No comment about the Boost (but I do have a pair of Boost Bostons on the way), but according to THIS, each additional oz of shoe weight costs you .83 seconds/mile.

So your Adidas Ultra Boosts are just under 3oz heavier than a Kinvara 4. The math says just over a minute.

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/kj

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Well, what an interesting amount of time to be costing me. I hope to PR by about 58 seconds and come in under 3 hours..

That article is a great reference, but it leaves up in the air the part I'm curious about:


So extra weight COULD be justified if it saves the wear & tear. So when I read stuff like THIS and THIS I'm still left wondering if I'm losing or gaining time by running in a slightly heavier shoe.

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Too old to go pro but doing it anyway
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If you are only running shorter distances (5/10k) then why not go with the lightest shoe? But marathon length? I'd want some cushioning, even at the expense of time savings.

Yeah I'm with you there. Anything less than 15ish in a race and I'll go light for the sake of light. It's the marathon distance that has me questioning all of these questionable claims.

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Too old to go pro but doing it anyway
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I train in Adidas Supernovas of some sort. Then I run races (now) in a pair of Adios Boost. The lighter weight definitely seems to give some extra "free" speed... if you're used to racing in even lighter shoes (and you can go marathon distance in those shoes) then you may find the extra weight of the Adidas shoes a drag towards the end of a long race, despite the marketing hyperbole. Figuring out exactly what the optimal tradeoff is between shoe structure and your personal durability is tricky, especially as the race distance goes up.

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Less is more.

That link didnt work for me, so I plugged it into the web archive:

https://web.archive.org/...-affect-performance/

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Just remember to take a nap AFTER the race :)

The different types of foam do have some energy-returning properties. Most running shoes will have this property. How much is probably debatable and depends on your mechanics.

Cushioning definitely makes a difference. Especially during training as you accumulate those miles on the legs.

Weight probably makes a difference, but for the marathon you have to weight that against the cushioning. I'd rather lose the 3-6 extra oz. from my own frame than give up the cushioning on my shoe personally.

Kind of the same comment I make to fat guys who brag about how light their superbike is...you just spent $10,000 to be within 28 lbs of me and my "entry level" carbon TT bike instead of 30, good job!

Color does trump all other factors - you have to look fast to run fast :-)

I have been racing in the Asics DS Racers and Asics Piranhas for a while now. The Piranhas are several ounces lighter, but have so much less cushioning. I've often wondered whether the lack of weight offsets the increased pounding my legs take on hilly courses. Running on flat ground, I love my Piranhas (just ran a half marathon PR in them yesterday) but my feet do hurt after running longer races in them.

I'll usually run low-priority races in the Racers just so my legs aren't hurting quite as much in the days following a race.

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I'm kind of surprised that while so many people obsess about the weight of their bikes, people don't seem to pay a lot of attention to the weight of their running shoes. That said, the lightest shoe is not always the fastest for me. I don't know if "energy return" is real or not but there is a sweet spot for midsole cushioning. Too firm and my legs hurt, too soft and the shoes have a sort of dead, running in sand feel.

It doesn't really work like that. You fling your feet forward with each step. Any weight on your foot is going to be magnified.

Proof? Hold a 20 pound weight at your chest. Do some squats. Easy right? Now hold it at arms length in front of you. Much harder.

So no, getting 6 ounce lighter shoes is not the same as losing 6 ounces of bodyweight.

Generalizing - yes I agree with you, but my point is that lighter gear is not the only answer.

Sure, but all else being equal - Lighter shoes on the run is pretty nice.

I just weighed my daily running shoe compared to my LunaRacer flats ---- 7.7 ounce difference per shoe.

7.7 oz X .83 seconds x 6 miles = 37 seconds faster overall

Worth it.

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Out of 3 shoe characteristics that make a fast shoe, weight is the least important. Often sacrificing weight can make the other 2 much worse.

I think for Triathletes, the savings are even larger since run mechanics for a triathlete fall apart sooner over the same race distance compared to an open run. Lighter shoes may allow you to maintain cadence just a little longer and therefore maintain good mechanics/economy just a little longer.

I know my A6's have enough padding to work well for 70.3 and have some real rubber for durability too. But are still very, very light. Lover racing in them.

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If you've trained for a specific pace, you're going to run that pace in whatever shoe you have (within reason). A 3oz difference isn't going to change your pacing goals. It may cause you to fatigue a little more rapidly but it shouldn't cause you to lose marathon speed.

I think the question is: If you can run 26 miles at 7 min/mile in a 5oz shoe, then how long can you run at 7min/mile in an 8oz shoe?

What are the other two shoe characteristics that make a fast shoe?

Plenty of studies showing that lighter foot weight offers lower O2 consumption. Lighter is better.


No, it wouldn't be allowed in a USATF race then. (tried to find the exact rule but couldn't in 2min)... basically the rule says that no footwear shall store and then return energy to the wearer. I.e. metal springs, etc.

Kind of a training question. If you've done heaps of mileage and are in tip top shape then I'd still opt for light weight. If you are under 40mpw and have a form that is prone to breaking down in the latter stages of a long even then go for the (slight) protection.

Duh. :)

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I'm in exact same boat. Love the Adidas. Will give the NB Zante a try for a racing shoe.

Which one do you feel better running in on a long, fast run? By "better" I don't mean lighter and I don't mean more cushioned. I mean which one feels like it protects you enough but otherwise gets out of your way and doesn't interfere with the way you run. . An ounce or two extra is nothing compared to a shoe that feels like that.


Not all, but it goes a long way!

That's a fun question.. I vary my shoes on long runs between Kinvaras, Hokas, and now the Adidas. Interestingly, I get a very similar feel between the Adidas and the Hokas, which is probably a good sign for the Adidas.

The part that makes it tough to read is that I choose based on how I am feeling pre-run. Beat up? Hokas. Light and fast? Kinvaras. So I guess, based on everyone's input, I am be leaning Kinvara because I hope to feel light and fast on April 20th, and I only hesitate because I've hit that 22 mark in the past and just felt beat up. But in the end I'm probably focused way too much on shoes here, as I've done way more miles this block so I should feel better from that alone. I do love the details though, so trying to balance the cushion-to-weight ratio will remain on my mind whether I want it to or not I'm sure.

But still.. every second counts...

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Too old to go pro but doing it anyway
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Well it's true that in the marathon, 22 great miles can be totally wiped out by 4 terrible ones. I was thinking more generally but in the case of the marathon, I have to admit I would probably err more on the side of a bit more cushioning.

It's just that more cushioning can sometimes feel fine for training but so... well... wrong for racing. For example, I have a couple of pairs of those Skecher shoes -- the model that Meb Keflezghi loves. Forget the name. I train in them and I really like them. The cushioning is fantastic and they are light. I've done tempo runs in them and liked them. So they should be fantastic for races, right? But every time I try to race in them, it's maddening. They feel like they're in the way, completely altering my stride, and not in a good way. They just totally do not work for me in races. I can't explain it. I've had a similar experience (though not as pronounced) in other shoes.

So whatever shoe you think you are going to pick, I'd be sure to test it out in a long race (half marathon? 10 miler) and be sure it doesn't just feel good in training.

Have you tried Hoka Cliftons? They are almost as light as Kinvaras. (0.2oz heavier) and considerably more cushioning.