A quick chemical change in muscles after exercise doesn't tell us if those muscles will grow bigger over time, which means we can't use this early signal to predict long-term muscle growth.

In guys who are new to weightlifting, how strongly their muscles signal growth right after a workout (at the 5-hour mark) seems to predict how much muscle they’ll gain over the next 4 months.

When young men lift weights, if a specific protein in their muscles gets activated strongly exactly 5 hours after working out, they tend to build more muscle over the next 4 months—so this protein spike might tell us who’s going to grow the most from training.

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 if your body releases a lot of muscle-building hormones after a workout, that doesn’t mean you’ll grow bigger muscles any faster than someone whose body releases way less—because studies show both people end up with the same muscle gains.

Even if your body releases a lot more of the 'muscle-building' hormones after a workout, it doesn’t mean you’ll grow more muscle than someone whose hormone levels stay low—studies show both groups end up with the same muscle size.