Validation of a novel instrumentation (FlexOmega system) measuring oar bending moments on-water in rowing

Abstract

Quantifying rowing performance can facilitate control of training load or assessment of skill level. Accordingly, the FlexOmega system was developed, which records the bending moment of the oar. This work aimed to validate this new instrumentation during a dynamic load case. Two force profiles were first derived from bending moments acquired during on-water rowing (one at race pace, one at training pace). These force profiles were then used to repeatedly load the instrumented oar on a newly developed test bench. To ultimately elaborate how precision and accuracy determined on the test bench affects everyday training, i.e., whether practitioners can reasonably use the FlexOmega system, the measurement variability observed on the test bench was related to the measurement variability seen for on-water measurements. On the test bench (featuring a mean precision of 99% and mean accuracy of 95%), a mean error of 3 Nm (mean precision: 98%, mean accuracy: 97%) was determined for the FlexOmega system for the force profile A characterised by bending moments of up to 300 Nm (racing simulated, 37 strokes per minute). For the force profile B with lower stroke rate and less force (21 strokes per minute, up to 150 Nm), the mean error was 2 Nm (mean precision: 98%, mean accuracy: 97%). The measurement variability observed on the test bench was on average for the two force profiles 30% (profile A) and 15% (profile B) of the measurement variability that occurred during on-water rowing. We conclude that improving the measurement characteristics of the instrumentation would hardly result in any practical benefit as on-water measurements seem mainly to be influenced by the rower’s skill level and environmental condition. Thus, the FlexOmega system can be used to control training intensity or to evaluate rowing performance. In addition, the presented approach for elaborating measurement characteristics could contribute to.

Keywords

• dynamic loading
• force profile
• measurement variability
• oar bending moment
• test bench