PROGKESSION ON AND IN THE WATER. 



83 



in an outward and backward direction (fig. 41, In this 

 movement the posterior surfaces of the arms take part; the 

 palms and posterior portions of the arms contributing to the 

 propulsion of the body. When the arms are flexed, the flat 

 of the hands is directed downwards (fig. 41, C). Towards 

 the end of flexion the hands are slightly depressed, which has 

 the effect of forcing the body upwards, and hence the bobbing 

 or vertical wave-movement observed in the majority of swim- 

 mers. -"^ 



During flexion the posterior surfaces of the arms act 

 powerfully as propellers, from the fact of their striking the 

 water obliquely in a backward direction. I avoid the terms 

 back and forward strokes, because the arms and hands, so long 

 as they move, support and propel. There is no period either 

 in extension or flexion in which they are not effective. 

 When the legs are pushed away from the body, or extended 

 (a movement which is effected rapidly and wnth great energy, 

 as shown at fig. 41, B), the soles of the feet, the anterior sur- 

 faces of the legs, and the posterior surfaces of the thighs, are 

 directed outwards and backwards. Tljis enables them to 

 seize the water with great avidity, and to propel the body 

 forward. The efficiency of the legs and feet as propelling 

 organs during extension is increased by their becoming more 

 or less straight, and by their being moved with greater 

 rapidity than in flexion ; there being a general back-thrust of 

 the limbs as a whole, and a particular back-thrust of their 

 several parts.^ In this movement the inner surfaces of the 

 legs and thighs act as sustaining organs and assist in floating 

 the posterior part of the body. The slightly inclined position 

 of the body in the water, and the forward motion acquired in 

 swimming, contribute to this result. When the legs and feet 

 are drawn towards the body or flexed, as seen at fig. 41, (7, ^, 



^ The professional swimmer avoids bobbing, and rests the side of his head 

 on the water to diminish its weight and increase speed. 



2 The greater power possessed by the limbs during extension, and more 

 especially towards the end of extension, is well illustrated by the kick of 

 the horse ; the hind feet dealing a terrible blow when they h'ave reached their 

 maximum distance from the body. Ostlers are well aw^are of this fact, and 

 in grooming a horse keep always very close to his hind quarters, so that if 

 lie does throw up they are forced back but not injured. 



