After a single workout with weights, your muscles temporarily slow down their protein-building process, and this might be because a specific energy-sensing molecule (AMPK) gets more active and tells the building machinery to take a break.

In healthy young adult males and females, a single bout of resistance exercise (e.g., 4 sets of 8–10 reps at 75–80% 1RM) is compared to a rest control condition on separate days. Muscle biopsies are taken immediately post-exercise and post-rest to measure AMPKα2 activity, 4E-BP1 phosphorylation at Thr37/46, and muscle protein synthesis rates via stable isotope labeling (e.g., D2O or L-[ring-13C6]phenylalanine).

Healthy young adults undergo a single resistance exercise session under two conditions: (1) placebo and (2) systemic AMPK inhibition (e.g., compound C or AICAR washout). Muscle biopsies are taken pre- and post-exercise to assess whether blocking AMPK activity prevents the observed reduction in 4E-BP1 phosphorylation and the decline in muscle protein synthesis.

In healthy young adults, muscle biopsies are collected before and immediately after a single resistance exercise session to simultaneously quantify AMPKα2 activity, 4E-BP1 phosphorylation status, MPS rates, and downstream anabolic pathway markers (e.g., mTORC1, S6K1) using multiplexed proteomics and phosphoproteomics to determine if changes in AMPKα2 activity correlate with reduced 4E-BP1 phosphorylation and MPS.

Human primary myotubes or C2C12 cells are subjected to mechanical stretch (simulating resistance exercise) and assessed for AMPKα2 activation, 4E-BP1 phosphorylation at Thr37/46, and protein synthesis rates under controlled nutrient conditions to determine if mechanical stress alone reproduces the observed molecular and synthetic responses.

A small group of healthy young adults undergoes a single resistance exercise session while undergoing continuous metabolic monitoring (e.g., indirect calorimetry, blood lactate, ATP/AMP ratios) and serial muscle biopsies to determine whether the timing of AMPK activation, 4E-BP1 dephosphorylation, and MPS suppression aligns with the peak in cellular energy demand.