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Did you know that… the approximate gearing ratio may be referenced to the average values for each boat type? More accurate adjustments require biomechanical measurement and experimentation with different oar settings, stroke rates and lengths with a purpose to maximise rowing power and speed.
Our BioRow Expert Chat (available at https://biorow.com/chatbiorow/ ) is becoming increasingly popular among our subscribers. After analysing its questions and answers, we found that about 70% of the replies make sense and adequately reflect our current knowledge in the area of rowing biomechanics. Here, we will focus on the questions that were relevant, but for which the available information was not presented clearly enough to allow an adequate answers.
A common question was: “How do I determine the optimal gearing ratio?”
First, we need to define criteria for optimising the gearing ratio. The common view is that oar gearing affects the “heaviness” of the stroke: overly “heavy” gearing slows drive velocity, increases drive time, and at higher stroke rates forces rowers to “rush the recovery”, shorten the stroke, or otherwise prevents them from achieving a high racing stroke rate. At the optimal gearing ratio, rowers should be able to achieve the target racing stroke rate, stroke length, and force application while maintaining a comfortable rhythm. This definition shows clearly that “optimal” gearing is a relative and conditional concept, depending on how the target values are set.
Very small gearing variations were found between boat types: about 1% between 1x and 4x, and about 2% between 2− and 8+. These differences are much smaller than the differences in rowing speed: 17–18% between 1x and 4x, and 15–16% between 2− and 8+. This suggests that such small gearing variations are unlikely to have a significant
The highest correlation of gearing dG was found only with deviations of HDF “burden factor” (r = 0.15 – still very low), which confirms the common understanding that a higher gearing ratio makes the drive slightly heavier. However, HDF was influenced much more strongly by other variables than by gearing: its highest correlations were found with force application (r = 0.41), deviation of drive time (r = 0.35), and stroke length (r = –0.19). Other correlations of dG were even lower (r < 0.1), indicating that the gearing ratio has an insignificant effect on biomechanical indicators, it is not possible to optimise the oar gearing using available biomechanical data.
Rowers can effectively manage the overall gearing ratio and stroke timing by adjusting oar angles and using dynamic gearing (the longer the catch and finish angles, the heavier the dynamic gearing), without changing the oar levers. Moreover, the actual points of force application are not necessarily located at the centres of the handle and blade. Grip position on the handle may vary significantly, which affects the handle force leverage. The centre of pressure at the blade depends on the oar angle and blade depth in the water. Therefore, the ratio of forces at the handle and blade is not equal to the oar levers ratio.
Q: “Is there a unit for effective work per stroke that I can see while rowing on RP3?”
The concept of Effective Work per Stroke (EWpS) was developed as a measure of a stroke effectiveness instead of “distance per stroke”. On water, the mechanical Work per Stroke (WpS) produced by an athlete is not the only factor influencing rowing speed; weather conditions (head/tail wind) and external rowing efficiency (e.g., blade slippage) also play significant roles, so EWpS is useful only under similar external conditions.
However, on rowing machines, there are no such external factors, and the rowing speed displayed on the monitor is derived directly from the measured rowing power. Therefore, on rowing machines, EWpS and WpS are effectively the same and can be calculated in Joules from rowing power and stroke rate.
On the RP3, WpS is displayed as “Energy per Stroke (J)”. Similarly, WpS can also be used on the water when rowing power is measured with systems such as the NK EmPower oarlock or similar devices. Without sensors, rowing power and WpS remain unknown, and EWpS can be used only as a relative measure.
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©2025 Dr. Valery Kleshnev