I’m preparing for the Mt. Evans Ascent just outside Denver, which is a 14.5 mile run from 10600’ to 12264’. The average gradient is approximately 5%. I’ve never done any running like this, so I would like to train by using a treadmill and adjusting the incline. Right now, my EZ runs are at 7 mph.
Here’s the question. Race day calculates a power of 370 watts for this speed (0% incline and 96 kgs). I can use Raceday to calculate a power (370 watts) for varying inclines and speeds. Does this sound like it would be representative? i.e. If I increase the incline to 5%, Raceday calculates my speed to be 10:40 for 370 watts. If I just want to get used to the incline, would calculating different speeds for different inclines be a similar type run (i.e. EZ run)? Has anyone ever done this?
Try: coachphil@physfarm.com
He will answer this for you. Other than that, I’d say HAMMER some hills a couple times a week!!! Good luck, sounds like fun.
I do this all the time, it is not exact but it is better than the alternative estimating method.
To start with though, if you are running on a treadmill, why not just set it for the incline, or rather a percent over the incline, it will be the most specific you can get.
To give an example of what we have done, I will map out the course of a race of interest, save it as a .tcx with an average speed and then load that it into race day or topofusion to see what sort of power is required to do that pace. You are assuming that the person runs at a steady pace through the run so it is a bit off, but probably not by much.
Good example was a lady who wanted to run a Boston time at Marine Corps Marathon. Her home training environment was very different than the terrain of marine corps marathon. I mapped out the course and put in the time needed to qualify and got the power requirement, let’s way it was 200 watts.
Then I knew that to have a shot, by the end of the training cycle she should be in a position to hold 200 watts for 26 miles. So her interval days at the track were done to correspond to 200 watts on the flat, whatever pace that was. And her tempo runs on her normal course were done so that they mapped out to over 200 watts. To do that, I had to map out her normal training route as well. Or if I needed to look after the fact I could use topofusion or raceday.
There are some caveats to the approach.
Depending hor different the courses you are looking at are, the muscle activation can be quite different so your flatland training will not be as helpful for the uphill run at 5% grade as you would hope.
Phil’s running power calculation is based off of the Mineti (sp?) data on running economy on slopes. Mineti did his studies on treadmills. Others have shown that running economy on a treadmill is less taxing than running outdoors and I saw a paper not too long ago that said treadmill on 1% grade = running outdoors, and fo course we all usually hear this in lay publications as well. I have not seen that same study done for outdoor slope running, but my own experience is that maybe due to this, the speed predicted by Phil’s running power is a bit optimistic. So while raceday might say that an 8:00 pace for flats = 8:30 pace for a given slope, to me it seems like 8:00 flat pace = 8:50 pace on a given grade.
So the big answer is yes, you can do it that way and get a pretty good idea of what sort of work is required and I do this all the time. Worked well for a guy on Sunday who was looking to run 40 minutes at the columbia tri, he ran 40:01 and the other time i used this extensively was the lady who wanted to qualify. She missed it by a bathroom break, got 3 minutes behind Boston time at 13 miles in and stayed 3 minutes behind until the end. But that wasn’t the fault of the model.
As for Phil, I have told him that I use the running power models this way, not sure if he uses them the same way.
Power during uphill running is simply weight x vertical speed and vertical speed is ground speed x sin(angle). The angle is the arctan of the grade. If you know the grade and the goal pace it is a simple calculation. Mechanical power during steady state running over level terrain is zero so I’m can’t imagine how you are getting a power for that. Perhaps it is a projected equivalent based on required Vo2 but power during level running makes no sense. The previous post suggesting you run on your treadmill is right; training at 7% is the best way to know how well you can run at 7%. No need to make things more complicated.
Edit/Correction: Mechanical power during steady state level ground running is not truly zero. There will be a small amount of mechanical power associated with steady state running related to aerodynamic drag but that is not the main determinant of metabolic demand.
Power during uphill running is simply weight x vertical speed and vertical speed is ground speed x sin(angle). The angle is the arctan of the grade. If you know the grade and the goal pace it is a simple calculation. Mechanical power during steady state running over level terrain is zero so I’m can’t imagine how you are getting a power for that. Perhaps it is a projected equivalent based on required Vo2 but power during level running makes no sense. The previous post suggesting you run on your treadmill is right; training at 7% is the best way to know how well you can run at 7%. No need to make things more complicated.
Edit/Correction: Mechanical power during steady state level ground running is not truly zero. There will be a small amount of mechanical power associated with steady state running related to aerodynamic drag but that is not the main determinant of metabolic demand.
Cheers,
Jim
???
Work = Force X Distance
Power is Work / Time
So power is the force applied over a distance divided by the time it took. The faster you run the less the time factor becomes and the more power it takes. And that is assuming ideal physics constraints. Add in heat generation and the work used to raise each foot 90 times a minutes and there is a lot of power being put out by the human body to run.
So power is the force applied over a distance divided by the time it took. The faster you run the less the time factor becomes and the more power it takes. And that is assuming ideal physics constraints.
Yes but during steady state running over level terrain the power (edit, power not forces) you produce during ground contact average to near zero. That’s because you have to decelerate your body’s mass in the first half of the support phase and accelerate in the second half. When I teach this to undergrads it is very upsetting to the runners.
Add in heat generation and the work used to raise each foot 90 times a minutes and there is a lot of power being put out by the human body to run.
Yes, but that is not mechanical power. Everyone who has ever run a step knows the metabolic cost is not zero but that is different than mechanical power.
Yes but during steady state running over level terrain the power (edit, power not forces) you produce during ground contact average to near zero. That’s because you have to decelerate your body’s mass in the first half of the support phase and accelerate in the second half. When I teach this to undergrads it is very upsetting to the runners.
No you don’t have to decelerate it. That’s the problem with the way most runners run.
Or rather, you only have to decelerate it if you overstride. One of the fundamental things that separates an elite Kenyan from Joe Sixpack is that the Kenyan’s deceleration in initial contact is minimal. By landing over his center of gravity instead of behind it (i.e. by not overstriding) he keeps the braking forces to a minimum during his support phase and is far more efficient
By landing over his center of gravity instead of behind it (i.e. by not overstriding) he keeps the braking forces to a minimum during his support phase and is far more efficient
Please tell us how far forward you can go with each stride if you plant your foot under your center of mass. Let me give you a hint, its called hopping in place. I’d also be really keen to know the source of your data showing that elite runners have reduced horizontal ground reaction forces than other runners.
Besides the horizontal forces (which must have negative and positive components in order to move forward) the vertical forces are the large ones. When your foot strikes the ground you have downward velocity. When you leave you have upward velocity. The eccentric work/power that you do to decelerate your mass vertically is equal to the concentric work/power you do to accelerate it.
Yes but during steady state running over level terrain the power (edit, power not forces) you produce during ground contact average to near zero. That’s because you have to decelerate your body’s mass in the first half of the support phase and accelerate in the second half. When I teach this to undergrads it is very upsetting to the runners.
No you don’t have to decelerate it. That’s the problem with the way most runners run.
Or rather, you only have to decelerate it if you overstride. One of the fundamental things that separates an elite Kenyan from Joe Sixpack is that the Kenyan’s deceleration in initial contact is minimal. By landing over his center of gravity instead of behind it (i.e. by not overstriding) he keeps the braking forces to a minimum during his support phase and is far more efficient
absolutely not. and you give some of the worst running advice on this forum. peace.
Please tell us how far forward you can go with each stride if you plant your foot under your center of mass. Let me give you a hint, its called hopping in place. I’d also be really keen to know the source of your data showing that elite runners have reduced horizontal ground reaction forces than other runners.
About as far as the forward momentum you already have from your pushoff can carry you, minus the horizontal braking force your foot placement applies when it lands. Land with your leg in front of your center of gravity = big horizontal braking force. Landing directly below your center of gravity = smaller horizontal braking force.
Honestly, I’m as much for being a barracks-room lawyer as the next guy but is this some sort of radical theory I have to prove to you now?
I’m sure my comments won’t change your mind, but I’ll be a good ST citizen and just present about a few very basic facts about running that may be interesting to STers in general. These are so basic they are easy to overlook and they tend to get lost in the lore and cultural language of running.
In order to move forward during steady state running, you must put your foot down in front of your center of mass.
The direction of the ground reaction force vector must pass through your center of mass. Otherwise your body would rotate. For example, when you slip on ice you have a vertical ground reaction force but no horizontal ground reaction force component. So the ground reaction force vector passes in front of your center of mass and you rotate backwards and fall on your butt.
The combination of 1 and 2 mean that you must have a backward acting horizontal ground reaction force during the initial part of the support phase and a forward acting horizontal component during the latter phase (when your foot is behind your center of mass).
During running the leg functions as a spring (except that the hip actively produces positive power in both flexion (swing phase) and extension (support phase). Because of the leg spring function you essentially bounce along. If you have any doubts about the leg acting like a spring please google for a video of Oscar Pistorius. Anyway, springs function with stiffness and together with mass exhibit a natural frequency. To my way of thinking, the notion of overstriding simply represents a stride length that is not consistent with your leg spring stiffness.
Those are great facts. I guess they might have a better chance of changing my mind if you could explain how they contradict what I’ve said. Whether the truth of overstriding coincides with your “way of thinking” or not (not to mention whether your way of thinking constitutes “fact”), is there any doubt that it puts your foot plant farther in front of your center of gravity then it should be? Is there any doubt that it acts as a braking force and slows you down?
Whether the truth of overstriding coincides with your “way of thinking” or not (not to mention whether your way of thinking constitutes “fact”), is there any doubt that it puts your foot plant farther in front of your center of gravity then it should be?
Maybe but no one knows what overstriding is. No study that I am aware of has quantified “overstriding” or even identified it. If you do a pubmed search (this will cover all relevant biomechanics journals) for the term overstriding you will find 3 studies on primate gait. “over striding” as a phrase will get you nothing. As far as I am aware it is a running lore concept only. Since no one know what it is its hard to say if it “puts your foot plant farther in front of your center of gravity then it should be”.
Is there any doubt that it acts as a braking force and slows you down?
Every stride during steady state running has braking forces. Shorter strides will have smaller braking forces but you will need to take more of them to travel any given distance. Longer strides will have larger braking forces but you will need less steps. Usain Bolt has some of the longest strides ever observed; reckon he needs some coaching? My point here is that horizontal forces must sum to zero during steady state running (except for the aerodynamic resistance term). What I believe you would find if you got Mr. Bolt into a biomechanics lab is that his stride length is appropriate for his leg spring characteristics. Along similar lines there are studies demonstrating that self selected stride frequency during endurance running is the most economical. That suggests that endurance runners have an intuitive sense for their leg spring characteristics and select stride characteristics accordingly. Some runners may be out of touch with this may run badly and those perhaps are “overstriding”.
When I said “to my of thinking” that meant that I don’t know of any study that has reported the basis of overstriding (in this case because there are none in the peer reviewed literature) but I am willing to speculate based on what I do know about leg spring characteristics, running biomechanics, and spring mass systems in general. Certainly does not constitute fact. I hope some STers find this helpful.