Stroke by stroke: understanding erg machine drag factor
Rachel Marbaker is a BCR member and a movement scientist studying at University of Colorado, Boulder, at the graduate level. She coaches BCR’s winter training sessions and writes about training on her Medium blog account. This is an excerpt from Rachel’s post about ergometer training — visit her Medium blog for the full-length version.
I couldn’t find a satisfactory (read: technical with engineering and physics included) write up on rowing drag factor. So I wrote one with equations and included recommendations for drag factor values for erg training. Since a Concept 2 machine is state of the art for rowing athletes, I will focus primarily on that machine. I’ll address resistance on magnetic resistance ergs at the end.
Air resistance — How to view drag factor on a Concept 2: Menu > More Options > Display drag factor. After a few strokes, the drag factor will appear on the up on the screen and will be recalculated on each stroke, though it should remain fairly consistent. The number on the screen reflects the deceleration of the erg flywheel during the recovery of the stroke.
The damper (lever 1–10 on the right side of the fan) controls airflow into the fan cage. The relevance of airflow into the cage is best explained in the context of air resistance (F). (Warning: the inner engineering / math nerd is about to be unleashed)
