EXERCISE FOR CHEST DEVELOPMENT. 523 



It is then from within outward that the force capable of ex- 

 panding the chest acts, and it is in reality to the lnngs and not to 

 the muscles that the chief share in the changes in form and size 

 of the chest belong. The most powerful inspiratory muscles can 

 not raise the ribs, unless the lungs participate in the movement 

 of expansion, and, on the other hand, the lungs can raise the ribs 

 without the aid of the muscles, for the chests of emphysematous 

 patients remain vaulted in spite of their efforts to lower the ribs 

 and complete the expiratory movement. 



If we sum up the facts we have just enunciated, we shall be 

 driven to the conclusion that, in order to raise the ribs and get 

 rid of the vicious conformation of flat chest, we must not seek to 

 act directly on the thoracic muscles, but to produce as extensive 

 respiratory movements as possible. 



There are two methods of amplifying respiration : one con- 

 sists in voluntarily expanding the thorax in all directions. This 

 method is in the domain of " chamber gymnastics " ; it has been 

 much extolled, and it may give good results. The other method 

 comes more directly into the field of our studies. It consists in in- 

 creasing by exercise the amplitude of the respiratory movements. 



The problem has now become clear and definite. "We need, in 

 order to develop the chest, to know what exercises are most fitted 

 to produce a series of very extensive respiratory movements. 

 Now, the amplitude of respiration, as well as its frequency, is in 

 direct ratio to the intensity of the respiratory need, and we know 

 that the intensity of this need depends on the quantity of me- 

 chanical work performed in a given time. 



The exercises which cause an accumulation of work are, then, 

 those most fitted for increasing the size of the thorax, and for 

 demanding increased work from the lungs. And we know that 

 this accumulation of work occurs especially in exercises of 

 strength and speed. 



Thus the mechanism of exercise, its performance by the aid of 

 these muscles or of those, are of secondary importance in pro- 

 ducing the result of which we are speaking. It matters little by 

 what process the muscular force is expended, provided that there 

 is great expenditure in a short period of time. It is indifferent 

 whether the movements are very slow, each of them representing 

 a great number of kilogrammetres, or whether they are extremely 

 rapid, each movement representing but a moderate effort. It is 

 merely necessary that the sum of work represented by these 

 movements, whether few or many, should be considerable in a 

 short time. 



Now, the quantity of work which a given muscular group can 

 perform in a given time is subordinated to the strength of this 

 group. There are muscular groups which are too weak to ex- 



