Fig. 5. Microadaptations of transcript expression relate to the training effect. Model of the increase in (mitochondrial) RNA and endurance performance with repetition of exercise. Each bout of exercise leads to an overshoot of transcript levels in the recovery phase from fatiguing exercise (RNA), which leads via translation to a microadaptation of the encoded protein and related structure. This relays to the gradual accumulation () of mitochondrial volume density and the improved oxidative capacity with repetition of endurance exercise. A match of transcriptional, structural and functional parameters is observed in recruited muscle groups between untrained and endurance-trained steady states. Black stippled and solid lines indicate the evolution of RNA levels and performance, respectively, during the training.