The leveling-off of oxygen uptake is related to blood lactate accumulation. Retrospective study of 94 elite rowers

Abstract

To assess whether the ability to demonstrate a plateau in oxygen consumption $({\mathop V\limits^{.}}\hbox{O}_{2})$ could be related to adaptation to exercise, the data obtained over a period of 10 years on 94 elite oarsmen who had participated in annual testing were re-evaluated. The test consisted in an incremental step protocol until volitional exhaustion. ${\mathop V\limits^{.}}\hbox{O}_{2},$ heart rate (HR), blood lactate ([La]_b) and respiratory exchange ratio (RER) were measured at each step. The maximal oxygen consumption $({\mathop V\limits^{.}}\hbox{O}_{\rm 2max}),$ the power corresponding to ${\mathop V\limits^{.}}\hbox{O}_{\rm 2max}(\hbox{P}_{\rm amax})$ and the maximal power achieved (P_peak) were recorded. Thirty-eight oarsmen achieved a ${\mathop V\limits^{.}}\hbox{O}_{2}$ plateau and were designated as Pla; 56 did not and were designed as N-Pla. The Pla and N-Pla ${\mathop V\limits^{.}}\hbox{O}_{\rm 2max},\,\hbox{P}_{\rm amax}$ and maximal HR values were similar. In comparison with N-Pla, the Pla group displayed a rightward shift of the [La]_b versus power curve, accounted for by both the increased percentage of ${\mathop V\limits^{.}}\hbox{O}_{\rm 2max}$ corresponding to 4 mmol l⁻¹ and the decreased value of [La]_b corresponding to P_amax (P < 0.05). Pla oarsmen attained a higher P_peak expressed as % of P_amax (P < 0.05) and also showed better ergometer performance (P < 0.05). In a sub-group of 53 oarsmen constituted on the basis of P_amax values close to 400 W, for a given power output, the Pla subjects had significantly lower HR, RER, and [La]_b values at each sub-maximal stage of the test. These results suggest that achieving a ${\mathop V\limits^{.}}\hbox{O}_{2}$ plateau during completion of an incremental step protocol accounts for greater muscle ability to maintain homeostasis during exercise. These differences give the oarsmen an advantage in rowing competitions.