PubMed: Effects of Drag Factor on Aspects of Rowing

[igoeja]

Essentially, ventilation was higher at a lower drag factor, most likely related to increased stroke rate:


Effects of Drag Factor on Physiological Aspects of Rowing

Int J Sports Med. 2007 Sep 13; [Epub ahead of print]

Kane DA, Jensen RL, Williams SE, Watts PB.

Department of Health, Physical Education and Recreation, Northern Michigan University, Marquette, MI, United States.

This study examined the effects of two resistances, or "drag factors" on selected physiological variables during incremental progressive rowing tests (seven 3-min stages) on a Concept2(R) ergometer. Subjects were seven male and seven female university club rowers. Their mean age, body mass and height were 19.6 +/- 1.5 years, 72.7 +/- 8.0 kg, and 172.2 +/- 7.5 cm, respectively. Progressive tests were conducted using drag factors 100 (D (100)) and 150 (D (150)) before the spring racing season. Values were determined for the following physiological variables: ventilation (V. (E)), oxygen uptake (V.O (2)), heart rate (HR), blood lactate concentration (BLC), respiratory exchange ratio (R) and rowing economy ( W/V.O (2)). Comparisons across all six submaximal stages showed no significant difference between D (100) and D (150) for any of the variables measured (p > .05). Maximal V. (Emax) was significantly greater at D (100) than D (150) (p < .02). Maximal V.O (2), HR, BLC, R, stroke rate (SR) and W/V.O (2) were greater at D (100) than at D (150), though not significantly so. The mean D (100) - D (150) differences in V. (E) and SR for each stage were significantly correlated (r = 0.76, p < .01), suggesting drag factor may affect V. (E) via SR.

[Nosmo]

Technical definition of Ventilation?

[PaulS]

Technical definition of Ventilation?

I'd think they would be refering to the avg rate of expiration, using a volume/time metric. i.e. 2 deep breaths could equal 4 shallow ones in a given time period, but 3 deep would be greater than 2 deep in the same given time period.

I suppose they could measure inspired volume also, but that creates even more resistance for the athlete and that can be pretty uncomfortable.

It did not appear that VO2 used was effected significanty, but that can be efffected by long term entrainment, so would be specific to a given athlete and avg out over a group.

[chgoss]

So, if I am reading this correctly.. and I doubt I am... it seems a bit more efficient to row at DF=100 than DF=150?

[igoeja]

Ventilation heart rate, etc, were all lower with D (150). If pace/power is matched, it would seem to be more efficient to row at higher resistance.

[chgoss]

Ah, good.. I recently started experimenting with increasing my DF from where I had it for the first 4m meters (100) up to 125.
It seems to suit me better, but I see all the really great rowers (Xeno, Cracknell, Pinsent) seem to keep the DF pretty low..

125 seems to work better for me, so I will keep it there for a bit. thanks for the info.

[jamesg]

Testing results at just two points, 100 and 150 drag, is somewhat comical. Maybe the individuals tested were taking the "researchers" for a ride. We all know the ideal is 120-130. One would expect at least three levels to be essential, otherwise how do we see the shape of the impedance curve?

Adjustable drag lets us work at our best force/speed combination by setting the load impedance to suit our characteristics, just as the impedance of a loudspeaker must equal that of the driver to maximise power transfer. At any other drag level the increase of one parameter is outweighed by the drop of the other since the two parameters are linked.

It's simple with volts and amps, where W=VA: open circuit, no current so no power; short circuit, no voltage so no power (and the driver burns out).
The same for speed/force and us. I can spin bike wheel with one hand only up to a certain speed, but no faster and no power since I can't catch up with it. I can move a 10 000 ton ship, if afloat, by leaning on her side, but no power however hard I push, because speed is almost zero.