ErgData - Drive Length whats yours ?

[Carl Watts]

After looking closer at the following post, the OP is 6ft 2 and has a drive length of 1.62m.

viewtopic.php?f=8&t=189554&p=494634&hil ... es#p494634

This really stood out to me as I am not that much shorter but my drive length is massively shorter. I have to really push it to go over 1.30m .I have seen 1.34m but typically its about 1.27m. Pretty much all my rowing is 20spm these days or even less.

So clearly there is something strange here or my technique is simply not utilizing my back enough and I'm sitting far to upright at the end of the drive. Pretty sure its not a problem at the end of the recovery. Will try and vary my technique to see if its even possible to get anywhere near this.

[mict450]

SWAG, but could it be a difference in inseam & sleeve length? Your 1.27 stroke length is just a skosh short of 70% of your nominal height. There must be a point of diminishing returns where excessive lean back leads to inefficiencies?
1.60 length is massive!! Just short of my overall height!!! I'd hafta be fully supine with the handle at my throat to equal that!

[Dangerscouse]

For a circa r20 stroke I'll usually be 1:42-47, and sometimes it's up to 1:52, with an emphasis on leaning back, but 1:45 is probably my average drive length.

When I'm doing r28+ it's almost always around 1:39

[Dino]

Watching some of Cam Buchans videos where he has had ergdata displayed

his 2k PB at rate 36 his drive length was 1.42-1.45
his 30min rate 20 however was 1.65-1.68

He is 6'9" or 206cm
so that's around 70% of height for 2k and 80% for 30r20.

I'll have to get Ergdata out again and see what mine is. I think arm length and body proportions has a lot to do with it, but rate seems biggest factor. Some pro rowers have purposefully high pull and lay back on the erg compared to OTW at the lower rates.

[MartinSH4321]

For normal UT2 training at 18-20SPM my drive length is around 1.51, for a 30R20 TT around 1.60. For faster stuff my length gets shorter, about 1.40 at R30 if I remember right.
Looks like the OP did a TT, so I guess his normal length is a good bit shorter.

[rtbrouwer]

I am 1.89m tall and my drive length is ussually around 1.32-1.35. On sprints sometimes just under 1.30 and if I focus on long strokes I get up to 1.40-1.42. I can get a stroke length of 1.50+ but that doesn't feel anywhere near efficient.

[jamesg]

The ergdata display with my PM5 on a C seems to be corrected to estimate the overall handle travel. The real travel under tension is 10-20 cm shorter, as can be seen by pulling short strokes, arms only, easy to measure.

This can also be seen by calculating Watts from Force, Length and Rating/60 as listed by ergdata, which gives about 12% more Watts (in my case) than the direct PM readout. Ergdata always shows exactly the same Watt reading as PM, since this is calculated referring only to flywheel inertia, speeds and times.

According to ergdata I pull 121-124, but measurement and calculation indicate 109 cm.

[hjs]

After looking closer at the following post, the OP is 6ft 2 and has a drive length of 1.62m.

viewtopic.php?f=8&t=189554&p=494634&hil ... es#p494634

This really stood out to me as I am not that much shorter but my drive length is massively shorter. I have to really push it to go over 1.30m .I have seen 1.34m but typically its about 1.27m. Pretty much all my rowing is 20spm these days or even less.

So clearly there is something strange here or my technique is simply not utilizing my back enough and I'm sitting far to upright at the end of the drive. Pretty sure its not a problem at the end of the recovery. Will try and vary my technique to see if its even possible to get anywhere near this.

160 is super long for such a short rower. I have seen Sam Blyth even a tad shorter, with also 160 plus strokes, but he close to horizontal finishing the stroke. I am 6.1 lenght 130/40 depending on rating.

[jurgwhitehouse]

Looks like the OP did a TT, so I guess his normal length is a good bit shorter.

Correct. That 1.60 stroke was an outlier - the final stroke of a 30R20 TT.

On an 18-20 spm piece at UT2 pace I see drive length values of 1.48-1.51m

[Allan Olesen]

which gives about 12% more Watts (in my case)

Same in my case. But I don't know if it is caused by a "wrong" averaging of handle force or an incorrect measurement of drive length.

This has annoyed me quite a lot, since there is no readout of stroke energy, so I often use handle force as the next best solution. (As long as I keep drive length constant, handle force will be proportional to stroke energy).

[lindsayh]

Carl I think that the drive length is mainly an individual metric which is hard to change much or at all (a bit like MHR) as long as technique is ok.
Mine is shorter than many - varies from 1.18 to about 1.35 depending on what I am doing. I don't worry about it all.

[jamesg]

if caused by a "wrong" averaging of handle force or an incorrect measurement of drive length.

Ergdata shows both average and peak force, which suggests PM knows the times between each successive pair of impulses, so can calculate flywheel acceleration and applied torque. This data is the same used for Watts, so will be consistent and equally accurate.

Stroke energy is Work done on the handle and is Watts/Rating; Power is defined as work/time.

[Carl Watts]

Some interesting replies an some of you immediately jumped to a stroke length as a percentage of your height. This is pretty logical because obviously the taller you are the longer the stroke length. Your wingspan would also have a small effect as well but clearly there must be an optimal drive length based on your height.

You would think that there would be some available data that just came out that it should be say 70% and then you could just move on and not worry your technique was way out of whack.

[Allan Olesen]

if caused by a "wrong" averaging of handle force or an incorrect measurement of drive length.

Ergdata shows both average and peak force

My point was that an average force can be calculated in several ways. It can be an average over time, an average over distance or something else.

Only an average over distance will give the correct energy when you multiply it with distance. An average over time will give the wrong result.

I have no information about how ErgData calculates the average, so I can't just go on and assume that ErgData's average force is valid in an energy calculation.

[Dangerscouse]

Some interesting replies an some of you immediately jumped to a stroke length as a percentage of your height. This is pretty logical because obviously the taller you are the longer the stroke length. Your wingspan would also have a small effect as well but clearly there must be an optimal drive length based on your height.

You would think that there would be some available data that just came out that it should be say 70% and then you could just move on and not worry your technique was way out of whack.

I wonder if there is a sweet spot in terms of how quickly you are able to get back to the most efficient catch position. I have tried emphasising my lean back a while ago but I think I gave up on it as I felt I lost time in getting back up straight and it didn't feel very natural.

I also agree with Lindsay's comments, it probably is what it is, and it's similar to drag factor: too subjective to find a definitive ideal