Mechanical energy on anaerobic capacity during a supramaximal treadmill running in men: Is there influence between runners and active individuals?

Abstract

This study verified whether mechanical variables influence the anaerobic capacity outcome on treadmill running and whether these likely influences were dependent of running experience. Seventeen physical active and 18 amateur runners, males, performed a graded exercise test and constant load exhaustive running efforts at 115% of intensity associated to maximal oxygen consumption. During the constant load were determined the metabolic responses (i.e., gas exchange and blood lactate) to estimate the energetic contribution and anaerobic capacity as well as kinematic responses. The runners showed higher anaerobic capacity (16.6%; p = 0.005), but lesser time to exercise failure (-18.8%; p = 0.03) than active subjects. In addition, the stride length (21.4%; p = 0.00001), contact phase duration (-11.3%; p = 0.005), and vertical work (-29.9%; p = 0.015). For actives, the anaerobic capacity did not correlate significantly with any physiologic, kinematic, and mechanical variables and no regression model was fitted using the stepwise multiple regression, while to runners the anaerobic capacity was significantly correlated with phosphagen energetic contribution (r = 0.47; p = 0.047), external power (r = -0.51; p = 0.031), total work (r = -0.54; p = 0.020), external work (r = -0.62; p = 0.006), vertical work (r = -0.63; p = 0.008), and horizontal work (r = -0.61; p = 0.008), and the vertical work and phosphagen energetic contribution presented a coefficient of determination of 62% (p = 0.001). Based on findings, it is possible to assume that for active subjects, the mechanical variables have no influence over the anaerobic capacity, however, for experienced runners, the vertical work and phosphagen energetic contribution have relevant effect over anaerobic capacity output.

Keywords: blood lactate; excess postexercise oxygen consumption; mechanical work; non-mitochondrial metabolic pathways; physical fitness level; time to effort failure.

FIGURE 1

The (a) shows the mean and standard deviation of time to effort failure (TTE) recorded in the constant‐load supramaximal effort at 115% of vV̇O_2max and the (b) shows the oxygen equivalents estimated from the oxidative (E _OXID), glycolytic (E _[La ⁻ _]), and phosphagen (E _PCr) metabolisms as well as the anaerobic capacity. In both panels, each symbol represents one participant.

FIGURE 2

Conceptual model summarizing the findings. While no relationships were observed between physiologic, kinematic, and mechanical variables for the active group, the runners group show a correlation between vertical mechanical energy (influencing external mechanical work, and consequently, total mechanical work) and anaerobic pathways energy contribution. This result evidence the relevant influence of mechanical and kinematic variables on anaerobic energy expenditure (highlighted in red).