pavedwave longboarding

gboom · Joined: 29 May 2008 Posts: 57 Location: Vancouver WA

This is a graph relating energy expenditure to velocity. This is from Allan Abbott and David Gordon Wilson's book titled Human Powered Vehicles. See the footnote for the original source. On this graph the skating is referring to ice skating and not skateboarding, but I would argue that the skateboarding, with a mix of pushing and pumping, with the proper equipment and surface would be close to ice skating. Maybe not quite as efficient.

I also added the red dashed line where Barefoot Ted was operating for 24 straight hours (10 mph*24 hours). Note that about 60% of his energy was spent fighting wind resistance.

Also note that the same amount of power on a bike would result in 324 miles (assuming 13.5mph). I could not find the ultracycling record. This data suggests the difficulty in achieving 300 miles in 24 hours on a skateboard. Wind resistance becomes a killer.

Anyways, thought I would throw this out here for reference.

Mark

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Ride your skateboard, save gas, sleep well.

pavedwave · Joined: 22 Oct 2007 Posts: 1120 Location: seattle wa usa

Oh Noes!! I see LDP record breakers going one of these directions:

1. nude
2. speedo LAZR suits
3. teh sphandex!!

Great stats Mark.

On many occasions I've drafted bikers out on the trail and discovered that chopping through the wind really does make a difference even at our "slow" speeds of 12-13mph.

I think Ted knows a guy that broke the cycling record, I'll check with him.

gboom · Joined: 29 May 2008 Posts: 57 Location: Vancouver WA

Mr. Pavedwave

I'm calling an offensive foul..... Shocked

I try to push on a little technical discussion about skating and such and you put that pic out here.. Your shiny posterior is one thing, but seriously.

Sorry, I gotta go scrub my eyes out with a brillo pad and some soap. Razz

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Ride your skateboard, save gas, sleep well.

LD skater since 1971 · Posted: Wed Aug 06, 2008 7:48 am Post subject:

A velodrome or flatland oval track sunken in the ground would be the best windless place to set a new record.
Sandy Snakenberg set a inline skating record of 324 miles in 24 hours on a flat oval track.
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Terry

Parson Adams · Joined: 02 Jun 2008 Posts: 93 Location: San Antonio

I will never be embarrassed to go shirtless at the beach ever again after that one. What is more disturbing is that that will be on this board indefinitely. May I also have a Brillo pad?
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pavedwave · Joined: 22 Oct 2007 Posts: 1120 Location: seattle wa usa

Ok sorry to overwhelm the post Mark Very Happy

I think the main point behind your post was Wind Resistance -- and I'd still like to hear more ideas on it, so I updated the spandex graphic until I can find a more appropriate one. ( No brillo needed Jim- admin power! )

But I'm becoming recently curious about whether anyone has really researched the energy expenditure difference, between pushing a dropped deck vs. pushing a topmount? What's piqued my interest is actually trying to make a decision on which to choose for a long ride, which is primarily uphill.

It's obvious that a drop deck requires less vertical movement of the leg that supports your weight, while your other leg does the pushing. So in essence you're doing less "squatting" and decompressing. For this reason it's well known by anyone who skates distances, that it's this supporting leg that tires out first, even though those who don't actually skate often think the pushing leg would be the first one to "blow out."

But what I've started thinking about is how one's technique might make a really significant difference, say for example when you're pushing uphill on a topmount, but crouching, and still keeping your overall motion minimal, save only for when you switch push legs... When you're not decompressing between pushes into a full standing posture again, but staying low the whole time, similar to how speed skaters stay low when switching push legs?

gboom · Joined: 29 May 2008 Posts: 57 Location: Vancouver WA

Oh my, sweet save JP and thanks. I honestly had an uber boss in my cube the other day while looking at the post. Fortunately I had it scrolled to the bottom. Now I can get fired for a much better reason.

Yeah, lot's of issues with the raising and lowering of the cg. I agree it is not as clear cut as comparing differences in deck height. If you really want to know, and not assume, energy expenditure, I believe you need to monitor your oxygen inhaled vs exhaled. Then you can do the fancy calculations. However, I think your observations at the end of a long trip are great observations.

Also, how does the fun factor come into figuring this all out.

LD skater since 71 has shown with one data point that the graph is far from perfect, but it is a starting point for the discussion. Thanks.
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Ride your skateboard, save gas, sleep well.

pavedwave · Joined: 22 Oct 2007 Posts: 1120 Location: seattle wa usa

gboom · Joined: 29 May 2008 Posts: 57 Location: Vancouver WA

Measuring O2 is done in a sports lab with the subject inhaling and exhaling into a tube/monitor. I don't know if anything portable exists - maybe nowadays it does.

Bike hubs with sensors are used to measure cranking force for bike training. I think these are pretty available and a few hundred bucks (not too bad really). I guess the equivalent for skating would be a shoe that could capture the forces exerted to the deck for pumping or to the pavement for pushing. That would be a cool thesis or project topic for some engineering student.

6200 feet uphill...did you get to enjoy some of the downhill on the return?
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Ride your skateboard, save gas, sleep well.

LD skater since 1971 · Posted: Sat Aug 23, 2008 10:05 am Post subject:

I forgot to post Sandy Snackenberg trains like a bicycle rider when he lived in San Diego he worked at bike shop.
I competed against him in extreme roller-skating in CASL contest and then he switched to rollerblades like my little brother.
I would see Sandy at team rollerblade demos my little brother was doing or races.
He told me he would go on ay least two 100 mile days a week in the east of San Diego in the hilly back country. He also averaged about 35 to 45 miles a day on the other days. Plus he skated the Velodrome here in San Diego.

I skateboarded the olympic velodrome in Los angeles at a NSA street contest I was building the obstacles for the contest. It is a blast to skate you can keep on going if you carve turns or doing off the lip kick turns, plus it virtually wind less down in the velodrome..
Bruce Walker was going all the way around and I followed him all the way around. I had not thought about going all the way around I was sticking to the street contest area. Then Bruce and I talked about east coast skateboarders verse west coast skater and other thing it was cool to meet him.

I went by San Marcos High School the other day I noticed they have a rubber track with a cement ring around it. It pretty much wind less because of the bleachers.
I am thinking of seeing how fast I can do a mile of pushing around it.
Maybe I will tie or beat my running personal best of a 4:52 mile when I was 22 years old that would be cool. I would be happy with a 5:30 mile also.

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Terry