For guys who don’t lift regularly, doing weight exercises doesn’t change a specific body signal (ERK1/2) 30 minutes after working out, no matter how hard or long they train — so this signal probably isn’t what tells their muscles to grow right after a fasted workout.

When guys who don’t work out lift weights, their muscles turn on a specific stress signal—no matter if they do 1 set or 5 sets. It’s like the signal just needs the weight to be lifted, not how many times they do it.

Even after working out with weights for 8 weeks, your muscles still respond to a single workout the same way as they did at the start—your body doesn’t get better at signaling muscle growth after training for a while.

When guys who don’t lift regularly do weight training, even doing more sets doesn’t change certain key muscle signals called Akt and mTOR—so those signals must already be maxed out at low workout levels, and something else is driving the bigger changes seen in other muscle signals.

When you lift weights, your muscles temporarily stop building protein, but right after you finish, they kick into high gear to repair and grow—this happens because key signaling molecules in your muscles get activated during recovery.

Even though your muscles get a signal to slow down energy use after lifting weights, they still keep building protein—like your body’s repair crew is ignoring the ‘slow down’ sign because the ‘build up’ signal is stronger.