Practical application of variability analysis
Did you know that improving rowing technique consistency is a critical component of rower progression? Variations in key indicators, such as timing, angles, and force-power metrics, continuously decreased, while others, like the force curve and rowing factors, exhibited non-linear improvements. These changes were likely achieved through proper and regular coaching, an essential aspect of rower development.
Rowing technique and its consistency were studied during the career progression of a young rower. Both the magnitude and variation of biomechanical indicators were analyzed in a junior rower over six years, from the second to the seventh year of their rowing career. The athlete began rowing at the age of 12, became a National Junior Champion in their second season, earned medals at the Junior World Championships in their fifth and sixth seasons, and successfully transitioned to the U23 category in their seventh season. Each year, the sculler performed a standard BioRow test in a single, and the average values of all samples are presented here.
The variation in timing indicators decreased significantly: stroke rate (duration of the stroke cycle) variation reduced by 43%, and drive time variation dropped by 56%, indicating substantial improvements in timing consistency throughout the rower’s development.
Interestingly, the total oar angle magnitude peaked at an Olympic target level (108°) very early - during the 2nd season. It then dropped sharply to 103° in the 3rd season before gradually increasing to 106°. The consistency of oar angles continuously improved, with variation decreasing from 1.2% to 0.5%.
The average force magnitude dramatically increased by more than 50%, reaching the Olympic target level by the seventh season. Force consistency improved, with its variation reducing nearly by half. Work per Stroke WpS increased by 59% compared to its initial value, while WpS variation more than halved, dropping from 6.8% to 2.7%, which is significant improvement in consistency.
Indicators of the force curve showed more complex development. Both the catch force gradient and the position of peak force were highest in the second and seventh years, indicating slower force application during the drive while remaining within the target zone. Midway through this period, the rower exhibited a more “front-loaded” technique. Force curve consistency improved significantly in the 6th and 7th years from 10-15% to 4–6%.
To continue validating the new analysis method, it would be interesting to correlate and compare average values of indicators calculated using the new and standard methods:
- Atyp: Values obtained with the standard BioRow method, based on typical (averaged) patterns of each variable during a sample.
- Astr: Indicators calculated for each stroke cycle and then averaged over the sample.
Timing indicators, oar angles, and RSF exhibited the highest correlations (r=0.98–1.00), with ratios close to 100%, which means they were the most valid and reliable. Stroke rate and oar angles had ratios slightly above 100%, indicating that average indicators calculated for each stroke cycle (Astr) were slightly higher than those obtained from typical patterns (Atyp).
Force and power indicators showed the highest discrepancies between the methods, with correlations of r=0.47–0.85 and ratios of 106–111%. This discrepancy might result from the smoothing method or an underlying mathematical regularity.
Force curve indicators and synchronization metrics displayed high correlations (r = 0.92–0.99) and ratios near 100%. The Catch Factor also had a high correlation (r = 0.95), but its ratio was 142.8%, the reason for which remains unclear. Suggestions and insights are welcome…
Overall, the new variation data correlates well with previous data, indicating that the new BioRow method for analyzing technique consistency is valid and reliable.
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©2024 Dr. Valery Kleshnev