To evaluate the relations between %HRmax, %HRR, %V˙O2max, and %V˙O2R in elite cyclists and to check whether the intensity scale recommended by ACSM in its 1998 position stand is also applicable to this specific population.
Twenty-six male elite road cyclists (25.1 ± 0.7 yr, 71.0 ± 1.2 kg, 70.9 ± 1.2 mL·kg−1·min−1, 433.9 ± 9.8 W) performed an incremental maximal exercise test (50 W·3 min−1). Individual linear regressions based on HR and V˙O2 values measured at rest, end of each stage, and maximum, were used to calculate slopes and intercepts, and to predict %HRmax, %HRR, %V˙O2max, or %V˙O2R for a given exercise intensity.
Below 85% V˙O2max or V˙O2R, predicted %HRmax values were significantly higher (P < 0.001) than the ACSM intensity scale (58, 65, 73, and 87% vs 55, 62, 70, and 85% HRmax at 40, 50, 60, and 80% V˙O2max, and 48, 61, 74% vs 35, 55, and 70% HRmax at 20, 40, and 60% V˙O2R). The %HRR versus %V˙O2max regression mean slope (1.069 ± 0.01) and intercept (−5.747 ± 0.80) were significantly different (P < 0.0001) from 1 and 0, respectively. Conversely, the %HRR versus %V˙O2R regression was indistinguishable from the line of identity (mean slope = 1.003 ± 0.01; mean intercept = 0.756 ± 0.7). Predicted %V˙O2R values were equivalent to %HRR in the 35-95%HRR range. %V˙O2max was equivalent to %HRR at and above 75%HRR, and it was significantly higher at (P < 0.05) and below 65%HRR (P < 0.001).
The intensity scale recommended by ACSM underestimates exercise intensity in elite cyclists. Prediction of %HRR by %V˙O2R is better than by %V˙O2max. Thus, elite cyclists should use %HRR in relation to %V˙O2R rather than in relation to %V˙O2max.
1Unit for Exercise Biology and Sports Medicine, University Hospital Center, Amiens, FRANCE; and 2Department of Human Biology, UCT/MRC Research Unit for Exercise Science & Sports Medicine, Faculty of Health Sciences, University of Cape Town, SOUTH AFRICA
Address for correspondence: Frederic Campion, Unit for Exercise Biology and Sports Medicine, Amiens University Hospital Center, Place Victor Pauchet, Amiens, France; E-mail: email@example.com.
Submitted for publication May 2006.
Accepted for publication September 2006.