Some thoughts about Stroke Rate and Stroke Power.

A possibly unique feature of rowing, and more so indoor rowing, is that its power production is a continuum of three interrelated factors: Force, Stroke Rate, and Stroke Length. Theoretically you can increase your boat speed by increasing any one of these factors while maintaing each of the others. Or you could produce the same speed by means of varying proportions of each of the three. Although various physical limitations of human anatomy and boat construction prevent the occurrence of large differences, in practice, this works to a certain extent, where for example a strong low rating crew overcomes a fatiguing high rating crew. Annual surveys of rigging and stroke rates of elite crews are conducted and arive at recommended targets. But, although anecdotal wisdom regarding training at a given Stroke Rate or Stroke Force (or Work per Stroke) abounds, there has not been much research into its physiological implications. Some work has been done on the efficacy of  low cadence training in cycling but it remains inconclusive.

I am puzzled by various coaches recommendations to row at SR16 for long rows and SR28 for Tempo etc. These usually neglect to mention in what type of boat and at what Stroke Pressure, or why. There is a huge difference between 28 in a Single and 28 in an VIII. And how fast you are moving at each stroke rate determines how hard you have had to pull each stroke. On an ergometer, rowing at easy pace, for me say 2:24 splits, at  Stroke Rate 16 results in the same work per stroke as I would put in during a flat out 2k at stroke rate 33. Stroke rate intrinsically is only a minor parameter of training load. The main considerations for me are boat speed or power (work x time), which stresses the cardiovascular an metabolic systems, and the force you need to apply in each individual stroke, which stresses the peripheral muscular system.

So to gauge the load or the potental training and fatigue effect of a piece we need to know the extent and duration of muscle tension required during that piece as well as the average power generated and the duration  to complete the piece. Now, the power is generated for the entire duration of the piece, but the muscle tension only occurs while you are pulling the oar through the water. So at a lower rating, for the same power output or boat speed, the muscle tension is higher. The muscular effect is therefore more strength orientated and, as the total number of these strokes increases, it becomes more strength-endurance oriented. This is apart from the fitness gained through just maintaining a level of power regardless of stroke rate. You can quantify the muscular load by counting the number of strokes over a given percentage of your work per stroke in a flat out 2k. But we need good research to determine what effect different proportions of each trainiing type  might have.