Cycling art, energy, and locomotion

by Robert P. Scott

ANKLE-MOTION AS SHOWN BY THE CYCLOGRAPH.

Throughout this work a slight tendency to urge the element of dead centre as against the crank-cycle may have been discovered. Makers and riders who find fault with this apparent praise of lever and non-dead-centre devices can derive considerable comfort by the study of ankle-motion. No better introduction to our diagrams, showing the possibilities arising therefrom, can be given than the following extract from the Irish Cyclist, via The Bicycling News and Wheelman’s Gazette:

“ANKLE-ACTION.

“Among the many thousands of riders in this country, says the Irish Cyclist, very few have any desire to improve their style or realize for a moment the vast importance of correct ankle-motion. You meet a rider plodding along, working his legs like pistons, with a heavy, lifeless motion. Remonstrate with him, and see what he will say: ‘Oh, he can go well enough; he does not believe ankle-action makes such a difference, and he does not want to “scorch” in any case.’ Now, we want our readers to grasp these facts. Any rider can acquire a tolerable ankle-action by careful practice, and the acquisition of such will increase his power by nearly one-fourth, and will enable him to ride hills never before attempted, and to keep up a better pace at the expense of the same amount of energy. This being so, the acquisition of such art should be a sine quâ non to every rider. That it is so can very easily be proved. In following the pedal the foot describes a complete circle. Suppose the circle to be divided into eight segments, taken in order from the highest point.[5] With a rider who does not use his ankles, force is applicable only through segments 1, 2, 3, 4, and in segments 1 and 4, the force not being applied at right angles to the end of the crank, a large proportion is wasted, and consequently it is only thoroughly effective through segments 2 and 3, or during one-fourth of the revolution. The rider who has mastered the mysteries of ankle-action will drop his heel as the pedal approaches the highest point, and he can apply a certain amount of force through segment 8. After passing the so-called dead point, his heel being still dropped, the force is applied at right angles to the crank, or nearly so, and consequently he can utilize his full power through segment 1. By rapidly straightening the ankle when entering segment 2 an additional impetus is imparted, and, as before, full power can be applied through segments 2 and 3. Entering segment 4, the heel should be raised and the pedal clawed backward, and this clawing action will enable the rider to work past the dead point and well through segment 5. Consequently, the man who rides with his ankles stiff can only work through segments 1, 2, 3, 4, or half the whole circumference, and his work is thoroughly effective only through segments 2 and 3, or one-fourth the circumference, whereas the man who utilizes his ankles can work through segments 8, 1, 2, 3, 4, and 5, or two-thirds the whole circumference, and his work is thoroughly effective through segments 1, 2, 3, and 4, or one-half the whole circumference. The advantage gained in the latter case is self-evident. The acquisition of the art is often tedious and troublesome, but if cyclists only knew the enormous increase of power which results they would not be content until they had mastered it. From the cycling volume of the Badminton Series, written by Lord Bury and G. Lacy Hillier, we take the following instructions:

“‘Seated either on a bicycle slung so that the wheel may revolve, or upon a home-trainer, the beginner should raise the pedal to its highest point, and then, steadying the wheel with the brake, place his foot upon the pedal, carefully fitting the slots in his shoes into their places, and seeing in any case that the foot is straight. Then, using the thigh muscle for the most part, let him thrust the foot (and pedal) forward in a horizontal direction; in fact, a sort of sharp forward kick, having the heel dropped as low as possible, the toes well up, and the foot firmly set on the pedal, which will be at an angle. This should be practised carefully with the brake slightly on, and for this purpose, though a bicycle may be used, a tricycle will be found much handier. If no home-trainer is available, the brake can be put slightly on by means of a piece of string or strap to the lever, tied to any convenient point, and the novice can spend a few minutes daily practising this exercise; in carrying out which programme the left foot should at first be used more than the right. As soon as the usual awkwardness of the ankle-joint has been worked off this action will be found remarkably effective in starting the machine; after a time the ankle muscles, and those of the calf, will become stronger, and a sharp straightening of the ankle, as the pedal passes through segments 1 and 2, will materially aid the propulsion of the machine. This straightening of the ankle will be continued until the foot is brought into a position at right angles to the leg, the muscular effort of which should now have by equal gradations become directly downward. The pedal will now assume a horizontal position, and the power of the leg with the weight of the body and the pull of the arms will all be exerted to force it downward; at this point the crank throw is in the most effective position, and the hardest work is put in. When the pedal begins to follow a backward course, the ankle-action becomes of the greatest value. The toe is gradually dropped, and the heel raised as the pedal gets nearer and nearer to the lowest point, the action having at length reached the backward or “clawing” stage. To secure the full advantage of ankle-work, this “clawing” action must be very carefully practised; the toes should be sharply pressed upon the sole of the shoe as if they were trying to grasp something, whilst the ankle should be straightened as much as possible, the foot being almost in a line with the leg, the calf muscles being strongly retracted, and the backward pull (which of course requires fitted shoes) can be made practically effective through segment 5, and also of service well into segment 6. The ineffective portion which exists on either side is soon reduced to a very small part of the circle, for as soon as segment 7 is entered upon the heel should be sharply dropped, and an upward and forward kick or thrust, as described in the directions for the first position, will lift the pedal forward and upward through segment 8, when, of course, the whole series of actions will be repeated.’—Bicycling News.”

Using the arrangement of cyclograph spoken of, by which ankle-motion may be shown, I find that I can begin to get a tangential resultant force on each crank at an angle of eighteen degrees back of the vertical line through the axle of the drive-wheel, beginning at d and ending at e, [Fig. 1],—in all, thirty-six degrees over a half-circle on each crank.

Fig. 1.

Ankle-power.

The diagram shows the sections 1 to 8, and also gives an idea of the extra power. To see the direct circular resultant force to turn the wheel, imagine the length of a crank from m to n without ankle-motion and then m n plus n o for the length of the crank with ankle-motion added. I have been able at each of the points a and i to get thirty pounds when the crank crosses the vertical line at the top and bottom. Thus it is discovered that by means of this ankle-motion on both cranks simultaneously, I can get a force of sixty pounds in the direction to turn the wheel, at a time when absolute dead centre would otherwise occur, amounting to two-fifths of the maximum pressure resulting from my entire weight on one crank at the best possible point, directly out in front, going down.

I have more than verified the results shown by the cyclograph by suspending a fifty-four-inch bicycle, with six-inch cranks, above the floor, placing myself in the saddle, and having an attendant attach a twenty-pound weight at a point on the rim, ninety degrees from the bottom. This weight I was able to raise at the dead-centre point of both cranks,—that is, vertically up and down,—which shows a real power at the pedals of ninety pounds, or forty-five pounds on each, and I do not suppose that I am by any means an expert in ankle-motion. The above ninety pounds is a much greater showing than I made on the cyclograph in actual running, but it is reasonably certain that, by practice, even such an amount could be obtained.

In the case of no ankle-motion,—that is, with a direct downward pressure on the crank,—a tangential force in the direction available in turning the wheel begins as the crank crosses the vertical at the top, and then increases as the sine of the angle the crank makes with the vertical, until such angle reaches ninety degrees or extends out horizontally, after which the power decreases as the sine of the angle the crank makes with the vertical below the centre until the crank crosses at the bottom, at which point the power ceases.

To represent this variation of power by actual length of lines, appended will be found a diagram, [Fig. 2], showing the tangential resultant or force to turn the wheel, imparted by a one-hundred-and-fifty-pound man with and without the use of ankle-motion.

A A is a line showing the divisions of the angles through which the crank passes in its revolution around the axle. The line a f i is a sine curve.

Using the middle section and beginning at the point a, which is that at which the crank crosses the vertical above the axle, making a zero angle therewith, we have a direct downward pressure and, without ankle-motion, zero power. Now, by means of ankle-motion on one crank at this point we get thirty pounds of power, represented by the length of the line from a to b; and by ankle-motion on both cranks we have sixty pounds, represented by the total length of the line from a to c. After the crank has advanced forward fifteen degrees, we have thirty-nine pounds of direct power (m n), and then adding the ankle-power of twenty-three pounds (n o), we have a total resultant of sixty-two pounds, represented by the length of the next line (m o), and so on up, the direct power increasing and the ankle-power diminishing till we come to the top of the curve f, when we have one hundred and fifty pounds of direct power. Passing through the angle of ninety degrees, and now counting from the vertical below the axle, we decrease in power inversely as we increased before.

[Fig. 1] will show a little more graphically to the eyes of some casual readers how the power expands. Take d a f i e as the regular swing of the crank with no power at a, then d b f h e as the increase of power on one and the dotted lines c and g as the auxiliary ankle-power on the other crank added.

Fig. 2.

Ankle-power sine curve.

[5] Observe Fig. 1, p. 58.