Another authority, Mr. Martin Cobbett, expresses an opinion about the leg stroke which almost coincides with our own upon the subject. It will be best to give it in his own words : Though the action of the soles of the feet upon the water helps the "drive," the momentum is also given by the " wedge " of water embraced and driven backwards by the action of the backs of the thighs and calves, as they almost come together at the completion of the leg stroke.' According to Mr. Wilson and Captain Webb this momentum is caused by the closing of the legs ; Sergeant Leahy and the Rev. J. G. Wood suppose it to be caused by the soles of the feet ; but Mr. Cobbett combines these two theories, and makes it plain that in reality progression begins as soon as the legs are sent outward and in a downward direction. That this is so we shall presently show. It stands to reason that the scissor action alone is not all which produces propulsion. If in the wedge ' or closing of the legs is centred all the propelling power, then why should it be necessary to draw the legs to the body and then to let them glide on and gently outward as far apart as possible, thus making two negative strokes in order to produce one propelling or positive Movement? If the closing of the legs is the only positive motion, why should the legs be drawn up to the body at all ? Much time and energy would be saved by simply opening the legs as widely as possible, without drawing them up to the body, fox then only one negative stroke would be made instead of two—that is, if the striking out of the legs from the body, no matter how performed, is non-propelling. We are not arguing that the legs should not be spread widely apart, because the wedge of water grasped with the extended legs should be as large as possible. What we do contend is, that as a matter of course the positive or forward motion of the body begins as soon as the feet are being sent out from the body, for the pressure of water in this instance is brought to bear on the front of the foot, up, and, along the shin to the knee-joint. This pressure is continued until the legs are nearly straightened. When the legs are extended and the inward or closing action begun, the pressure is transferred to the back of the thighs, sides of the calves, and along the side and sole of the foot to the toes.
To prove this it is only necessary carefully to observe the effect the legs have on the water just as they are sent out wide apart. At that moment, if the kick be properly made, a great swirl in the water will occur, and the body shoot forwaid. This forward. motion will be still further accelerated by the closing of the legs. The swirl which occurs when the legs are being straightened is made by the foot as the leg is extended from the knee-joint when, by the force employed, a flip or a small semicircle is made by the whole of the foot from the ankle.
In this description of the stroke we are to some extent confirmed by Mr. Martin Cobbett, who has noticed the proper action of the feet at the particular point, and describes it in the following terms : - There is a trick about the latter [referring to the kick] which will come with practice, and I will try to explain it by a familiar simile.' Everybody knows the difference between a bowl' argil a throw ; in the first the ann being kept rigid, while in the second a certain twist of forearm and wrist gives extra impetus to the delivery. So in swimming, you will, with practice, acquire a somewhat similar action of the knee in straightening the leg Which will give an extra flip to the stroke.
It is this ' trick ' or ' flip' of the legs, so often found wanting amongst ordinary swimmers, but always to be noticed in experts, which has most to do in propelling the body through the water. There is not the slightest doubt that the theory of the scissor action only, without the extra impetus given by the downward or opening stroke of the legs, is not quite accurate. To contend that the latter is a negative movement cannot, on the face of it, be correct ; how can it ? The very fact of sending the legs backward, providing it is not done by pressing the water with the sole of the foot, and the legs are not sent out with a jerk, must tend to send the body in a forward direction.
Our theory is confirmed by Charles Steedman in his famous treatise, published in Melbourne in 1867. The various motions are thus explained by him : A negative stroke iT one in the line of progress.
A positive stroke is one in the opposite direction.
All movements made in any other direction than these two are more or less negative, as they approach or recede from the direction of progress.
All forward movements of the limbs are negative or retarding.
All backward movements should be positive or propelling (when they are not so, it is owing to the inexperience or want of skill on the part of the swimmer).
The first principle of correct swimming is, that all negative action should be performed gently, the limbs being so advanced as to present as little resisting surface as possible.
. All ppsitive action should be vigorous, the limbs presenting the greatest resisting surface available.
Prior to beginning the practice of the leg stroke, the learner should ascertain that the water is sufficiently deep, so that when standing it shall reach up to the breast. He should then : a. Take hold of the steps or bar of the bath with one hand above the surface, and place the other hand against the side or the steps of the bath, some eighteen inches below the surface.
These points having been carefully noted, the leg movements should be proceeded with as follows : I. Turn the toes outward to the right and left respectively, with the heels nearly touching ; draw up the feet gently to wards the body somewhat above the level of the back, and as they near the body separate the feet a few inches. When drawn up, the soles of the feet should be facing upwaid and be just below the surface, whilst the knees should be turned outward to the - right and left, and not drawn up under the body (fig. r) z. To develop the next movement the legs must be smartly kicked in the outward direction to their widest extent without straining the thighs ; and in kicking out, the lower part of the leg from the knee-joint to the toe should be swept with a vigorous downward and arched or rounded movement from the knees, the water being slashed with the whole of the front of the foot as the leg is being straightened.' By keeping the ankles loose a flip will be imparted with the foot as the legs are being brought to the third position (fig. 2).
3. As soon as the legs have been straightened, continue the stroke without interruption by closing the legs with vigour until they nearly touch each other in line with the body, pre paratory to bringing them up into the first position (fig. 3).
During this practice the pupil should— a. Avoid looking behind to watch the action of the feet, and keep the face always to the front when exercising them.
b. Avoid any inclination to bridge the back. Observe steadiness and regularity in each movement, and be careful not to jerk or toss the head about.
c. Perform all the movements of the limbs with as little vigour as possible in accomplishing the outward and inward sweep of the legs, and note that no stoppage takes place during the outward and inward sweep.
d. When the legs are extended, keep the feet and toes turned well back as if standing on tip-toe, and be particular that the sweep of both legs is simultaneously performed. Simply go through all movements with an easy swinging motion.
e. Continue the practices with care and deliberation for five or six minutes at a time, blending the three sets of actions into one smooth and clean mechanical movement.