NK's empower wireless oarlock power meter review

[sandor]

Has anyone explored the use of work/Joules in using the EmP Oarlock for training? Forgive me if I misunderstand, but I think this measures work per stroke independent of stroke rate and is a combination of the effectiveness of your technique and fitness. Holding technique and fitness as constant (I know, dubious), could it also help optimize the rigging. So, for example, if shortening the oar to get more length increases work/Joules would that suggest you have a better set up?

i have not used "work" to adjust anything yet, but it is the constant that i look at across all my training now.
no matter what the SPM or distance or time, i want my work output to be the same -> the same force over the same stroke length = same work per stroke.

[track_bites]

So, how much rigging adjustment is needed when using this oarlock in a Empacher C cup rigger (bow mount). I'm told you need to replace the C cup with one that will fit this oarlock.

The NK site says you need to replace the c-cup.



I replaced the brackets on my fluid to fit the empower oarlock and I needed to move the whole rigger 2cm to the bow to compensate for the deeper bracket and keep the pin location in the same place relative to the foot stretcher.

[boston_1x]

Has anyone explored the use of work/Joules in using the EmP Oarlock for training? Forgive me if I misunderstand, but I think this measures work per stroke independent of stroke rate and is a combination of the effectiveness of your technique and fitness. Holding technique and fitness as constant (I know, dubious), could it also help optimize the rigging. So, for example, if shortening the oar to get more length increases work/Joules would that suggest you have a better set up?

i have not used "work" to adjust anything yet, but it is the constant that i look at across all my training now.
no matter what the SPM or distance or time, i want my work output to be the same -> the same force over the same stroke length = same work per stroke.

Ditto that. I was using the WEBA system for a few years & beta-tested the Empower last year. You use catch/finish angles to get rigging right & for timing drills... then for training set the Classic View to show Effective Length and Joules in the bottom two windows... the first is a measure of how "square" your force curve is... the second is how "big" it is (ie area under the curve).

Consistent with old school sculling coach mantras: Length then rhythm then power. Even pressure front to back, even pressure left to right, even pressure every stroke.

Blazing insights, re improving #s? Length matters. Catching through the stretcher matters. Pulling harder generates less speed than pushing faster. Maintaining length/joules as rating goes up into mid-high 30s/40s, managing perception of fatigue, is where you will be challenging yourself & spending a lot of time.

Seeing the #s is very enabling, re eliminating bad strokes in particular. One big warning if in a 1x... stay mindful of surroundings, steering can go to sh*t if you focus too much on the #s.

[rowsandall]

Has anyone explored the use of work/Joules in using the EmP Oarlock for training? Forgive me if I misunderstand, but I think this measures work per stroke independent of stroke rate and is a combination of the effectiveness of your technique and fitness. Holding technique and fitness as constant (I know, dubious), could it also help optimize the rigging. So, for example, if shortening the oar to get more length increases work/Joules would that suggest you have a better set up?

i have not used "work" to adjust anything yet, but it is the constant that i look at across all my training now.
no matter what the SPM or distance or time, i want my work output to be the same -> the same force over the same stroke length = same work per stroke.

Ditto that. I was using the WEBA system for a few years & beta-tested the Empower last year. You use catch/finish angles to get rigging right & for timing drills... then for training set the Classic View to show Effective Length and Joules in the bottom two windows... the first is a measure of how "square" your force curve is... the second is how "big" it is (ie area under the curve).

Consistent with old school sculling coach mantras: Length then rhythm then power. Even pressure front to back, even pressure left to right, even pressure every stroke.

Blazing insights, re improving #s? Length matters. Catching through the stretcher matters. Pulling harder generates less speed than pushing faster. Maintaining length/joules as rating goes up into mid-high 30s/40s, managing perception of fatigue, is where you will be challenging yourself & spending a lot of time.

Seeing the #s is very enabling, re eliminating bad strokes in particular. One big warning if in a 1x... stay mindful of surroundings, steering can go to sh*t if you focus too much on the #s.

I do agree with this, and have gravitated to this setup as well. Stroke rate top left, power top right, effective length bottom left, and work per stroke bottom right. I do tend to change that Work per stroke screen with technique related stuff though. I like seeing wash, as for me it is an excellent indicator to flag bad technique.

I also agree with the remark about staying mindful of surroundings. I wonder why nobody has made a head-worn SpeedCoach yet. Good posture should prevent you from looking at the SpeedCoach for every stroke. Putting the information on a Google glass or something like this: https://www.konicaminolta.com/about/res ... index.html would be really cool.

[Steven M-M]

I have a Watts to splits question. I know on the erg that watts and splits can be directly converted to each other. A cross fitter with horrible form pulling high Watts will have fast splits (at least for a brief moment). I am also using Watts for my workouts because there is considerable current in my river this spring, so Watts are a better measure of my work. (To give you a sense of the flow, when I last did my 4 * 6' pieces, it was 3 upstream and 1 downstream.)

So here is my question: in flat, calm, no current conditions would watts to splits (or M/S) be a good measure of efficiency. If a sculler 1 pulls 200W to go 2:00/500m and sculler 2 pulls 220W for 2:00/500m is this a good indication/measure of their relative efficiency?

[sandor]

I have a Watts to splits question. I know on the erg that watts and splits can be directly converted to each other. A cross fitter with horrible form pulling high Watts will have fast splits (at least for a brief moment). I am also using Watts for my workouts because there is considerable current in my river this spring, so Watts are a better measure of my work. (To give you a sense of the flow, when I last did my 4 * 6' pieces, it was 3 upstream and 1 downstream.)

So here is my question: in flat, calm, no current conditions would watts to splits (or M/S) be a good measure of efficiency. If a sculler 1 pulls 200W to go 2:00/500m and sculler 2 pulls 220W for 2:00/500m is this a good indication/measure of their relative efficiency?

Roughly, yes, if efficiency includes rigging, gearing & shell differences.

This is basically what Kleshnev was testing between shells in the indoor tank - instead of solving for rower, with the boat and rig staying the same, he was solving for boat with rower & rig remaining constant.

[bloomp]

I have a Watts to splits question. I know on the erg that watts and splits can be directly converted to each other. A cross fitter with horrible form pulling high Watts will have fast splits (at least for a brief moment). I am also using Watts for my workouts because there is considerable current in my river this spring, so Watts are a better measure of my work. (To give you a sense of the flow, when I last did my 4 * 6' pieces, it was 3 upstream and 1 downstream.)

So here is my question: in flat, calm, no current conditions would watts to splits (or M/S) be a good measure of efficiency. If a sculler 1 pulls 200W to go 2:00/500m and sculler 2 pulls 220W for 2:00/500m is this a good indication/measure of their relative efficiency?

Mechanical efficiency comparisons should certainly include the mass of the system. If someone is 10% heavier and needs 10% more watts, relatively speaking are they not just as efficient?

And while mechanical efficiency tells much of the story, metabolic efficiency is ultimately what matters.

[Steven M-M]

Thanks for the helpful comments. Lets pose the question differently. For an individual sculler in a 1x, at a relatively consistent weight, level of metabolic efficiency, and wind/current, would changes in Watts to speed indicate relative efficiency. For example reducing layback may reduce watts while not reducing, and maybe increasing, speed. Is it possible that NK could develop some indicator of work in/speed out that we could use to evaluate changes in technique, much like the use of slip and wash to measure efficiency of catches and finishes? Both work and speed are already measured making the challenge to come up with a meaningful indicator of efficiency.

[beagle]

I do this, off-line, for post row analysis. I create my own spreadsheet with reports for my own training purposes.

IOW, I calculate the percentage of Effective Length divided by Total Length. I use this to identify opportunities to address stretcher location and/or adjustments to reach and layback.

I will say that I am noticing differences between SS rows and HIIT-type sessions, obviously. Also, obviously, there are speed differences between these and even depending on interval lengths and intensities. I am more aware, and pleasantly satisfied, that I am not losing length and being relatively effective, when intensity and ratings increase, and what speeds I am generating as a result of application of power.

Not sure I am answering your question, but I am able to at least evaluate effectiveness and speed differences at different ratings and intensities. I put all the data together and create meaningful reports for myself.

[Steven M-M]

I understand "effective length" and I'm interested if there is equivalent that would be M/S / Watts (or some such measure for speed per amount of work).

[rowsandall]

I do this, off-line, for post row analysis. I create my own spreadsheet with reports for my own training purposes.

IOW, I calculate the percentage of Effective Length divided by Total Length. I use this to identify opportunities to address stretcher location and/or adjustments to reach and layback.

I will say that I am noticing differences between SS rows and HIIT-type sessions, obviously. Also, obviously, there are speed differences between these and even depending on interval lengths and intensities. I am more aware, and pleasantly satisfied, that I am not losing length and being relatively effective, when intensity and ratings increase, and what speeds I am generating as a result of application of power.

Not sure I am answering your question, but I am able to at least evaluate effectiveness and speed differences at different ratings and intensities. I put all the data together and create meaningful reports for myself.

For post-row analysis beyond spreadsheets, you might want to take a look at my web app rowsandall.com. It is free for basic use and doesn't cost much for Premium membership (15 EURO/year). Contact me if you want to know more.

Here is an example chart that you can make:


Here is a graphical report on Wash as measured on my recent outings:


I am open to suggestions for new (derived) metrics, like effective length / total length as suggested by you.

Regarding footstretcher setting and effectiveness, I tried to assess that last Saturday. My write-up is in this blog post: http://blog.rowsandall.com/2017/05/13/s ... r-setting/

I did 4x250m, two rows in each distance, two rows for each footstretcher setting. I think it is important to do these kind of assessments on quiet water, with as little wind as possible, and rowing in both directions and averaging the split.

The differences that you are looking at may be so small that you have to worry about water temperature and effects of slight differences in wind and waves, when comparing from session to session.

[sandor]

Thanks for the helpful comments. Lets pose the question differently. For an individual sculler in a 1x, at a relatively consistent weight, level of metabolic efficiency, and wind/current, would changes in Watts to speed indicate relative efficiency. For example reducing layback may reduce watts while not reducing, and maybe increasing, speed. Is it possible that NK could develop some indicator of work in/speed out that we could use to evaluate changes in technique, much like the use of slip and wash to measure efficiency of catches and finishes? Both work and speed are already measured making the challenge to come up with a meaningful indicator of efficiency.

i like the idea. i am trying to think how best to go at it.

the same idea would work if you are attempting to fine-tune rigging -can you get an extra 1/2 second somewhere? and how best to measure for the change?

the caveats right now would be impeller vs. GPS & water temperature (cooler = slower) & then the current sampling rate of the EmPower - what we know so far shows that *when* the force is applied can affect overall boat speed, so we need higher sampling rates for force curves as well.