Dynamic vs Stationary

[jliddil]

COMPARISON OF ROWING ON A CONCEPT 2 STATIONARY AND DYNAMIC ERGOMETER
http://www.jssm.org/vol10/n2/4/v10n2-4abst.php

Full Text article is free.

[slwiser]

I agree with the conclusions based on my experience.

One thing that is not made clear is why the efficiency drop between the Dynamic (D) and Static (S) machines. To me the reason is that on the D one has to use more muscle to keep the load at the same level as on the S, hense the V02 increase. This increase may be directly proportional to the increase in muscle utilization on the D. I do keep my SR about 4-6 higher on the D compare with when I am on the S machine for about the same load rating.

These conclusions supports my finding that the challenges that are SR limited are more difficult for those of us using the D.

[Tinus]

I agree with the conclusions based on my experience.

One thing that is not made clear is why the efficiency drop between the Dynamic (D) and Static (S) machines. To me the reason is that on the D one has to use more muscle to keep the load at the same level as on the S, hense the V02 increase. This increase may be directly proportional to the increase in muscle utilization on the D. I do keep my SR about 4-6 higher on the D compare with when I am on the S machine for about the same load rating.

These conclusions supports my finding that the challenges that are SR limited are more difficult for those of us using the D.

Why would one need to use more muscle to keep the load the same? Also, the used force/load on the D was lower.

There may be an additional explanation for the difference in VO2max. A research by Hofmijster et al. (http://pubget.com/paper/19346978) may explain this. Hofmijster et al. considers also the work done by moving the foot stretcher and this makes a big difference. Benson et al. only considers the work done by moving the handle. That is a systematic error in the research because energy can be lost by moving the dynamic erg back and forth. Also energy can be lost by moving the rower mass back and forth. Hofmijster et al. eventually conclude that the loss (absorption of energy at the catch) of energy by moving the body back and forth has no effect on efficiency however they did find a higher requirement in energy to move the erg back and forth (friction of the erg on the slides). In the particular research the erg was dampened (to resemble friction/dampening of a boat in the water) so possibly the effect may be less in other situations but still, the effect must be measured to know for sure.

Another interesting difference with other research is the RER. Benson et al. found that the anaerobic system is less used on the dynamic (slides) rower. In one of the recent rowing biomechanical newsletters by Kleshnev an exact opposite effect was found. That particular issue discussed the newly developed concept erg.

[slwiser]

To answer your question of why? With the Dynamic it is much harder to throw ones weight around (anchor hauling) so the muscles have to do the work otherwise done using this method to keep the load at the same level as on the static.

Now if you assume perfect or near perfect stroke methods I guess this might not be the case but with my stroke I think the difference is in having to use my muscles vs the natural anchor hauling that is so easy to do on the static and much more difficult on the Dynamic. The Dynamic encourages a better stroke by default I would think.

Just my opinion of course.

[Tinus]

To answer your question of why? With the Dynamic it is much harder to throw ones weight around (anchor hauling) so the muscles have to do the work otherwise done using this method to keep the load at the same level as on the static.

I am still not sure what this means exactly. "So, the muscles have to do the work"

What (extra?) work do the muscles have to do exactly? If it is the work normally done by the weight of the body... that type of work is not free work and first needs to be provided by muscle as well. The effect of using the weight of the body means that you can apply a bit more work with the legs in the beginning of the drive (storing it as kinetic energy in the moving body mass) and apply it to the flywheel later (when the body mass slows down). However, this work/energy still needs to be done by the muscle but now only at a different moment in the drive.

[slwiser]

I really can't explain it much better than I have already attempted but I will try again. To me when I am on the static I can throw my back (to me this implies weight) into to stroke in a way that I have much more difficulty with on the dynamic. Therefore, not being able to throw my back into it I have to compensate with more leg and glut effort (muscle). Again, probably wrong and poorly explained by about the best I can do.

What in your mind is the concept of "anchor hauling?" Maybe I have the wrong concept and this is just another stroke technique that you encourage those on the static to use in order to better utilized their "kinetic energy?"

[Carl Watts]

Good artical but skip the waffle to the conclusion and keypoints.

The conclusion I would come to is the Dynamic is much more technique sensitive if you wish to obtain a similar power output while trying to maintain an identical stroke rate and HR to a static erg. This would be more inline with OTW requirements as fast on a static doesn't automatically mean your going to go fast OTW. It would therfore make the Dynamic Erg the better choice if your primary goal is to train to compete OTW.

If your just not interested in OTW and only interested in virtual racing then the static is the way to go. In terms of acheiving peak fitness it doesn't matter which machine you choose, you just have to increase your pace slightly on the static to compensate for the fact that your "Efficiency" is not going to be as high on the Dynamic.

Needless to say there is no good reason for me to go rushing out anytime soon to buy a Dynamic.

[JRBJR]

Needless to say there is no good reason for me to go rushing out anytime soon to buy a Dynamic.

Not unless you're suffering from back discomfort/injuries and you buy the line from the folks at RowPerfect (Europe and Australia) and some of their customers that the static erg is bad for the spine and the dynamic is safe. Still waiting for in-depth studies of this hypothesis from the scientific community.

[Carl Watts]

Needless to say there is no good reason for me to go rushing out anytime soon to buy a Dynamic.

Not unless you're suffering from back discomfort/injuries and you buy the line from the folks at RowPerfect (Europe and Australia) and some of their customers that the static erg is bad for the spine and the dynamic is safe. Still waiting for in-depth studies of this hypothesis from the scientific community.

Well I guess that comes down to the individual, if your back hurts on the Static Erg and your DF is right and so is your technique then perhaps the Erg just isn't right for you full stop.

Having rolled a car and done my lower back no good at all, The static Erg and swimming makes the Chiropractic visits few and far between, however take road cycling for example, it gives my lower back hell being stuck in a truely "Static" bent over position for any length of time so go figure.

Also reacently read some litterture at the Millennium institute of sport (This will be in respect to OTW)

"Rowing uses all the major muscle groups, relying approximately 65% on the legs, 25% back and 10% arms. It's unique in that it relies on both aerobic and anaerobic energy systems along with requiring strength and power"

So the bottom line is your back is always going to be a significant player in the sport regardless of the Erg you on.

[jamesg]

What's the point of such long windy articles with no conclusions? He didn't even mention Newton, who explained all the differences a few hundred years ago. Not a hint of impedance, essential to understanding work transfer from source to load..

Anyway, back problems are caused by lack of exercise, cars, desks and suchlike. Ergs solve them. The only time rowing caused me back problems was when lifting the boat out of the water with bad posture. Must get the wife to do it for me. Add a bit of kayak and freestyle for good measure..

No doubt strong youngsters (hardly my case) can hurt themselves, especially against high drag. Hence the importance of learning how, whatever we do. International oarsmen and women, who can 't be accused of not pulling hard, just no harder than necessary, use perfect posture and very long strokes with blades buried all the way. Those who don't, lose.

Saw them.. and tried the Dynamic this week in Henley. The major difference for me is not the slide action, but the freewheel. The 20-30 cm slack at the catch disappears, evidently there's a new clutch system, and this makes it much more like a 1x with a quick catch. This result was partly reached using slides, due to Newtonian effects that made the catch quicker and shorter and hence the net stroke longer. The advantages of lower inertial losses and so quicker return and very high ratings (if we wish) are the same, but as ever we have to learn to use them, nothing comes automatically.

[Rockin Roland]

Rowing on a static erg differs from a dynamic erg for the following reasons. During the entire range of motion the progressive movement of the joints and loading up of the muscle groups follow different patterns as they meet different forms of resistance during the stroke.

On a static erg the horizontal velocity movement of the body mass reduces the ability of the rower to leverage open through the hips compared to a dynamic erg. The glutes on a static erg are not used anywhere near as much as on a dynamic erg.

The body has to move with the dynamic system on a dynamic erg. If the quads stop pushing then the body won't continue to open up the hip angle. Hence more tension is created in the hamstrings and glutes to pry open the body and as the quad forces decrease the power is transfered into the hip extension.

Consequently there is more power generation through the hip extension on a dynamic erg compared to static. As the power of opening of the back via hip extension differs between the two ergs this could explain the relatively high incidence of lower back injuries on static ergs.

[slwiser]

Needless to say there is no good reason for me to go rushing out anytime soon to buy a Dynamic.

Not unless you're suffering from back discomfort/injuries and you buy the line from the folks at RowPerfect (Europe and Australia) and some of their customers that the static erg is bad for the spine and the dynamic is safe. Still waiting for in-depth studies of this hypothesis from the scientific community.

Good comments all...But here is where I am coming from and my goals and why I think the Dynamic is for me; not very scientific but from my experience.

My experience is coming from a body that was essentially debilitated and having to build from a true couched potato. Ten years ago working with Airdyne Stationary Cycle I could barely get my HR above 120 bpm no matter how much I tried. Now I can push over my estimated MHR any time I try (>160). My debilitation was a result of years of tendon, cartilage, muscle deterioration for being not able to exercise at any significant level due to the gradual decrease in heart capacity. I buy into the theory that certain tissue takes longer to build than others; i.e., muscle half life is ~6 months while tendon/cartilage ~2.5 years. Having not been able to stress these tissues I was really weak. I have been building now since my quad-by-pass surgery in Feb 08 and having started Cardio Rehab in May 08. I first sat on the C2 in May 09. I got my C2E a couple of weeks after that following a long search for the "perfect" machine to bring home. I had been looking for a treadmill and now am very happy with my selection of the C2 type machine.

In '10 I was putting in 300k+ a month during the summer and think I over used some back tendons and/or muscles. This is when I got the slides and started working with them. Compared with the Static, I found the Dynamic to focus my efforts toward the legs and gluts as opposed to the "kinetic energy" of the motion swing compressing my back and extending it during each stroke. It took me three months to build back up to the level load level after getting my slides. This of course shows just how poor my stroke technique was and I would guess I was "anchor hauling" my way into back issues.

Keeping my focus on what I am after which is building cardio strength and after reading the relatively small amount of comments about the Dynamic and with the experience I had using the slides I went for the Dynamic. Additionally, the slides provide a little extra clumsiness to the layout and being an older person may in the future cause a tripping issue for me. I know you younger guys never think of these types of things. I sold my slides quickly as well as my C2E for a favorable amount of money. Yes I lost on the money deal but I have gained much more than I lost over all.

My take on the Dynamic is that it requires much more focus on technique when compared with either the Static or the Static on slides. Technique is one thing that anyone wanting to increase performance or to ensure the potential for less injury should be concerned. If my technique had been near perfect then maybe the use of slides or the Dynamic would not have been such an issue but coming from where I came anything that pushes me toward better technique is a positive in my book. This is where the Dynamic is most favored by me. It requires me to focus on technique to get my load up. I see my heart rate higher than with the static for the same efforts. I now have two months on my Dynamic with over 400k meters.

My most recent efforts have been to build a better cardio based to get my HR back down for the same load; i.e., long slow workouts at UT2 and UT1 levels. Yesterday I did an 8x10 min 2r session at ~151 watts (2:12.5). I have been doing a couple of 6x10s and one 8x10 a week for a while now and taking a day or two off if my back becomes a little sore. It seems that I can do these between 150 and 162 watts within the UT1/UT2 range depending on how much rest I have had. This is the aerobic base I have right now. My first season (2010) I averaged ~134 watts, my second season (2011) I averaged ~144; this season (2012) I am averaging ~155 watts for every meter recorded in my Concept 2 log. Being 60 years old, I have to take more recovery time compared with the average guy here and I think this slows down progress even more but progress is being made. Yes, I am significantly weaker than most of you here but I do continue to build slowly and hopefully without injury.

[johnlvs2run]

tried the Dynamic this week in Henley. The major difference for me is not the slide action, but the freewheel. The 20-30 cm slack at the catch disappears, evidently there's a new clutch system, and this makes it much more like a 1x with a quick catch.

James, are you sure the slack at the catch disappears?

I found this post of yours from a few years ago and am curious, as the empty space is something that I often ran into on the concept2 erg. A 20-30 cm slack is a much greater percentage of total stroke length for shorter rowers, and the empty space is likely greater at higher stroke rates. So I'm curious how much of this is reduced or if it does disappear on the c2 dynamic. From the videos that I've seen, the empty catch is still a major issue on the c2 dynamic.

There's nothing to be done about the sloppy catch on the erg, however much we improve speed and coordination off the stretcher or fiddle with the drag. We still have to accelerate our entire mass to engage the idler and catch up with the flywheel. Together with decoupling, this is the one big improvement the erg needs, but it's probably impossible. Not that it matters, it's a training machine and it works anyway. Compare the first stroke on a stationary wheel. Slides improve things a little, thanks to Newton. Even better, try a 1x. By judicious juggling of vertical hand speed, stretcher pressure and so on, the catch can be effectively instantanous and the stroke a lot longer than on the erg.

What is decoupling?

[jamesg]

I was surprised too, noting immediately the difference at the catch; clearly it's not zero slack, but I found it much shorter. There must be some smart engineering somewhere in there, no longer like a bike's rear wheel. There wasn't time to check whether it stayed short at all ratings/speeds.

The connection is no longer a chain, but a piece of string, hi tec string no doubt, which maybe supports the thought that the freewheel differs.

Decoupling was a term used to mean on slides, so that the machine is no longer a part of (i.e. coupled to) the earth, but floats like a boat and can move on the fore and aft axis. Slides would not be the only way to do it, in theory, hence the more general term.

The Dynamic machine had me rating 25-28 immediately, against my usual 20-21, and 1:55 to 2:00 instead of 2:15 or so from cold. So the usual effects of the slides are there as expected, and somewhat more discipline is needed to keep the power level within sustainable limits.

As you say, the slack catch is a big disadvantage if you're not the usual 190cm 100kg oarsman, so you might find a test interesting.

[Carl Watts]

Slack on the catch at the beginning of the drive ?? I'm confused, basically the way a one way bearing in the flywheel works is it locks up on the shaft as soon as the rpms of the chain sprocket exceed that of the rpms of the flywheel so I can think of 3 possible reasons.

1. The bearing is faulty and it is slipping.

2. Your drive is TO SLOW in the inital phase, or more likley just to slow for the entire drive.

3. Your DF is way to low and the flywheel simply is not decelerating enough.