A CINEMATOGRAPHICAL ANALYSIS OF THE LEG ACTION OF CYCLING Thesis for the Degree of M. A. MICHIGAN STATE UNIVERSITY GAIL ELLA MERCER 1970 ' ABSTRACT A CINEMATOGRAPHICAL ANALYSIS OF THE LEG ACTION OF CYCLING By Gail Ella Mercer The purpose of this study was to analyze and compare the leg movements of six selected subjects with the leg movements recommended in most cycling literature. Using the cinematographic technique described by Cureton, the projected image of each of the subjects was used to determine movement patterns while he or she was riding the rollers, a mechanical device for indoor train— ing that accommodates both the rider and his bicycle. Mechanics of the bicycle that directly relate to the performance of the cyclist and mechanics of the leg action were analyzed. A comparison of the subjects' performance with theories commonly found in bicycle literature was made. Basically, the recommended adjustments of the bi- cycle commonly found in most cyling literature did not vary significantly from those of rider comfort. The leg supplying the driving force is the most important concern of cycling. Maximum knee extension Gail Ella Mercer occurred at an average angle of l6l.2° and maximum foot extension at the 169.5° crank position. Knee flexion began at 171° and flexion of the foot at 205°. The range of knee movement was from 57° to 73°. The range of move- ment was from 19° to 45° for the ankle. The average area in which force could be applied effectively in the first half of the pedal revolution was through a range of “1° to 180°. The area of least force was at 90° and those crank positions most nearly approach— ing this point. The findings of this study, generally, were in agreement with the recommendations most commonly found in cycling literature. There were differences, however, with regard to the foot being in a horizontal position at 90°. The degree of ankling which would be most efficient could not be determined. A CINEMATOGRAPHICAL ANALYSIS OF THE LEG ACTION OF CYCLING By Gail Ella Mercer A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF ARTS Department of Health, Physical Education, and Recreation 1970 (A ,a-o f‘ . ' XI! i ,’7 4./ I ’ " " Lu}- IL’ 4 t '4‘ ’ / 3'/@‘}0 ACKNOWLEDGMENTS The writer wishes to express appreciation to Dr. Heusner of the Men's Physical Education Department and members of the Akron Bicycle Club--Jim Beres, Fred Dennis, Martha Pinder, John Pinder, Don Zachary and, especially Robert Yeager-~for their patience and assistance during this research. ii TABLE OF CONTENTS Page ACKNOWLEDGMENTS. . . . . . . . . . . . . ii LIST OF TABLES . . . . . . . . . . . . . v LIST OF FIGURES. . . . . . . . . . . . . vi Chapter I. INTRODUCTION . . . . . . . . . . . 1 Statement of the Problem . . . . . . l Pertinence of the Study . . . . . 2 Delimitations. . . . . . . . . 3 Limitations . . . . . . . . A Definition of Terms. . . . . . . . 5 II. REVIEW OF THE LITERATURE . . . . 8 III. METHODS OF PROCEDURE . . . . . . . . 15' Research Method . . . . . . . . . 15 Subjects . . . . . . . 18 IV. PRESENTATION OF DATA . . . . . . . 19 Analysis of the Bicycle . . . . 19 Bicycle Adjustment . . . . . 19 Bicycle Resistances. . . . . 23 Momentum . . . . . . . . . . . 26 Forces Affecting Momentum. . . . . 26 Velocity . . . . . . 31 Analysis of the Cyclist . . . . . . 33 Analysis of Knee Action as Related to Crank Position . . 33 Analysis of Ankle Action as Related to Crank Position 50 Analysis of Leg and Foot action in Relation to Crank Position . . 51 Leg Action Comparison with Other 53 Cycling Literature . . . . . . iii Chapter V. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS Summary. . Conclusions . Recommendations REFERENCES APPENDIX iv Page 61 61 61 67 69 Table A1. A2. A3. A4. A5. A6. LIST OF TABLES Comparison of bicycle adjustments. Bicycle resistances . . . . . . Body weight on handlebars, seat and pedals. Pedalling rate and velocity. . . . Comparison of knee flexion and extension Range of effective force during first 180°. Comparison of crank and ankle positions closest to 90° . . . . . . . . Subject weights and segment lengths . Bicycle data. . . . . . . . . Bicycle resistances Crank angle (in degrees) from the vertical. Degrees of knee flexion and extension Degree of ankle flexion and extension Page 20 25 30 32 M8 5A 56 83 8A 87 90 91 92 Figure \ooofloxm 10. ll. l2. 13. l“. 15. l6. 17. LIST OF FIGURES Basic bicycle components Rollers for indoor training Cyclist riding rollers Force diagram for Velocity Velocity Velocity Velocity Velocity Velocity Relation Relation between knee, tions - Subject B. Relation between knee, tions - Subject C. Relation between knee, tions — Subject D. Relation between knee, tions - Subject E. Relation between knee, tions — Subject F. Comparison of important extension of the knee an of between knee, tions - Subject A. crank crank crank crank crank crank determining moments . rotation rotation rotation rotation rotation rotation 0 vi ankle, and ankle, and ankle, and ankle, and ankle, and Subject A. Subject B. Subject C. Subject D. Subject E. Subject F. ankle, and crank crank crank crank crank crank posi— posi- posi- posi- posi- posi— points of flexion and d ankle in degrees . Page 16 29 314 35 36 37 38 39 Al U2 “3 Au 145 M6 Figure 18. 19. Al. A2. A3. A“. A5. A6. A7. A8. A9. A10. Force needed to overcome resistances when there is no momentum - male cyclists Force needed to overcome resistances when there is no momentum - female cyclists. Points of measurement on bicycle. . . . Leg action of Subject A at different crank angles . . . . . . . . . . . . Comparison of net body weight on handlebars male cyclists . . . . . . . . . Comparison of net body weight on handlebars female cyclists . . . . . . . . Comparison of body weight on seat - male cyclists. . . . . . . . . . . . Comparison of body weight on seat — female cyclists. . . . . . . . . . . Comparison of minimum force on pedal (rider seated) - male cyclists. . . . . Comparison of minimum force on pedal (rider seated) - female cyclists . . . Comparison of maximum force on pedal (rider standing) - male cyclists . . . . . . Comparison of maximum force on pedal (rider standing) - female cyclists . . . vii Page 59 6O 7O 71 73 7D 75 77 78 79 80 82 CHAPTER I INTRODUCTION Since the inception of the bicycle in the 1800's, man has incorporated its use for work, recreation, and competitive sport. There have been and will continue to be refinements of a machine that, all in all, has with- stood the censures of time. There has been limited scientific inquiry of a per- son's mechanical relationship to the bicycle. A test was conducted by Scott (7) in the 1890's with a special pedal adaptation to record the force applied during a pedal revolution. Singh (17) explored the mechanical adjustment of cycling for safety, comfort, and speed. The main cycl- ing publication in the United States, American Cycling, features a monthly technical section by DeLong. He has briefly discussed a large number of aspects of both the bicycle and the cyclist. Certain theories have been formed as to the mechanics of cycling, but no cinemato- graphic evidence was found to support these theories. Statement of the Problem Man cannot rely on observation alone. Aided by high speed photography, anatomical data, mechanics, and 1 moments of force, the writer tried to provide a scientific base to substantiate present conceptions commonly found in most cycling literature. That is, (a) there is an im- portant relationship between the rider and his bicycle, especially at the three points of contact: the handle- bars, the seat, and the pedals; (b) the most critical factor in cycling is the leg action; (0) the degree of ankling contributes to the rider's efficiency. The writer was interested in determining whether or not there were any appreciable differences between the subjects' leg movements and the related riding techniques commonly described in bicycling literature. Stated briefly, the toe is raised at the top of the stroke, presses the pedal forward, and is in a horizontal position when the crank is at 90°. The toe points downward and draws the pedal back at the bottom of the stroke. Pertinence of the Study For the serious-minded cyclist, there are a limited number of publications relating to the Sport available in the United States. There is a dependence on other coun- tries, especially Great Britain, for books and periodicals in this subject area. In most references regarding past research, the writer was unable to determine the scientific base upon which conclusions were drawn. There has been recently, however, an increase in the number of studies being con- ducted and other technical data available. Cycling is a common experience, and with the growing amount of leisure time and the present stress on physical fitness, the demand for such a lifetime sport becomes even more important. Once the initial investment of the machine is assumed, it is an ineXpensive form of recreation and sport by riders of all ages. One can participate with a group, as a family, or individually anyplace in the world. After the rider has learned a certain degree of profi- ciency he or she will experience an extremely pleasurable form of activity. The writer has had much contact with cyclists of all skill levels. It was hoped that by better understanding the technical implications of cycling the writer would be better able to share useful information with other cycling enthusiasts. Delimitations While the writer was primarily concerned with the mechanical principles of the cyclist, there were mechanics of the bicycle alone that had to be considered. No at- tempt was made to ascertain the correct fit and adjustment Of the bicycle to the rider as it has been covered by Singh (17), DeLong (8, 9), and others. By necessity, each subject rode the bicycle of his or her own choosing. The selection of seat, handlebar, and gear ratio adjustments were also left up to the individual. No muscular analysis or physiological requirements are explained in this study. The primary concern is the mechanical function of the leg. Relationships with other parts of the body and the bicycle are discussed only as necessary. Limitations 1. It cannot be assumed that the camera speed was held perfectly constant. 2. There may have been some unknown lens and camera irregularities. 3. There was a small and not truly random sample. A. The bicycle adjustments for seat, handlebar, and gear ratio were set according to rider comfort and not recommended adjustments. A comparison was made to see if there was great variation between recommended adjustments and those governed by comfort. 5. Variables may have been present that were not known to the writer. 6. While the rollers, a mechanical device for indoor training, are used during the winter season to perfect pedalling technique by racing cyclists, variables may have been either introduced or lacking that would ordinarily be found while riding under road conditions. 7. The principles of physics cannot be applied to the human being perfectly. 8. The study was limited by the maximum speed of the camera. Definition of Terms 1. Ankling. The use of one's ankles to vary the flexion and extension of the feet throughout the pedal revolution to permit smoother pedalling with less effort. 2. Bicycle. A machine with a tubular frame, two wheels 27" x l l/A", dropped handlebars, saddle, and metal pedals upon which a rider balances and propels himself forward by pushing on the pedals. Horizontal Handlebar Top Tube ___,Saddle F_______Rear Sprocket Crank Crank Hanger or Bottom Backret Chain Wheel Figure l.--Basic bicycle components. 3. Cleats. Metal pieces of varying designs con- taining slots to fit over the metal rat trap pedal. They are attached to the sole of the cycling shoe. A. Cycling Shoes. A lightweight, leather shoe with a special reinforced sole to equalize pressure on the ball of the foot. 5. Cyclist. For purposes of this paper, a cyclist is any person riding a light-weight, multi-geared bicycle for pleasure and/or recreation. 6. Dead Centers. "Near the top and bottom of each stroke the rider's weight can no longer be used for pro— pulsion...These points are called 'dead centers'" (7, p. 20). 7. Gear Ratio. A ratio of the number of teeth on the front chain wheel to the number of teeth on the rear sprocket. When multiplied by the diameter of the wheel times pi, would represent the distance travelled for each turn of the crank. 8. Handlebars. They are an underslung type of bar that reduces pressure on the saddle,permit8 the back to bend forward which relaxes the spine, distributes the body weight more evenly between the front and rear wheels, and permits the upper body to assist with propulsion (l). 9. Rat-trap Pedals. This type of pedal is made of metal, is lighter than rubber pedals, and because of a toothed surface provides a better grip for cycling shoes. 10. Rollers. Three cylinders, two at the rear and one at the front, are placed so they will accommodate a cyclist and his machine. The bicycle is placed atOp the rollers, and with careful balance the rider can practice pedalling technique indoors within a limited area. Belt providing driving force for the front cylinder \ Supporting cylinders for the bicyle Figure 2.--Rollers for indoor training. ll. Saddle. A narrow, leather, unsprung unit designed to permit free movement of the thighs. l2. Toe Clips and Straps. These attach to the rat— trap pedal to prevent the foot from sliding too far for- ward and to assist in the upward motion of pedalling. CHAPTER II REVIEW OF THE LITERATURE Limited availability of literature in the United States related to bicycling necessitates dependence on other countries for much of that which is procurable. It has been established, however, that: A bicycle is a mechanical aid to allow an individual to convert muscular energy into motion. Unless its rider is so disposed that his muscular team is most effectively uti- lized, premature fatigue, discomfort, or loss of performance will result (9, p. 16). There seems to be common agreement that bicycling is an act requiring balance and the most efficient use of one's body and machine. The term ankling is referred to as an efficacious means of accomplishing this very thing in almost all literature pertaining to cycling. The pedal is the point at which the energy of the rider is transmitted to the cycle, and so forms the chief connecting link between the cyclist and the wheel. The degree of per- fection with which the connection is made goes far to determine the whole character of one's riding. . . . (13, p. 70) Shaw (l6) and the Philadelphia AYH (1) state simply that in ankling the toes are raised on the upstroke, the foot is in an almost horizontal position when it is half way around, and the toes begin to press back on the pedal at the bottom of the stroke. The Athletic Institute, in cooperation with the Bicycle Institute of America and the Amateur Bicycle League of America (2), wrote of ankling with more clarity. With the foot moving in a clockwise direction the recrea- tional rider most effectively applies power to the pedals from just after twelve o'clock all the way around to past six o'clock—-more than half way around for each foot. The heel is drOpped as the foot rises. Force application starts just after twelve o'clock by extending the ankle-- applying forward power to the pedal. The ankle continues a steady extension until it is fully extended at the bottom of the stroke where backward pressure is applied to the pedal. The racing cyclist, aided by toe clips, can exert a pull between six o'clock and twelve o'clock enabling power to be applied all the way around. There is, of course, more strength on the downstroke. Varied degrees of proficiency are possible, and many who pose as good riders, states Porter, have poor ankle action. With good pedalling the rider will be able to apply power through one half, or more, of each revolution, and perfect pedalling will permit him to do so to an even greater extent. ,., Also, the heel must rise uniformly as the crank de- cends so that half way around the toe and heel 10 are level and the power is applied to the end of the crank at exactly right angles where the work is easiest and most effective. By acquiring good ankle motion instead of exerting pressure with each foot through only one hundred and fifty to one hundred and eighty degrees, it becomes possible to apply power through two hundred to two hundred twenty de— grees and it also applies the power more effec- tively throughout the whole distance (13, pp. 76,80). R. P. Scott (7), in the 1890's, developed a pedal 1 which could measure the force applied to it and record it on a spring wound rotation drum. There was a fall-off of effort at the top and bottom of the stroke. When effort is greatest, such as during hill-climbing, the variation is greatest. In one section he considered only the verti- cal uniform pressure and found that ". . . only 13% of the effort is effective in the top and bottom 30° of rotation, 37% in the second and fifty 30° and 50% in the center third of the pedal stroke" (7, p. 21). The crank is the means of transferring the rider's driving power to the bicycle, but there is little scien- tific evidence as to prOper crank length. DeLong (10) cites the contribution of several men. First, Mons. Perrache stated as a rule of thumb that crank legnth should be l/lOth the rider's inside leg measurement. Mons. Bourlet calculated that the maximum crank length a rider can effectively use is one half his thigh bone length. Both these men made their contributions near the turn of the century. 11 Professor Sharp in England (1896) pointed out . . . that the shorter the crank length in proportion to the rider's leg length, the more nearly the rider's knee motion approaches simple harmonic motion. This is to say, in simplicity, the starting, acceleration, deceleration and stopping of the knee motion becomes a smoother function (10, p. 1A). Milton Morse, an interested cyclist, asked the following questions in his contribution to the question of crank length: "Which is more tiring--the short crank with rapid cadence, or the slow, powerful strokes of the long crank?" (12, p. 15). Re and his wife gradually in- creased crank lengths over a long period of time from 6.5 inches to over 8 inches. As the crank length in— creased, up to 7.75 inches, so did the number of miles they were able to ride each day. Gearing was changed as crank length was increased. They found the 7.75 inch crank length most satisfactory and found that daily dis- tances actually decreased with cranks longer than 7.75 inches. They preferred long cranks and slow, powerful strokes. Vaughn Thomas (18) of England conducted a study in which he tried to standardize the mechanical variables of the bicycle into one parameter which was the saddle height. The subjects rode with a heavy work load (500 kg/m), and the subjects were timed in performing this work load at four different saddle heights. The experiment showed l2 quite conclusively that the most efficient saddle height is 109% of the inside leg measurement. He found that the better the rider (in terms of racing ability) the more he tends to have his saddle set to the recommended height. Another study of significance was conducted by Singh concerning the mechanical adjustment of cycling for safety, comfort, and speed. He concluded that no two persons would have the mechanical adjustment on their bicycles the same way; that the cyclist should know how to select the bicycle according to individual body needs and to be able to ride the machine cor- rectly; and be able to adjust it as required for safety, comfort, and minimum power loss. (17, p, 95) First of all, the height of the bicycle de- pends on the height of the cyclist. The height of the frame . . . to the axis of the bottom bracket should be about 10" less than that of the rider's inside leg measurement. . . . (17, p, 29) Singh (17) further stated that the saddle should be adjusted for rider comfort so that the pedal can be reached at its lowest point. Also, the top of the handle— bars should be about two inches lower than the saddle. A Schwinn Bicycle Company pamphlet (8) stresses the importance of fitting the bicycle to the rider. Figure Al in the Appendix gives reference to the points of measure- ment for determining correct fit of the bicycle. Their first recommendation was that the frame size should be such that the top horizontal bar permits the rider to just straddle it with both feet flat on the ground. If the 13 frame is too small it will not permit proper setting of the saddle and handlebars. The nose of the saddle should be set two inches behind an imaginary line drawn through the center of the crank hanger. Then, by placing the heel on the pedal at its lowest point and sitting on the saddle, the leg should be straight. When in the proper riding position, the knee will have a very slight bend. The saddle top should be level and not at an angle. Portuesi (1“) adds further emphasis to this. If tipped down, extra pressure is applied to the arms and wrists to keep from sliding forward in the saddle. While Schwinn (8) says the angle should be neither up nor down, Portuesi ~(1’4) says the saddle top should be level or with a very slight tip-up. Schwinn (8) continues on to say that the top of the handlebars should be no higher than the top of the saddle. The distance of the bars from the seat should be such as to permit a natural arm position with the back inclined approximately U5° forward. Anklin ermits the rider to take full ad— vantage gfpthe principles of leverage. The heel should be dropped to give an increasing forward push to the pedal with the thrust reaching fu force when the foot is in its most forward posi- tion (17, p. 98). Though only several sources have what might be con- sidered a true scientific base, Scott's study (7) in 1890 14 and Porter's (13) in 1895, would seem to have set forth_ the principles of cycling. Once the bicycle is properly adjusted, the cyclist should be ready to learn more cycling techniques of which cadence is a part. Research, says Schwinn (8), has shown that a person operates most efficiently in the pedal speed range of 55 to 85 revolutions per minute. For normal rid- ing, pedal speed should be to the middle or higher side of this range. Yet another individual reports (6) varied laboratory studies have been made which would indicate greater muscular efficiency at from A2 to 60 revolutions per minute. CHAPTER III METHODS OF PROCEDURE This study used the cinematographic technique as described by Cureton (A) for analyzing the mechanics of leg action in cycling. By using projected images as a guide for plotting the movement patterns for each subject, pertinent data could then be obtained. Research Method The subjects performed their cycling techniques while riding the rollers. As shown in Figure 3, the rear wheel of the bicycle is placed over two closely spaced cylinders. Rotation of the back wheel provides the turn— ing force for these cylinders. They in turn are connected to the front cylinder by a belt thereby causing the front cylinder and the front wheel of the bicycle to rotate. Three practice trials were given to the cyclists who could already ride the rollers and five or more for the inexperienced cyclists several weeks before the filming. All but one had achieved complete independence of a Spotter by the time of the filming. The rollers were placed on the University of Akron gym floor near the wall on which a plain background paper 15 16 {i} C: UN Figure 3.—-Cyclist riding rollers. had been hung. Vertical and horizontal measures were placed in the camera field of view by the rollers, and their positions were checked with a level. A cardboard disc, sub—divided into eight parts, was attached to the bicycle behind the crank of each rider for later referral to crank positions and to provide an unobstructed View of foot actions. It was only used, however, to provide an unobstructed View of the foot. Since rides on the rollers are usually of short duration, no warm-up was given. Rather, those desiring it, rode laps around the gym. The three-minute riding 17 time given each subject was divided into three one—minute segments with filming being done near the end of each minute. The camera, a motor driven Bell and Howell 16mm, Model 70J was set 36 feet 11.5 inches from the subjects. The camera was aimed at the hip joint as measurements were to be taken from all joint centers of both the upper and lower limb segments. Measuring from the center of the lens the camera was placed at a height of U feet. A 1:2.N Pan—Cinor Zoom Lens was used at f/5.6 and the camera speed set at 6“ frames per second. Each frame was .03023 of a second using the ball drop procedure suggested by Cureton (4). Beginning with the crank in a vertical position, each location of the crank was recorded as were several surface landmarks put on the subjects prior to filming to indicate joint centers. The location of the surface land- marks and the determination of the centers of gravity were found by using techniques proposed by Williams and Lisner (19). There was one unaccountable source of error. There appeared to be a shortening of the leg and crank at the top and at the bottom of the pedal revolution. This was present in all male subjects and in the female subjects to a lesser degree. It was not significantly present in the upper part of the body for any of the subjects. One 18 possible explanation was that surface landmarks may have been improperly positioned enough to cause a slight shift when the leg was in different positions. Another explana— tion may be that the leg may have turned away from the camera at these points in the revolution causing an angle change in relation to the lens. Subjects Six cyclists from the Akron Bicycle Club volunteered for this study. All were selected because: (a) of the limited number of subjects available, and (b) one was experienced in riding the rollers, three had limited ex- perience, and the other two had a willingness to learn. The subjects are referred to alphabetically as sub— jects A through F. Subject A, Jim Beres, was the model against whom the other cyclists were compared. He used to compete professionally and, not including other accomplishments, won the Budapest—to—Vienna 200 mile race four times--once in nine hours, 22 minutes and 38 seconds, a record that still stands. He has logged over 500,000 miles in his yet unfinished career. All other subjects were recreational/touring cyclists. CHAPTER IV PRESENTATION OF DATA Motion pictures were taken of six cyclists riding rollers to analyze the mechanics of cycling and to compare the results with recommended techniques in most cycling literature. First to be considered, was the mechanics of the bicycle as directly related to the performance of the cyclist. Second, the mechanical analysis of the leg action during pedal rotation was studied. Third, a com— parison was made between the leg actions of the subjects and theories commonly found in bicycle literature. Analysis of the Bicycle Bicycle Adjustment Often recommended bicycle adjustments were com- pared with the actual adjustments, shown in Table l, of each rider whose bicycle was set according to personal comfort. Recommended adjustments, as found in most cycl— ing literature (1—3, 8-9, 13-17), are as follows: 1. The rider should be able to just straddle the top horizontal bar with both feet flat on the ground if the frame size is correct. 19 2O popcopxm I as H om AconmHe ooa omH om hm m o o Bonamv mEh< m mm AamucoNfihon owm om: 0mm 0mm 00 o Eonm mmmpwmpv xomm m e seem eHeedm eHeeem eHeeem AeHeemm HAHN. new. . .0 m. . lm PM E m cm>m sHecmHHm need em m sHpanHm Hun HHm H HthMtMemmm o.m .ms.m eo.m =m.m =mm.m eo.m mHeeem do mmoz : _ . .. . m :M.Nm :m.©m :m.:m :O.:m RQOH :m.mm .Hmm.um :m.mm :m.mm SO.mm 20.:m HMSPO< _. m mHeemm ecdetem ends pcmetem pandApm ezdeAem pstdAem weH ezmHHm th mmH me weH H eHeemm :m.© :mb.© :m>.@ :mb.© :mw.© :mw.w SuwcmH XCMLO ma. eom. eoo.o eo.H eom. emm. Amaze do» 0» Home : than go nopono Song wocmawwdov mNHw mEmpm m m O O m d. mpemfinsm .mpcmEpmSwom mHohOfin I'll mo comfimmosoonl.a mqm V4 _ _ __ F F 2'CG2 a 3 ’ CG 3 Fl CGl Fun IR2 . (Force on seat) CGL; 4" R1 (Force on bars) F5 v-CG5 I X5—~ 4://”/// XR3——>- R3 (Force on pedal) Figure A.-—Force diagram for determining moments. TABLE 3.--Body weight on handlebars, seat and pedals. 3O Subjects Force (Rider Seated) A B C D E F Total Body Weight 156 185 197 1A0 185 133 % Net Body Weight on Handlebars A5° 13.7 11.6 12.1 15.8 12.0 13.A 90° 12.9 11.5 12.0 15.2 13.2 13.3 135° 12.9 11.0 11.7 15.3 13.1 13.3 180° 12.9 11.0 11.7 15.3 13.1 12.8 i of Net Body Weight on Seat A5° 53.6 59.6 61.9 51.A 60.0 5A.0 90° 57.6 65.7 6A.7 56.6 60.5 59.A 135° 62.3 66.3 67.2 58.6 62.9 61.7 180° 60.6 63.0 6A.1 52.3 61.A 60.0 % of Net Body Weight on Pedal A5° 12.0 10.7 10.9 11.5 12.1 10.8 90° 10.2 8.7 8.1 8.7 9.0 8.A 135° 8.5 8.A 7.2 7.6 8.0 7.5 180° 9.3 10.0 8.7 8.3 8.7 8.5 Actual Net Body Weight on Pedal in lbs. A5° 18.8 20.9 21.A 16.1 22.A 1A.A 90° 16.0 15.9 16.0 12.2 16.7 ll.A 135° 13.2 15.5 1A.2 10.7 1A.6 10.1 180° 1A.6 18.5 17.2 11.6 16.0 11.7 31 to how much the Opposite leg affected the changes in weight on the seat. Load on the pedal varied due to the severe changes in the horizontal crank position. As force is applied to the pedal to maintain velocity, the force that the rider has available is due only to his ability to transfer his weight from the seat to the driving leg. Velocity The pedalling rate in the study refers to the speed with which the crank rotated. The speed used was such that it permitted good balance on the rollers but was not so fast as to cause undue fatigue. One influencing factor on speed was the gear ratio used. Too high a gear ratio would increase the pedal resistance and raise the amount of force necessary to maintain momentum. Too low a gear ratio would lower the force necessary to maintain momentum. In that case, the subject in try— ing to keep steady pressure on the pedals would have to spin the cranks too fast. This would cause bouncing on the seat and random movements throughout. Each subject used a gear ratio that permitted him to have enough speed to maintain good balance and yet not tire before the end of his three—minute filming period. The gear ratio chosen and the resulting speeds are shown in Table A. 32 TABLE A.--Pedalling rate and velocity. Subjects Subject A B C D E F Gear ratio 3.11:1 3.06:1 3.50:1 3.57:1 3.57:1 3.06:1 No. of frames for one revolution 30 32 37 A5 A8 39 Time/sec. of pedal Revolu— tion for one frame .907 .967 1.119 1.36 1.A51 1.18 Revolutions per minute 66.15 62.05 53.80 AA.13 Al.35 50.85 Miles per hour 15.56 15.06 1A.70 12.26 11.67 12.71 It was previously stated in the Review of Literature that one source maintains that a person operates most efficiently at 55 to 85 revolutions of the crank per minute (RPM) (8). Another source indicated greatest mus- cular efficiency at from A2 to 60 RPM (6). While this is an area of study in itself, it might be interesting to note that the lowest RPM for the subjects was Al.35 and the highest 66.15. This would seem to indicate that some of the subjects were not Operating efficiently according to either criterion. However, all subjects were riding a higher gear ratio on the rollers than they would under normal riding conditions. It must be assumed that, under 33 normal riding conditions, the subjects would be riding one to two gear ratios lower. This would permit an easier and faster pedalling rate referred to by cyclists as "spin- ning." This might well permit the riders to fall into the suggested RPM ranges for maximum efficiency previously mentioned. The velocity of each change in crank position was found for each rider and interpreted in terms of feet per second. Figures 5 through 10 show the velocity patterns during one pedal revolution of each rider. The irregu— larities were due in part to measurement error and were averaged out in some sections of the graph. The first 50°, 100° to 200° and from 275° to 360° represented the areas of greatest fluctuation. It should be noted that Subject A, the best rider, had the least overall variation in velocity. This, of course, was expected. Every change in velocity represents an individual expenditure of energy according to Newton's second law. Subject A was the most efficient rider according to his velocity curve. Analysis of the Cyclist Analysis of Knee Action as Related to Crank Position Subject A was compared to each of the other six sub- jects in regard to knee action relative to crank position. 3A .COHQBHOH xcmpo go zpfiooao>ll.m ossmfim < BQMhmDm coaumpom xsmho go mopmom 0mm mmm oom mum 0mm mmm oom mma omH mmH OOH mu om mm o _ P _ u d 1 h h P . _ p L L L H H a. a q H H q u w- _ 1 x\\\\\I/iIllItIl\\I\\1Il|1l4\\tlI/I\\lII/1|IIII/(\\IIl/l\\1\l\\)/lI/(\\. + om A OOH 11 SH e oma 1. m: puooeg Jag qaag 35 r omm _ 3 mmm _ 1 com mum “ b omm _ d .cofipmpos xcmso mo mpHoOHo>ll.m opsmfim m Homhmam nofiumpom xcmso mo mmsmom mmm OON muH omd mmH OOH mm Om mm O p _ P . A _ I! I 1 J u 1 A. h ‘h mm r + OOH t mmH puooas Jag 1993 e OmH in mNH 36 “I" omm 4 mmm p J oom H mum m 0mm _ 4 .QOHpmpog O Bomwmbm QOHpMpom xcmho mo Common mmm OON mmH OmH mmH _ p b r p q .- - d 4 xcmso mo mpHOOHw>Il.~ mpswfim OOH m5 om mm O q:— 1h— - qu- : OOH A T mmH puooeg Jag 138E i OmH % mmH .QOHumpog xcmso Mo szOOHm>Il.O ohswfim O BOMhmOm COHpmpom xsmno mo mopmom omm mmm com mum 0mm mmm oom m: omH mmH t 1 A A _ OOH m5 om mm O _ p _ L H — P u d I 41 1 d d .— 1.— db- /\/>\lr/\/l\/\/\/:mm 37 i OOH -- mmH -- omH H m: puooas Jed 133E .QOHpmpop xcmpo mo mpHOOHo>II.m mpsmHm m BOmmem COHpmpom xcmpo mo oopmom omm mwm oom mum 0mm mmm oom me omH mmH OOH ms om mm o _ b . _ _ h A . — . H H A . J H H ¢ “ m n m />\/>\(>J>\ll.OH mssmHm m Bommmam 20Hpmpom xsmho Ho moswma 0mm mmm oom mum Omm mmm oom mmH OmH mmH OOH mm om mm O r _ H p _ H A L p . p H H H H 1 H q A H b LP F a H d d A /\/\|J\\/\//\/\/\/>\/\o 0p Oopomc mohomln.mH mustm omH OOH OzH ONH OOH om OO O: ON O p H 1.. .4 .7- ‘- du- H- 4.. OIOOH 1-OmH 1-O:H .-O©H 1- OOH CHAPTER V \ SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS Summary Certain theories have been formed as to the mechan- ics of cycling, but no evidence was found to support these theories using a cinematographic analysis. Conceptions commonly found in most cycling literature are that (a) there is an important relationship between the rider and his bicycle, especially at the three points of contact-- the handlebars, seat and pedals; (b) the most critical factor in cycling is the leg action; and (c) the degree of ankling contributes to the rider's efficiency. Six subjects from the Akron Bicycle Club volunteered and were filmed for the study. The cyclists rode on rollers, a mechanical device for indoor training. The film was analyzed frame by frame with the patterns of the leg action plotted on white paper. Conclusions On the basis of observations and data taken from this study, the following conclusions were drawn: 61 62 The recommended bicycle adjustments and those of rider comfort did not vary significantly. The leg, supplying the driving force was, of course, the most important part of cycling. The degree of knee extension and flexion was dependent on the seat height, crank length, and amount of ankling. Maximum knee extension was reached before the halfway position of crank rotation—-at approxi- mately 16l.2°. Maximum knee flexion was reached at 167° and 186°. For most subjects the maximum knee extension was reached before the halfway position of crank rotation or 180°. Discounting the rider at the extreme end of the range of knee movement, the average range of motion was 69.4°. In relation to the lower leg, the foot is at its greatest degree of flexion when the pedal is in a vertical position. Changes in foot extension form a stair-step pattern rather than a smooth one. The heel drops slightly prior to each increase in foot extension. 10. ll. l2. l3. 14. 15. l6. l7. 18. 63 Maximum foot extension was reached at an average 206° crank position. All riders ankled to some degree wiht the range of ankle motion 19° to 45°. Flexion of the foot began at an average 205°. With the exception of one subject, the maximum foot extension was held briefly as the crank continued to rotate. Again discounting the rider at the extreme range, the subjects were able to effectively apply force at an average 41° crank position. The cyclists were unable to apply force effec- tively past an average of 180° insofar as actual pounds of pressure could be determined. The average area in which actual pounds of force could be effectively applied was 41° to 180°. It must be assumed that the subjects in this study did not achieve a true horizontal foot position when the crank was at 90°—~neither in relation to a horizontal reference line nor in relation to the lower leg. No valid means of establishing the skill level of the cyclists could be determined. There was no significant difference between male and female cyclists. 64 19. The degree of knee and ankle motion that would be most efficient could not be reliably deter— mined within this study as was originally in- tended. However, it would appear that the magnitude of ankling is not as important as the duration of ankling. 20. The "dead center" at the top of the stroke encompasses an area of 40° on the first part of the stroke but could not be reliably determined for the other areas. Basically, the findings of this study are in agree- ment with the recommendations most commonly found in cycl— ing literature. There was a discrepancy, however, with regard to the foot being in a horizontal position at 90°. Considering the angle of the foot in relation to the lower leg, the foot approaches the 90° position. But, when the foot is, in fact, in a true 90° position the crank is not. The effective pressure which may be applied begins at an average 41° and not 15° as suggested by one author- ity, even though the foot is pressing forward. The amount of pressure which could be applied throughout the full revolution could not be reliably determined. As a result, even though it was found that all subjects ex— perience some degree of ankling, its actual range of effectiveness could not be determined. 65 Recommendations On the basis of this study of the leg action and related areas of cycling, the following recommendations are made: 1. It would facilitate timing the film if a timer were placed within the field of view of the test area. Keep both the vertical and horizontal reference objects on the same plane. Pictures taken from the side and the front would provide more opportunity to observe any random movements that might occur. A larger sample might be considered more truly representative of the population. A pedal adaptation that would record the amount of force applied to the pedal would more reliably relate the effectiveness of ankling. Other areas of study are as follows: a. Determine what is the proper crank length. b. Determine how much force can be applied to the pedals under various conditions. c. Determine the degrees of ankling which would be most efficient. d. Do the same kind of study with a higher speed camera—~4OO frames/second. REFERENCES 66 10. 11. REFERENCES American Youth Hostels. Cycling Guide. Philadelphia: Philadelphia Council, American Youth Hostel n.d. Bicycle Institute of America, and Amateur Bicycle League of America. How to Improve Your Cycling. Chicago: The Athletic Institute of America, 1968. . Bike Fun. New York: Bicycle Institute of America, 1959, 47. Cureton, Thomas K., Jr. "Elementary Principles and Techniques of Cinematographic Analysis as Aids in Athletic Research" as quoted from the Scientific Principles of Coaching by John W. Bunn. Englewood Cliffs: Prentice-Hall, Inc., 1962. DeLong, Fred. "Cyclodynamics." Am. C 01., 5 (July, 1966), 20-21. "Crank Length. Am. Cycl., 5 (May, 1969), 30—31. "Dead at Center." Am. Cyc1., 5 (August, ” l966), 20-21. Derailleur Lightweights--A New Dimension in Cycling. Chicago: Schwinn Bicycle Co. n.d. (Pamphlet.) "Handlebars and Riding Position." Am. Cycl., 5 (April, 1966), 16. . "What Length Cranks?" Am. Cycl., 7 (Sept., 1967), 14-15. r Co. Rolling Resistance of ion Bic cle Tires to Compare Regular Product vs.ySpecial vs. Competition. A letter to W. D. Harmon, Tire Test Division, March 9, 1965. Goodyear Tire and Rubbe 67 l2. l3. l4. 15. 16. 17. l8. 19. 68 Morse, Milton. "Experiments with Crank Lengths." Am. Cycl., 7 (Sept., 1967), 15. Porter, Luther H. Cycling for Health and Pleasure. New York: Dodd, Mead and Co., 1895. Portuesi, Gene. Cyclo-Pedia: Cycling Handbook and Catalog. 8th ed. Detroit: 1967, 28. Semat, Henry, and Blumenthal, Ralph H. College Physics: A Programmed Aid. New York: Holt, Rinehart and Winston, 1967. Shaw, Reginald C. Teach Yourself Cycling. London: The English Universities Press Ltd., 1963. Singh, Sukhwant. "Mechanical Adjustments of Cycling for Safety, Comfort and Speed." Unpublished Master's thesis, Springfield College, 1963. Vaughn, Thomas. "Scientific Setting of Saddle Position." Am. Cycl., 6 (June, 1967), 12-13. Williams, M., and Lisner, H. Biomechanics of Human Motion. Philadelphia: W. B. Saunders Co., 1962. APPENDIX 69 7O Saddle to Bracket Saddle Height Frame Height Crank Length Figure A-l.—-Points of measurement on bicycle. 71 +—Chainwheel l. Leg Position When 2. Leg Position When Crank is Vertical. Crank Angle Nearest to 90°. 1 0° 02° 1770 When 3. Leg Position When 4. Leg Position Ankle Angle Nearest Crank Nearest 180°. to 90°. Figure A—2.—-Leg action of subject A at different crank angles. 72 86° I ' 4 5. Leg Position When 6. Leg Position When Crank Angle 247°. Crank Angle Again at 90° (270°) to the Vertical. 6 0 95° I I 7. Leg Position Prior to 8. Leg Position AS Ankle Flexion Begins. Beginning of Ankle Flexion. Figure A—2.-—(Continued) Force in lbs. Force in lbs. Force in lbs. Force in lbs. 73 50 -_ 25 a g ' fl W 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT A 50 -~ 25 111- - - 1 - O 25 5O 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT B 50 .- 25 ‘bw—J‘Wfi‘fkfi A {—4 O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT C 50 1 25 "- W vi‘r ‘ ‘ ‘ ‘fi/N O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT E Figure A-3.-—Comparison of net body weight on handlebars-male cyclists. 74 3501— r1 5:: fi251ho—M—w—o—OMW m 0 a £2 = 1‘ 1 : . . . ' l l 9| O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT D a; :3 50 v G v{ (1)25 4- 0 +4’- ‘7 3 ‘F—‘fi‘f‘ k<+;—: a o :11 ' i l 7 I i i I O 25 5O 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT F Figure A-4.-—Comparison of net body weight on handlebars—female cyclists. Force on seat in lbs. Force on seat in lbs. 75 100 ‘ 7 75 ‘- l l 1 l l l A I I l I I I fl 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT A 125 7 EA A /\ 100 ‘h/ 75 ._ 50 1 25 ~ 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT B Figure A-5.--Comparison of body weight on seat- male cyclists. Force on seat in lbs. Force on seat in lbs. 76 150 T 125 1 100 _ 75 1— 50 1 25 .. AL 1 l l l l l l ' i I V I ' 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT C 125 T 100 1 75 «— 50 + 1 n A ‘2 i 1 I l I 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT E Figure A-5.--(Continued) Force on seat in lbs. Force on seat in lbs. 77 100 - A N U1 50 - 25 . f i i i i i 1 4—fi 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT D 100 T 75 "W 50 -~ 25 1 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT F Figure A-6.-—Comparison of body weight on seat- female cyclists. Force on Force on Force on Force on one pedal one pedal one pedal one pedal 78 U1 O 5' [\3 U1 l l 1 T I t f f g + 1 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT A 50 A 25 “w J Y 1 I 1 l I 1 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT B 50 “r 25 “W l l I A T I I 1 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT C 50 v 2555\ ' V'L‘: AAAAAAA I l 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT E —Comparison of minimum force on pedal (rider seated) male cyclists. Figure A-7.— Force on one pedal Force on one pedal 79 25 1 : JV i i 5 i i *3 O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT D I 25 1 O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT F Figure A-8.—-Comparison of minimum force on pedal (rider seated) female cyclists. Maximum Force on Pedal Maximum Force on Pedal 175-r' 80 150—1.. 125‘” 100-- 75‘? 50H.— 25-— I’ l l l L ' l I ‘l I J: i i O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT A 150—? 125Jr lOO—— 75-— 50H— 25—- I l l l I i I l J T I I l I l I I O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT B Figure A-9.——Comparison of maximum force on pedal (rider standing) male cyclists. Force on one pedal Force on one pedal 175-.. 150-— 125-— lOOHe 75-- 50-— 25-- I I I I +— I I I O 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT C 175—F 150-1 125-- 100-1 75—— 50__ 25-— I 1 I I I I I I l I l l l l I 1 0 25 5O 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT E n H—If‘nht i YIHF‘IT) Force on one pedal Force on one pedal 125 7- lOOH— 75-- 50-- 25__ 11 l l I I I I I I I I I I I I fl 0 25 50 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT D 125-F 100-- 75—- 501- 25“ l J J I I l J I l I I I l I I O 25 5O 75 100 125 150 175 200 Degree of Crank Rotation SUBJECT F Figure A—lO.——Comparison of maximum force on pedal (rider standing) female cyclists. 83 m.O mm.O mm.O mm.O OOH.O mm.m boom m.mH mHm.OH ms.mH m.pH m.pH mm.OH th 0.0H ms.OH ONO.mH ONO.mH O.pH mmO.mH Oane mmH.O m.OH mmH.O ONO.OH mam.OH 0.0H enmtcom m.OH m.mH mam.m O.mH O.mH mam.HH Eta ONO.Hm mmH.Om 0.0m m.mm O.Om m.Om scans Ocm some .Ommm monocH CH mcpwcoH pomewmm mmH mOH OOH HOH OOH OOH mosses cH pgmHmz m m a O m < paowmpmo muowwosm .mepmcmH pcmewtm Oct mpanmz OOOOOOOII.H< mqmmm OH.H Hms.H Om.H OHH.H FOO. FOO. mgmno std mocooom mo .02 m6 Op mp6 SO 36 mp6 3:05” 51 xcmpo mo npwcmq m.:m mm.mw m.mw O.mw mpm.:m mp.mw monocH :H Homzz can mo moocoameSOLHo wcHHHom p.mm 116m :60 mém p.mw O.:m Hows: Emma on» no LopoEmHo on» mmEHp OHumn ammo HNOO.m Hupm.m H1pm.m Huom.m HHOO.m HHHH.m OHumm ammo OH\OO OH\Om OHxOm OH\OO OH\OO Oxsm Otxoozam\Hmmcz Ichzo Loo snoop wo .02 mm mm Hm mm m.mm OH A.moHv ucmez mHomon m m O O m < zpowmpmo mpotnnsm .Muwo mHo>0HmII.m< mqm¢e FORMULAS FOR FIGURING BICYCLE RESISTANCES Rolling circumference - A chalk mark is placed on the bike tire plus one on the ground horizontal to the tire. The subject sits on the saddle and moves the bicycle forward for one revolution of the tire. When the mark on the tire is exactly vertical and on the ground again, another chalk mark is put on the floor at this point. The measured distance between these two marks is the rolling circumference. Rolling resistance = Expressed in foot pounds — .72/100 lbs. R I‘ The rolling circumference of the tire. The pedal radius. The per cent of rolling resistance of the tire re 100 lbs. pressure. The amount of force required to overcome rolling resistance. The amount of force needed to overcome bearing, chain and sprocket losses. The total amount of force needed on the pedal when the pedal is 90° from the vertical. It is also the amount of force needed on the pedal to maintain momentum under the same conditions. 85 86 (Formulas for Figuring Bicycle Resistances, Cont.. _ No. of teeth in front sprocket _ Ratio of wheel to . No. of teeth in rear sprocket — pedal revolution , Rolling re- P = 72 .total weight of rider and bike) = sistance of ‘ \ 100 tire re 100 lbs. load R 2 Rolling circumgirence of tire = Radius of tire r = Pedal radius or crank length T = k P R = Force required to overcome l r rolling resistance g’bearing, chain, and sprocket Force needed to T _{ resistances T = overcome bearing, 2 _'\%5Rolling resistance of tire 1 chain, and sprocket resist- ance T = T + T = Amount of force needed to maintain momentum l 2 87 mm.mH mo.Om Hp.om mm.pm HH.:m mm.mm HBO EnocmEoE CHOchmE on vopmoc conch .mp4 mm.HH mO.mH OO.NH HO.HH OH.OH mO.OH HOBO OOOOOH ptxOOLOm ocm chco .wcHnmon oEoopo>o op mopom mHm.p :H.OH mo.m m0.0H pm.m mH.OH AHBV cocwumHmmc wsHHHo.H oEooco>o on mmocom m.m O.p mp.O mp.m mp.w mp.O Acv msHOmm Hmomm mO.MH mm.mH mH.mH Hm.mH m2.MH pH.MH Amv mocmcmmesocHo wcHHHom OmH.H Om.H OmH.H OOm.H Om.H OH.H HOV tocmpmHmtt wcHHHom mOO.m pm.m pm.m m.m mmO.m O.m Axv 20Hp3H0>mc Hmomo on Hows: no OHpmm m m O O m < pcommpmo mpoowosm .mmocmpmHmmh oHomonII.m< mqm