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Adjustment Factors

Weight Adjustment Factor

The weight adjustment factor (WAF) for weight correction is:
[weight in kilogrammes/77.27]2/9.

For timed pieces, corrected time is the actual time multiplied by the WAF. For distance pieces, the corrected distance is the actual distance divided by the WAF.

Weight Factor Weight Factor Weight Factor Weight Factor
50.0 kgs 0.908 67.5 kgs 0.971 82.5 kgs 1.015 97.5 kgs 1.053
52.5 kgs 0.918 70.0 kgs 0.979 85.0 kgs 1.022 100.0 kgs 1.059
57.5 kgs 0.937 72.5 kgs 0.987 87.5 kgs 1.028 102.5 kgs 1.065
60.5 kgs 0.946 75.0 kgs 0.994 90.0 kgs 1.035 105.0 kgs 1.071
62.5 kgs 0.954 77.5 kgs 1.001 92.5 kgs 1.041 107.5 kgs 1.076
65.0 kgs 0.963 80.0 kgs 1.008 95.0 kgs 1.047 110.0 kgs 1.082

Alternative WAF

There is another weight adjustment factor that is used on the American Indoor Sport Services website, in the formula above substitue 77.27 with 122.73:

"Originally, we used 77.27 to normalize the weight adjusted scores because 77.27kg (170lb) was approximately the average weight of all rowers. But about a year ago we realized that by using a different number to normalize the weight adjusted score we could give the adjusted score more meaning. By using 122.73, the weight adjusted score becomes a pretty good estimate of a person’s potential speed in an eight. To put it another way, if the average adjusted score using this formula of the 8 rowers in an eight is 6:00, then that boat should be capable of a 6:00 2k race on the water—given perfect conditions and near perfect rowing effectiveness (nobody rows perfectly). We believe that this will be approximately true for all types of crews."

This isn't so relevant for the average 'indoor rower' and so not generally used for result adjustment, but maybe an interesting comparison for some.

Age Adjustment

Age adjustment is based on the following formulae, which have come from research done by Eddie Fletcher of Fletcher Sports Science:

For men: performance is held to decline at 0.12% per year from the ages of 26-55 and at 0.83% a year from age 56 onwards.
For women: performance is held to decline at 0.23% per year from the ages of 26-55 and at 0.74% a year from age 56 onwards.

You can download an Excel spreadsheet which has tables showing the decline in performance from ages for men and women. Base times for men range from 5:40 (340 seconds) to 10:00 (600 seconds) and for from women 6:25 (385 seconds) to 10:00 (600 seconds)

Download Age Decline Tables