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ISSA, International Sports Sciences Association, Certified Personal Trainer, ISSAonline, What Is Hypertrophy? Definition, Types, Training Tips & More

What Is Hypertrophy? Definition, Types, Training Tips & More

Reading Time: 5 minutes 54 seconds


DATE: 2021-11-04

People exercise for a variety of reasons. They may engage in cardio because they want to make their heart muscle stronger. Maybe heart disease runs in their family and they’re willing to put in the work to reduce their risk. Or they focus on strength training because they want to improve their physique. They’re tired of feeling self-conscious at the beach.

Drilling down a client’s fitness goal helps trainers know what type of exercise routine will offer the desired results. In some cases, this result may be muscle hypertrophy.

What Is Hypertrophy?

Hypertrophy is an increase in muscle size. It involves building muscle so it gets bigger. This is different than training to increase muscle strength. While muscle may still get stronger with hypertrophy training, that isn’t the primary goal. The goal is bigger muscle.

If a client says that they want muscle growth, does this automatically mean that they want hypertrophy? Not necessarily. Certainly, they may mean that they want to increase the size of their muscle mass. But they might also mean that they want to grow their muscle strength. Asking for clarification can help determine their ultimate goal.

2 Types of Muscle Hypertrophy

To make the issue a bit more complex, there are two types of skeletal muscle hypertrophy:

  • Myofibrillar hypertrophy. This type of muscular hypertrophy involves an increase in the number of protein filament bundles known as myofibrils. Myofibrils help the muscle contract and relax. Increasing myofibrils boost muscular strength. With myofibril hypertrophy, the muscle also becomes more dense.

  • Sarcoplasmic hypertrophy. You can also increase the volume of fluid within the muscle. This is called sarcoplasmic hypertrophy. This fluid provides the energy the muscle needs during weight training. Similar to how adding water to a balloon makes the balloon grow, more fluid in the muscle makes it look bigger.

Technically, there is another type of hypertrophy: cardiac hypertrophy. This refers to an increase in heart muscle mass. While this increase is sometimes a result of intense physical activity, it can also be caused by stress, hypertension, or heart attack. Research indicates that these non-exercise causes can potentially lead to heart failure. Genetics can play a role in cardiac hypertrophy, as well. If the heart has abnormal genes, the chamber walls can become abnormally thick. This is a condition called hypertrophic cardiomyopathy and reduces blood flow in the heart.

Certainly, any type of cardiomyopathy—or disease of the heart—is important (and serious). Yet, for the purposes of this article, we will focus solely on muscular hypertrophy.

Muscular Hypertrophy Benefits

From a vanity standpoint, bigger muscles can create a more appealing physique. This is particularly true for competitive bodybuilders, where muscle size is valued over muscle strength. Though, people not involved in bodybuilding can benefit as well. They might feel more comfortable wearing tank tops with larger shoulder and arm muscles, for instance.

Since muscle burns more calories than fat, bigger muscles equal a greater number of calories burned throughout the day. This benefits people who are trying to lose weight. It helps turn their body into more effective fat-burning machines.

Plus, we typically lose muscle tissue as we age. This is referred to as muscle atrophy. (Though, you can also experience atrophy if you are relatively sedentary). One way to help combat this is by increasing muscle size via a regular resistance training program.

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Factors That Affect Muscle Growth

A person’s ability to increase the size of their muscle mass is impacted by a variety of factors. Genetics is one. This growth factor dictates how fast you can achieve muscle growth. It also affects how much you are able to boost muscle size.

Another factor to consider is the ratio of muscle fiber types. People have differing amounts of type I and type II muscle fibers. Type I fibers are often associated with endurance whereas type II fibers are connected with strength. So, someone with more type II fibers is thought to have an easier time increasing the size of their skeletal muscle.

Though, it should be noted that some research refutes this. For instance, one article in the Strength and Conditioning Journal reports that type I fibers can also play an important role in muscle gain. That is, as long as they are targeted with low-load training.

Muscle growth potential is also impacted by one’s musculoskeletal makeup. For instance, the shorter the tendons, the greater the ability to increase muscle size. Science Daily goes as far as to say that “tendon length is practically the discerning factor where muscle size and potential muscle size is concerned.”

One look at this list can leave you feeling defeated. You can’t, after all, change your genes or musculoskeletal makeup. You also have a limited ability to affect your muscle fiber types. Yet, the one factor that you do have control over that can improve the size of your muscle mass is your workout schedule and type. Though, it’s important to recognize that strength training and hypertrophy training are not the same.

Strength Training vs Hypertrophy Training: What’s the Difference?

There are many training differences depending on whether the goal is to increase muscle strength or size. One is the recommended load. If the goal is to boost strength, the load should be greater than 85% of the one-rep max (1RM). If muscle hypertrophy is the goal, the load is a bit lower, or somewhere between 67% and 85% of the 1RM.

Another training difference is the number of reps. A workout designed to increase muscle strength typically involves doing fewer reps (six or less). Conversely, resistance training focused on muscle size means more reps (six to 12).

Differences such as these highlight why it is so important to know the ultimate exercise goal. This goal will dictate what type of exercise plan should be followed.

Hypertrophy Training Strategies

How do you maximize hypertrophy if the goal is bigger muscles? Here are a few strategies to consider:

  • Engage in strength training regularly. You can’t just work a muscle once and expect it to grow. It needs to be stressed repeatedly over time. Resistance training two to three times per week can provide the tension needed for the muscle to adapt and grow.

  • Increase resistance over time. Starting with lighter weights gives the muscle time to adjust to a new weight training program. But once that weight becomes easy to lift, it needs to be increased if the goal is hypertrophy. The general rule is to increase the weight being lifted by no more than 5-10% to prevent injury.

  • Aim to overload the muscle or muscle group. If you walk out of your weight training sessions feeling as if you could go through the sets and reps again, you’re not overloading your muscle enough. While you don’t want to go to the point of pain, growing muscle requires a certain level of overload. During your workout, aim to push your muscle as much as you can while still being safe.

  • Lift heavy for higher reps. A hypertrophy workout involves lifting fairly heavy weights. You also want to shoot for higher reps than if your goal was strength. Again, you have to overload the muscles to a certain extent if you want them to grow.

  • Reduce your rest periods. The amount of rest time between sets changes based on whether the goal is to increase muscle size or strength. For strength increases, the recommended rest period is generally between two and five minutes. To increase muscle size, this period is shortened to 30 to 90 seconds.

  • Allow adequate time for muscle recovery. Adequate recovery is critical to building bigger muscles. It is during this recovery that muscle damage is repaired. Therefore, if you don’t allow enough time for this repair to occur, not only will muscles not reach their maximum size, but you also risk injuring them. Allow 24 to 48 hours before working the same muscle group again.

  • Eat your protein. Research indicates that achieving muscle hypertrophy requires balancing muscle protein synthesis and muscle protein breakdown. Additionally, consuming protein within 24 hours of weight training can provide a positive net balance. This net balance supports muscle growth. Follow your workouts with higher protein meals or shakes to give the body the nutrients it needs to achieve maximum hypertrophy.

Again, while anyone can have a goal to increase muscle size, this aspect of fitness is often more important to those involved in bodybuilding. If this is your desired clientele as a trainer, ISSA offers Bodybuilding Specialist certification. This course teaches you how to maximize results for clients engaging in this sport for fun or competition.

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