If you’re looking to see how much muscle you can gain in a month, you’d be wise to focus on strength training first and foremost. “Muscle mass is increased through training and nutritional programming which, over a given period of time, can increase the size of the muscle fibers,” she explains. “Those exercisers who are genetically male may experience faster, seemingly easier increases in muscle growth when compared to females,” she says. “With high genetic potential, it may be possible for someone to gain up to two pounds of muscle mass in a month,” she says. Resistance Training RegularlyThe most important action you can take in building muscle mass, according to Crockford, is regular resistance training (heavy resistance training, to be exact).