When untrained young men lift heavy weights three times a week for five months, they get much stronger—some exercises more than double their original strength.

If you're a guy who's been lifting weights for a while, doing either 2 or 4 workouts per week for each muscle can boost your strength by about 8–11% in just 8 weeks—as long as you do the same total amount of work overall.

Lifting heavy weights fewer times, three days a week for a month, helps young active men build more muscle and get stronger than lifting lighter weights many times.

In people who have not previously trained, doing three sets of resistance exercises per movement for twelve weeks leads to a 25% increase in muscle strength and a 4.4% increase in muscle mass, compared to doing only one set per movement.

If young guys who already lift weights do intense leg workouts every day for two weeks, they get about 6% stronger in their leg press, showing their muscles and nerves adapt quickly.

People get noticeably stronger in just 4 weeks of heavy weightlifting—even before their muscles get bigger—because their nerves learn to fire better.