Scientists compare two exercise styles to see which wears you out faster

This study looked at how the body uses energy during two types of leg exercises—eccentric (lengthening muscles) and concentric (shortening muscles)—done until exhaustion. Fourteen healthy young women exercised on a special machine at moderate and then high effort. Researchers measured oxygen use, muscle oxygen, and blood lactate to understand the metabolic differences. This is a basic science study, not a treatment trial.