Individuals respond variable to nutritional strategies, such as ergogenic sports supplements like sodium bicarbonate or caffeine. A more personalized approach is recommended, however it is unknown which intra-individual factors cause these differences. Muscle fiber typology, the distribution of fast and slow skeletal muscle fibers, might be involved as both fiber types possess specific characteristics leading to different physiological outcomes and therefore, contributing to the metabolism of dietary supplements. In this project, we want to investigate if muscle fiber typology can explain the occurence of responders and non-responders to ergogenic sport supplements and if we can identify real responders and non-responders. To tackle these research questions, we will use a replicated randomized, double-blind, placebo-controlled crossover design were participants (both men and women) will be enrolled in 4 test days (2x supplement and 2x placebo) to counter day-to-day variability. Prior to this test period, screening of muscle fiber typology will be performed using non-invasive techniques, such as carnosine proton-magnetic resonance spectroscopy, femoral nerve electro stimulation and lactate post wingate. During the experimental period, subjects will consume supplements, such as sodium bicarbonate, caffeine, glucose, etc., and perform exercise tests.