When young men do one set of really tiring weightlifting, it gives the smallest boost to muscle-building signals right after exercise, compared to doing max-stretch moves or multiple sets that take the same total time.

When young men do a specific type of hard strength training, their bodies send strong signals to build muscle for hours afterward.

When young men do a specific type of hard weight training that focuses on lowering weights slowly, it triggers more muscle-building signals in their bodies compared to other common workout styles, even if the workout time is the same.

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.

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 you lift weights, how hard you push or pull (the force) matters more for muscle growth signals than how long you hold the weight, based on comparing workouts that take the same time but use different amounts of force.