Stroke Rate and Perceived effort

[gregsmith01748]

I did an experiment today. Obviously it will require a bunch more trials to get some kind of confidence factor, but the outcome was interesting.

A week ago, I did a half marathon at 20 SPM, and a split of 2:03.4. At 20 minutes, my heart rate was 150, at completion, it was 167, an increase of 11%.

Today I did 90 minutes at 22 SPM and a split of 2:01.6. At 20 minutes, my heart was the same 150. At completion, it was 163, an increase of 9%.

So, the pace was faster, the time was 4 minutes longer, and the cardiovascular drift was lower. Is there anyone else out there who would do the same experiment so we could share data and see how much person to person variation there is?

I am going to repeat the experiment at 24 and 18 SPM. I'm not sure if I can make it all the way to 90' at 18SPM and a 2:02 split, but I'll give it a go.

If anyone is interested, let me know. The protocol is easy...
90' session at a pace that you know you can do. I used 2K -20, but I wished I used 2k-22.
10' splits
constant pace (either 18,20,22 or 24 for the entire session)

[Mike Caviston]

I made a couple of comments on this thread that might be of interest.

http://www.c2forum.com/viewtopic.php?f=3&t=4544

[gregsmith01748]

Mike,
Thanks for posting the link. There was some good stuff there.

[claus hansen]

As an extreme example of your answer You might want to read 'Rangers training thread', .

As far as I understand rangers quest all his training has one overall aim: to increase his application of power to the handle in every single stroke towards 13 SPI and at the same time adapting his bodys ability to row fast with this extreme force.

I like to compare the odd 30r20 (fixed low spm) with my longer rows to compare the HR creep, SPI of 8.8 is where I am now getting really ineffective....

[NavigationHazard]

Sorry, you do NOT necessarily need higher peak power to maintain constant pace at lower rates, drag factor and drive duration and drive length equal. You need higher average power, one component of which may be higher peak power at some point during the drive. It depends on the force-curve profiles involved.

Here's 1:48 pace at 31 spm:



And 1:48 pace at 19 spm:



Drag factor constant. Drive duration is NOT quite equal*- I'd have to find the laptop and cables for ErgMonitor and hook them up and play around to equalize that exactly. Still, it's patently obvious that peak force for the stroke at 1:48 r31 is a LOT higher than it is for the stroke at 1:48 r19. As I wrote, you don't necessarily need higher peak power [sic; talking here about handle force] to maintain constant pace at lower rates. It depends on the force curve profiles involved. If I get bored enough I'll see if I can dig up some ErgMonitor screenshots showing instantaneous watts (power) curves demonstrating the same thing with actual peak power.


*Offhand, I'd guesstimate the second drive is maybe 5 hundredths of a second longer in duration.

[hjs]

What is the point of showing two strokes with two different techniques? And also being two strokes you never use in you training/racing. Isn't the point of this thread not taking about real training?

If you want to compare two strokes, use a high rate stroke you really use and a low rate stroke you really use. Coments on that makes sense, the two above mean nothing much, other than the fact you are able to make them.

[NavigationHazard]

What is the point of refusing to admit that your original statement was too categorical?

I responded to this:

You are missing one thing. The lower rate, the more peakpower per stroke you need per stroke to get you upto pace. Rowing is infact giving power for a short while and breaking for a longer while, If you would do that in a car, giving gas and breaking, the shorter you give gas and the more you need to give, not just relatively but also absolutely.
The highest rate will always give te lowest peak power and the best result if we leave the energy expended on the slide away.

It is simply not true that you necessarily require more peak power at lower rates to maintain constant pace. If the shape of the force curve changes the peak-force and peak-power requirements may also change, such that at the lower rate you need the same or even less peak force. Amplitude is not the only quality of a force curve. It's total area that counts, and that can be achieved by making the force curve thicker/wider rather than taller.

You introduced the idea of "equal technique" (whatever that means in this context) after the fact. And whether or not I (or anyone else) routinely use the stroke profiles in the screen shots is irrelevant to the fact that they clearly contradict your original assertion.

[claus hansen]

Navigation Hazard, I think you're pointing out very precisely something that is valuable to daily training.

In my 30r20 sessions I thought I was only/primaryly increasing peakforce, but reaching my limit (force, not aerobic) at pace 2.05 (I'm a newbie and a weak one, admitted) I had to realise I was increasing the strokelength, too, and too much really. Point here is, that You have to keep focus on technique and all other things equal when you're increasing peakforce.

[hjs]

What is the point of refusing to admit that your original statement was too categorical?

I responded to this:

You are missing one thing. The lower rate, the more peakpower per stroke you need per stroke to get you upto pace. Rowing is infact giving power for a short while and breaking for a longer while, If you would do that in a car, giving gas and breaking, the shorter you give gas and the more you need to give, not just relatively but also absolutely.
The highest rate will always give te lowest peak power and the best result if we leave the energy expended on the slide away.

It is simply not true that you necessarily require more peak power at lower rates to maintain constant pace. If the shape of the force curve changes the peak-force and peak-power requirements may also change, such that at the lower rate you need the same or even less peak force. Amplitude is not the only quality of a force curve. It's total area that counts, and that can be achieved by making the force curve thicker/wider rather than taller.

You introduced the idea of "equal technique" (whatever that means in this context) after the fact. And whether or not I (or anyone else) routinely use the stroke profiles in the screen shots is irrelevant to the fact that they clearly contradict your original assertion.

Ok true, I should have said I talk about reality not about fiction, me bad

To come back to the strokes you showed, you are a 6.25 (this) season rower, let's say your 2k rate is 31, so your stroke would be this stroke rate 31 pace 136/37m ish, and this stroke should not be a rangeresk stroke, but a stroke you use in a 2k sort of effort. Look at that profile for a real rate 31 stroke.
Compare this with a lower rate stroke, again a real stroke, not a made up one.
Then, I asume, at least I do, that we use a stroke that stays more or less the same, not longer or shorter. (Only my sprintstroke looks very different)

If you compare those two strokes, I now for sure that the peakpower is higher in the low rate one. At least mine is
So you can convince me me by showing 2 of those strokes I discribe above, not the 2 ones you showed, you never row at rate 31 pace 1.48 and that rate 19 1.48 is pacewise maybe real, but I know for sure you would never like your stroke profile look that way. So the first does not excist at all and the second only if you row poorly.

[sander]

dW = F.ds where dW is a work increment, F is instantaneous force and ds is a stroke length increment.

Integrate over entire stroke length to obtain work per stroke. Divide over stroke duration (in seconds) to obtain average power. So, one can increase the average power by increasing stroke length, increasing average force over the stroke, and increasing the frequency. Added to that we have to take into account a small but not negligible power for "just moving back and forth on the slide".

In real life all these things are coupled through the flywheel inertial moment, drag factor and muscle efficiency/dynamics.

A body needs to provide energy to the muscles to perform work. Changes in (perceived?) effort result in changes in heart beat. I am not at all sure there is a one to one correspondence to heart beat and (perceived?) effort. I bet it depends on many other factors as well.

Finally, all sensor's signals are nonlinearly and fuzzily processed by the brain and translated in "perceived effort". I guess even purely subjective inputs like fear, emotions, not being used to rowing at this distance/stroke rate, etc are part of the mix.

That's what sport is about.

[NavigationHazard]

(snip)

To come back to the strokes you showed, you are a 6.25 (this) season rower, let's say your 2k rate is 31, so your stroke would be this stroke rate 31 pace 136/37m ish, and this stroke should not be a rangeresk stroke, but a stroke you use in a 2k sort of effort. Look at that profile for a real rate 31 stroke.
Compare this with a lower rate stroke, again a real stroke, not a made up one.
Then, I asume, at least I do, that we use a stroke that stays more or less the same, not longer or shorter. (Only my sprintstroke looks very different)

If you compare those two strokes, I now for sure that the peakpower is higher in the low rate one. At least mine is
So you can convince me me by showing 2 of those strokes I discribe above, not the 2 ones you showed, you never row at rate 31 pace 1.48 and that rate 19 1.48 is pacewise maybe real, but I know for sure you would never like your stroke profile look that way. So the first does not excist at all and the second only if you row poorly.

You have a hard time with the concept of "I was wrong." Okay, I'll humor you by comparing a 2k SB stroke at 1:35 r31 to something at the same pace and a lower rate, never mind that nobody trains at 2k pace and significantly lower than 2k rating. Drag factor and "technique" (defined by me as rowing the same way without thinking about it) constant:



1:35 r31, per request.



1:35 r27, for comparative purposes.



1:35 r24. Go ahead. Continue to insist that peak force MUST be higher at lower rates, with the added stipulation (not present in your original assertion) that the general contour of the force curve remain "more or less the same."

[gregsmith01748]

Hi Nav,

Not to step into the middle of your "discussion", but I have a question about the pics you posted. How "hard" do you find it to pull these different strokes? For example, would you be able to pull a full 2K with this split at any of the rates that you posted? If not, what do you think is the limiting factor?

Thanks

[hjs]

1:35 r31, per request.



1:35 r27, for comparative purposes.



1:35 r24. Go ahead. Continue to insist that peak force MUST be higher at lower rates, with the added stipulation (not present in your original assertion) that the general contour of the force curve remain "more or less the same."

The word "must" is not used by me, in the first statement you keep referring to.......

But you show that if one does ones best, you can show otherwise.

If I do two pieces of the same lenght and pace and to compare two pieces, for me that is a given, the lower I rate, the higher my strokecurve comes out. Rangeresk strokeprofiles don't mean much to me.

And people look for yourself and your own real Strokecurves and see what they do at different ratings.


But I know it makes you happy so I repeat it, I was wrong !!!!!!!!!!!!!!

[NavigationHazard]

How hard would it be? 1:35 pace is a second and a half faster than my season-best pace of 1:36.5. It's just off my all-time 2k PB and also the age-group WR for 2k. So it would be very hard indeed.

The limiting factor(s)? The same things that conspire to limit everyone who rows a 2k -- human physiology -- and no that's not a flippant response. No one ergs a world record 2k trivially.

The fallacy of the single stroke is that 'if I can only perfect a drive/recovery cycle, then technique is solved and all I have to do is replicate that perfection X times to row a piece of Y duration.' That's not how it works. Contrary to some assertions you might read elsewhere around here, erging is NOT fundamentally a matter of technical coordination. It's fundamentally physiological, because your skeletal muscles require fuel and oxygen (there are limits to your anaerobic pathways; sooner or later oxygen debt needs to be redeemed; so-called aerobic metabolism is always going on in the background, and in fact provides the lion's share of the energy required in a 2k). Most people with normal coordination can 'get' basic erging technique quickly. Once you get the basics down, relatively subtle changes in technique won't matter anywhere near as much to your results as will physiological factors and training.

Two things that have been left out of the thread so far: drive/recovery ratio and duration. I think both are highly significant when considering rate-vs-effort.

As for the first: for puropses of argument let's assume a constant drive duration of 0.5 seconds. At 20 spm a complete stroke cycle takes 3.0 seconds. If the drive portion takes 0.5 seconds, the recovery (defined as not-drive) must take 2.5. Your D:R ratio is 1:5, implying that the muscles you used on the drive collectively have five times as long to recover from contraction as they spend contracting on the drive.* At 30 spm a complete stroke cycle takes 2.0 seconds. Given a drive of 0.5 seconds, recovery now shrinks to 1.5 seconds and D:R is 1:3. Now the muscles you used on the drive collectively have but three times as long to recover. At 40 spm the cycle is 1.5 seconds and the ratio shrinks to 1:2. This trend is (mainly) what undermines the sustainability of trading rate for pace, i.e. taking more strokes to go as fast or faster rather than rowing with the same or increased input on the drive. You may be working less hard per drive at higher rates, but you have to take more drives. Somehow you have to solve the tradeoff.

As for the second: duration comes into play here because your ability to sustain a given pace/rate combination will vary both from individual to individual and also from piece to piece depending on your physiological capacity and training. What works for a maximum-effort piece of duration x and rate y cannot possibly work for a piece of duration 2x or 3x and rate y. There are always such tradeoffs to consider. Moreover, because the mix of energy pathways we use will vary with pace/rate and distance/duration, it behooves us to target them in training accordingly. This is why any sensible training plan will have you rowing at a variety of rates and a variety of prescribed paces/pace ranges for a variety of prescribed distances/durations....


* It's actually more complicated, as you use your muscles sequentially on the drive, but.... Let's keep it simple.

[sander]

It's fundamentally physiological,

... and psychological.