Strengthening your muscles and joints are fundamental for your fitness game. Duh. But one muscle that no one talks about? Your breathing muscles, which you should be working to boost your capacity for cardio endurance.

Known as your “intercostal muscles,” your breathing muscles are located around your ribs and help you breathe easier. “[They] help make up the chest wall and protect the lungs,” says Kasey Kotarak, trainer and coach at Fit Body Boot Camp, adding that they play a very important role in the mechanical aspect of our breathing. They help to expand and shrink the size of the chest cavity, adds Steve Stonehouse, NASM, a coach and director of education for Stride.

And when you’re doing a cardio workout, you’re obviously breathing a lot harder than, say, when you’re sitting on the couch binge-watching 90 Day Fiancé—which is where intercostal strength comes into play. “The intercostal muscles make it possible for the larger air flow required for cardio, and also work to allow an increased breath rate,” says Kotarak. So these muscles are helping your body adjust to all of the inhaling and exhaling required during a cardio workout. “Without these muscles, your body wouldn’t be able to adapt to the physiological changes that come with exercise,” she adds. “Stronger intercostal muscles can help increase your stamina, endurance, and reduce shortness of breath.” Um, wow.

Your diaphragm, which activates your parasympathetic response, is also important for your breathing-during-workouts game, and is the first thing to kick into gear. “Then your intercostal muscles expand your ribs,” says Stonehouse. “Ideally, and when trained properly, your chest moves last and least,” he says. As for strengthening these all-important muscles, cardio and breathing exercises help, but there are also strength training moves and even yoga poses you can do,  too. Here are the moves to do to strengthen your intercostal muscles for ninja-like breathing capabilities—just note that a key element of doing these exercises is to focus on your breath.

1. Dumbbell pull-over: Lie flat on a bench, making sure your head and neck are supported. Both feet should be flat on the ground. Hold one end of the dumbbell with both hands directly above the chest, keeping a slight bend in the elbows. Then lower the dumbbell over the head as far as your body will allow while keeping the arms tucked in. Lift the weight back to starting position while engaging the core, says Kotarak.

2. Oblique heel touches: Lie on the floor with knees bent and feet flat, notes Kotarak. Move your heels in until your knees are pointing upward. Looking at the ceiling, raise your head, neck, and shoulders slightly off the floor, and with your arms at your sides reach for one heel by engaging the core. Then bring the arm back to the start. Complete a full set on one side before switching, or alternate side to side.

3. Chest fly: Stonehouse recommends this move, which involves lying on a flat bench with a dumbbell in each hand resting on top of your thighs. Your palms should be facing each other. Use your thighs to help raise the dumbbells, and lift one weight at a time so you can hold them in front of you at shoulder-width. Raise the dumbbells up like you’re pressing them, but stop and hold before you lock out—this should be your starting position. With a slight bend in the elbows, lower your arms out at both sides in a wide arc until you feel a stretch in your chest. Breathe in as you perform this portion of the movement, and keep the arms stationary—the movement should only be at the shoulder joint. Raise your arms back to starting position as you squeeze your chest muscles and breathe out, and use the same arc of motion to lower the weights.

4. Side plank hip dip: Kotarak likes this move to work your core and strengthen your intercostal muscles at the same time. Begin on your side with your elbow directly underneath your shoulder, and stack your feet on top of each other or stagger the front foot in front of the other in a side plank. Once you’re stable, press up into the low side plank. Engage your core and dip your hips up and down, bringing them as close to the ground as you can. Keep your opposite arm at the hip or ear, and be sure to do both sides.

5. Extended side angle: Kelly Clifton Turner, yoga instructor and director of education for YogaSix, loves the extended side angle for this purpose, as it “stretches the top ribs and asks the bottom ribs to stabilize and strengthen,” she says. Begin in a Warrior II yoga pose with your right knee bent in the front, and bring your right elbow down to your right knee. Inhale to bring your left arm up toward the ceiling, then exhale with your arm over the ear, making a straight line along the left side of your body.

If you’ve ever wondered, here’s what trainers have to say about doing cardio or strength training first in a workout. And this is what to know about power in fitness, which is a less-discussed important part of your strength game.