Abstract

Performance in endurance sports is affected by a variety of factors, including exercise-training habits, nutrition and other lifestyle components. Endurance performance can also be seen as a multifactorial phenotype influenced by genetic and non-genetic factors. Current models in quantitative genetics and experimental data available in the sport sciences literature suggest that the effects of genetic variation on endurance performance can be observed as (a) the consequence of a character highly determined by the genotype which is correlated with endurance performance, (b) inherited differences in endurance performance exhibited by individuals of a sample or population, and (c) genotype-dependent individual differences in the response to endurance training.
This review considers the evidence for genetic effects in several determinants of endurance performance, namely: body measurements and physique, body fat, pulmonary functions, cardiac and circulatory functions, muscle characteristics, substrate utilisation, maximal aerobic power and others. Moreover, the response to aerobic training of indicators of aerobic work metabolism and endurance performance is reviewed, with emphasis on the specificity of the response and the individual differences observed in trainability.
It is concluded that there are considerable interindividual differences in the level of endowment for endurance performance. This genetic effect remains, however, quite modest when compared with other phenotypes, such as the skeletal dimensions of the body. Moreover, while trainability of the capacity for endurance performance is quite high on the average, there are important individual differences in the sensitivity to endurance training. Recent data suggest that this sensitivity to aerobic training is largely genotype-dependent.