5.5 Frequency: Distributing Volume Across the Week
The muscle protein synthesis (MPS) response to a training stimulus peaks around 24 hours and returns to baseline within ~36–48 hours in trained individuals [12]. Training a muscle once per week (the traditional “bro split”) leaves a long period at the end of the week with no elevated MPS, and—because muscle protein breakdown outpaces synthesis during this window—much of the anabolic potential of the training week is squandered. Spreading the same weekly volume across at least two sessions keeps MPS elevated more frequently and results in greater long‑term hypertrophy per unit of volume.