Two-Week Volume Sprint
He explains the POS1 study where participants doing 32 sets per exercise per week gained 23% more CSA than those doing 10 sets. This was largely due to increased cycloplasmic proteins, intracellular water, and glycogen, which persisted ~8 days. The supercompensation effect occurs because the body anticipates higher training demands and stores more glycogen, pulling water along. The higher ATP demand during high volume increases cycloplasmic enzymes (creatine phosphate, etc.), which later support greater energy production for future training. The swelling from the pump stretches integrins, which are mechanosensors that activate MAPK and mTOR signaling to initiate permanent protein synthesis. Thus, temporary sarcoplasmic expansion can seed lasting myofibrillar growth. He suggests that you don't need to sustain high volume; occasional spurts are enough to reap these adaptations, aligning with Dr. Mike Israetel's block periodization concepts. The key is to layer this stimulus on top of standard mechanical tension training. He emphasizes not to go high volume all the time to avoid burnout.
High volume increases intramuscular ATP turnover and cycloplasmic enzyme concentration; glycogen supercompensation draws water into muscle, expanding sarcoplasm; swelling stretches integrin mechanosensors, activating mTOR and satellite cell fusion; increased blood flow from VEGF signaling (via metabolic component) aids protein synthesis.
you could do like your standard model of training with whatever volume you usually do and do a two week sprint of high volume, not just for mechanical and myofibrillar growth, like we talked about first, but this temporary growth that you might see that's really kind of cool.