Adam Shore - @nimzie - Please read this and feel free to respond

Hi buds. It was a gentle ribbing, that’s all. Everyone knows that it’s actually some other recreational activity no one here does that really makes you fat. And I think we all can agree to that. :wink:

@nimzie thanks for the offer but I hurt myself bad enough crashing on a 30lb MTB with a 0.2hp motor. 3 orders of magnitude more power and an order of magnitude more weight sounds like a combination that could be dangerous for me.


lolz, chek ur cabels

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This should be a sponckerd post.

Oh yea and please pretty please stop calling me fat. I get a bit of a complex.

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This isn’t the case generally. Riding quickly on a dirt bike is difficult, easily as hard or harder than a MTB, depending on terrain for both.
Your HR will be similar and if you are not conditioned, you will fade MUCH faster on the dirt bike as you simply will not be able to hang on, arm pump is nasty.

Racing is another story, IMO, racing MX/SX/enduro is the most physically demanding sport there is, generally speaking. You need massive cardio, and a lot of overall body strength. Plus the ability to cope with high heat while kitted up in a lot of gear.
Racing a MTB in XC is a bit different, its not as demanding, most XC courses are not that hard to ride technically, and races for expert/elite can be 2+ hours. A typical SX race can be 15 min, 20 min is considered long. MX is a bit longer but the courses are more open, GNCC stuff can be long, but its not as intense, its kind of like MTB XC stuff.

I have spent quite a bit of time on dirtbikes and currently race bicycles and cars. I got into racing bikes to condition myself better for the car racing I do, which is another perhaps not so obvious sport where you need to be fit to do well.

One issue is with respect to one’s definition of fitness. Clearly it encompasses all physiological (e.g. strength), mental (e.g. skill), and emotional (e.g. will to win) factors that are necessary for the sport at hand. So comparing fitness between two sports is an apples and oranges comparison.

As an example for MX and XC-MTB, two relatively similar sports that I really don’t excel at, it’s not even a fair comparison. The power to weight ratio of a moto is largely independent of the rider weight (the bike weighs more than the rider), whereas it is highly dependent on rider weight for XC (the bike weighs much less than the rider). A corollary to this is that the centre of mass of an MTB + rider is more heavily dependent on the rider’s body positioning than it is on a moto, so the rider’s positioning affects the handling in XC more than it does in moto.

So there are many tradeoffs. Here are a few (and I am talking about elites, as you have):

  • XC race is longer so the rider must have higher aerobic threshold (VO2max). A short moto race (much less than an hour) will be largely anaerobic. For runners it’s almost like comparing 5000m to a full marathon. Opposite ends of the spectrum of distance events in athletics.
  • XC climbs are largely dependent on power to weight ratio so the rider can’t afford extra upper body weight
  • Moto handling must be more dependent on steering inputs (see centre of mass analysis), so must require more upper body strength
  • XC rider must provide the motive power to the bike, whereas the moto (not surprisingly) has a motor. So that enables completely different portioning of cardio resources

And these are just obvious conclusions about aerobic fitness and strength based on the physics of the systems and not considering technical skill.

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Yeah! Kick 'em in the nutz!

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