PEOGRESSION ON AND IN THE WATER. 



87 



and legs are forced backwards (fig. 43, c d). The right arm 

 and legs move together, and alternate with the left arm, 

 which moves by itself. The right arm and legs are flexed 

 and carried forwards, while the left arm is extended and 

 forced backwards, and vice versa. The left arm always moves 

 in an opposite direction to the right arm and legs. We have 

 thus in the side stroke three limbs moving- together in the 

 same direction and keeping time, the fourth limb always 

 moving in an opposite direction and out of time with the 

 other three. The limb which moves out of time is the left 

 one if the operator swims on the left side, and the right one 

 if he swims on the right side. In swimming on the left 

 side, the right arm and legs are advanced slowly the one 

 instant, and forced in a backward direction with great energy 

 and rapidity the next. Similar remarks are to be made re- 

 garding the left arm. When the right arm and legs strike 

 backwards they communicate to the body a powerful forward 

 impulse, which, seeing the body is tilted upon its side and 

 advancing as on a keel, transmits it to a considerable distance. 

 This arrangement reduces the amount of resistance to forward 

 motion, conserves the energy of the swimmer, and secures in a 

 great measure continuity of movement, the body being in the 

 best possible position for gliding forward between the strokes. 



In good side swimming the legs are made to diverge 

 widely when they are extended or pushed away from the 

 body, so as to include within them a fluid wedge, the apex of 

 which is directed forwards. When fully extended, the legs 

 are made to converge in such a manner that they force the 

 body away from the wedge, and so contribute to its propul- 

 sion. By this means the legs in extension are made to 

 give what may be regarded a double stroke, viz. an outward 

 and inward one. When the double move has been made, 

 the legs are flexed or drawn towards the body preparatory to 

 a new stroke. In swimming on the left side, the left or 

 cutwater arm is extended or pushed away from the body in 

 such a manner that the concavity of the left hand is directed 

 forwards, and describes the upper half of a vertical ellipse. 

 It thus meets with comparatively little resistance from the 

 water. When, however, the left arm is flexed and drawn 



