In our last post we learnt that pace varies with the cube of power. IE doubling your pace needs 8 times as much power.
Realistically it’s not easy to double your pace, so let’s use a more practical example. Assume a base pace of 2:30/500m. Holding this requires 104W. Now let’s consider the power needed to change the pace by 10s:
2:20/500m – 128W (24W more)
2:30/500m – 104W
2:40/500m – 85W (19W less)
First notice that the faster the pace, the more power needed, as expected. However, due to the cubic relationship, more Watts are needed to go 0:10/500m faster, than Watts saved by slowing down 0:10/500m (24W vs 19W). It logically follows that this effect is amplified as pace increases (eg for a baseline 2:00/500m (203W), quickening (263W) vs slowing (159W) by 0:10/500m translates to a difference of 60W vs 44W).
How is this information relevant in practice?
Mainly it helps with pacing. Whether rowing a fixed distance in the fastest time (eg the Team Row of our Dynamic Row class) or trying to cover maximum distance in a fixed time (eg the 5min Test in our Power Row class), the most efficient strategy is always a constant pace. This is because energy “saved” by slowing down does not adequately compensate for that needed to “make up” time/distance lost. [Note: this only considers energy expanded, not taking into account mental and physiological factors. Negative splitting is a valid pacing method]
Example: Say two people row for 30min. Amy rows consistently at 2:30/500m, covering 6000m producing 104W on average. Bob rows 12min at 2:00/500m, then 18min at 3:00/500m, also covering 6000m. Bob’s average power is (12×202+18×60)/30 = 117W! Bob put in more effort to row the same distance in the same amount of time as Amy, thus Bob was less efficient. This reinforces the point made earlier about pacing, and also explains why sometimes you may feel like you rowed harder and have higher average Watts, but your distance doesn’t go up.
A last note: Since calories are calculated from power (we’ll go into detail about calories in the next post), in our example, Bob burned more calories for the same distance rowed in the same time span.