Sifan Hassan ran her world record in cheater spikes, does it count!?!?

You forgot about cheater track! Everyone knows Monaco is a few meters short! LOL

You sound like a Vatican representative explaining how the solar system works in 1633.

Salvatore Stitchmo wrote:Any, I repeat ANY, kind of cushioning is detrimental to this maximal force and will limit how fast you run. This is because our feet only contact the ground for a very short period of time. For any cushioning in a shoe to be close to perfectly efficient in terms of energy transfer it needs to compress and "pack out" almost completely in the time that the foot is in contact with the ground and transferring the athletes peak force.

Great post, but I think this part is a little misleading. The speed that you can put down force is always reduced by cushioning, sure, but cushioning also CAN increase economy, and it's not just the Vaprofly that does it. Toss a pair of racing flats on just about anyone, and they will consume less oxygen at the same pace than if they were running barefoot, even accounting for the weight of the shoes.

if you think it was the shoes that broke this record you are extremely bitter about your own running. Hard plates have been around for decades

Rojo, the rule is clearly not enforceable as written, and it wasn't designed to be. It replaced the old rule that mentioned "springs" because that was written by someone who didn't understand that all shoes are springs. All the rule does is articulate a vague aspiration, leaving the IAAF some latitude to issue clearer guidance down the road if it comes up with a reasonable way of doing so.

Incidentally, here's a statement that the IAAF made about the rule:

These Muir spikes are not the same ones worn by Hassan in Monaco. Her 4:30 road mile was a contract obligation and had only just arrived from a very heavy training camp segment. She raced an outdoor 1500m soon after the road mile and raced handily. Sounds like sour grapes from "the Olympian". Enjoy your nonupdated trash adidas in its 25th colorway.

You sound like someone with no substantive argument whatsoever.

Anyone else prepared to prove you're not suckers?

OutlawG wrote:

Hard plates have been around for decades

this, and it's still not about energy return, but about elasticity and contact area.

Bad Wigins wrote:

Grenio wrote:

You sound like a Vatican representative explaining how the solar system works in 1633.

You sound like someone with no substantive argument whatsoever.

Anyone else prepared to prove you're not suckers?

Please don't lecture anyone on physiology or biomechanics. You're an author- not an expert on any of the aforementioned categories- stop pretending you are.

straw man countering a claim that I never made. Nothing directly addressing the factuality or logic of what I actually wrote. One needn't be an "expert" to understand something and express it correctly.

Next!

None of what I wrote is misleading - I never once mentioned economy or reduction of economy.

Cushioning slows down the rate at which an athletes max force is transferred to the ground (as you wrote) as soon as it slows this process down to a time greater than the athletes natural footstrike /impulse time then it's impossible to transfer all the force possible and the athlete will not run as fast as they can. Simple.

Under what basis does cushioning increase economy? Cushioning makes it more comfortable to run - simply because it disperses and reduces max force. The best running shoes find the right balance of reducing and dispersing force to the point it is comfortable enough to complete the distance the shoe was intended for while still allowing the most force to be transferred to the ground as possible. I guess you can make a argument that because of this, added comfort allows a smoother gait and more economy (think running on a road in barefoot where the uneven surface localizes pressure points and makes it seem like you are running on hot coals) - but this is hard to measure even though we know it somewhat exists.

When you speak on a scientific level you eliminate such variables (as an uneven road). So what you said is incorrect. If you were to run on a perfectly smooth surface barefooted vs in racing flats at a set speed, you would improve VO2max barefooted due to the added weight of wearing even the lightest shoes. This because VO2max (the most basic measure of the rate of oxygen consumption) is a measure of the amount of oxygen processed per min per kilogram of body weight. (O2 per min/kg). That's not even up for debate - it's math.

Don't confuse the impact comfort has on running form as a basic measure of increasing economy.

I'll reiterate - any cushioning is detrimental to performance. It's a matter of how much discomfort caused by the lack of cushioning your body can handle which is the important factor. It's why a 100m spike has no cushioning - because most athletes can handle 9-45 seconds of running on a flat track without it being an issue. The same reason a shoe designed for 10000m running is cushioned - because 1500+ seconds of running - even on a cushioned track probably becomes unbearable without some kind of cushioning.

SS

So Monaco is shorter only for 1500m ? Because in 400m the record of the track is absolutely normal....

It's not just about comfort. The mechanism of increased economy isn't clear, but it is a real effect that has been repeatedly documented. There have been a number of studies out of the University of Colorado. I'm sure you can find them with a little googling, but I don't have time at the moment. One of the interesting ones used a treadmill covered in midsole foam, so you could run with the cushioning of a shoe without carrying the weight.

The theory is that because cushioning returns energy, it allows some of the work that would have to be done metabolically, through muscle contractions, to be unloaded onto the metabolically costless (except for weight) shoe cushioning. Though of course, nobody knows for sure what's happening.

Because of the weight/cushioning tradeoff, not all shoes are going to be more efficient than running barefoot. It's also likely that different kinds of cushioning (not just materials, but the way the materials are "tuned") will return energy more effectively. There may be an optimum amount of cushioning to effectively increase economy, which explains why some of the studies conducted on consumer/commercial treadmills (highly cushioned decks) did not shoe improvement vs. barefoot running, whereas studies using lab-grade treadmills (as hard as asphalt, if you've ever tried one), did show improvements with shoes.

This research is still pretty new, but I think it's sufficient to conclude that cushioning isn't always going to make you slower in races where economy comes into play.

4% is the new epo wrote:

Carbon plates are the new EPO.

Carbon plates are the new EVA

Here is an article I've written about the matter after getting a response from the IAAF:

https://www.letsrun.com/news/2019/07/track-and-fields-shoe-rule-makes-no-sense-might-sifan-hassans-wr-need-to-be-invalidated/

How about we just let people wear whatever. Lets cut out all the subversion and just allow some Kangoo Kicks or Spring Shoes.

old shoe wrote:

This isn't a $20,000 CF bike. It's a $250 shoe. Short use shoes have been around as much as run racing has.

Stop yelling at the clouds, go do some training, and wear whatever makes you fastest come race day.

Good comparison to bikes. Pros often have custom bikes that aren't yet released to the public (or never will be).

Salvatore Stitchmo wrote:

Under what basis does cushioning increase economy?

SS

It allows running with greater leg stiffness, which is more energy efficient. Hard surface / lack of cushioning is associated with increased compliance and more movement in the knee and the hip., i.e. more muscular work is needed to keep loading rates at safe levels. The positive effect of optimal cushioning in decreasing oxygen cost of running is well described in literature.

Here are a few studied to start with:

(review)

comedyrelief wrote:

How about we just let people wear whatever. Lets cut out all the subversion and just allow some Kangoo Kicks or Spring Shoes.

Ask and you shall receive: