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Re. Hilly vs. flat: you lose more on the uphill than you gain on the down. With cycling, it is difficult to maintain constant power over an undulating course. I would think the same is true for running, though less pronounced.

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Re. Hilly vs. flat: you lose more on the uphill than you gain on the down. With cycling, it is difficult to maintain constant power over an undulating course. I would think the same is true for running, though less pronounced.

And what makes it even more pronounced in cycling is that the speeds you need to get to on the downhills to offset the climbing time lost means that Aero Resistance is tapping away at those watts at a significant rate...

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So a big discrepency between uphill aero resistance vs downhill aero resistance, for cycling.

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With running, I think the speeds are low enough that aero resistance differencesĀ  are more insignificant.

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PS. In theory...

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Don't get me wrong, I'm not saying that "power" isn't a good training tool. I'm just saying that calling it "power" is not technically accurate and it should rather be called something like "normalised pace".

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What you have not done is actually answer the questions that I asked in my previous post. I will ask the main one again so you don't have to refer back:

Why, if the same power will give you the same average pace regardless of how flat or hilly the course is, have all the marathon world records been set on flat courses and not hilly ones?

Because I don't know all the answers, If i did I would have.Ā  It is something B-Rad raised with regard to a course that goes from A to B and is uphill mostly, it also leaves unanswered questions, ..... perhaps less fatigue when running in the red zone to set world records on flats than hills, can get into better rhythm and have momentum on flatter courses as changing to hills will affect this, same as a twisty turning course, psychologically it is easier?.... pick one, none or anything else.. am sure you have your thoughts.

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I know that if I run Pirates 21km over Northcliff at 230w and also run Irene Village 21km at 230w which is flat, I finish pretty much in similar times and have done so.Ā  Same as if I set our on a LSD training run at 200w which is equivalent to around 6mins/km.Ā  Training at 200w over whatever distance whether flat or hilly, my garmin post run will give me my average pace close to 6mins/km.... the only difference being that with running on power i will slow down on going up the hills and not burn matches, whereas if I ran on pace, I would burn matches keeping to a 6min/km pace up hills.

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As for the terminology of whether power is correct, take it up with the likes of stryd, garmin, polar and others.Ā  At the end of the day it is another metric to use with regard to pacing and racing and for now they call it power, being an indication of the force used when running, perhaps that will change as things develop in the market.

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Don't get me wrong, I'm not saying that "power" isn't a good training tool. I'm just saying that calling it "power" is not technically accurate and it should rather be called something like "normalised pace".

Ā 

What you have not done is actually answer the questions that I asked in my previous post. I will ask the main one again so you don't have to refer back:

Why, if the same power will give you the same average pace regardless of how flat or hilly the course is, have all the marathon world records been set on flat courses and not hilly ones?

A case in point I have an athlete who recently did 2 * 10km run within a month.Ā  One was flat the other had some climbs.Ā  In both cases he averaged 305 watts.Ā  In the case of the flat he held 3:45/km in the case of the other 3:50/km.Ā  in the 2nd his Run efficiency was impacted by the hills from .99 to .97.Ā 

If we then calculate the course CVI we can then establish individually how elevation impacts the individual runners efficiency and can then accurately predict times at various power over differing known courses.

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Because I don't know all the answers, If i did I would have.Ā  It is something B-Rad raised with regard to a course that goes from A to B and is uphill mostly, it also leaves unanswered questions, ..... perhaps less fatigue when running in the red zone to set world records on flats than hills, can get into better rhythm and have momentum on flatter courses as changing to hills will affect this, same as a twisty turning course, psychologically it is easier?.... pick one, none or anything else.. am sure you have your thoughts.

Ā 

I know that if I run Pirates 21km over Northcliff at 230w and also run Irene Village 21km at 230w which is flat, I finish pretty much in similar times and have done so.Ā  Same as if I set our on a LSD training run at 200w which is equivalent to around 6mins/km.Ā  Training at 200w over whatever distance whether flat or hilly, my garmin post run will give me my average pace close to 6mins/km.... the only difference being that with running on power i will slow down on going up the hills and not burn matches, whereas if I ran on pace, I would burn matches keeping to a 6min/km pace up hills.

Ā 

As for the terminology of whether power is correct, take it up with the likes of stryd, garmin, polar and others.Ā  At the end of the day it is another metric to use with regard to pacing and racing and for now they call it power, being an indication of the force used when running, perhaps that will change as things develop in the market.

Ā 

Ā 

And what makes it even more pronounced in cycling is that the speeds you need to get to on the downhills to offset the climbing time lost means that Aero Resistance is tapping away at those watts at a significant rate...

Ā 

So a big discrepency between uphill aero resistance vs downhill aero resistance, for cycling.

Ā 

With running, I think the speeds are low enough that aero resistance differencesĀ  are more insignificant.

Ā 

PS. In theory...

Ā 

Ok, I think this answers my question.

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In summary, because the speed differentials uphill and downhill in running are not hugely significant (due to there being less imbalanced outside forces, e.g wind resistance), the same power output over a different course will not result in a large pace differential.

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Happy to agree on that? I admit that I would have expected the differences to be bigger but the above explanation makes sense to me as to why they are not.

Ā 

Sorry if I came across as being a bit of a dick.

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So, I commented yesterday that I would be keen to try a run using the Garmin data field. I never got to run, for reasons posted below, but I have since found an app on the Apple Watch (Power2Run) which Is keen to try in parallel with my Garmin. So if you see someone running with two devices on, itā€™s me, not DCRainmaker.

Ā 

As for the reason not to run, I had to change plans as I got the news from my Mom that my Dad has passed away. We knew it was coming and we said our goodbyes on Saturday. My next run, like last nightā€™s Zwift ride, might just empty the tank.

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Condolences to you and your family Gerald , RIP

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Because I don't know all the answers, If i did I would have.Ā  It is something B-Rad raised with regard to a course that goes from A to B and is uphill mostly, it also leaves unanswered questions, ..... perhaps less fatigue when running in the red zone to set world records on flats than hills, can get into better rhythm and have momentum on flatter courses as changing to hills will affect this, same as a twisty turning course, psychologically it is easier?.... pick one, none or anything else.. am sure you have your thoughts.

Ā 

I know that if I run Pirates 21km over Northcliff at 230w and also run Irene Village 21km at 230w which is flat, I finish pretty much in similar times and have done so.Ā  Same as if I set our on a LSD training run at 200w which is equivalent to around 6mins/km.Ā  Training at 200w over whatever distance whether flat or hilly, my garmin post run will give me my average pace close to 6mins/km.... the only difference being that with running on power i will slow down on going up the hills and not burn matches, whereas if I ran on pace, I would burn matches keeping to a 6min/km pace up hills.

Ā 

As for the terminology of whether power is correct, take it up with the likes of stryd, garmin, polar and others.Ā  At the end of the day it is another metric to use with regard to pacing and racing and for now they call it power, being an indication of the force used when running, perhaps that will change as things develop in the market.

I like your point re what we call it?Ā  A new product that we are involved with is a swimming paddle using similer tech as the STRYD.Ā  They have made a conscious decision to use the term FORCE measurement and IMPULSE rather than POWER and avoid that whole argument.

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Ok, I think this answers my question.

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In summary, because the speed differentials uphill and downhill in running are not hugely significant (due to there being less imbalanced outside forces, e.g wind resistance), the same power output over a different course will not result in a large pace differential.

Ā 

Happy to agree on that? I admit that I would have expected the differences to be bigger but the above explanation makes sense to me as to why they are not.

Ā 

Sorry if I came across as being a bit of a dick.

We all here to learn, even though have been using stryd for 2 years am still learning.Ā  In fact some question from this discussions have also got me thinking and researching more.Ā  All I can point to is to on hand experience of training and racing with one.Ā  It has improved my running and pacing, I know that if I run at a certain power I will be within probably a minute of so of my target finish time irrespective of the topography and as have pointed out in the 2 examples of CPT marathon and Dubai70.3, I have some left in the tank to push and finish strongly rather than stagger over the line :)

Edited by shaper
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True, forgot about that.

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Even then, 3.6% difference feels like a small difference. That is a 13s difference in pace on a 6min/km target pace between running the Up vs running Down.

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But these are the records, not normal human beingsĀ  ^_^.Ā 

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To those that have done multiple Comrades? How big is the difference between your Up and Down Run PR's? What I remember people saying is that they can't fully utilise the "Down" aspect of it due to the loading on the joints. so for a long event that then probably offsets the elevation gains.

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Outside of the distance variable between the Up and the Down, another factor to consider is that up until 60k (Hillcrest) into the Down you are still net uphill. It only really starts dropping in the last 30k.

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Then you have to factor in the physical aspect. For the stronger (faster) runners will benefit from the last 30k in pace terms and if you look through the results of the top 20 men you can often see this reflected. However on Fields etc you can't take maximum advantage on the drop without doing significant damage to your legs. The overall hammering your legs take on the last 30k is substantial and left many runners with their dreams disappearing as fast as.Ā 

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So you have had to work really hard up until 60k mark to keep your pace up and then have to push hard on those fatigued legs. it is a very different dynamic transitioning from a decent like Fields on to the relative flat of the highway around Pinetown.

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On the up run, you effectively plateau from 40km (Botha's) and have far easier down gradients to run which means your legs get beaten less and can maintain a steadier pace.Ā 

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My personal experience is that my legs are far more fatigued and broken on the Down than the Up. I feel more able of taking advantage of the drop from Umlaas road to Ashburton.

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5-10 seconds per km over that distance is significant, don't discount how hard that is to do and maintain for 90km. For me that's the difference between T20 and winning the race.

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So, I commented yesterday that I would be keen to try a run using the Garmin data field. I never got to run, for reasons posted below, but I have since found an app on the Apple Watch (Power2Run) which Is keen to try in parallel with my Garmin. So if you see someone running with two devices on, itā€™s me, not DCRainmaker.

Ā 

As for the reason not to run, I had to change plans as I got the news from my Mom that my Dad has passed away. We knew it was coming and we said our goodbyes on Saturday. My next run, like last nightā€™s Zwift ride, might just empty the tank.

Sorry to hear this. Thinking of you
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To interrupt the power discussion. Just seen that Poobie Naidoos in pmb burnt down this morning. That shop had been a part of me my entire life. Bought by fist pair of running shoes from there and my kids first pair too. Amazing shop with always great deals. Gonna be tough coming back from that

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To interrupt the power discussion. Just seen that Poobie Naidoos in pmb burnt down this morning. That shop had been a part of me my entire life. Bought by fist pair of running shoes from there and my kids first pair too. Amazing shop with always great deals. Gonna be tough coming back from that

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Horrible news

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Thank you all for this insightful Running Power discussion, Iā€™ve learned a lot about something Iā€™ve not seriously considered up to now.

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Some further thoughts:

What RP seems to provide is firstly a metric for accurately (& more importantly, consistently) measuring expended effort. By mapping this metric during training, it can be used to predict how much total effort is available at your current fitness level, and to optimally expend all that available effort during the course of a race. The second metric it provides is running efficiency and by mapping this during training it is possible to predict its relationship with terrain & fatigue and use that info to inform an appropriate race effort level.

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A third factor in efficiency (in addition to terrain & fatigue) is fuelling which is partly accounted for in running fatigue but needs to be managed carefully in long events to make sure you have available energy resources to meet the effort demands.

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It is generally accepted that to complete a course in the least amount of time, even effort or a slight negative split is optimal (all other things like terrain & weather & fuelling being equal); well trained & elite athletes are able to control their training environment so that they can accurately know what that effort is & feels like, and are able to monitor & adjust their effort when racing. For those of us who do not have that controlled preparation environment and have a less developed ā€˜feelā€™, RP provides us with that info on our wrists.

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With regards to flat vs hilly courses, efficiency losses will usually have a greater impact on hilly courses (uphill as well as downhill). Also, as others have said, it is sometimes not physically possible to run fast enough on the downhill to maintain the required effort level (RP).

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My understanding regarding wind resistance is that aero effects are negligible at slower than around 20km/hr (3:00min/km). But remember that this refers to velocity relative to the air, so at a running speed of 10km/hr (6:00min/km) a headwind of only 10km/hr (2.8m/s) will to start to have an impact, and this impact will be greater on the downhill when you are running faster to maintain uniform effort. So it can also impact overall performance (time) more on hilly vs flat courses, albeit to a lesser degree.

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Eventually got round to switching off and headed out for a run. I used both the Garmin data field and the Apple Watch app ( https://apps.apple.com/za/app/power2run/id1183088585 ) on both devices. Halfway through the run, I realized I left my HRM-Tri strap behind - not sure if that makes a difference to the power.

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Here are the stats from the run - Power2Run vs Garmin.

Will be following Shaperā€™s tips on logging the data on a spreadsheet and taking it from there.

0fbd3a862e67986706d82504509260bb.jpg11bc0322284f6a46acb0d508b5876d78.jpg

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