Scand J Med zyxwvutsrqpon Sci Sports 1994: 4: 91-112 Prmted zyxwvutsrqpon in Denmark All rights reserved Copyright 0 Munksgaard 1994 Scandinavian Journal of MEDICINE zyx & SCIENCE IN zyx SPORTS ISSN 0905-7188 Review ar tide zyxwvut Quantification of anaerobic capacitv Gastin PB. Quantification of anaerobic capacity. Scand J Med Sci Sports 1994: 4: 91-112. zyxwvut 0 Munksgaard, 1994 Anaerobic capacity may be defined as the maximal amount of ATP formed by the anaerobic processes during a single bout of maximal exer- cise. While several methods have been presented to measure a person’s anaerobic capacity, none have become universally accepted. The muscle biopsy technique provides information on the anaerobic energy release from direct measures of ATP and CP breakdown and muscle lactate con- centrations. As a practical measure of anaerobic capacity, the method may be limited, as it is an invasive, skilled technique. Furthermore, it has the limitation of measuring relative changes in concentrations, not amounts, such that the anaerobic contribution is estimated from estimates of the active muscle mass involvement. Measurement of lactate in blood after exhaustive exercise has frequently been used, but several factors sug- gest that, while it provides an indication of the extent of anaerobic gly- colysis, it cannot be used as a quantitative measure of the anaerobic energy yield. The mean power during an all-out effort on a bicycle ergometer has also been assumed to be a measure of anaerobic capacity, yet it pro- vides only an indication of the ability to maintain high power outputs. Concerns over the duration of the test, the protocol and type of ergometer used and the contribution of the aerobic energy system to the energy supply also limit its validity as a measure of anaerobic capacity. The oxy- gen debt, defined as the recovery oxygen uptake above resting metabolic rates, has been discredited as a valid and reliable measure of the anaerobic capacity, as it is generally acknowledged that mechanisms other than the metabolism of lactate also contribute to the post-exercise oxygen uptake. The recent work of M e d b ~ et al. in re-examining the issue of oxygen deficit has created considerableinterest in its use as a measure of anaerobic capacity. The measurement of oxygen deficit directly depends on the ac- curate assessment of the energy cost of the work completed. This is not difficult during submaximal exercise, as the steady-state oxygen uptake represents the energy costs. During exhaustive supramaximal exercise, the validity of the maximal accumulated oxygen deficit as a measure of the anaerobic capacity has been questioned, as the energy cost is estimated and not measured, either by assuming a given mechanical efficiency or by extrapolating the submaximal relationship between work intensity and oxygen uptake to supramaximal levels. Despite these theoretical objec- tions, the maximal accumuiated oxygen deficit method remains a promising measure of the anaerobic capacity, as it provides a non-invasive means of quantifying the anaerobic energy release during exhaustive exercise. The energy required for muscle contraction comes from the splitting of adenosine triphosphate (ATP). As ATP stores in the muscle are limited, well regu- lated chemical pathways exist for the regeneration of ATP. There are 3 distinct yet closely integrated processes that operate together to satisfy the energy requirements of the muscle. The first process in- volves the splitting of the high-energy phosphagen creatine phosphate (CP), which together with the stored ATP in the cell, provides the immediate en- P. B. Gastin School of Human Movement & Sport Sciences, University of Ballarat, Mt Helen, Victoria, Australia Key words: accumulated oxygen deficit; anaerobic capacity; blood lactate; energy demand; ergometric assessment; mechanical efficiency; oxygen debt; supramaximal exercise zyx P. B. Gastin, School of Human Movement & Sport Sciences, University of Ballarat, P.O. Box 663, Ballarat 3353, Victoria, Australia Accepted for publication 11 July 1993 ergy in the initial stages of intense exercise. The sec- ond process involves the non-aerobic breakdown of carbohydrate, mainly in the form of muscle glyco- gen, to lactic acid through glycolysis. The non-aero- bic breakdown of glycogen and the splitting of stored phosphagens comprise the anaerobic energy system. These pathways are capable of regenerating large amounts of ATP per unit of time and can result in large muscle power output during brief intense ex- ercise. The anaerobic system is, however, limited by 91