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). 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) or no measured Y-intercept (7-Y). In addition, GE of the last submaximal bout (GE) was used to estimate AnWC, and critical power (CP) from TT (CP) was used to estimate mechanical work above CP (W', i.e., "AnWC").

Results: Average PO during TT was 5.43 ± 0.30 and CP was 4.48 ± 0.23 W∙kg. The TT-associated GE values were ~ 22.0% for both 7 + Y and 7-Y and ~ 21.1% for GE (both P < 0.001). The AnWC were 269 ± 60, 272 ± 55, 299 ± 61, and 196 ± 52 J∙kg for the 7 + Y, 7-Y, GE, and CP models, respectively (7 + Y and 7-Y versus GE, both P < 0.001; 7 + Y, 7-Y, and GE versus CP, all P < 0.01). For the three pair-wise comparisons between 7 + Y, 7-Y, and GE, typical errors in AnWC values ranged from 7 to 11 J∙kg, whereas 7 + Y, 7-Y, and GE versus CP revealed typical errors of 55-59 J∙kg.

Conclusion: These findings demonstrate a substantial disagreement in AnWC between CP and the other models. The 7 + Y and 7-Y generated 10% lower AnWC values than the GE model, whereas 7 + Y and 7-Y generated similar values of AnWC.