In the two previous posts, I have looked at hypothetical force profiles. Here I present the simulation results on more realistic ones.
Figure 1 shows the profiles used in the simulation. As you can see, all are defined by two points (x1,F1) and (x2,F2). The first point defines the handle position at maximum leg force. From that point on, the force can stay on a plateau or go downhill immediately. This is defined by the second point (x2, F2). The force curves look more or less like what can be observed on a Concept2 ergometer screen. One could interpret the differences as differences in style, and perhaps also body proportions. For example, T3 could be a rower with shorter legs and a longer torso compared to T2. T5 is equal to “trapezium” in my two previous posts.
Figure 2 shows the mean boat velocity achieved for a rower in the single, using standard rigging (catch angle 63 degrees). Each data point represents a different stroke rate, increasing from 25 spm to 35 spm in steps of one stroke per minute. Again, the differences are small. The most efficient strokes seem to be T2 and T5. T3 seems to be the most inefficient. It is interesting to look at the difference between T2 and T3. It seems like keeping a strong stroke as long as possible pays off. This is in agreement with common coaching practices.
Figure 3 shows the same plot as figure 2, with a changed rigging. The rower has moved the footboard towards the bow and reduced the catch angle to 43 degrees. Still, the rowing style “T2” is the most efficient, although the differences are reduced. In conclusion, a flatter force profile leads to more efficient rowing, independent of the catch angle, although smaller catch angles are more forgiving.
The differences between T2 and T3 are that the short-legged rower T3 has to push harder in the beginning of the stroke to reach the same velocity. He therefore loses more energy due to blade slip. The more balanced stroke of T2 wins.