The intercostal muscles are the muscles that are between your ribs, there are three types of intercostal muscles; External, Internal, and Innermost.
The external intercostals are used when breathing in, the internal intercostals are used when breathing out, and the innermost intercostal muscles also help with breathing out. The three layers of intercostal muscles help make up the chest wall.
The muscles themselves are often overlooked by gym goers and sports performers, as they aren’t exactly mirror muscles. But there are actually a lot of benefits to working on them.
The stronger your intercostal muscles are the more efficient your respiratory system will be, your lungs will be able to expand more, which means that you can increase your inspiration and expiration.
This can help you improve your cardiovascular performance in sports, and help you in the gym.
Exercises to Improve Intercostal Muscle Strength
In this section we will look at weighted exercises that can improve your intercostal muscles, we will be looking at alternative ways to strengthen them later on in the article.
Lie on a bench or on a Swiss ball and hold a single dumbbell above your chest using two hands.
Take a deep breath and then bring the dumbbell backwards until your arms are parallel to the floor.
Breathe out forcefully and pull the dumbbell over in an arc until the dumbbell is resting over your chest again. Pause, and then repeat the movement.
This exercise is probably the best exercise for strengthening the intercostal muscles as it really expands the chest throughout the movement.
If you are performing this on a Swiss ball then you will have even more range of motion, just make sure that you have good balance, the last thing you want to do is fall off!
Basically the same exercise as the dumbbell version but you can perform this with a slightly wider grip (obviously).
Instead of lying on the bench vertically like you normally would, lie on it horizontally with your lower back unsupported and just your upper back touching the bench.
Then hold the bar over your chest and pull backwards until your arms are parallel to the floor. Pause and then breathe out heavily as you pull the bar over until it is resting above your chest again.
Dumbbell Chest Fly
According to Jen Weir of azcentral.com  a great exercise for stretching the intercostal muscles is the dumbbell chest fly.
Lie on a bench holding a dumbbell in each hand. Hold the weights above your chest using a neutral grip. Create a slight bend in your arms, but keep them mostly straight.
Breathe in and then pull the weights apart bringing your arms out until your chest is fully stretched. The weights should be around parallel to the floor. Breathe out and pull the weights back together again.
Alternative Ways to Strengthen the Intercostal Muscles
Lifting weights is not the only way to do it, there are a couple of other options – ones that most bodybuilders would never consider!
The first one is deep breathing, it stands to reason that breathing would strengthen the muscles required to help you breathe!
Spend 5 minutes each day breathing in and filling your lungs before slowly breathing out again.
This process will really help relax you and is considered a form of meditation – try doing it just before bed.
Another way to strengthen those intercostal muscles is to try yoga.
Not only does it involve exercises such as the cow face pose  that can strengthen the muscles, but it also involves a lot of deep breathing.
You can also increase your intercostal strength by performing high intensity cardio, or low intensity steady state if you prefer.
If deep breathing can strengthen these muscles, then what better way to work them than running as hard as you can?
The final thing we will look at are regular abdominal exercises, because a lot of these actually can help strengthen the intercostal muscles.
Think about the regular abdominal crunch, you are flexing and extending the upper part of the torso, stretching out the intercostal muscles on the way down. Performing abdominal crunches on a decline bench could further increase the stretch.
One thing that you might have noticed while reading this article is that the way to strengthen the intercostal muscles is to perform strength based exercises, core exercises, and cardio.
In other words just follow a regular strength based training program.
Add in some yoga and a bit of pre-bed deep breathing and you’ll build stronger intercostal muscles without even thinking about it.
Live a healthy life, exercise regularly, try to reduce stress, and you’ll be amazed at all the benefits you will find, and intercostal strength is just one of them.