Comparison of blood lactate levels between treadmill running and over-ground running during incremental tests : A study on elite male runners

Sammanfattning: Tests to evaluate runners' aerobic capacity aiming to design training programs are often performed on a treadmill, while the training mainly takes place on over-ground surfaces. Studies have shown that different degrees of inclination on treadmills can compensate for the differences in heart rate (HR) response between running on treadmills and over-ground surfaces. The purpose of the study was to test whether the blood lactate concentration (BLC) differs between over-ground running and treadmill running at matched HR, and if so; can inclination of the treadmill be adjusted to generate equal BLC at matched HR? Eight male elite runners performed three incremental running tests where HR and BLC were measured; on a flat treadmill at six running velocities, on a running track at six velocities equal to the HR at test one, and on a treadmill at a fixed HR on different inclines (0°, 0.3°, 0.6°, 0.9°, 1.1° and 1.5°). The results revealed a non-significant trend indicating that over-ground running yields higher BLC at matched HR than treadmill running, and that 0.3° incline on treadmill correlated best with over- ground running. This study demonstrates a clear tendency of higher BLC at a given HR when running on an over-ground surface in comparison to running on a treadmill. Furthermore, a 0.3° incline on a treadmill is suggested to compensate for the difference in BLC at matched HR, between running on a treadmill and on an over-ground surface. However, more research with a larger sample size is needed to conclude and generalize the results.