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How to run 50% faster without external energy (2020)

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Re: How to run 50% faster without external energy (2020)

#61

Post by justsocrateasin »

onetimeuse92304 wrote: post #53
rottencupcakes wrote: post #48

Earlier quoted context omitted.

The idea that your muscles have enough strength on the upstroke to contribute meaningfully to cycling is actually a bit of a misunderstanding. Your leg muscles for lifting are much much much weaker than your leg muscles for pushing - they're designed to only lift up the weight of your leg and not much more. The main advantage of the clips is to keep your leg in contact with the pedal throughout the cycle and make sur…

Any muscle is trainable. To some extent. If you cycle enough, you will develop muscles necessary to pull the pedal up. Additionally, the goal isn't to double your power output. It is to be better than the other cyclist. Even by just a tiny bit. I personally think that clipping the feet helps more with left right stability. Also, if you are pulling with one leg, you can potentially push more with the other. Normally y…

This is true for certain metabolic zones but not others. If you're sprinting then yes, you get a higher power output while pulling up on the pedal. However if you're going for any kind of endurance (longer than a minute) the limiting factor is not muscular but cardiovascular/aerobic, and using less efficient muscles (the ones used for pulling up) will actually hinder your performance since you'll need to be supplying those with oxygen, thus decreasing total cycling economy.

Re: How to run 50% faster without external energy (2020)

#62

Post by LeifCarrotson »

checkyoursudo wrote: post #25

Naruto run. Don't even need to read the article. "Without external energy (but with external device attached)" is ... a bit disappointing. At what point does it cease to be running and start to be run-assisted catapulting? Or catapult-assisted running? It seems like more than just running .

As the father of a 6 year old who's never (yet) shared Naruto with my son, it's remarkable to observe that small children innately know how to do the Naruto run. Tragically, most children seem to forget the truth sometime around middle school age.

To be serious, though, the article suggests:

> Cycling is faster than running partly because the rolling motion of the wheels prevents collisional energy losses from stepping, but also because wheels can support the weight of the body in place of the legs, while pedals enable the human to supply energy continuously in the air instead of intermittently when the leg is on the ground.

but I think they miss the point by focusing on the last element rather than the first. I have lots of experience with running (where reducing ground contact time is often advantageous for efficiency), with cycling with clipless pedals where I can supply energy continuously, and with cycling with flat pedals. On the bike, I can sprint on the flats to about 16 m/s or 36 mph while clipped in. I don't do hard workouts nearly as often on flat pedals, so the data is more spotty, but I know I can reach at least 14 m/s or 32 mph; I'm just about spun out but typically not in my highest gear. I've never specifically tried to do a short-duration time trial on flat pedals, it might be higher than that, but it's not more than a 10% differential between intermittent and continuous connection to the pedals.

But running? In my prime, I could barely hit 9 m/s or 20 mph (I'm not and have never been a sprinter). If you tied a rope to my chest and towed me to 36 mph (using the rope to eliminate energy loss to air resistance) I'd be road pizza after a single step.

I can go faster on a pair of roller blades or ice skates, with one foot at a time providing an inefficient combination of sideways and rearward thrust, or a kick scooter using only one foot, than I could ever hope to run. The problem is not about the intermittent application of force, it's all about the need to convert angular velocity of your joints which has a very limited effective range into linear velocity over the ground. It turns out that cranks and chains over sprockets of various tooth counts are a great way to do this.

Re: How to run 50% faster without external energy (2020)

#63

Post by stouset »

rottencupcakes wrote: post #48
hinkley wrote: post #37

Earlier quoted context omitted.

One of the reason pro cyclists clip their feet to their pedals is so they can load the “other” leg through the back of the stroke, and across the bottom as well by pulling back on the loaded leg. Come unclipped in a sprint and you’re fucked. Sounds like this is the same thing for running.

The idea that your muscles have enough strength on the upstroke to contribute meaningfully to cycling is actually a bit of a misunderstanding. Your leg muscles for lifting are much much much weaker than your leg muscles for pushing - they're designed to only lift up the weight of your leg and not much more. The main advantage of the clips is to keep your leg in contact with the pedal throughout the cycle and make sur…

> The idea that your muscles have enough strength on the upstroke to contribute meaningfully to cycling is actually a bit of a misunderstanding.

Absolutely not, and there are plenty of easy counterexamples.

If you've ever raced track, team pursuits start from a dead standstill. You have to expend a ton of force to turn a huge gear, and the contribution of the lifting leg is crucial to getting up to speed. Of course it's not going to contribute as much as your lead leg, but all four of your limbs are at maximum exertion getting the bike up to speed. Even not racing at a track, you can test this on any road bike. Shift into high gear, come to a standstill, and time yourself getting up to speed.

Another trivial counterexample that anyone (with clipless pedals) can test is a hill climb. Being able to lift on the upstroke is an enormous additional benefit and the difference can be easily measured and proven. Perform a lengthy climb with and without involving your trailing leg, at a given level of intensity. Repeat this multiple times, and it will be patently obvious that your trailing leg is performing significant useful work. The steeper the climb, the more important this is.

Sprint finishes are another place where this is critically important, but it's harder to set up a simple test.

What all of these have in common are situations where outputting a higher force is more important than long-term endurance. Lifting on the upstroke is difficult to do at high pedal speeds, but at medium or low pedal speeds, it's a clear differentiator.

Re: How to run 50% faster without external energy (2020)

#64

Post by asoneth »

Their model seems to predict a theoretical top speed of 18-20.9m/s (or 40.0-46.8mph, 64.8-75.2kph): https://www.science.org/doi/10.1126/sciadv.aay1950#F2

As much as I want to imagine people chasing down cheetahs, without empirical testing I have to admit I am skeptical of their claims.

Re: How to run 50% faster without external energy (2020)

#65

Post by onetimeuse92304 »

justsocrateasin wrote: post #61
onetimeuse92304 wrote: post #53

Earlier quoted context omitted.

Any muscle is trainable. To some extent. If you cycle enough, you will develop muscles necessary to pull the pedal up. Additionally, the goal isn't to double your power output. It is to be better than the other cyclist. Even by just a tiny bit. I personally think that clipping the feet helps more with left right stability. Also, if you are pulling with one leg, you can potentially push more with the other. Normally y…

This is true for certain metabolic zones but not others. If you're sprinting then yes, you get a higher power output while pulling up on the pedal. However if you're going for any kind of endurance (longer than a minute) the limiting factor is not muscular but cardiovascular/aerobic, and using less efficient muscles (the ones used for pulling up) will actually hinder your performance since you'll need to be supplying…

I am not versed with cycling economy. But yeah, it makes sense.

On a bike, if you want to put up more power you have options to push harder or spin faster. If you had to push harder than your weight, you could always change your gears to rather spin faster.

Re: How to run 50% faster without external energy (2020)

#66

Post by 303uru »

fwip wrote: post #12
ck2 wrote: post #4

Inline skates on flat ground are technically "no external energy". And they can race a marathon in under an hour, so that's 26+ mph (42 kph)

Presumably there are areas/applications where "running" is important - otherwise we can just use a bicycle.

Historically, human survival. No other animal can cover ground the way we can. We've evolved to be highly efficient, one example; we cool ourselves better than any other animal we can maintain a fairly high power output almost indefinitely due to sweating.

Re: How to run 50% faster without external energy (2020)

#67

Post by renewiltord »

oezi wrote: post #35
renewiltord wrote: post #15

I considered using jumping stilts to run to work rather than skating or cycling. However, the skill level required to master them sufficiently to run required more training than I was willing to put in. I eventually ended up buying some shift.io moonwalkers, which do have quite a speed-up effect. The problem is that they're quite heavy and the walking motion required to use them effectively ended up requiring my ante…

What are you trying to achieve? Keep weight/volume of the device low? Or is about training running but being bicycle-fast?

I want to get somewhere faster with portable tools. Used to skate, but annoying to take skateboard everywhere. I live in SF, so bike gets stolen. Currently use Lyft e-bike rental but ideally have similar speed but backpack-able portability.

Honestly, maybe I wear cooling vest and just jog to work. Walking too slow: 15+ min / mile.

Re: How to run 50% faster without external energy (2020)

#68

Post by pharmakom »

hinkley wrote: post #37
tech_ken wrote: post #31

ITT: people who read scientific articles by skimming the pictures. The proposal isn't "springs under your feet" it's "springs along your legs that you load while your leg is in the air". The point is that by loading the spring with a leg which is otherwise not doing anything you're able to increase the overall energy output of the body. Their Fig. 2 shows exactly the (theoretical) difference between the naive "jumpin…

One of the reason pro cyclists clip their feet to their pedals is so they can load the “other” leg through the back of the stroke, and across the bottom as well by pulling back on the loaded leg. Come unclipped in a sprint and you’re fucked. Sounds like this is the same thing for running.

I believe this was disproven actually. The real reason is security under heavy power output.

Re: How to run 50% faster without external energy (2020)

#69

Post by rhn_mk1 »

stouset wrote: post #63
rottencupcakes wrote: post #48

Earlier quoted context omitted.

The idea that your muscles have enough strength on the upstroke to contribute meaningfully to cycling is actually a bit of a misunderstanding. Your leg muscles for lifting are much much much weaker than your leg muscles for pushing - they're designed to only lift up the weight of your leg and not much more. The main advantage of the clips is to keep your leg in contact with the pedal throughout the cycle and make sur…

> The idea that your muscles have enough strength on the upstroke to contribute meaningfully to cycling is actually a bit of a misunderstanding. Absolutely not, and there are plenty of easy counterexamples. If you've ever raced track, team pursuits start from a dead standstill. You have to expend a ton of force to turn a huge gear, and the contribution of the lifting leg is crucial to getting up to speed. Of course i…

Those are not necessarily examples of lifting. Those could as well be explained by the contribution of not pressing on the opposite pedal (to keep the foot from sliding).

And not pressing doesn't shine any light on the force of lifting.

Re: How to run 50% faster without external energy (2020)

#70

Post by altairTF »

nvy wrote: post #41
checkyoursudo wrote: post #25

Naruto run. Don't even need to read the article. "Without external energy (but with external device attached)" is ... a bit disappointing. At what point does it cease to be running and start to be run-assisted catapulting? Or catapult-assisted running? It seems like more than just running .

I googled "Naruto run" and it's just... Anime characters running with their arms outstretched behind them. That's not what TFA is discussing, you should probably read it.

I found strangely amazing your inability to realize it was a joke the moment you googled "Naruto run"
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