Powerlung uses Respiratory Therapy exercises that strengthen muscles that support your breathing. Just like any other muscle in your body, the best way to make them stronger and more efficient is to utilize strength training. Threshold resistance is a proven method of training used by PowerLung Breathing Exercisers. When you breathe in and out through PowerLung, you are working against a threshold of resistance that is the same for every breath. You are not breathing through a restricted orifice where the load can be reduced just by changing the way you breathe. Breathing is a very important aspect of any exercise program, particularly for athletes and individuals with respiratory problems. More and more coaches are recognizing the importance of Improving Breathing to provide better health and fitness. PowerLung is a lung exercise to help improve lung capacity. PowerLung manufactures four different models that differ in resistance. These respiratory exercisers include the Powerlung AireStream, the Powerlung BreatheAir, the Powerlung Trainer, and the Powerlung Sport. PowerLung Breathing Therapy helps improve Respiratory Health by increasing lung capacity and strengthening the muscles of the air passages. PowerLung is available in four different models featured below: Powerlung AireStream – provides low resistance. The PowerLung AireStream is for people accustomed to light activities and who are in good health. The PowerLung AireStream is also great for stretching or warming up the breathing muscles before any activity and cooling down afterward. Powerlung BreatheAir – provides medium resistance breathing training to help improve respiratory health of moderately active and low intensity exercise programs. Powerlung Trainer – provides high resistance respiratory training for individuals who are in good shape and exercise or train at high levels of intensity. Powerlung Sport – provides maximum resistance training for elite athletes who participate in strenuous, competitive training and sporting events. The PowerLung Sport model is not suited for the casual user.