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The Physician and Physical Education of the School Child
The Physician and Physical Education of the School Child GORDON R. CUMMING, M.D.
In recent years government and educational leaders have emphasized the importance of adequate physical education programs in the schools. Physicians are required to counsel parents and schools on the advisability of specific children partaking in physicial education classes, and, in addition, they should be prepared to see that the school their own children attend provides a suitable physical education curriculum. Unfortunately, most physicians have not been sufficiently exposed to the science of physical education, and scientific lmowledge of physical exercise in health and various disease states is far from complete. Many in the medical profession have been remarkably apathetic to the problems of physical education and even to physical fitness in general. "Fitness for what?" and 'Who lmows what fitness is, anyway?" are hackneyed phrases used by those who often have a personal antithesis against most forms of physical exertion. Our society accepts that a certain degree of strength, endurance, agility and proficiency in a variety of motor skills are desirable characteristics for children, and it is the responsibility of the health professions to understand these attributes and to promote their attainment. The modem trend toward increase in leisure time and reduced physical labor with increased mental strain has made physical education an important topic for every citizen. WORKING CAPACITY
Exercise physiologists are in general agreement that the best measure of over-all fitness is the aerobic capacity of a subject, expressed as the maximal oxygen consumption (V02 max. in L./min.). The measurement of V02 max. requires a maximal effort by the subject, demanding full cooperation and motivation. Some of the subjective elements of this Supported in part by the Manitoba Heart Foundation and the National Fitness and Amateur Sports Directorate, Department of National Health and Welfare, Ottawa, Canada.
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measurement can be removed by requiring a pulse rate of over 200 in children, a rise in blood lactic acid to over 70 mg. per 100 mI., or by showing a plateau in the oxygen consumption work load curve where a further increment for work load fails to produce a rise in oxygen uptake. A plateau effect can only be demonstrated in about half of the children2 compared to four fifths of the adults. 12 • 13 Astrand2 has published a detailed study of maximal exercise tests in children who were a little above average in physical abilities. In this study, V02 max. for boys increased from 1.01 L./min. at age four to six, to 2.46 L./min. at age 12 to 13, and 3.53 L./min. at age 14 to 15. Values were lower for girls: 0.88 to 2.90 L./min. Per kilogram of body weight V02 max. in boys was 49, 56 and 58 ml./min./kg. at ages six, eight and 15 years respectively and corresponding V02 max. in girls was 48, 54 and 46 ml./min./kg. Values from this laboratory (Table 16) have been obtained from studies of entire classes of school children not oriented to any special physical education programs and probably better reflect North American average values. A brief analysis of the maximal capabilities of children is of some value in understanding their response to strenuous athletics. Per kilogram weight, the V02 max. of girls was 10 to 20 per cent below that of boys in our subjects, while Astrand found Swedish girls' performance to be closer to that of boys, and the small difference he observed could be explained on the basis of the relatively higher total body fat content of the girls. In relation to total body hemoglobin, which is a reflection of the muscle mass, aerobic capacity of the girls in Astrand's study was equal to that of the boys. The girls potentially may have the same aerobic capacity as boys per unit of lean body mass, and sex differences in physical capacity can probably be explained on the basis of size in the younger age groups, and on social pressures influencing physical activity in the older age groups, rather than on any inborn biological difference in exercise metabolism. In this country the physical. working capacity and the strength of girls increase with age only in proportion to growth, while the relative strength and working capacity of boys increase progressively until age 18 to 20. Maximum pulse rates in children range from 200 to 220 beats per minute, lesser values usually indicating submaximal efforts. Astrand found that the oxygen pulse ratio increased from about 4 mI. per beat at age four to 15 mI. per beat at age 15. With graded work loads the oxygen pulse ratio increases slightly with increased pulse rates in young children and progressively in older children and adults to reach a plateau at a pulse rate between 190 and 200 beats per minute. Thus there is no evidence of a decrease in stroke volume at these high heart rates. Resting oxygen uptake at age six to eight is 6.0 ml./min./kg.,4 and an 8 fold increase is possible. At age 15, resting oxygen uptake is 3.6 ml./kg./min., and a 15 fold increase is possible. Thus the older child and the adult
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have a larger range of oxygen intake to call upon during times of strenuous exercise. Yet on the basis of surface area or muscle mass, the working capacities of average children are the equal of those of well trained adults -food for thought for those of us who are hypercritical of the softness of today's overpampered child. Although the best way to assess how much work a subject can do is to have him perform a maximal test, submaximal tests are easier to administer, and the results are sufficient for most clinical purposes. The bicycle ergometer test described by Wahlund14 has been used in over 2000 children, normal and abnormal, in this laboratory, and if used with proper attention to a few details, the results are reproducible and correlate moderately well with the maximal tests. In this test the subject pedals for two or three successive work periods of increasing intensity of six minutes each on a calibrated exercise bicycle. A pulse rate work load curve is constructed, and the work necessary to produce a pulse rate of 170 beats per minute is arbitrarily defined as the physical working capacity (PWC). Subjects with lower working capacities are working at Table 16. MEAN MAXJSCHOOL
AGE IN
NUMBER OF
MEAN
MEAN PWC
MEAN MAXIMAL
MUM OXYGEN
GRADE
YEARS
STUDENTS
SURFACE AREA M2
KG-M/MIN./M2
PULSE RATE
UPTAKE
BEATS/MIN.
ML./KG./MIN.
203 207 203 210 208 209 208 202 201 200
46.4 46.2 48.5 49.3 53.0 51.5 52.0
202 206 205 210 208 210 206 205 206 201
42.0 43.1 39.3 36.6 43.4 42.7 43.6
Boys--U nse1ected Classes, 1964 1. ... 5-6 3 .... 7-8 4 .... 8-9 6 .... 10-12 7 .... 12-14 8 .... 12-15 9 .... 13-16 10 .... 15-18 11 .... 16-18 12 .... 16-20
55 52 54 27 36 31 28 21 15 17
.88 1.04 1.09 1.27 1.36 1.50 1.67 1.85 1.88 1.85
295 366 372 312 355 380 470 480 469 452
Girls-Unse1ected Classes, 1964 1. ... 5-7 3 .... 7-8 4 .... 8-9 6 .... 10-11 7 .... 12-13 8 .... 13-14 9 .... 14-16 10 .... 14-16 11. ... 15-17 12 .... 17-19
46 56 63 28 26 29 22 15 15 15
.84 1.02 1.06 1.24 1.33 1.63 1.51 1.61 1.59 1.61
254 294 289 199 268 263 260 340 273 298
PWC = physical working capacity = steady state work load required to produc e a minute pulse rate of 170.
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about 65 to 70 per cent of their maximal at this point, and those with higher working capacities at 75 to 80 per cent of their maximal, so that the capacity of poorer conditioned subjects may be underestimated by this test. 5 It requires emphasis that the exercise intensities must be such that a pulse rate of at least 165 beats per minute be produced, for extrapolation from lower pulse rates will frequently overestimate the PWC value (G. R. Cumming and W. Friesen: Unpublished data). The work loads suggested by Adams et aU to perform the test may be too low. PWC per unit surface area obtained in a recent survey of Winnipeg school children (Table 1) shows a progressive increase in boys up to age 14 to 15, indicating a relative increase in power, while in girls there was no increase with age. PHYSICAL EDUCATION FOR THE CARDIAC PATIENT
Physical educators, the general public and many physicians are most wary of allowing vigorous exercise in any patient with even a suggestion of cardiac disease. A few children are seen each year in cardiac clinics who have been banned from physical education classes for one to 10 years because of innocent heart murmurs. The fact is that the majority of children with organic heart lesions are able to take regular physical education classes with very few restrictions. Many physicians seem to reason thus: "This patient has heart disease. I do not really know whether physical education will do him any harm or not-but it might-and if I said he was fit for vigorous exercise and anything happened, I would be blamed." The parent may be anxious, and the result is a medical report prohibiting participation in the school physical education program. This recommendation may follow the child throughout his or her entire school career, and at the age of 20 the young adult with a minor cardiac lesion may end up a poor physical specimen, introspective and worried about health; or the more aggressive patient will find that he can do everything that the others do without symptoms, will exercise out of school, and understandably decide that his physicians did not know much anyway. Certainly a more positive approach by the physician is necessary, and the questions should be phrased: "Is there actually any valid reason why exercise will be harmful in this patient?", and if some forms of exercise might be harmful, "What can this patient do?", rather that prohibiting physical education entirely. Cardiac lesions that might make physical exercise dangerous or harmful are (a) significant aortic stenosis and also severe mitral and pulmonary stenosis, (b) recent myocarditis or any evidence of myocardial disease, (c) rheumatic heart disease for one year after active carditis, (d) rheumatic valvular disease with cardiac dilatation, (e) congestive heart failure, (f) postoperative cardiac patients such as those with tetralogy of Fallot and ventricular septal defects for one year after
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operation, atrial septal defects and pulmonary stenosis for about three months, and (g) severe pulmonary hypertension, primary or secondary. Patients with Marfan's and Ehlers-Danlos syndromes may have weakening of the aortic wall and should also avoid strenuous activity. Asymptomatic cardiac patients who should be allowed full unrestricted activity are (a) patients with mild congenital heart lesions such as secundum atrial septal defects, ventricular septal defects with shunt under 25 per cent of pulmonary blood flow and pulmonary artery systolic pressures under 40 mm. of mercury, (b) pulmonary stenosis with the right ventricular pressures under 60 mm., aortic stenosis with peak aortic gradients under 30 mm. of mercury, (c) complete congenital heart block with normal exercise tolerance with the ability to increase heart rate moderately with exercise, and (d) patients with rheumatic valvular disease with mild to moderate mitral or aortic regurgitation when symptoms are absent and cardiac dilatation is minimal. Even patients with obvious cardiac disability may participate in regular physical education classes, stopping to rest with the onset of dyspnea or fatigue and avoiding the activities that are known to always produce symptoms. A few illustrative cases, some showing the value of working capacity tests, follow. CASE 1. W. S. was a 12-year-old girl with a normal physical examination and a grade 2 to 3 innocent heart murmur who was thought to be weak and underdeveloped by the mother, who would not accept the fact that the heart murmur was innocent. The family physician was persuaded to send a report to the school advising that the girl be excused from physical education. When tested, the exercise capacity of this girl on the bicycle was above average. Only when faced with this evidence would the mother agree that the child was probably fit and allow her to take physical education. CASE 2. R. S. was an ll-year-old girl with a diagnosis of congenital aortic stenosis, who showed a left ventricular-aortic peak systolic gradient of 96 mm. of mercury at heart catheterization. The girl denied symptoms, and her father pushed her into all activities, denying that there was anything wrong with the child other than the murmur that she would grow out of. Her exercise capacity on a bicycle was found to be that of a five-year-old girl, and the test produced much diZZiness. Based on this evidence, consent for operation was obtained. One year after operation the patient had a normal working capacity and was safely performing numerous physical activities. CASE 3. A 44-year-old woman school teacher has mild pulmonary stenosis. When she was seven, leading cardiologists of London and Paris gave the parents a poor prognosis, and a year of bed rest, with complete abstinence from all exercise for life, was advised. The patient ignored this advice, played tennis at school, and currently rides a bicycle 5 miles to her work daily. She has the highest physical working capacity value of any woman over 30 tested in this laboratory. CASE 4. G. F., age 14 with a diagnosis of tetralogy of Fallot, had a Potts anastomosis at age seven. His resting arterial oxygen saturation is 84 per cent, and, after running on the spot or doing 25 toe touches, this falls to 62 per cent.
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He still takes the regular physical education course, does all the calisthenics, and plays basketball, baseball and hockey with his friends. He avoids all tests of endurance and sprints of over 25 yards, and sits on the sideline when fatigue sets in during the calisthenics, but this is seldom necessary. CASE 5. C. D., age 17, is a patient with origin of both great vessels from the right ventricle and is considered inoperable. He is still able to ride a bicycle one mile to school in warm weather. He goes to all physical education classes, and when younger performed all calisthenics and played most games. His activity tolerance is now being limited, and he does what he can with calisthenics. During games he now serves as scorekeeper, umpire or referee.
The physical working capacity scores of many children with congenital heart defects that eventually have corrective heart surgery are not much below that of the normal average group. Duffie and Adams 6 found only a few children falling completely outside the limits of normal when tested by the bicycle ergometer physical working capacity test. Maximal tests were carried out with safety in patients with various congenital heart defects by Kramer and Lurie,S who found that such tests often do not separate those with congenital heart defects from those normals who have had no extra physical training. In the young, a healthy myocardium can well compensate for the extra mechanical burden of mild to moderate structural heart defects. Obstructive lesions, if not of critical degree, are well tolerated. Valvular regurgitation does not necessarily get worse during exercise, since increased heart rate may decrease the diastolic interval to reduce aortic regurgitation, and decreased peripheral resistance may reduce mitral regurgitation. The magnitude of shunts through atrial and ventricular septal defects does not increase, and may actually fall with exercise. Thus most children with compensated heart defects score well on bicycle ergometer tests and at least well enough to fall within the normal range despite the fact that heart surgery is often recommended. These bicycle tests involve considerably more work than that encountered in the majority of physical education programs. The heart rate response to physical education classes, and to athletic events, can be monitored by radio telerrietry. There is little encumbrance to most activities wearing an 8-ounce radio with chest electrodes. Work load, pulse rate and oxygen uptakes can be obtained beforehand from bicycle or treadmill exercises. Because of the consistency of the work load-pulse rate relation with these two forms of exercise, it is then assumed that this relation holds true during other activities. The pulse rate produced during physical education classes can then be interpreted to be equivalent to a measurable amount of work on the bicycle with a measurable oxygen uptake. Unfortunately, emotional, climatic, body temperature, and other factors may alter the pulse rate-work load response, particularly at low levels of work, and more research is necessary in this area. Figures 26 and 27 show some electrocardiograms obtained during
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a physical education class and during a hockey game. Preliminary results of this investigation show that, if left on their own, the majority of young children do not work very hard during most physical education classes, but if given individual attention and pushed, maximal heart rates may be reached. During competitive games such as hockey, peak pulse rates are the rule even in lO-year-olds who are well motivated toward winning the game.
Figure 26. Electrocardiogram of a boy aged 9 years taken during gymnasium class. A, Vault off box-rate 179. B, Running around gymnasium-rate 210. C, Climbing rope-rate 208. Considerable muscle artifact, and the subject was not able to pull himself up the rope. D, During front rolls on mat-easiest activity for him and slowest rate-169.
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Figure 27. Electrocardiogram of a boy aged 11 taken during a hockey game. A, At rest on bench in the middle of a period-slowest rate recorded for entire period, 141. B, During backchecking-rate 200. C, Carrying puck-body checked with fall to ice-rate 206.
RESPIRATORY DISEASES
Patients with chronic respiratory disease benefit from training programs that increase cardiorespiratory fitness and endurance. This increases their exercise capacity and reduces symptoms, although little objective evidence of improvement can be shown by pulmonary function testing. Jones et al,7 have shown that most children with asthma may have few or no physical signs and good ventilatory function at rest, but will develop bronchospasm with markedly reduced ventilation after five to 10 minutes of exercise. Such children should take bronchodilators before any severe physical exercise. Patients with mild acute respiratory infections or recovering from more severe infections are a common problem facing the physical educator. In general, if the child feels well enough to take physical education, there seems little justification for its prohibition. In cold weather adequate shower facilities should be available, and a rest before going out in the cold is advisable.
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DIABETES AND EXERCISE
Diabetic children tend to have lower working capacities and decreased scores in cardiorespiratory and motor fitness tests l l which can be improved by training.1/ Exercise lowers the insulin requirements of the diabetic child (see p. 928), but whether it has any effect on the disease process or on the incidence of eventual vascular complications is not known. Nevertheless all diabetic children should be encouraged to take part in regular physical education programs just as they should learn to integrate themselves into all normal activities. If normal activity is not allowed, the chances of psychologic maladjustment would seem to be increased. EPILEPSY
Epileptic children likewise can take part in the normal physical education programs. Vigorous physical exercise does not increase the chances of an epileptic seizure. Injury in some activities such as vaulting, or working at heights, is a possibility the physical educator should be aware of, and swimming requires closer supervision. Nevertheless participation in physical education programs and in sports can only help the epileptic gain in self-confidence and social acceptance. NEUROMUSCULAR AND ORTHOPEDIC PROBLEMS
Children with neuromuscular disorders such as postpoliomyelitis paresis, muscular dystrophy and cerebral palsy, and orthopedic handicaps such as amputations, scoliosis and congenital hip dislocations, cover such a wide range from the totally disabled to the almost normal in function that only a generalized statement is possible. Some harm can occur with the attitude of, "Go to it-if you work those bones and muscles hard enough, they will come around," and overstraining with stretching of ligaments and muscles leading to an increase in deformity must be avoided. In the majority of schools the physical educator is overworked and unable to give special attention to such children. In addition, with the high level of general health in the school-age population, most schools do not have a sufficient number of handicapped children to justify the expense of providing therapeutic classes. This area would seem best taken care of in most communities through Crippled Children's Societies and physiotherapy departments in the hospitals. If possible, these children should be fitted into the standard school program and allowed to do as much as they can. Acute problems such as athletic injuries are covered elsewhere (p. 1Q27). It is obvious that no child should be allowed to risk permanent
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injury even for that "all-important game," and the physician must be as objective as possible in assessing when it is safe to allow the injured to return to competitive sports. Children who are poorly coordinated, or awkward, and the obese and the underdeveloped child constitute a special situation for the physical educator. These children are often self-conscious and are ridiculed by their peers, and scolded by their teachers for not producing. In addition, there is the so-called tired child who, on the day of having his physical education class, comes home completely exhausted, complaining to the mother, who eventually gets a physician's certificate allowing the child to escape the ordeal. All such children, it would seem, would benefit considerably from extra physical education with some effort toward actual training, and, of course, they need encouragement rather than criticism.lO These children may cause anguish to the physical educator who wants only a winning team, but there is no valid medical reason for excusing these children from physical education classes. The physical educator would be well advised to spend more time with the awkward child, even though this allows less time for the natural athletes in the school. THE ATHLETE
One of the obvious conclusions to be drawn from the recent Olympic Games is that youth is no deterrent to success in strenuous athletic performance, especially in swimming. Victory in the modem Olympics requires a large amount of natural ability, but also a great deal of perseverance, self-denial, and plain hard work to the point of physical torture. With graduated training programs, overstrain does not occur, and in general there is no proof of any permanent ill effect from these heroic efforts. Thus the question of how much and how severe should the exercises be in a school physical education program is more sociological than physiological. Some of the improvement of athletic performances of youth in recent times may be due to growth, nutritional and health factors, but most of the gains in athletic records are probably the result of intensive and systematic training. As pediatricians, we must concern ourselves whether such training at an early age is harmful in any way, either physically or mentally. The report by Astrand et aLB on 30 girl swimmers, 12 to 16 years of age, who trained 28 hours weekly is one of the few complete studies attempting to answer these problems in an unbiased and scientific manner. Most of the girls were from upper middle class families, and the parents had been active in athletics and were actively interested in the athletic prowess of their girls. Problems possibly peculiar to swimming, such as respiratory infections, sinus and ear difficulties, did not seem to be troublesome, and the possibility of gynecologic complications was considered in detail. The girls' heights had been above
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average even at age seven, and growth was accelerated beyond average in the early teens, but this may well have been due to prior constitutional traits rather than to the training. Psychologic studies showed intelligence above average, normal social development and energetic, purposeful, extroverted attitudes in the girls, the latter traits being fundamental to meeting the challenge of the training. According to the parents, the girls were always this way, and these traits were not the result of the training. There were no detrimental psychologic effects attributable to the rigorous training and loss of leisure hours. The mean maximum oxygen uptake of the swimmers was only 10 per cent above that of girls not in training, but almost half of the 30 subjects had maximal oxygen uptakes over 2 standard deviations above the mean of the average girls. The maximum oxygen uptake for the distance swimmers was equal to or higher than that found in normal young men. There was good correlation between the oxygen uptake on the bicycle test and swimming proficiency. This was a study of the top swimmers, and a comparison with girls who trained perhaps just as hard without achieving success was not obtained. An unanswered problem is whether an increased working capacity with increased heart and lung volumes is easier to achieve with training in adolescence during a rapid growth phase rather than later in life. More studies such as this one are urgently needed on this continent with various sports where children are involved in serious athletic training often starting at age 10. Such studies should commence before the training has started, not when the child is a well trained young athlete. SUMMARY AND CONCLUSIONS
The objectives of physical education are those of education in general with emphasis on the physical process-the promotion of health, good citizenship and ethical character, preparation for vocation, higher learning and recreation with help in the use of leisure time, and assistance in finding social acceptance and enjoyment of life. In any child with an illness, participation in vigorous physical exercise brings out anxieties and uncertainties in the minds of the child, the parent, the physical educator and, unfortunately, the physician. With a little common sense, most children going to school can fit into the standard physical education program. There is a middle-of-the-road course between keeping anyone with a disability out of physical education, and the overzealous attitude that anyone who is well enough to go to school and does not do everything in the physical education class is a shirker. In the handicapped the activity must not aggravate the illness, injury or a deformity. The activity must be appropriate to the age level of the child, and the educator must develop in the child an interest in and enthusiasm for the program. The child should be able to achieve some
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success in what he is doing; particularly when his peers are doing better, the child with the mild handicap needs encouragement and praise for any improvement he shows. If possible, activities in older children should be, in part, directed so as to provide lasting recreational value. With a common-sense approach the majority of children can take part in regular physical education programs, and this includes those children with congenital and rheumatic heart disease, diabetes, epilepsy, and mild neuromuscular and orthopedic disorders. There is perhaps too much tendency on the part of the physician to take the easy way out to satisfy the parent, rather than help with the education of the child. In many instances communication between physician and the physical educator leaves a great deal to be desired.
REFERENCES 1. Adams, F. H., Linde, L. M., and Miyake, H.: The Physical Working Capacity of Nonnal School Children. California Pediatrics, 28:55, 1961. 2. Astrand, P.O.: Experimental Studies of Physical Working Capacity in Relation to Sex and Age. Copenhagen, Egner Monksgaard, 1952. 3. Astrand, P.O., and others: Girl Swimmers, with Special Reference to Respiratory and Circulatory Adaptation and Gynecological and Psychiatric Aspects. Acta Pediat., Suppl. 147, 1-75, 1963. 4. Cassels, D. E., and Morse, M.: Cardiopulmonary Data for Children and Young Adults. Springfield, Ill., Charles C Thomas, 1962, p. 57. 5. Cumming, G. R., and Danzinger, R.: Bicycle Ergometer Studies in Children. II. Correlation of Pulse Rate with Oxygen Consumption. Pediatrics, 32:202, 1963. 6. Duffie, E. R., Jr., and Adams, F. H.: The Use of the Working Capacity Test in the Evaluation of Children with Congenital Heart Disease. Pediatrics, 32:757, 1963. 7. Jones, R. S., Wharton, M. J., and Buston, M. H.: The Place of Physical Exercise and Bronchodilator Drugs in the Assessment of the Asthmatic Child. Arch. Dis. Childhood, 38:539, 1963. 8. Kramer, J. D., and Lurie, P.: Maximal Exercise Tests in Children. Am. J. Dis. Child., 108:283, 1964. 9. Larsson, Y., Sterky, G., Ekengren, K., and Moller, T.: Physical Fitness and the Influence of Training in Diabetic Adolescent Girls. Diabetes, 11: 109, 1962. 10. Mathews, D. K., Kruse, R., and Shaw, V.: The Science of Physical Education for Handicapped Children. New York, Harper and Brothers, 1962. 11. Sterky, G.: Physical Work Capacity in Diabetic School Children. Acta Pediat., 52:1,1963. 12. Taylor, H. L., Buskirk, E., and Henschel, A.: Maximal Oxygen Uptake as an Objective Measure of Cardio-Respiratory Perfonnance. J. Appl. Physiol., 8:73, 1955. 13. Taylor, H. L., Wang, Y., Rowell, L., and Blomqvist, G.: The Standardization and Interpretation of Submaximal and Maximal Tests of Working Capacity. Pediatrics, 32:703, 1963. 14. Wahlund, H.: Determination of the Physical Working Capacity. Acta Med. Scandinav., Suppl. 215:9, 1948. The Children's Hospital Winnipeg 3, Manitoba Canada
In recent years government and educational leaders have emphasized the importance of adequate physical education programs in the schools. Physicians are required to counsel parents and schools on the advisability of specific children partaking in physicial education classes, and, in addition, they should be prepared to see that the school their own children attend provides a suitable physical education curriculum. Unfortunately, most physicians have not been sufficiently exposed to the science of physical education, and scientific lmowledge of physical exercise in health and various disease states is far from complete. Many in the medical profession have been remarkably apathetic to the problems of physical education and even to physical fitness in general. "Fitness for what?" and 'Who lmows what fitness is, anyway?" are hackneyed phrases used by those who often have a personal antithesis against most forms of physical exertion. Our society accepts that a certain degree of strength, endurance, agility and proficiency in a variety of motor skills are desirable characteristics for children, and it is the responsibility of the health professions to understand these attributes and to promote their attainment. The modem trend toward increase in leisure time and reduced physical labor with increased mental strain has made physical education an important topic for every citizen. WORKING CAPACITY
Exercise physiologists are in general agreement that the best measure of over-all fitness is the aerobic capacity of a subject, expressed as the maximal oxygen consumption (V02 max. in L./min.). The measurement of V02 max. requires a maximal effort by the subject, demanding full cooperation and motivation. Some of the subjective elements of this Supported in part by the Manitoba Heart Foundation and the National Fitness and Amateur Sports Directorate, Department of National Health and Welfare, Ottawa, Canada.
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measurement can be removed by requiring a pulse rate of over 200 in children, a rise in blood lactic acid to over 70 mg. per 100 mI., or by showing a plateau in the oxygen consumption work load curve where a further increment for work load fails to produce a rise in oxygen uptake. A plateau effect can only be demonstrated in about half of the children2 compared to four fifths of the adults. 12 • 13 Astrand2 has published a detailed study of maximal exercise tests in children who were a little above average in physical abilities. In this study, V02 max. for boys increased from 1.01 L./min. at age four to six, to 2.46 L./min. at age 12 to 13, and 3.53 L./min. at age 14 to 15. Values were lower for girls: 0.88 to 2.90 L./min. Per kilogram of body weight V02 max. in boys was 49, 56 and 58 ml./min./kg. at ages six, eight and 15 years respectively and corresponding V02 max. in girls was 48, 54 and 46 ml./min./kg. Values from this laboratory (Table 16) have been obtained from studies of entire classes of school children not oriented to any special physical education programs and probably better reflect North American average values. A brief analysis of the maximal capabilities of children is of some value in understanding their response to strenuous athletics. Per kilogram weight, the V02 max. of girls was 10 to 20 per cent below that of boys in our subjects, while Astrand found Swedish girls' performance to be closer to that of boys, and the small difference he observed could be explained on the basis of the relatively higher total body fat content of the girls. In relation to total body hemoglobin, which is a reflection of the muscle mass, aerobic capacity of the girls in Astrand's study was equal to that of the boys. The girls potentially may have the same aerobic capacity as boys per unit of lean body mass, and sex differences in physical capacity can probably be explained on the basis of size in the younger age groups, and on social pressures influencing physical activity in the older age groups, rather than on any inborn biological difference in exercise metabolism. In this country the physical. working capacity and the strength of girls increase with age only in proportion to growth, while the relative strength and working capacity of boys increase progressively until age 18 to 20. Maximum pulse rates in children range from 200 to 220 beats per minute, lesser values usually indicating submaximal efforts. Astrand found that the oxygen pulse ratio increased from about 4 mI. per beat at age four to 15 mI. per beat at age 15. With graded work loads the oxygen pulse ratio increases slightly with increased pulse rates in young children and progressively in older children and adults to reach a plateau at a pulse rate between 190 and 200 beats per minute. Thus there is no evidence of a decrease in stroke volume at these high heart rates. Resting oxygen uptake at age six to eight is 6.0 ml./min./kg.,4 and an 8 fold increase is possible. At age 15, resting oxygen uptake is 3.6 ml./kg./min., and a 15 fold increase is possible. Thus the older child and the adult
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have a larger range of oxygen intake to call upon during times of strenuous exercise. Yet on the basis of surface area or muscle mass, the working capacities of average children are the equal of those of well trained adults -food for thought for those of us who are hypercritical of the softness of today's overpampered child. Although the best way to assess how much work a subject can do is to have him perform a maximal test, submaximal tests are easier to administer, and the results are sufficient for most clinical purposes. The bicycle ergometer test described by Wahlund14 has been used in over 2000 children, normal and abnormal, in this laboratory, and if used with proper attention to a few details, the results are reproducible and correlate moderately well with the maximal tests. In this test the subject pedals for two or three successive work periods of increasing intensity of six minutes each on a calibrated exercise bicycle. A pulse rate work load curve is constructed, and the work necessary to produce a pulse rate of 170 beats per minute is arbitrarily defined as the physical working capacity (PWC). Subjects with lower working capacities are working at Table 16. MEAN MAXJSCHOOL
AGE IN
NUMBER OF
MEAN
MEAN PWC
MEAN MAXIMAL
MUM OXYGEN
GRADE
YEARS
STUDENTS
SURFACE AREA M2
KG-M/MIN./M2
PULSE RATE
UPTAKE
BEATS/MIN.
ML./KG./MIN.
203 207 203 210 208 209 208 202 201 200
46.4 46.2 48.5 49.3 53.0 51.5 52.0
202 206 205 210 208 210 206 205 206 201
42.0 43.1 39.3 36.6 43.4 42.7 43.6
Boys--U nse1ected Classes, 1964 1. ... 5-6 3 .... 7-8 4 .... 8-9 6 .... 10-12 7 .... 12-14 8 .... 12-15 9 .... 13-16 10 .... 15-18 11 .... 16-18 12 .... 16-20
55 52 54 27 36 31 28 21 15 17
.88 1.04 1.09 1.27 1.36 1.50 1.67 1.85 1.88 1.85
295 366 372 312 355 380 470 480 469 452
Girls-Unse1ected Classes, 1964 1. ... 5-7 3 .... 7-8 4 .... 8-9 6 .... 10-11 7 .... 12-13 8 .... 13-14 9 .... 14-16 10 .... 14-16 11. ... 15-17 12 .... 17-19
46 56 63 28 26 29 22 15 15 15
.84 1.02 1.06 1.24 1.33 1.63 1.51 1.61 1.59 1.61
254 294 289 199 268 263 260 340 273 298
PWC = physical working capacity = steady state work load required to produc e a minute pulse rate of 170.
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about 65 to 70 per cent of their maximal at this point, and those with higher working capacities at 75 to 80 per cent of their maximal, so that the capacity of poorer conditioned subjects may be underestimated by this test. 5 It requires emphasis that the exercise intensities must be such that a pulse rate of at least 165 beats per minute be produced, for extrapolation from lower pulse rates will frequently overestimate the PWC value (G. R. Cumming and W. Friesen: Unpublished data). The work loads suggested by Adams et aU to perform the test may be too low. PWC per unit surface area obtained in a recent survey of Winnipeg school children (Table 1) shows a progressive increase in boys up to age 14 to 15, indicating a relative increase in power, while in girls there was no increase with age. PHYSICAL EDUCATION FOR THE CARDIAC PATIENT
Physical educators, the general public and many physicians are most wary of allowing vigorous exercise in any patient with even a suggestion of cardiac disease. A few children are seen each year in cardiac clinics who have been banned from physical education classes for one to 10 years because of innocent heart murmurs. The fact is that the majority of children with organic heart lesions are able to take regular physical education classes with very few restrictions. Many physicians seem to reason thus: "This patient has heart disease. I do not really know whether physical education will do him any harm or not-but it might-and if I said he was fit for vigorous exercise and anything happened, I would be blamed." The parent may be anxious, and the result is a medical report prohibiting participation in the school physical education program. This recommendation may follow the child throughout his or her entire school career, and at the age of 20 the young adult with a minor cardiac lesion may end up a poor physical specimen, introspective and worried about health; or the more aggressive patient will find that he can do everything that the others do without symptoms, will exercise out of school, and understandably decide that his physicians did not know much anyway. Certainly a more positive approach by the physician is necessary, and the questions should be phrased: "Is there actually any valid reason why exercise will be harmful in this patient?", and if some forms of exercise might be harmful, "What can this patient do?", rather that prohibiting physical education entirely. Cardiac lesions that might make physical exercise dangerous or harmful are (a) significant aortic stenosis and also severe mitral and pulmonary stenosis, (b) recent myocarditis or any evidence of myocardial disease, (c) rheumatic heart disease for one year after active carditis, (d) rheumatic valvular disease with cardiac dilatation, (e) congestive heart failure, (f) postoperative cardiac patients such as those with tetralogy of Fallot and ventricular septal defects for one year after
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operation, atrial septal defects and pulmonary stenosis for about three months, and (g) severe pulmonary hypertension, primary or secondary. Patients with Marfan's and Ehlers-Danlos syndromes may have weakening of the aortic wall and should also avoid strenuous activity. Asymptomatic cardiac patients who should be allowed full unrestricted activity are (a) patients with mild congenital heart lesions such as secundum atrial septal defects, ventricular septal defects with shunt under 25 per cent of pulmonary blood flow and pulmonary artery systolic pressures under 40 mm. of mercury, (b) pulmonary stenosis with the right ventricular pressures under 60 mm., aortic stenosis with peak aortic gradients under 30 mm. of mercury, (c) complete congenital heart block with normal exercise tolerance with the ability to increase heart rate moderately with exercise, and (d) patients with rheumatic valvular disease with mild to moderate mitral or aortic regurgitation when symptoms are absent and cardiac dilatation is minimal. Even patients with obvious cardiac disability may participate in regular physical education classes, stopping to rest with the onset of dyspnea or fatigue and avoiding the activities that are known to always produce symptoms. A few illustrative cases, some showing the value of working capacity tests, follow. CASE 1. W. S. was a 12-year-old girl with a normal physical examination and a grade 2 to 3 innocent heart murmur who was thought to be weak and underdeveloped by the mother, who would not accept the fact that the heart murmur was innocent. The family physician was persuaded to send a report to the school advising that the girl be excused from physical education. When tested, the exercise capacity of this girl on the bicycle was above average. Only when faced with this evidence would the mother agree that the child was probably fit and allow her to take physical education. CASE 2. R. S. was an ll-year-old girl with a diagnosis of congenital aortic stenosis, who showed a left ventricular-aortic peak systolic gradient of 96 mm. of mercury at heart catheterization. The girl denied symptoms, and her father pushed her into all activities, denying that there was anything wrong with the child other than the murmur that she would grow out of. Her exercise capacity on a bicycle was found to be that of a five-year-old girl, and the test produced much diZZiness. Based on this evidence, consent for operation was obtained. One year after operation the patient had a normal working capacity and was safely performing numerous physical activities. CASE 3. A 44-year-old woman school teacher has mild pulmonary stenosis. When she was seven, leading cardiologists of London and Paris gave the parents a poor prognosis, and a year of bed rest, with complete abstinence from all exercise for life, was advised. The patient ignored this advice, played tennis at school, and currently rides a bicycle 5 miles to her work daily. She has the highest physical working capacity value of any woman over 30 tested in this laboratory. CASE 4. G. F., age 14 with a diagnosis of tetralogy of Fallot, had a Potts anastomosis at age seven. His resting arterial oxygen saturation is 84 per cent, and, after running on the spot or doing 25 toe touches, this falls to 62 per cent.
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He still takes the regular physical education course, does all the calisthenics, and plays basketball, baseball and hockey with his friends. He avoids all tests of endurance and sprints of over 25 yards, and sits on the sideline when fatigue sets in during the calisthenics, but this is seldom necessary. CASE 5. C. D., age 17, is a patient with origin of both great vessels from the right ventricle and is considered inoperable. He is still able to ride a bicycle one mile to school in warm weather. He goes to all physical education classes, and when younger performed all calisthenics and played most games. His activity tolerance is now being limited, and he does what he can with calisthenics. During games he now serves as scorekeeper, umpire or referee.
The physical working capacity scores of many children with congenital heart defects that eventually have corrective heart surgery are not much below that of the normal average group. Duffie and Adams 6 found only a few children falling completely outside the limits of normal when tested by the bicycle ergometer physical working capacity test. Maximal tests were carried out with safety in patients with various congenital heart defects by Kramer and Lurie,S who found that such tests often do not separate those with congenital heart defects from those normals who have had no extra physical training. In the young, a healthy myocardium can well compensate for the extra mechanical burden of mild to moderate structural heart defects. Obstructive lesions, if not of critical degree, are well tolerated. Valvular regurgitation does not necessarily get worse during exercise, since increased heart rate may decrease the diastolic interval to reduce aortic regurgitation, and decreased peripheral resistance may reduce mitral regurgitation. The magnitude of shunts through atrial and ventricular septal defects does not increase, and may actually fall with exercise. Thus most children with compensated heart defects score well on bicycle ergometer tests and at least well enough to fall within the normal range despite the fact that heart surgery is often recommended. These bicycle tests involve considerably more work than that encountered in the majority of physical education programs. The heart rate response to physical education classes, and to athletic events, can be monitored by radio telerrietry. There is little encumbrance to most activities wearing an 8-ounce radio with chest electrodes. Work load, pulse rate and oxygen uptakes can be obtained beforehand from bicycle or treadmill exercises. Because of the consistency of the work load-pulse rate relation with these two forms of exercise, it is then assumed that this relation holds true during other activities. The pulse rate produced during physical education classes can then be interpreted to be equivalent to a measurable amount of work on the bicycle with a measurable oxygen uptake. Unfortunately, emotional, climatic, body temperature, and other factors may alter the pulse rate-work load response, particularly at low levels of work, and more research is necessary in this area. Figures 26 and 27 show some electrocardiograms obtained during
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a physical education class and during a hockey game. Preliminary results of this investigation show that, if left on their own, the majority of young children do not work very hard during most physical education classes, but if given individual attention and pushed, maximal heart rates may be reached. During competitive games such as hockey, peak pulse rates are the rule even in lO-year-olds who are well motivated toward winning the game.
Figure 26. Electrocardiogram of a boy aged 9 years taken during gymnasium class. A, Vault off box-rate 179. B, Running around gymnasium-rate 210. C, Climbing rope-rate 208. Considerable muscle artifact, and the subject was not able to pull himself up the rope. D, During front rolls on mat-easiest activity for him and slowest rate-169.
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Figure 27. Electrocardiogram of a boy aged 11 taken during a hockey game. A, At rest on bench in the middle of a period-slowest rate recorded for entire period, 141. B, During backchecking-rate 200. C, Carrying puck-body checked with fall to ice-rate 206.
RESPIRATORY DISEASES
Patients with chronic respiratory disease benefit from training programs that increase cardiorespiratory fitness and endurance. This increases their exercise capacity and reduces symptoms, although little objective evidence of improvement can be shown by pulmonary function testing. Jones et al,7 have shown that most children with asthma may have few or no physical signs and good ventilatory function at rest, but will develop bronchospasm with markedly reduced ventilation after five to 10 minutes of exercise. Such children should take bronchodilators before any severe physical exercise. Patients with mild acute respiratory infections or recovering from more severe infections are a common problem facing the physical educator. In general, if the child feels well enough to take physical education, there seems little justification for its prohibition. In cold weather adequate shower facilities should be available, and a rest before going out in the cold is advisable.
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DIABETES AND EXERCISE
Diabetic children tend to have lower working capacities and decreased scores in cardiorespiratory and motor fitness tests l l which can be improved by training.1/ Exercise lowers the insulin requirements of the diabetic child (see p. 928), but whether it has any effect on the disease process or on the incidence of eventual vascular complications is not known. Nevertheless all diabetic children should be encouraged to take part in regular physical education programs just as they should learn to integrate themselves into all normal activities. If normal activity is not allowed, the chances of psychologic maladjustment would seem to be increased. EPILEPSY
Epileptic children likewise can take part in the normal physical education programs. Vigorous physical exercise does not increase the chances of an epileptic seizure. Injury in some activities such as vaulting, or working at heights, is a possibility the physical educator should be aware of, and swimming requires closer supervision. Nevertheless participation in physical education programs and in sports can only help the epileptic gain in self-confidence and social acceptance. NEUROMUSCULAR AND ORTHOPEDIC PROBLEMS
Children with neuromuscular disorders such as postpoliomyelitis paresis, muscular dystrophy and cerebral palsy, and orthopedic handicaps such as amputations, scoliosis and congenital hip dislocations, cover such a wide range from the totally disabled to the almost normal in function that only a generalized statement is possible. Some harm can occur with the attitude of, "Go to it-if you work those bones and muscles hard enough, they will come around," and overstraining with stretching of ligaments and muscles leading to an increase in deformity must be avoided. In the majority of schools the physical educator is overworked and unable to give special attention to such children. In addition, with the high level of general health in the school-age population, most schools do not have a sufficient number of handicapped children to justify the expense of providing therapeutic classes. This area would seem best taken care of in most communities through Crippled Children's Societies and physiotherapy departments in the hospitals. If possible, these children should be fitted into the standard school program and allowed to do as much as they can. Acute problems such as athletic injuries are covered elsewhere (p. 1Q27). It is obvious that no child should be allowed to risk permanent
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injury even for that "all-important game," and the physician must be as objective as possible in assessing when it is safe to allow the injured to return to competitive sports. Children who are poorly coordinated, or awkward, and the obese and the underdeveloped child constitute a special situation for the physical educator. These children are often self-conscious and are ridiculed by their peers, and scolded by their teachers for not producing. In addition, there is the so-called tired child who, on the day of having his physical education class, comes home completely exhausted, complaining to the mother, who eventually gets a physician's certificate allowing the child to escape the ordeal. All such children, it would seem, would benefit considerably from extra physical education with some effort toward actual training, and, of course, they need encouragement rather than criticism.lO These children may cause anguish to the physical educator who wants only a winning team, but there is no valid medical reason for excusing these children from physical education classes. The physical educator would be well advised to spend more time with the awkward child, even though this allows less time for the natural athletes in the school. THE ATHLETE
One of the obvious conclusions to be drawn from the recent Olympic Games is that youth is no deterrent to success in strenuous athletic performance, especially in swimming. Victory in the modem Olympics requires a large amount of natural ability, but also a great deal of perseverance, self-denial, and plain hard work to the point of physical torture. With graduated training programs, overstrain does not occur, and in general there is no proof of any permanent ill effect from these heroic efforts. Thus the question of how much and how severe should the exercises be in a school physical education program is more sociological than physiological. Some of the improvement of athletic performances of youth in recent times may be due to growth, nutritional and health factors, but most of the gains in athletic records are probably the result of intensive and systematic training. As pediatricians, we must concern ourselves whether such training at an early age is harmful in any way, either physically or mentally. The report by Astrand et aLB on 30 girl swimmers, 12 to 16 years of age, who trained 28 hours weekly is one of the few complete studies attempting to answer these problems in an unbiased and scientific manner. Most of the girls were from upper middle class families, and the parents had been active in athletics and were actively interested in the athletic prowess of their girls. Problems possibly peculiar to swimming, such as respiratory infections, sinus and ear difficulties, did not seem to be troublesome, and the possibility of gynecologic complications was considered in detail. The girls' heights had been above
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average even at age seven, and growth was accelerated beyond average in the early teens, but this may well have been due to prior constitutional traits rather than to the training. Psychologic studies showed intelligence above average, normal social development and energetic, purposeful, extroverted attitudes in the girls, the latter traits being fundamental to meeting the challenge of the training. According to the parents, the girls were always this way, and these traits were not the result of the training. There were no detrimental psychologic effects attributable to the rigorous training and loss of leisure hours. The mean maximum oxygen uptake of the swimmers was only 10 per cent above that of girls not in training, but almost half of the 30 subjects had maximal oxygen uptakes over 2 standard deviations above the mean of the average girls. The maximum oxygen uptake for the distance swimmers was equal to or higher than that found in normal young men. There was good correlation between the oxygen uptake on the bicycle test and swimming proficiency. This was a study of the top swimmers, and a comparison with girls who trained perhaps just as hard without achieving success was not obtained. An unanswered problem is whether an increased working capacity with increased heart and lung volumes is easier to achieve with training in adolescence during a rapid growth phase rather than later in life. More studies such as this one are urgently needed on this continent with various sports where children are involved in serious athletic training often starting at age 10. Such studies should commence before the training has started, not when the child is a well trained young athlete. SUMMARY AND CONCLUSIONS
The objectives of physical education are those of education in general with emphasis on the physical process-the promotion of health, good citizenship and ethical character, preparation for vocation, higher learning and recreation with help in the use of leisure time, and assistance in finding social acceptance and enjoyment of life. In any child with an illness, participation in vigorous physical exercise brings out anxieties and uncertainties in the minds of the child, the parent, the physical educator and, unfortunately, the physician. With a little common sense, most children going to school can fit into the standard physical education program. There is a middle-of-the-road course between keeping anyone with a disability out of physical education, and the overzealous attitude that anyone who is well enough to go to school and does not do everything in the physical education class is a shirker. In the handicapped the activity must not aggravate the illness, injury or a deformity. The activity must be appropriate to the age level of the child, and the educator must develop in the child an interest in and enthusiasm for the program. The child should be able to achieve some
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success in what he is doing; particularly when his peers are doing better, the child with the mild handicap needs encouragement and praise for any improvement he shows. If possible, activities in older children should be, in part, directed so as to provide lasting recreational value. With a common-sense approach the majority of children can take part in regular physical education programs, and this includes those children with congenital and rheumatic heart disease, diabetes, epilepsy, and mild neuromuscular and orthopedic disorders. There is perhaps too much tendency on the part of the physician to take the easy way out to satisfy the parent, rather than help with the education of the child. In many instances communication between physician and the physical educator leaves a great deal to be desired.
REFERENCES 1. Adams, F. H., Linde, L. M., and Miyake, H.: The Physical Working Capacity of Nonnal School Children. California Pediatrics, 28:55, 1961. 2. Astrand, P.O.: Experimental Studies of Physical Working Capacity in Relation to Sex and Age. Copenhagen, Egner Monksgaard, 1952. 3. Astrand, P.O., and others: Girl Swimmers, with Special Reference to Respiratory and Circulatory Adaptation and Gynecological and Psychiatric Aspects. Acta Pediat., Suppl. 147, 1-75, 1963. 4. Cassels, D. E., and Morse, M.: Cardiopulmonary Data for Children and Young Adults. Springfield, Ill., Charles C Thomas, 1962, p. 57. 5. Cumming, G. R., and Danzinger, R.: Bicycle Ergometer Studies in Children. II. Correlation of Pulse Rate with Oxygen Consumption. Pediatrics, 32:202, 1963. 6. Duffie, E. R., Jr., and Adams, F. H.: The Use of the Working Capacity Test in the Evaluation of Children with Congenital Heart Disease. Pediatrics, 32:757, 1963. 7. Jones, R. S., Wharton, M. J., and Buston, M. H.: The Place of Physical Exercise and Bronchodilator Drugs in the Assessment of the Asthmatic Child. Arch. Dis. Childhood, 38:539, 1963. 8. Kramer, J. D., and Lurie, P.: Maximal Exercise Tests in Children. Am. J. Dis. Child., 108:283, 1964. 9. Larsson, Y., Sterky, G., Ekengren, K., and Moller, T.: Physical Fitness and the Influence of Training in Diabetic Adolescent Girls. Diabetes, 11: 109, 1962. 10. Mathews, D. K., Kruse, R., and Shaw, V.: The Science of Physical Education for Handicapped Children. New York, Harper and Brothers, 1962. 11. Sterky, G.: Physical Work Capacity in Diabetic School Children. Acta Pediat., 52:1,1963. 12. Taylor, H. L., Buskirk, E., and Henschel, A.: Maximal Oxygen Uptake as an Objective Measure of Cardio-Respiratory Perfonnance. J. Appl. Physiol., 8:73, 1955. 13. Taylor, H. L., Wang, Y., Rowell, L., and Blomqvist, G.: The Standardization and Interpretation of Submaximal and Maximal Tests of Working Capacity. Pediatrics, 32:703, 1963. 14. Wahlund, H.: Determination of the Physical Working Capacity. Acta Med. Scandinav., Suppl. 215:9, 1948. The Children's Hospital Winnipeg 3, Manitoba Canada