Reproducibility and responsiveness between separate measurements of running energy cost of transport

Method

Each volunteer performed two running assessments, on a treadmill, on two different days, according to running speed tested: a setup at 8.5 km∙h-1 and another at 14.2 km∙h-1. Three measurements of CoT in each setup were made. Pulmonary gas exchange was assessed breath by breath using a gas analyzer and CoT, in J∙kg-1∙s-1, determined following previous methodologies.

Reproducibility was represented using intraclass correlation coefficient (ICC) and responsiveness using minimum detectable difference (MDD). Comparisons were made using generalized linear models. Results: Participants were five proficient male long-distance runners.

The ICCs between CoT measurements were excellent. The CoT at 14.2 km∙h-1 (3.6 J∙kg-1∙s-1) was higher than that at 8.5 km∙h-1 (3.4 J∙kg-1∙s-1). However, the mean difference between CoT obtained (0.2 J∙kg-1∙s-1) in both setups was lower than the MDD (0.4 J∙kg-1∙s-1).

Conclusions: Reproducibility for CoT between two different velocities was high, but the responsiveness was not good, indicating necessary changes in CoT, whether increased or decreased, to be around 12% considering that they are not consequences of individual variations or measurement errors.