Just curious, how did you come up with the math? Can you break it down please?

It is rough, but let's go with this

For every watt of mechanical work 4 watts of heat is generated.

If Lange is running at 16kph, the person 10% heavier will move very coarsly at 14.4 kph for the same amount of mechanical work (watts to the ground). If both people are going the same speed, then the guy who is 10% heavier will generate 40% more heat.

If both are doing the same work and Lange is moving 10% faster, they both generate the same heat, but because Lange is moving 10% faster he has more cooling advantage, so for he same workload he has more radiator cooling effect due to more airflow over his radiator....(of course that comes with a bit of an air resistence penalty).

Bottom line, light people have a virtuous cycle running at speed in the heat versus large athletes...the exact same dynamic hurts the light athlete in borderline cold no wetsuit swims....that person is more likely to get hypothermic....and thus Kenyan marathoners are built the way they are, and channel swimmers built another way!!!

This is why I asked if Sam has 5 lbs to lose for Kona. At Kona many get the drafting benefit from others on the bike but if they are large the weight penalty on the run.

Dev

I have no idea if he has anything to lose between here and Kona. If you say he has nothiing to lose, then that's fine. But the fastest way to be fast is Kona is be lighter (and yes, it may be unhealthy). Its just how the physics of that course plays out.

Dev, you're treating weight as a closed system. Decreased weight can also lead to injury, not being recovered well enough, not fueled well enough, not strong enough. It's this overly simplistic engineering-thinking that is harmful. Weight loss is not a sure fire way to be faster or cooler on race day. Often, it is a sure fire to perform poorly. I'm not someone who's ever had to battle with weight loss, so this is not a PC response; this is just being holistic. We don't only look at bike weight; we look at rolling resistance, aerodynamics, etc. Your enthusiasm is great, but this view that "the fastest way to be fast in Kona is to be lighter" is just dangerous and ignorant. I mean, you're talking about a guy, Sam, who is probably under 6% body fat and has no unneeded muscle.

I have no idea if he has anything to lose between here and Kona. If you say he has nothiing to lose, then that's fine. But the fastest way to be fast is Kona is be lighter (and yes, it may be unhealthy). Its just how the physics of that course plays out.

Hey I am not wanting into get into a debate about ethics of coaching, health, and all the other aspects. I am just talking pure physics. There are always trade offs and yes, this is why in endurance sport there are so many psychological and health disorders. It's not like I invented the physics around heat transfer and mechanical energy and heat dissipation. But as you said, with it comes all the down sides so each athlete has to find their personal balance point.

I just asked if Sam has any weight to lose. I barely know what the guy looks like (I have never seen the guy stripped down). You know him and say he is on his limit, so I support what you are saying.

Only one point, tthat is irrefutable....for the same pace being lighter you generate less heat. You can't get around those physics. Being lighter you may end up being unhealhier ....that I support you on. You just can't be cooler at a given pace being heavier. This works against what Isaac Newton formulated for work and machines. A heavier machine required more force to move it through the same distance and if the force is higher and the distance is covered in the same time, then more work (joules) are needed. Human body roughly produces 4W of heat for 1W of mechanical work so if you do more mechanical work you generate 4x more heat for that incremental amount.

Racing Andorra 70.3 this weekend.

Do we know how he is swimming lately?


Probably a few seconds per 100 off where he was, i.e. a couple of minutes ahead of Long

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That explains the comment from one of his mates the other day,which was something like, "Road or TT on Sunday?"
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This discussion reminds me of when Lionel overreacted to his second place finish in 2017, went semi vegan and basically starved himself in an effort to cut weight for Kona.

Check how emaciated he looked in video 1 below versus his body in 2021 where he is an absolute unit (video 2)





Think we all remember how that turned out (took more time to turnaround than just realizing not to super concentrate gatorade endurance)

Fortunately based on Sam’s videos and social media I don’t think he’s concerned one bit about his weight. Also thinks he has decent surface area to mass, which he does, which isn’t as nice as being 140 lb on the run, but does help

If he is racing Andorra 70.3 why did he give his fast wheels to Matthew Van Der Poel for today''s TdF ITT?

For every watt of mechanical work 4 watts of heat is generated.

If Lange is running at 16kph, the person 10% heavier will move very coarsly at 14.4 kph for the same amount of mechanical work (watts to the ground). If both people are going the same speed, then the guy who is 10% heavier will generate 40% more heat.

Thanks. Uh… the general argument makes sense to me, but not how absolute and relative numbers work? Lange will need to produce 1200 watts of energy (mechanical+heat) to run at 300 watts output (300 watts of mechanical, 900 watts of heat). Fat guy (LOL) will need a 330 watt mechanical output to achieve the same speed, requiring 4x330=1320 watts in total, or still 10% more than Lange’s 1200, including 1320-330=990 watts of heat (10% more than Lange’s 900).

Sam's 8:07 with a 54 min swim, 4:18 bike and 2:51 run were very similar to what Normann Stadler used to win Kona 2006. Sam outran Stadler by 4 minutes, but the swim and bike were identical (it just occurred to me that the race splits were very alike).

But in any case everyone was beating on Sam at Tulsa. It just goes to show that some days you're on, other days not so much. Congrats to Sam. All the threads are about Lionel's implosion, but what a performance by Sam Long bouncing back so quickly from Tulsa.

I screwed up the explanation. 120extra watts blows up in heat for the big guy. Meanwhile Lange is putting out 300W to the road. 120W is 40% of Lange's 300W. That's the big guy "heat overhead" of going at the same pace. There is the mechanical overhead (30 extra watts). Big guy has a bigger heart and lungs and legs, but but the heat part is painful. As others have pointed out if it is a big guy with large surface to volume ratio then that is a bit of a help.