Figure 1.

Hypothetical representation of ribosome and mitochondrial biogenesis and the respective signaling responses to endurance and resistance exercise in untrained and trained states. Untrained individuals present a more generic response to exercise, with increases in both 5' AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1) signaling with either endurance or resistance exercise, which may ultimately lead to a concomitant increase in ribosome and mitochondrial biogenesis. Upon training, the signaling responses to exercise seem to be attenuated and mitochondrial biogenesis is prioritized with endurance training, while ribosome biogenesis is prioritized with resistance training. Note that even in trained subjects, AMPK exhibits a more generic response to exercise compared to mTORC1.