What is the need for expiratory muscles trainers on the move?

Question: What is the need for expiratory muscles trainers on the move?       

       Oxygen supply in sportsman’s body and carbon dioxide excretion are provided by the ventilation of lungs. It is a well-known fact that the ventilation of lungs bases on the work of expiratory muscles. These muscles perform a set of other functions besides breathing ones, connected with human’s voluntary movements. The control of expiratory muscles is realized by a respiratory center. Expiratory muscles work is synchronized with the activity of locomotion system.
               It is common knowledge that expiratory muscles, which are not trained, may “steal” up to 70% of oxygen that is inhaled from the muscles, used in motional act, decreasing effectiveness of its execution and effectiveness of the work of basic functional body systems.
               Thus, appearance of “breathlessness” that attends heart rate increase and significant rise of the blood pressure while we are doing exercises, is connected with the reduction in a level of development of expiratory muscles.
               Development of expiratory muscles force and endurance improves with their training.
               Physical activity changes both respiratory characteristics and the “source” of the breath control. The more intensity the physical exercise has, the greater is the role of signals coming from working muscular and tendinous structures of locomotor apparatus in control of breathing and in work of  expiratory muscles

               When it happens, almost all vital functional systems of a human (cardiovascular, neuromuscular, immune, blood circulatory, etc.) improve, and expiratory muscles develop without changes in kinematic and dynamic structures of the movement that is performed.
               It is the phenomenon, which is realized neither by  Frolov’s exerciser, nor by “Samozdrav” or by Powerbreathe (see the table).