Anaerobic work capacity in cycling: the effect of computational method

Purpose To compare the anaerobic work capacity (AnWC, i.e., attributable anaerobic mechanical work) assessed using four different approaches/models applied to time-trial (TT) cycle-ergometry exercise. Methods Fifteen male cyclists completed a 7 × 4-min submaximal protocol and a 3-min all-out TT (TT AO ). Linear relationships between power output (PO) and submaximal metabolic rate were constructed to estimate TT-specific gross efficiency (GE) and AnWC, using either a measured resting metabolic rate as a Y-intercept (7 + Y LIN ) or no measured Y-intercept (7-Y LIN ). In addition, GE of the last submaximal bout (GE LAST ) was used to estimate AnWC, and critical power (CP) from TT AO (CP 3´AO ) was used to estimate mechanical work above CP ( W’ , i.e., “AnWC”). Results Average PO during TT AO was 5.43 ± 0.30 and CP was 4.48 ± 0.23 W∙kg −1 . The TT-associated GE values were ~ 22.0% for both 7 + Y LIN and 7-Y LIN and ~ 21.1% for GE LAST (both P < 0.001). The AnWC were 269 ± 60, 272 ± 55, 299 ± 61, and 196 ± 52 J∙kg −1 for the 7 + Y LIN , 7-Y LIN , GE LAST , and CP 3´AO models, respectively (7 + Y LIN and 7-Y LIN versus GE LAST , both P < 0.001; 7 + Y LIN , 7-Y LIN , and GE LAST versus CP 3´AO , all P < 0.01). For the three pair-wise comparisons between 7 + Y LIN , 7-Y LIN , and GE LAST , typical errors in AnWC values ranged from 7 to 11 J∙kg −1 , whereas 7 + Y LIN , 7-Y LIN , and GE LAST versus CP 3´AO revealed typical errors of 55–59 J∙kg −1 . Conclusion These findings demonstrate a substantial disagreement in AnWC between CP 3´AO and the other models. The 7 + Y LIN and 7-Y LIN generated 10% lower AnWC values than the GE LAST model, whereas 7 + Y LIN and 7-Y LIN generated similar values of AnWC.