Concept2 Forum

ErgData 2.0.0 has a variable Drive Ratio it can display. I can’t find anywhere online how this is calculated and what values are “good form”. Apologies if this is a dumb question!

I haven't ever used it, but I assume Drive Ratio is only useful for maintaining a specific SPM, so I can't see how there can be any use outside of this, but, as has been proven many times, I might be wrong

I assume it is the drive to total stroke ratio. So my drive is around 0.65 seconds, the total stroke is 2.7, so the stroke ratio is 0.24.

It is interesting to know where you spend most of your time, as the recovery is assumed to be longer as the drive. That being said, in OpenRowingMonitor I removed it as a metric as no external analysis tool understood it, and the absolute numbers are much more interesting. For example, it is interesting to know that my drivetime stays the same regardless whether I am in steady state or sprint, while my SPM goes up, suggesting I gain my speed by shortening the recovery. That is hard to read from strokerate alone.

Any chance this is the ratio between time spent on the drive and time spent on the recovery ?

OTW coaches like to say "2:1 ratio, make the recovery much longer than the drive, let the boat run during the recovery, clear your puddles... " This is a qualitative statement, meant to drive a point. People who row don't actually know (or care about) their ratio when rowing. They do care about big drive and play games (fast hands, slow legs, etc.) to get the recovery as long and as smooth as they can given the SPM, boat speed and power.

As you point out, this only makes sense at a particular stroke rate. At a sprint no way you are hitting 2:1. At very low stroke rates your ratio is much higher than 2:1 -- the recovery gets very long.

Suggested use. With the my current (and your pervious) ErgData I use "stroke length" as an indicator that my form is breaking down, usually on a longer row when I am not paying attention. I know where it should be, and if it's not there I focus for the next few strokes. I don't want it longer or shorter, I want it where it should be -- where it is when I'm focused on form.

Maybe drive ratio can be used the same way. As a canary in the coal mine to show you that your form/stroke is changing so that you can notice and take action (if any required). Over time in a steady state row it seems this ratio would be constant unless something unintended was happening or you were intentionally changing something.

edit: Good article: https://www.rowperfect.co.uk/teaching-r ... and-ratio/

Thank you for your reply because, as someone new to rowing, recently I’ve been focusing on my drive length for the reason you shared (form breaks down as fatigue creeps up). Your post gave me peace of mind about my attention to drive length - with bad discs between L3-5, I can’t afford to let my form deteriorate.

Do you have any resource recommendations regarding what is an appropriate drive length? I’ve been estimating how long my drive length should be by tracking the length for legs only (~0.75m), legs+body (~0.95m), legs+body+arms (~1.20m), which leads me to estimate my drive length should be ~1.2m. But I would appreciate a resource or seasoned rower’s opinion to help me better understand how to look at drive length.

Tsnor wrote: ↑

July 15th, 2022, 11:55 am

Any chance this is the ratio between time spent on the drive and time spent on the recovery ?

OTW coaches like to say "2:1 ratio, make the recovery much longer than the drive, let the boat run during the recovery, clear your puddles... " This is a qualitative statement, meant to drive a point. People who row don't actually know (or care about) their ratio when rowing. They do care about big drive and play games (fast hands, slow legs, etc.) to get the recovery as long and as smooth as they can given the SPM, boat speed and power.

As you point out, this only makes sense at a particular stroke rate. At a sprint no way you are hitting 2:1. At very low stroke rates your ratio is much higher than 2:1 -- the recovery gets very long.

Suggested use. With the my current (and your pervious) ErgData I use "stroke length" as an indicator that my form is breaking down, usually on a longer row when I am not paying attention. I know where it should be, and if it's not there I focus for the next few strokes. I don't want it longer or shorter, I want it where it should be -- where it is when I'm focused on form.

Maybe drive ratio can be used the same way. As a canary in the coal mine to show you that your form/stroke is changing so that you can notice and take action (if any required). Over time in a steady state row it seems this ratio would be constant unless something unintended was happening or you were intentionally changing something.

edit: Good article: https://www.rowperfect.co.uk/teaching-r ... and-ratio/

ejweisto wrote: ↑

August 18th, 2022, 9:50 pm

Do you have any resource recommendations regarding what is an appropriate drive length? I’ve been estimating how long my drive length should be by tracking the length for legs only (~0.75m), legs+body (~0.95m), legs+body+arms (~1.20m), which leads me to estimate my drive length should be ~1.2m.

No, not really. As long as stroke form is good any drive length should be fine. 1.2 seems a reasonable drive length, but if you were rowing with good style and saw 1.3 or 1.15 or 1.35 they are all good. The final pull with the arms can really change the reported drive length, so when looking at drive length make sure your arms are finishing the stroke.

Concept2 says this about drive length --> https://www.concept2.com/news/drive-length

This thread says how your drive length should vary with stroke rate. viewtopic.php?f=3&t=185701, so you won't find a single perfect drive length.

Concept2 Australia has some great videos on rowing form avail on youtube. Get the form right the correct drive length will follow. https://www.youtube.com/user/Concept2Au ... pp=desktop

Common Errors: If you try to get a longer drive (not a bad thing) do *not* get it by the following:
1. don't stretch farther forward at the catch. Your body angle needs to be set before your knees come up at the recovery.
2. don't bend / curve your back to get extra length. This puts your back in a weak position. Instead get all your forward lean from pivoting at your hips. This is really hard to learn. You want a strong, straight back. The back does not change shape during the stroke, instead the hips rotate swinging your back from 11pm to 1pm clock position.
3. don't have excessive lean back. You can get longer by leaning backwards more, but this slows you down. Stop the backward lean at 30% or 11pm clock position. This may be less lean than you expect. (I don't know of anyone who has too much forward hip rotation -- your hip flexors will stop you first).
4. don't pull your hands too high. Your drive length will be longer the higher you pull in the handle at the finish, but you will not go faster. Erging does tend to have the handle end up higher than on the water rowing however the handle should not end up at your chin. Elbows should end up a little out from your body, but not high up.
5. don't overcompress. At the catch your shins should be vertical, not past vertical. You can get longer by compressing more, but you will be slower - once you are past vertical your legs are in a poor position to develop push. It is fine to have your heels come off the foot stretch as you go to the catch, just keep your shins from getting past vertical.

We can set our erg drag factor so that the pull is quick and the recovery slow. The resulting rhythm is what makes effective training possible: each stroke pulled long hard and fast at low rate, so not too many per minute.

If young and strong, the DF to get this effect will be around 130.

If the rhythm is a round number, 2:1 or 3:1, it's much easier to follow the stroke man and get some work done. Same on the erg.

ejweisto wrote: ↑

August 18th, 2022, 9:50 pm

Thank you for your reply because, as someone new to rowing, recently I’ve been focusing on my drive length for the reason you shared (form breaks down as fatigue creeps up). Your post gave me peace of mind about my attention to drive length - with bad discs between L3-5, I can’t afford to let my form deteriorate.

Do you have any resource recommendations regarding what is an appropriate drive length? I’ve been estimating how long my drive length should be by tracking the length for legs only (~0.75m), legs+body (~0.95m), legs+body+arms (~1.20m), which leads me to estimate my drive length should be ~1.2m. But I would appreciate a resource or seasoned rower’s opinion to help me better understand how to look at drive length.

I read (or dreamt) somewhere that drive length should be about 2/3 of height. Not sure if this is for SS or ‘at pace’. As said, at higher SPM the drive length shortens.
For me at 1.96m my steady state drive length is 1.4x, so a bit over 2/3. I sometimes see 1.5 but know I’m over reaching, so a good form check. At 28+ SPM I shorten to 1.33

Tony Cook wrote: ↑

August 19th, 2022, 3:19 am

I read (or dreamt) somewhere that drive length should be about 2/3 of height. Not sure if this is for SS or ‘at pace’. As said, at higher SPM the drive length shortens.
For me at 1.96m my steady state drive length is 1.4x, so a bit over 2/3. I sometimes see 1.5 but know I’m over reaching, so a good form check. At 28+ SPM I shorten to 1.33

That corresponds with my results too. When I used to use Ergdata and stroke length, it was usually 1:42-1:45 for SS, and 1:37-1:39 for an unrestricted TT, which is always done at r28-30

I inquired about drive length some time ago.

viewtopic.php?f=3&t=204169

It's something I use to monitor my form. I'm going to add drive ratio to my readout and see if it is a useful parameter.

One big caveat around using DRIVE LENGTH as a new rower.

Many rowing errors end result in a short drive. Some are not immediately correctable. Example, it take a long time (months, years) to get enough hip rotation so you are not rowing too vertical.

Having a target drive length opens you up to compensating errors as you change your stroke to get the target drive length number, even though you can't. Errors repeated while you are learning to row are very hard to correct later.

You are far better off rowing short than rowing over-compressed (etc.) to reach your target length. Get the stroke right, don't focus on length until you have a good stroke.

Thank you for taking the time to help me learn - I continue to be amazed by how everyone is so generous with their knowledge and time.

I have a bit to digest, but your key point is to continue focusing on technique (not drive length). You also imply I need to continue being patient yet committed to learning and improving my technique. I can still include drive length (among other indicators) to gauge the risk of my form degrading due to fatigue.

Thank you Tony - your reply is helpful because my 1.20m drive length estimate is 2/3rds of my height (1.8m). And building off of Tsnor’s insights, I’ll continue to focus on developing and maintaining good form, using drive length as another fatigue indicator besides heart rate and respiration rate.

Tony Cook wrote: ↑

August 19th, 2022, 3:19 am

ejweisto wrote: ↑

August 18th, 2022, 9:50 pm

Thank you for your reply because, as someone new to rowing, recently I’ve been focusing on my drive length for the reason you shared (form breaks down as fatigue creeps up). Your post gave me peace of mind about my attention to drive length - with bad discs between L3-5, I can’t afford to let my form deteriorate.

Do you have any resource recommendations regarding what is an appropriate drive length? I’ve been estimating how long my drive length should be by tracking the length for legs only (~0.75m), legs+body (~0.95m), legs+body+arms (~1.20m), which leads me to estimate my drive length should be ~1.2m. But I would appreciate a resource or seasoned rower’s opinion to help me better understand how to look at drive length.

I read (or dreamt) somewhere that drive length should be about 2/3 of height. Not sure if this is for SS or ‘at pace’. As said, at higher SPM the drive length shortens.
For me at 1.96m my steady state drive length is 1.4x, so a bit over 2/3. I sometimes see 1.5 but know I’m over reaching, so a good form check. At 28+ SPM I shorten to 1.33