Does Flexing Build Muscle? 5 Benefits Of Tensing Your Muscles

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When you’ve been working hard in the gym, there are few things more fun and gratifying than periodically checking out your physique in the mirror by flexing your muscles

Whether you like to flex your biceps or maximally extend your leg to flex your quad, tensing or flexing your muscles is a great way to see your progress.

But are there any other benefits of flexing your muscles? Does flexing help build muscle? Does flexing abs build muscle?

In this article, we will answer your question, “Does flexing build muscle?” and discuss the benefits of flexing your muscles and whether flexing or tensing your muscles can actually help build muscle.

We will cover: 

  • Does Flexing Build Muscle?
  • 5 Benefits of Flexing Your Muscles
  • Is Flexing Your Muscles Enough to Build Muscle?

Let’s get started!

A person flexing their bicep.

Does Flexing Build Muscle?

So, does flexing help build muscle?

Flexing your muscles involves contracting or tensing your muscles and holding the contraction.

We often think of flexing muscles as just a way to make our muscles “pop” to see the gains from strength training workouts. 

But does tensing build muscle? Does flexing abs build muscle?

Perhaps surprisingly, tensing or flexing your muscles isn’t just a way to check yourself out.

Flexing your muscles can help increase strength and may potentially help build muscle.

Muscles can be strengthened when they contract.

A person flexing their biceps at the gym.

For example, when you perform a biceps curl, your muscles first contract concentrically (shortening) as you lift the weight towards your shoulders and then contract eccentrically (lengthening) as you lower the weight back down.

Flexing muscles also involves performing a type of muscle contraction called an isometric contraction.

Isometric contractions refer to muscle contractions in which you contract your muscles so they are doing work, but no movement occurs. 

A good example of an isometric exercise is a plank.

When you perform a plank, you are tensing the muscles in your abs, glutes, shoulders, and even the muscles in the upper back, chest, and arms to some degree.

In isometric exercises and isometric muscle contractions, the muscles are still working and resisting force even though the contractions aren’t moving the joints.

A person flexing their biceps.

5 Benefits of Flexing Your Muscles

There are several potential benefits of flexing your muscles:

#1: Flexing Your Muscles Can Strengthen Your Muscles and Improve Joint Stability

Flexing your muscles tenses the muscle fibers, meaning that you generate muscle tension.

The longer you tense or flex your muscles, and the harder you squeeze as you contract, the more work your muscles are doing.

In this way, flexing can strengthen your muscles, and depending on your current level of strength, and how much flexing you do, it may also help build muscle.

Many people are particularly interested in whether flexing your abs builds muscle. Flexing or tensing your abs can strengthen your core, as is the case when you contract your abs during an isometric plank hold. 

As long as you have a healthy spine and no contraindications to flexing your spine, you can also contract or flex your abs in the contracted portion of a crunch. Holding this contraction as an isometric hold will also help strengthen your abs.

A person flexing their upper body.

#2: Flexing Your Muscles Can Improve Posture and Spine Health

Many people have jobs or lifestyles that require them to sit for long periods of time at a desk. The core muscles and postural muscles that help support the spine and encourage optimal posture can fatigue, leading you to slouch.

Isometric exercises, such as planks, side planks, and reverse planks, as well as flexing your abs, can strengthen your core muscles and lower back muscles. This can help improve the fatigue resistance of these supportive muscles, helping you maintain proper spinal alignment and good posture for longer periods of time.

#3: Flexing Your Muscles Can Strengthen Muscles During and After Injuries

If you have an injury to a mobile joint, such as when you are recovering from a rotator cuff repair in your shoulder or an ACL or meniscus repair in the knee, there is usually a period of time during the postoperative period in which you cannot use your joint or at least are not permitted to move your joint through the normal range of motion.

In the case of knee surgery, for example, you might not be cleared to perform squats and lunges for quite some time. However, you can still perform isometric rehab exercises to help maintain the muscle strength in your surrounding muscles.

For example, you can lie on your back or sit up straight with your leg extended in front of you. Then, you can flex your quads and hold the squeeze, performing slow reps of quad muscle isometric contractions.

A person flexing their biceps.

#4: Flexing Your Muscles Can Reduce Blood Pressure

Performing isometric exercises, such as flexing or tensing your muscles, has been shown to help reduce systolic and diastolic blood pressure.

When incorporated into a well-rounded fitness program, adding isometric holds is a great way to help reduce the risk of hypertension.

Note that strength training, in general, has also been shown to improve cardiovascular health and reduce the risk of type 2 diabetes.

#5: Flexing Your Muscles Can Be Done Anytime and Anywhere

Although you certainly aren’t going to get all of the same muscle-strengthening benefits from just flexing your muscles as you would if you hit the weights at the gym or even do a dynamic bodyweight circuit at home, when you are traveling or just want to add a little bit of exercise sprinkled into your day, you can tense your muscles anytime and anywhere. 

You don’t need exercise equipment, and you don’t even need space to move your body. You can be in an airplane seat, driving to work, standing in line at the grocery store, lying in bed, or even brushing your teeth. You can flex your glutes, flex your abs, flex your biceps and triceps, flex your quads, etc. 

In this way, flexing your muscles can be a good alternative when you can’t fit in a formal workout and can be a way to boost your fitness by activating your muscles throughout the day outside of your planned workout sessions.

A person flexing their upper body at the gym.

Is Flexing Your Muscles Enough to Build Muscle?

It’s important to note that just flexing your biceps in the mirror before you take a shower or tensing your butt as you stand in line at the store is not enough to build muscle.

Firstly, you’ll want to perform isometric exercises like planks, glute bridges, and wall sits.

These exercises require your muscles to contract and hold tension under a load—your body weight and gravity.

More importantly, to effectively build more muscle, you’ll need to include other resistance training exercises that do use weights and do involve movement.

One of the primary shortcomings of isometric exercises, both in terms of increasing strength and building muscle, is that the muscles remain in the same position throughout the duration of the exercise. 

A person flexing their bicep.

This means that the muscles are being strengthened in just this one position rather than throughout their entire range of motion. While isometric exercises can help improve stability around a joint, they do not improve mobility, and they will not strengthen all of the muscle fibers in a muscle equally. 

Because no movement is occurring, isometric exercises also don’t necessarily translate to increase functional strength. You will develop strength in certain places but not throughout the usable range of motion. 

For this reason, it’s really important to incorporate other dynamic resistance training exercises that do place your muscles under tension throughout the range of motion so that they develop functional strength.

Additionally, when you actually want to build muscle or increase the size of your muscles, you need to overload your muscles enough to stimulate muscle protein synthesis.

Workouts targeted at building muscle, termed hypertrophy training, typically involve high volume and moderate to heavy loads.

A person flexing their bicep.

Most strength training experts suggest using a weight or load that is at least 65 to 85% of your one-repetition maximum (1RM) for an exercise for three sets of 8-12 reps when your goal is hypertrophy.

Therefore, just flexing your muscles or doing isometric exercises is unlikely to elicit the stimulus you need to trigger muscle growth. 

You will want to add weights and do more reps and sets.

Overall, flexing your muscles can be more than just an “exercise” in vanity; there are benefits to flexing. However, just tensing your muscles isn’t going to build muscle, so you’ll want to include other exercises in your workout program.

To get started on a program, check out our strength training guides for more information.

A person flexing their bicep.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

1 thought on “Does Flexing Build Muscle? 5 Benefits Of Tensing Your Muscles”

  1. You can’t grow muscle from flexing. To grow muscle you must put your muscles under mechanical tension (load) and progressively increase that load or repetitions over time. Because flexing your muscles doesn’t offer any actual resistance, your muscles will NOT grow from it.


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