A single 10-minute bout of high-intensity interval training (HIIT) engages distinct skeletal muscle phosphorylation signaling networks compared to work-matched moderate-intensity continuous training (MICT), as revealed by a global phosphoproteomic analysis identifying over 8,500 phosphorylation sites.

High-intensity exercise makes muscles work much harder in short bursts, creating different chemical signals inside the muscle cells compared to steady moderate exercise. These signals switch on different protein helpers that attach tiny tags to many proteins, changing how the cells respond. The tagging patterns are so different that the muscle cells are told to do different things, like building more energy factories. The body does this by detecting the amount of effort and sending specific messages through the muscle tissue.