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dynamic and sliders drag

Posted: September 13th, 2012, 10:25 pm
by The_Giant0
Hi,

I have a couple related questions. I have been training using a static erg at drag factor of 110 for the past bit of time. I am trying to switch over to dynamic or using sliders. What would be the equivalent drag factor using each of those two to produce the same power per stroke?

Thanks

Re: dynamic and sliders drag

Posted: September 14th, 2012, 2:59 am
by Citroen
Drag isn't related to power per stroke. Drag simply controls how much air flows through the cage and how fast the flywheel is damped from spinning to a dead stop. With the same wattage input into the system you'll always get the same power reading (watts, pace or calories) recorded and displayed.

There's no connection between the monitor and the damper lever other than the flywheel tacho which simply counts flywheel revolutions. Damper 1 or damper 10 makes no difference to the way that tacho works.

The thing drag does to you as the rower is determine your stroke dynamics, how much you'll focus on legs, how fast your legs have to be to spin the flywheel. It's there so you can configure your ergo to more closely match the boat you'll be rowing on the water. The difference between a static and a dynamic is the amount of mass that moves during the stroke. With a static ergo you're moving your body mass. With a dynamic ergo your body stays still and the mass of the ergo moves under you. That will have an effect on your stroke dynamics as you'll be able to rate higher. That effect will be much more significant than variations in drag.

Re: dynamic and sliders drag

Posted: September 14th, 2012, 12:51 pm
by Bob S.
Citroen wrote: Damper 1 or damper 10 makes no difference to the way that tacho works.
Please pardon the pedantry, but the damper actually goes from 0 to 10. Incidentally, although the drag works the same way on dynamic as on the other models, there is a variation in the damping. The dynamic includes a removable baffle on the top of the cage. With the baffle out, the damper settings will give about the same drag factors as on the static models, but the baffle will lower the drag factor.
Citroen wrote: The difference between a static and a dynamic is the amount of mass that moves during the stroke. With a static ergo you're moving your body mass. With a dynamic ergo your body stays still and the mass of the ergo moves under you. That will have an effect on your stroke dynamics as you'll be able to rate higher. That effect will be much more significant than variations in drag.
Another point of pedantry - well 2 points actually: On slides, the whole erg other than the seat moves. The body is not still, but moves a lot less than on a grounded erg and the distance the body moves is dependent on the weight of the erger. On the dynamic, the main mass of the erg does not move, just the handle, stretcher, cable, and chain mechanism. The body still moves a little bit, but less than on the other models on slides.

Bob S.

Re: dynamic and sliders drag

Posted: September 17th, 2012, 12:17 am
by ausrwr
The general advice seems to be to lower the DF by 10-15 from static to sliders (having not used dynamic for more than the minute which took me to decree it a hateful machine).

I'm actually not too sure about this, I'd go the other way. I think historically, the DF has been too high on the statics (I've done most of my ergos on statics in the last few years at 105-115), and is too low on the sliders. You can't rate 50+ full slide in the boat for the last 500 racing, and the slides cheat this.

YMMV... Or be totally and utterly different.

Re: dynamic and sliders drag

Posted: September 23rd, 2012, 8:02 am
by slwiser
You can refer to this link for a comparison of the static, dynamic and on-the-water rowing drag factors. Check out the table on the lower right side of the page. I think these tests assume clean (new) machines.

http://biorow.org/news/the_latest_newsl ... 11-02-03-6

Based on my personal experience and my strength level (very low), the dynamic is much harder for me to sustain and maintain equal performance with the static. My technique is poor as well I am sure. I moved from static to the static with slides, to finally the dynamic because of back issues. The dynamic has successfully arrested my real back issues but I still get sore while my muscles in my posterior and legs take a real licking. Stroke rates for me are at least five-eight strokes per minutes higher on the dynamic than when I am on the static. I am a fitness user not a competitor.