Purposes: 1) to compare the pattern of the work rate (WR)/VO2 and of the WR/heart rate (HR) relationship in incremental cycling; 2) to ascertain the occurrence of a VO2deflection (VO2def) and to compare it with the HR deflection point (HRdef ); 3) to compare the VO2 at the ventilatory threshold (VT) and at VO2def, if present. Methods: 24 professional cyclists performed an incremental test on a wind-load cycle ergometer. WR, HR,VO2 and VCO2 were recorded. Results: 1) The WR/VO2 relationship was linear up to submaximal WR and curvilinear thereafter, due to VO2attenuation. The WR and VO2 at the beginning of the attenuation (VO2def) were mathematically determined in all subjects. The ratio ΔWR/Δ VO2 up to VO2def was significantly lower than above VO2def (90 ± 11 versus 133 ± 35 watts/L.min-1, P < 0.0001). 2) The WR/HR relationship was linear up to submaximal WR and curvilinear thereafter. The WR and HR at the beginning of the HR attenuation (HRdef) were mathematically determined in all subjects. 3) The WR values at VO2def and at HRdef (329 ± 32 and 326 ± 34 watts) were significantly correlated (R2 = 0.96, P < 0.0001) and in good concordance (limits of agreement from -4.7 to 3.2%, Bland-Altman analysis). 4) The VO2 at VAT was determined in all subjects. The VO2values at VO2def and at VT were significantly correlated (R2 = 0.99, P < 0.0001) and in strong concordance (limits of agreement from -1.9 to 1.0%, Bland-Altman analysis). Conclusion: A VO2 attenuation starting at 82% VO2maxin coincidence with HRdef and VT has been demonstrated in professional cyclists during incremental tests.
Identification of a VO2 deflection point coinciding with the HR deflection point and ventilatory threshold in elite cyclists
GRAZZI, Giovanni;MAZZONI, Gianni;CASONI, Ilario;ULIARI, Simone;COLLINI, Gabriella;CONCONI, Francesco
2008
Abstract
Purposes: 1) to compare the pattern of the work rate (WR)/VO2 and of the WR/heart rate (HR) relationship in incremental cycling; 2) to ascertain the occurrence of a VO2deflection (VO2def) and to compare it with the HR deflection point (HRdef ); 3) to compare the VO2 at the ventilatory threshold (VT) and at VO2def, if present. Methods: 24 professional cyclists performed an incremental test on a wind-load cycle ergometer. WR, HR,VO2 and VCO2 were recorded. Results: 1) The WR/VO2 relationship was linear up to submaximal WR and curvilinear thereafter, due to VO2attenuation. The WR and VO2 at the beginning of the attenuation (VO2def) were mathematically determined in all subjects. The ratio ΔWR/Δ VO2 up to VO2def was significantly lower than above VO2def (90 ± 11 versus 133 ± 35 watts/L.min-1, P < 0.0001). 2) The WR/HR relationship was linear up to submaximal WR and curvilinear thereafter. The WR and HR at the beginning of the HR attenuation (HRdef) were mathematically determined in all subjects. 3) The WR values at VO2def and at HRdef (329 ± 32 and 326 ± 34 watts) were significantly correlated (R2 = 0.96, P < 0.0001) and in good concordance (limits of agreement from -4.7 to 3.2%, Bland-Altman analysis). 4) The VO2 at VAT was determined in all subjects. The VO2values at VO2def and at VT were significantly correlated (R2 = 0.99, P < 0.0001) and in strong concordance (limits of agreement from -1.9 to 1.0%, Bland-Altman analysis). Conclusion: A VO2 attenuation starting at 82% VO2maxin coincidence with HRdef and VT has been demonstrated in professional cyclists during incremental tests.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
