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Did you know that… the Peach system produces basic biomechanical data about oar angles, forces, and rowing power, although these may be overestimated? The BioRow system provides extended information including blade work in the water, rowing style, and advanced data analysis.
The Peach Powerline telemetry system is popular in rowing squads, so a common question from our clients is: “How do Peach numbers and curves correspond to the data obtained with BioRow system?” We have investigated this area before with a focus on the mechanical differences between measurements taken at an oar and at a gate. Over the past 15 years, equipment and data-processing methods have been continuously developed, and previous conclusions require updates.
The experiment was conducted in a JW8+ boat, instrumented with both Peach and BioRow systems. The crew performed three 2000 m runs of the standard BioRow step-rate test (eight samples per run from 20 to 34 spm), and data was acquired simultaneously with both systems at 50 Hz with Peach and 25 Hz with BioRow. The recordings were downloaded to a PC and the BioRow data was processed using our standard methods. Peach data was exported to a text file and processed using two methods:
The first method examines only the mechanical specifics of the systems, while the second evaluates both data acquisition and processing.
While oar movement is fully controlled by the rower, the gate is not firmly connected to the oar and may exhibit backlash relative to the oar sleeve and button, especially at the catch and the finish. The most significant differences were found before and after the catch, which resulted in a 1.3° longer catch angle measured by the Peach system. At the finish, the discrepancy was visually smaller, but the finish angle was 2.5° longer, resulting in a total angle 3.9° longer with the Peach system. The average data from all rowers and samples confirms this: total angles measured by the Peach system were about 3% longer than those from the BioRow system.
Gate force measured with the Peach system consists of the handle force measured with BioRow plus the blade force. To compare absolute values, Peach force data was converted into Newtons and multiplied by the ratio of actual outboard (pin to blade centre) to actual oar length (handle to blade centres), which was 0.693 in this case. It was found that gate force measured with Peach increases more slowly after the catch, reaches a slightly later and higher peak, and remains higher during the second half of the drive. Therefore, the Peach force curve is shifted toward the finish.
At the beginning of recovery, the Peach system recorded a significant negative gate force caused by oar inertia during negative acceleration. Approaching the catch, the gate force becomes positive as oar acceleration changes sign. Therefore, in Peach data, gate force continuously increases during recovery, while handle force measured by BioRow remains flat because the measurement is taken with the oar feathered.
Force measured by Peach sensors was found to be 5.2% higher, and rowing power 6.2% higher, than in BioRow system.
The boat acceleration curves had very similar magnitudes at extreme points, while BioRow data appears smoother than Peach data. Rowing speed was measured using GPS in both systems, but Peach data showed 1.8% higher average speed.
The highest correlations between per-stroke data of the two systems were found in rowing power and catch force gradient, while the lowest were in maximum force.
Average per-stroke rowing power from the Peach system was 11.1% higher than from the BioRow system. Averages of finish angles and maximum force were lower in Peach data, whereas in Table 1 they were higher, most likely due to processing-specific differences in the Peach system.
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©2025 Dr. Valery Kleshnev