Muscle growth is a slow process and takes both consistency and patience. Gaining 15 pounds of muscle in three months is difficult, let alone 50. Training, eating and supplementing properly can help accelerate what is naturally a slow process.
Muscles Are Important
You may want to gain muscle for aesthetic purposes. Having more muscle mass fills out your frame and can make you look leaner. Athletes who play contact sports like hockey or football gain muscle to perform better. Muscles also act as armor, cushioning blows from impact.
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Perhaps you just want to gain muscle to be a little healthier. A July 2018 study published in the British Medical Journal found that low levels of lean body mass, including muscle mass, are related to higher mortality rates. In other words, gaining muscle can help you fight many causes of death, particularly those stemming from health problems like heart disease.
Young people aren't the only ones who should be concerned with gaining muscle mass. Sarcopenia is a term for the gradual loss of muscle mass that comes with age. It's a common condition among adults, according to a February 2017 study published in Aging Clinical and Experimental Research.
Sarcopenia is associated with a lower quality of life and increased risk of death and disability. Older people should focus on building muscle to prevent the natural loss that occurs with age.
How Muscles Grow
Although your muscle tissue is made of protein, there's actually very little protein in your muscles. In fact, a majority of your muscle mass is liquid. Roughly 76 percent of your muscles is water or other liquids, according to an August 2019 study published in the journal Nutrients.
When you lift weights, you gain more muscle mass. This simply means that your muscle, as a whole, is getting bigger. However, not all of that growth is from the actual muscle tissue. Your body recruits more water and fluid too. It also accumulates more substances that give the muscle energy to contract, like glycogen from carbohydrates and triglycerides from fat.
The American Council on Exercise explains that there are two main ways a muscle can grow. The terms they use are sarcoplamic or myofibrillar hypertrophy. Hypertrophy just means that the muscle is growing.
Sarcoplasmic hypertrophy means that the sarcoplasm of muscle cells is getting bigger. The sarcoplasm is the actual fluid in the cell, which means that it's accumulating more fluid. Myofibrillar hypertrophy is when the actual muscle fibers are getting thicker.
Researchers generally measure something called lean body mass (LBM) when they calculate muscle growth. LBM is the amount of muscle and bone in your body, according to the Centers for Disease Control and Prevention.
Scientists can get more accurate measurements of muscle mass by using tools like magnetic resonance imaging and dual-energy X-ray absorptiometry. These are two of the most accurate tools to assess muscle mass, according to a June 2018 study published in the Journal of Investigative Medicine.
Read more: Your Ultimate Guide to Gaining Lean Muscle
Differences in Muscle Growth
When you read about increases in muscle mass from training, keep in mind that this is usually measured as the increase in lean body mass, which doesn't necessarily mean that the muscle itself is growing. It simply means that the non-fat tissues are getting bigger.
People gain muscle at different rates, according to an article from the American Council on Exercise. Variables like age and gender affect how quickly people gain muscle mass. For example, a 20-year-old male will likely gain muscle faster than a 50-year-old woman. There are factors within your control, like training and diet, but there are also many things you can't control.
Genetics play a role in how much muscle mass you can gain from resistance training. A December 2018 study published in Sports Medicine looked at the phenomenon of "non-responders to exercise." While everyone is capable of building muscle, some people require much more effort and time in the gym.
The authors explain that everyone responds differently to exercise, including how much muscle mass and strength they gain from a resistance training program. Those who have trouble gaining muscle can increase the volume, intensity or duration of their workouts. In other words, some people will simply have to work harder to gain muscle.
Studies like these show that everyone has a different rate at which they build muscle. The question is not how much muscle people can build in three months; the question is how much you, specifically, can gain.
Working with what you can control is the best way to gain muscle quickly. Your training plan and nutrition are things you can tweak to maximize muscle growth. As far as training goes, you should focus on lifting weights.
How Much Growth Is Possible?
A January 2019 study published in the European Journal of Applied Physiology compared muscle growth in subjects who lifted weight to those who did cardio. Over the eight-week training period, the people who lifted weights gained an average of 1.3 kilograms of lean body mass, whereas the people who did cardio gained none.
Keep in mind that 1.2 kilograms comes out to roughly 2.5 pounds. That was over eight weeks, and the study was conducted on men who averaged 28 years of age. That means that over three months, you might see up to 4 pounds of muscle gained, which is nowhere near 50.
It's unheard of for young men to gain 50 pounds of muscle in three months, so other populations would have an even tougher time. A December 2016 study published in Biogerontology looked at protein supplementation and resistance training in women, ages 50 to 70. The researchers put the women on a 12-week resistance training program and gave them protein supplements.
They found that, on average, less than half a pound of lean body mass in the legs was gained over the course of the study. This is a strikingly small amount, and it shows how difficult it is for different populations to gain muscle.
To put things into perspective, a September 2014 study published in PLOS One examined the effects of anabolic steroids on muscle gain. While steroids are illegal and dangerous and should never be consumed, the study provides insight into how much muscle the human body can gain with artificial aids.
In the study, the researchers compared two groups of men. Both groups trained for 12 weeks. One group used steroids and the other did not. The drug-free group gained roughly 4 kilograms of lean body mass in their legs, which is about 9 pounds. The group using steroids gained twice that amount, totaling about 18 pounds of growth each.
This study shows that even with an illegal aid, the maximum amount of muscle the human body can gain over three months is about 18 pounds. Since steroids are out of the question, you'll have to use proper training and diet techniques to gain as much muscle as possible.
Basics of Muscle Building
Resistance training is the best form of exercise if you want to gain muscle. It can involve lifting barbells, dumbbells or kettlebells, or working with resistance bands or cable machines. You might want to seek professional help from a personal trainer or physical therapist to make sure you use proper technique before beginning a weight-training program.
Read more: Kettlebells vs. Dumbbells
According to the U.S. Department of Health & Human Services, adults should train each muscle group at least twice per week. That means you can do two full-body workouts per week or split them up and do a different body part each day.
The National Strength and Conditioning Association recommends that beginners get in two to three training sessions per week. Intermediate trainees can train three days per week, if they use full-body workouts, or four days per week if they split their routines. A split routine means you focus on a different body part for each workout. For example, you could do two days of leg workouts and two days of upper-body workouts.
Read more: The Best Way to Gain Lean Muscle Mass
Advanced trainees should have four to six sessions of resistance exercise each week. They can even train multiple times per day. While frequency is important, something called "training volume" is perhaps the most important thing to keep in mind.
A May 2018 study published in Sports Medicine looked at how important training frequency — the number of times you train per week — is for building muscle. They found that it doesn't really matter, as long as volume is held constant.
Volume is the product of the number of sets, reps and weight that you use for each exercise. For example, if you squat with 20 pounds for 3 sets of 10 reps, your volume is 600 (20 times 3 times 10). In other words, it doesn't matter if you spread your squats out over different days of the week, as long as you're increasing your total volume over time.
To increase your volume, you can do more sets or reps, add more weight or even do a combination of all three. You can also work out more often, as long as the extra days allow you to increase your total weekly training volume.
Nutrition for Muscle Growth
Training helps, but diet is also important. While you can put time and effort in at the gym, you also have to give your body the resources it needs to recover.
Eating more calories is often recommended to gain more muscle. According to a December 2017 paper published in the International Journal of Exercise Science, the extra muscle mass gained is probably from water. If you want to gain more muscle, you should increase your protein intake.
An article from the American College of Sports Medicine (ACSM) says that the generally recommended protein intake for adults is 0.8 grams daily per kilogram of body weight. For a 150-pound person, that's a minimum of 54 grams of protein per day.
However, the ACSM recommends that active people, including those on weight-training programs, eat more protein. Aim for between 1.2 and 1.7 grams of protein per kilogram of body weight per day. For a 150-pound person, that's between 82 and 116 grams.
- American College of Sports Medicine: "Protein Intake for Optimal Muscle Maintenance"
- Sports Medicine: "Effect of Resistance Training Frequency on Gains in Muscular Strength: A Systematic Review and Meta-Analysis."
- National Strength and Conditioning Association: "Determination of Resistance Training Frequency"
- U.S. Department of Health & Human Services: "Physical Activity Guidelines for Americans"
- PLOS One: "Effects of Long Term Supplementation of Anabolic Androgen Steroids on Human Skeletal Muscle"
- Biogerontology: "Twelve Weeks’ Progressive Resistance Training Combined With Protein Supplementation Beyond Habitual Intakes Increases Upper Leg Lean Tissue Mass, Muscle Strength and Extended Gait Speed in Healthy Older Women"
- European Journal of Applied Physiology: "Comparison of Changes in Lean Body Mass With a Strength- Versus Muscle Endurance-Based Resistance Training Program"
- Sports Medicine: "Do Non-Responders to Exercise Exist—and If So, What Should We Do About Them?"
- American Council on Exercise: "How Muscle Grows"
- Journal of Investigative Medicine: "Advanced Body Composition Assessment: From Body Mass Index to Body Composition Profiling."
- British Medical Journal: "Predicted Lean Body Mass, Fat Mass, and All Cause and Cause Specific Mortality in Men: Prospective US Cohort Study"
- Aging Clinical and Experimental Research: "Sarcopenia: An Overview"
- Centers for Disease Control and Prevention: "About Adult BMI"
- Nutrients: "The Role of Water Homeostasis in Muscle Function and Frailty: A Review"
- American Council on Exercise: "10 Things to Know About Muscle Fibers"
- International Journal of Exercise Science: "The Effects of Overfeeding on Body Composition: The Role of Macronutrient Composition – A Narrative Review"