifrance.com/Afcos/slc02blancpod.htm