Mitochondrial respiration is the most important generator of cellular energy under most circumstances. It is a process of energy conversion of substrates into ATP. The Seahorse equipment allows measuring oxygen consumption rate (OCR) in living cells and estimates key parameters of mitochondrial respiration in real-time mode. Through use of mitochondrial inhibitors, four key mitochondrial respiration parameters can be measured: basal, ATP production-linked, maximal, and proton leak-linked OCR. This approach requires application of mitochondrial inhibitors-oligomycin to block ATP synthase, FCCP-to make the inner mitochondrial membrane permeable for protons and allow maximum electron flux through the electron transport chain, and rotenone and antimycin A-to inhibit complexes I and III, respectively. This chapter describes the protocol of OCR assessment in the culture of primary myotubes obtained upon satellite cell fusion.