While your rib cage protects your lungs, the rib muscles help your lungs expand and contract -- you use rib muscles every day to laugh, talk and just breathe. Your intercostal muscles are the ones between each rib, and your diaphragm sits between them, right below the lungs. Strengthening these rib muscles will increase your lung capacity and improve respiratory fitness. All you have to do is breathe. Breathing exercises with deep breaths and forceful exhalations particularly strengthen the rib muscles.
Sit comfortably with your spine straight and chest lifted so you can fill and expand your lungs fully. Inhale for two seconds, hold for two seconds and exhale for four seconds. As you improve over time, try to increase it to three, three and five seconds, then four, four and six seconds. Try a more advanced breathing exercise called bellow's breath that emphasizes your diaphragm muscle while strengthening your entire respiratory system. Inhale to fill your lungs completely, then exhale sharply, contracting your abs with a quick, forceful movement to expel all of the air as fast as possible. Repeat for 30 seconds. Increase your speed as you get better at the exercise.
According to the American Council on Exercise, strengthening your intercostals and diaphragm improves your respiratory system's efficiency by expanding and strengthening your lungs. That means you can take in more oxygen to fuel your muscles during exercise or sports. Being aware and conscious of your breathing also centers your energy, focuses and clears your mind, and can improve your attitude. These are all boons for athletes and everyone else.
According to a 2003 Brown University study published in the "Journal of Applied Physiology," strength training in the weight room also strengthens both your intercostal muscles and your diaphragm. Situps and biceps curls were found to strengthen these rib muscles the most, and bench presses and power lifts recruited them, too. Any exercise that applies pressure against your abs activates the diaphragm to absorb some of the pressure. As a result, your diaphragm strengthens. If strength training isn't already part of your regular exercise program, include it at least twice a week to strengthen your rib muscles.
Aim to do a breathing exercise before or after every workout you do to make sure you're giving your rib muscles that extra workout regularly. Unless otherwise instructed in the exercise, assume you should inhale and exhale through your nostrils. Keep your body as relaxed as possible during breathing exercises. Stretch your intercostal muscles after a breathing exercise by doing side stretches with one arm overhead and arching your torso sideways. This will further encourage lung expansion and flexibility.
Ben Prien is a fitness writer, personal trainer and workout enthusiast. He's been writing fitness articles since 2012 and has worked at "Men’s Fitness" and "Muscle & Fitness" magazines. He specializes in sports conditioning, muscle training, weight loss and sports nutrition.