Validity of the two-parameter model in estimating the anaerobic work capacity

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• The power-time (P-t) relationship curvature (W quote) is theorized to be constant above critical power (CP) and indicative of anaerobic work capacity (AWC).
• Previous research suggests W quote represents AWC, but its accuracy and comparison to other measures like W (90s) quote and AWC require further investigation.

Purpose of the Study:

• To compare the anaerobic work capacity (AWC) determined from the power-time (P-t) relationship curvature (W quote) with measures derived from a 90-second all-out test (W (90s) quote and AWC).

Main Methods:

• Fourteen participants completed an incremental VO2max ramp test followed by three constant load exhaustion tests at varying percentages of P-VO2max to calculate W quote.
• Participants also performed two 90-second all-out efforts to determine W (90s) quote (work above CP) and AWC (work above estimated VO2-derived power).

Main Results:

• W quote and W (90s) quote were not significantly different (13.6 vs. 13.9 kJ) but were significantly lower than AWC (15.9 kJ) by 24% and 17%, respectively.
• While all variables were correlated, significant disagreement was observed between W quote, W (90s) quote, and AWC, indicating substantial variability.
• The underestimation of AWC by W quote and W (90s) quote is attributed to the exclusion of aerobic inertia in their calculations.

Conclusions:

• The curvature of the power-time relationship (W quote) and the 90-second all-out test measure (W (90s) quote) underestimate true anaerobic work capacity (AWC).
• Due to significant disagreement and underestimation, W quote, W (90s) quote, and AWC should not be used interchangeably in exercise physiology research and practice.