When you lift weights, the pulling force on your muscles is what makes them grow bigger—not because of hormones or feeling burned out, but because your muscles sense the tension and respond by building more muscle fibers.

In healthy adult humans, compare muscle hypertrophy after resistance training with mechanical tension isolated via load-controlled devices (e.g., isokinetic machines with variable resistance) versus matched training with added hormonal suppression (e.g., GnRH analogs) or metabolic inhibition (e.g., lactate blockers), measuring myofibrillar protein synthesis via stable isotope labeling over 12 weeks.

In human skeletal muscle biopsies taken pre- and post-resistance training, assess activation of mTORC1, FAK, and YAP/TAZ via phospho-protein arrays and nuclear localization, while pharmacologically inhibiting each pathway individually (e.g., rapamycin for mTORC1, FAK inhibitor, verteporfin for YAP/TAZ), to determine if hypertrophy is blocked despite preserved mechanical tension.

Compare muscle hypertrophy in humans undergoing two matched resistance training protocols: one maximizing mechanical tension (heavy load, slow eccentric) and another maximizing metabolic stress (light load, blood flow restriction), with identical volume and frequency, to determine if tension alone drives hypertrophy without metabolic stress.

In humans with genetic variants or CRISPR-edited muscle cells (ex vivo) lacking key mechanosensors (e.g., integrin β1, FAK, or YAP), measure whether resistance training fails to induce myofibrillar protein accretion despite normal mechanical tension exposure.

Track resistance-trained individuals over 6 months using wearable sensors to quantify mechanical tension (force x time) during each session, and correlate it with longitudinal changes in muscle mass and protein synthesis rates, while controlling for hormonal and metabolic biomarkers.