Broxterman, R. M., Wagner, P. G., & Bender, P. A. (2009). Comparison of RPE to blood lactate levels in cyclists based on mileage per year. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 2792.

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This study examined the effect of number of miles cycled per year on use of the BORG-RPE (6-20) scale to predict blood lactate accumulation while cycling. Male cyclists (N = 30) were grouped according to number of miles ridden per year (Group 1 <1000, Group 2 = 1,000-2,000, Group 3 >5,000). Ss completed an incremental stage cycling protocol, increasing resistance every three minutes. Rating of perceived exertion, revolutions per minute, and heart rate were recorded every minute. Blood lactate concentration was collected every three minutes and an additional sample was taken when the S reported an RPE of at least 13. Lactate threshold was defined as an RPE of 13 on the BORG-RPE scale and by a one millimole (mmol/l) increase in blood lactate accumulation. Onset of blood lactate accumulation was defined as a blood lactate concentration of 4.0 mmol/l.

There was a significant difference in the RPE reported at the lactate threshold. Groups 1 and 2 reported an RPE of 13 (mode) and Group 3 reported a mode RPE of 16. However, there was no significant difference between the RPE reported at the 4 mmol/l lactate accumulation level between the three groups. There was a significant difference in heart rate at 175 watts. The mean heart rates for Groups 1, 2, and 3 were 150, 144, and 126 bpm respectively. There was a significant difference in power output between the three groups for both the lactate threshold and the 4 mmol/l lactate concentration.

Implication. Training higher than 5,000 miles per year is associated with an over-estimation of the lactate threshold using the Borg Scale RPE. All three groups were able to predict 4 mmol/l lactate concentrations using RPE.

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