A computational model predicts that muscle hypertrophy requires a lag of several weeks due to the slow accumulation of ribosomes, which are sterically hindered by the dense myofilament lattice, and that this delay explains why muscle growth is not immediately visible after starting resistance training.

When you lift weights, the stretching of muscle fibers pulls on a special protein called titin, which acts like a molecular switch. This switch turns on a signal that tells the cell to make more protein-making machines called ribosomes. But these machines can't move easily through the crowded space inside muscle fibers, so it takes weeks for enough of them to build up before the muscle can start growing visibly.