A Comparison between Different Methods of Estimating Anaerobic Energy Production

Purpose: The present study aimed to compare four methods of estimating anaerobic energy production during supramaximal exercise. Methods: Twenty-one junior cross-country skiers competing at a national and/or international level were tested on a treadmill during uphill (7) diagonal-stride (DS) roller-skiing. After a 4-minute warm-up, a 4 x 4-min continuous submaximal protocol was performed followed by a 600-m time trial (TT). For the maximal accumulated O-2 deficit (MAOD) method the <(V)over dot>O(2-)speed regression relationship was used to estimate the <(V)over dot>O-2 demand during the TT, either including (4+Y, method 1) or excluding (4-Y, method 2) a fixed Y-intercept for baseline <(V)over dot>O-2. The gross efficiency (GE) method (method 3) involved calculating metabolic rate during the TT by dividing power output by submaximal GE, which was then converted to a <(V)over dot>O-2 demand. An alternative method based on submaximal energy cost (EC, method 4) was also used to estimate <(V)over dot>O-2 demand during the TT. Results: The GE/EC remained constant across the submaximal stages and the supramaximal TT was performed in 185 +/- 24 s. The GE and EC methods produced identical <(V)over dot>O-2 demands and O-2 deficits. The <(V)over dot>O-2 demand was similar to 3% lower for the 4+Y method compared with the 4-Y and GE/EC methods, with corresponding O-2 deficits of 56 +/- 10, 62 +/- 10, and 63 +/- 10 mL.kg(-1), respectively (P < 0.05 for 4+Y vs. 4-Y and GE/EC). The mean differences between the estimated O-2 deficits were -6 +/- 5 mL.kg(-1) (4+Y vs. 4-Y, P < 0.05), -7 +/- 1 mL.kg(-1) (4+Y vs. GE/EC, P < 0.05) and -1 +/- 5 mL.kg(-)1 (4-Y vs. GE/EC), with respective typical errors of 5.3, 1.9, and 6.0%. The mean difference between the O-2 deficit estimated with GE/EC based on the average of four submaximal stages compared with the last stage was 1 +/- 2 mL.kg(-1), with a typical error of 3.2%. Conclusions: These findings demonstrate a disagreement in the O-2 deficits estimated using current methods. In addition, the findings suggest that a valid estimate of the O-2 deficit may be possible using data from only one submaximal stage in combination with the GE/EC method.