I just got a pair of Adidas Ultra Boosts and I’ve been breaking them in for the Boston Marathon. They are incredibly comfortable and promise “the most energy return” possible. Fist, is that a real (non-marketing BS) metric?
But I am used to running in the very light (relatively) Saucony Kinvaras. I can feel the weight difference in the Ultra Boost shoes.
So:
Is energy return real? Does the cushioning protect my muscles from enough fatigue to make up for the weight difference? Does the fact that the Adidas are a cooler color outweigh all other variables?
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.
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:
Basically, as shoe weight went lighter the cost also dropped some, but when the shoe weight went too light, then the cost went up because there was getting to be less midsole cushioning and the runner’s muscles had to start absorbing more landing shock and that costs more energy.
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.
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.
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:
Basically, as shoe weight went lighter the cost also dropped some, but when the shoe weight went too light, then the cost went up because there was getting to be less midsole cushioning and the runner’s muscles had to start absorbing more landing shock and that costs more energy.
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.
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.
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.
That link didnt work for me, so I plugged it into the web archive:
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.
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.
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.
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?
But I am used to running in the very light (relatively) Saucony Kinvaras. I can feel the weight difference in the Ultra Boost shoes.
Plenty of studies showing that lighter foot weight offers lower O2 consumption. Lighter is better.
Is energy return real?
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.
Does the cushioning protect my muscles from enough fatigue to make up for the weight difference?
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.
Does the fact that the Adidas are a cooler color outweigh all other variables?
Duh.
