Hansen, J.D.

Sloan, A.W.

English

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508 S.A. MEDICAL JOUR AL 26 April 1969NUTRITION AND PHYSICAL FITNESS OF WIDTE, COLOURED, AND BANTUmGH-SCHOOL CHILDREN*A. W. SLOAN, B.sc., MD. (GLASG.), PH.D. (CAPE Tow), F.R.C.P. (GLASG.), M.R.C.P., F.R.S.S.AF. AND J. D. L.HANSE , M.D. (CAPE Tow), F.R.C.P., D.C.H. (E G.), Departments of Physiology and Child Health, Universityof Cape Townstandard scores (T-scores: sigma scores'O). For all theboys and for all the girls the mean (x) and the standarddeviation (a) were calculated for the results of each test.For each test for boys and for girls the range x± 3a wasequated to the range 0 - 100 of the corresponding standardscore. The scores for the runs were 'inverted', since theshortest time corresponds to the best performance. Eachindividual raw score was then converted to the corre-sponding standard score. The 7 standard scores for eachindividual were added and the total divided by 7 to give a'fitness index', which was taken as the measure of physicalfitness.In each age-group of boys and of girls the heights,weights, and fitness indexes of the 3 racial groups werecompared. The heights and weights were compared alsowith standards of height and weight for British children."By analysis of covariance the effects of eliminating theheight factor or the weight factor on the differences inphysical fitness were determined. The analysis was per-formed on an ICT 1301 computer.191817AGE in YEARS13 14 15 1612BOYS11481074727068vi 66UJI 64UZ62c60f-I 58 //QUJ 56IPRESENT INVESTIGATIONIn an investigation of the physical fitness of 5,962 CapeTown high-school children' the height and weight of eachchild were measured and the children performed 7 testsof athletic fitness. The children's ages were from 12 to 18years and they were attending White, Coloured, andBantu high schools; the Coloured group included a smallproportion of Asians. Height was measured (barefoot) tothe nearest t inch and weight (barefoot and wearing lightgymnastic costume) to the nearest 1 lb. The physicalfitness tests performed were those recommended by theAmerican Association for Health, Physical Education andRecreation.' The test battery comprises: pull-ups (modi-fied pull-ups for girls), sit-ups, shuttle run, standing broadjump, 50-yard run, softball throw for distance, and 600-yard run-walk. Full details of each test are given in aprevious paper.'In each age-group White boys were taller and heavierthan Coloured and Bantu boys and were superior at 6 ofthe 7 tests. There was no consistent difference in heightor in weight between Coloured and Bantu boys but theColoured were superior at 5 of the tests. White girls weretaller than Coloured and Bantu girls and heavier thanColoured. Bantu girls gained weight rapidly from the ageof 14 years to become the heaviest in the older age-groups.There was no consistent difference in fitness between Whiteand Coloured girls but the Bantu were the poorest at 5of the tests.The differences in height and weight between White andnon-White children, already noted by other investigators,'"could be due to a number of factors, of which nutritionaland economic status are probably the most important:··Since poor athletic performance may be due to poornutrition even before clinical signs of malnutrition aremanifest,' it was decided to analyse the data further inorder to ascertain whether the poorer performance of thissample of non-White children could be attributed toundernutrition as suggested by their lower heights andweights.In the original investigation every pupil at 15 high schools,who had not been excused from physical activity onmedical grounds, was subjected to the tests. For thepresent analysis racial groups of comparable size of boysand of girls were selected in each age-group (a total of1,050 children). Since the selection was random they maybe regarded as a representative sample of the populationoriginally investigated.In order to obtain a single index of physical fitness foreach child the raw scores for each test were converted to'Paper presented at the 66th Annual Congress of the South AfricanAssociation for the Advancement of Science. LoureneD Marques, July1968.Fig. 1. Height of boys. Continuous lines on Figs. 1 - 4 arecorresponding percentiles for British children. W =White; C = Coloured; B = Bantu.26 April 1969 S.A. TYDSKRIF VIR GE 'EESKU DE 509TABLE I. INTER-RACIAL DIFFERENCES IN PHYSICAL FITNESS - BOYS1918..oB1716_. .W,.- - - 50thI,,,,,14 1513o $·:::.·-..c.." ,," .x.... ..... .,', I:' I.' '" 0"- .....)/~,I ,<~"",,', )C/, '-0'_. .,'I,..,)(12AGE in YEARSFig. 3. Weight of boy.GIRLS50 L.c:::: --'-_--'-_-'--_'- --'-_--'-_.......10 11 12 13 14 15 16 17 18 1950 '--~-~-~-~-'-----~-""""'-~10 1170190170150If)0z::::>0 130Q.c:.-I-110Il:)W~ 9070BOYS190170U'iISO0z::::>0 130~c:.-~110Il:)W~ 9019W>C>B(W~C»BW>B*W>C>BW>C*Weight factorexcludedW~C*17 1816,·W__ --,----.-" 50thHeight factorexcludedW~CW~CW>C>B(W~C»B(C~W) (C~A)W>BW>C>BW>C>B13 14 15AGE in YEARSFig. 2. Height of girls.12TruedifferenceW~CW>CW>C>B(W~C»B(W~C»BW>C>BW>C>B4810 11GIRLSRESULTSFigs. 1 - 6 give the mean values for height, weight, andfitness index in each sex and age-group for White,Coloured, and Bantu children, and relate the heights andweights to those of British children. The inter-racialdifferences in height, weight, and physical fitness corre-spond to what might be expected from the data of theoriginal investigation. AB the heights and weights fellwithin the normal range (above the IGth percentile) forBritish children.By analysis of covariance it was found that eliminationof the height factor or the weight factor resulted in nomajor change in the inter-racial differences of fitness inboys. It is permissible to eliminate the height factor or theAge(Years)12131415161718w = White; C ~ Coloured; B = Bantu.> greater than (5 % level of significance).~ not significantly different (5 % level of significance).• influence of weight on criterion is not similar in all groups.AGE in YEARSFig. 4. Weight of girls.510 S.A. MEDICAL JOURNAL 26 April 1969weight factor only if the relation of performance to heightor of performance to weight is similar in each of thegroups being compared. In the comparison of White andColoured boys aged 13 years, this condition was notsatisfied for exclusion of the weight factor; the heavierWhite boys were fitter, whereas the heavier Coloured boyswere less fit. The relation of weight to fitness in 16-year-old boys was similar in White and Bantu but different inColoured; at 18 years of age it was similar in White andColoured but different in Bantu subjects.DlSCUSSIOThe AAHPER test battery is a satisfactory and widelyaccepted measure of the physical fitness of adolescentsand young adults. Since there is a low correlation betweenthe results of the different tests"·13 it is assumed that theymeasure different aspects of physical fitness (strength,flexibility, agility, power, speed, coordination, and en-durance). The fitness index derived from the results of the7 tests is therefore a fair indication (without loading theresults of individual tests) of general fitness for athleticactivity.BOYS GIRLS70 70,.,oX_·-·_·xc......x .....xc.'.'.'I;'"><-...... ,.. .........*=' _.-.x.....- ......X""._.-.~.-.T·~-.""-""· ,~ •__,. '~' --------Wx 0.' I, I, I.4060xwo. 55ztf)tf) 50wz~u.4565.0·········0········.080 .••..•••..0 .... //1'8.' ····c{....cl.wII,I,I•IIIII,.,,,,,.I,,II." )<-" /I .'" I• I" .iI .I" ,., '", .I~.-._.)(6560xw0 55ztf)50tf)wZ~u.454012Fig. 6. Fitness index of girls.35 L-_L----''----'~--'_---'"_---'"_--'-_---'13 14 15 16 17 18 19AGE in YEARSFig. 5. Fitness index of boys.12 13 14AGE15 16in YEARS17 /9TABLE IT. INTER-RACIAL DIFFERE CES IN PHYSICAL FITNESS - GIRLSFor girls, as for boys, elimination of the height factoror the weight factor caused no major change in theinter-racial differences in fitness (Table II).w = While; C = Coloured; B = BanlU.> grealer Ihan (5 % level of significance).-;:::::, nol significantly differenl (5 % level of significance).Age(years)12131415161718TruedifferenceW-;:::::,CC-;:::::,WW-;:::::,C-;:::::,B(C~W»B(C~W»B(C:::::W»BC>W>BHeight factorexcludedW:::::CW-;:::::,CW-;:::::,C-;:::::,B(C:::::W»B(C-;:::::,W»B(C-;:::::,W»B(C-;:::::,W»BWeight factorexcludedW-;:::::,CW-;:::::,CW-;:::::,C-::::::.B(C-;:::::,W»B(W-;:::::,C»B(C-;:::::,W»B(C-;:::::,W»BClose agreement of the mean values for height andweight in each group of the sample with the mean valuesin the original investigation shows that the sample fairlyrepresents all the children tested.The non-White high-school children are presumablyfrom the higher-income families since school attendancedeclines with age in the lower income groups. Althoughmost of the inter-racial differences in height and weightare statistically significant they may not be biologicallysignificant, since all the mean values fall within thenormal range for British children; this excludes any grossnutritional deficiency. It does not however exclude minordegrees of mal- or undernutrition as the cause of theobserved inter-racial differences in physical fitness of thepresent series. However, if this were the explanation ofthe poorer performance of some non-White children, we26 April 1969 TYD KR1F I R GEE K DE 511should expect the taller and heavier of the non-Whitechildren to have the same performance a White childrenof the ame height and weight. Elimination of the factorof height and weight by analy is of co arianc showedthat this wa not 0; the inter-racial differences in phy icalfitness remained even when the factor of height andweight were excluded. Con equently we are led to theconclusion that the inter-racial differences in physicalfitness are not due to undernutrition of the children withthe poorer athletic performance. The explanation mu t besought in terms of other factor which influence the per-formance of athletic tests, such as genetically determinedpatterns of body structure, skill, training, and motivation.In Texas, Ponthieux and Barker" found egro childrensignificantly better than White at most of the AAHPERtests; the heights and weights of the children were notrecorded. With a similar test battery, Ikeda'o foundJapanese children superior to American at 6 of 7 tests,although the Japanese were shorter and lighter. Asmussen'·has shown how particular body shapes favour performanceof particular athletic events; for instance, greater staturefavours jumping and throwing, whereas a more compactbuild favours the weight-lifter and would be of advantagein the pull-up test. A detailed anthropometric study ofSouth African school-children has shown significant inter-racial differences in other parameters as well as in heightand weight."Although some skill, and the coordination on which itdepends, may be inherited. skill is improved by training.as are speed, strength, and endurance.'s". The degree ofhabitual physical activity of different groups of childrenmay be a major factor in determining their relative physi-cal fitness. Kammeyer," in Washington State, found thatthe physical fitness of high-school girls was related to thedegree of extracurricular physical activity. Rosenstein andFrost," in New York State, found little correlation betweenphysical fitness and extracurricular physical activity inhigh-school children, but Rosenstein" found that thephysical fitness of the children was related to the qualityof the physical education programme at the differentschools. Although physical education formed part of theweekly curriculum of all the schools included in thepresent survey, every White school had a gymnasium anda trained physical education teacher, whereas most of thenon-White schools had neither.Although motivation is a major factor in the perform-ance of strenuous tests of fitness,""'" it is very difficult toassess. In the present investigation motivation was en-couraged by making the tests competitive between schools.At each school the pupils were told which rival schoolswere performing the tests and that the results would becompared. Since degrees of motivation cannot be mea-sured an attempt must be made to attain the maximummotivation in every case.The full explanation of the inter-racial differences inphysical fitness which we have observed in Cape Townhigh-school children is still to be found.SUMMARYFor 1,050 healthy Cape Town high-school children (a represen-tative sample of approximately 6,000 investigated) the meanheight and weight of ea h age-group of ca h ex of White,Coloured, and Bantu children were 'ompared , ith the orre-ponding figures for lhe other ra ial groups and with tandardsfor Briti h hildren. White S uth African boy were taller andheavier than Coloured and Bantu boy. and White SouthAfri an girl were laller and heavier than 01 ured and tallerthan BanlU girl , but the height and weight of all the S?,-!lhAfrican groups fell within lhe normal range for Bntl hchildren.A compo ite filne index wa derived for each outhAfrican child from the result of 7 tests of athleti fitness, andinter-ra ial compari on were carried ut for each age-groupof either ex. At mo t ages White boy were fitter thanColoured. who were fitter than Bantu, and White and olouredgirls were fitter than Bantu. After elimination of the heightand weight factors by analysis of covariance the inter-ra ialdifference in fitness were substantially unchanged, whichsugge ts that the poorer performance of some non-Whitechildren was not due to undernutrition. The difference may bedue to inherent genetic factors, to difference in training or inhabitual physical activity, or to different degrees of motivation.Our thank are due to the Staff Research Fund of theUniversity of Cape Town and to SPHS Grant AMO 3~95for financial support. We wish to thank Prof. G. G. Troskieand Messrs W. B. de V. Smit and Z. Zaltzman for thestatistical analy is.The statistical data on which Fig. I - 6 are ba ed may beobtained on request.REFERE 'CESI. Sloan. A. W. (1966): Afr. Med. J .. 40. 62.2. American Association for Health. Physical duc3lion and Recreatton(195): )'olllh Fillless Tesl Mallual. Washinglon. D : AAHPER.3. Wood row. E. P. and Robenson. I. (I 50): S. fr. Med. J .. 24, 7614. Lurie. G. M. and Ford. F. J. (195 ): Ibid., 32, 1017.5. Hansen. J. D. L. (1962): Proc. utI. Soc. Sth Afr.. 3, J26.6. Wittmann. W.. Moodie. A. D.. Fellingham. S. A. and Hansen.J. D. L. (1967): S. Afr. Med. J .. 41. 664.7. Van haBie. T. B., Sinisterra, L. and Slare, F. J. (1956): J. AmerMed. Assoc .. t62, 1120.8. Curelon. T. K. (1947): Ph}'sical Fillless Appraisal alld Guidallce. SILouis: C. v. Mosby.9. Sloan, A. W. and Wiggeu. R. (1967): J. Sporl Med. (Torino), 7, 192.10. Campbell. W. R. and Tucker. '. M. (1967): All IIIIrodllcrioll to TeM,and Measurements in Physical Education. London: G. Bell & Sons.11. Tanner, J. M .. Whilehou e. R. H. and Takaishi, M. (1966): Arch.Dis. Childh., 41, 454 and 613.12. Fowler, W. M. and Gardner. G. G. (1963): Pediatrics, 32, 77 .13. Hunsicker, P. A. and Reilf, G. G. (1966): J. Hlth Phys. Educ ..37, 23.14. Ponthieux. A. and Barker, D. G. (1965): Re. Quart. AmerAssoc. Hlth Phys. Educ., 36, 46 .15. lkeda, . (1962): Ibid., 33, 541.16. A mussen, E. (1964): Proceedings of the International Congres onSport Science, Tokyo. p. 67.17. Smil, P. J., POlgieler. J. F.. eser, M. L. and FeBingham. S. A(1967): S. Afr. Med. J., 41, 422.18. Knuttgen, H. G. and Steendahl, K. (1963): Res. Quan. Amer. AssocHJth Phys. Educ., 34, 34.19. Banister, E. W. (1965): Ibid., 36. 3 7.20. Kammeyer, S. J. (1956): Ibid., 27, 310.21. Rosenslein, I. and Frost, R. B. (1964): Ibid., 3S, 403.22. Rosenslein, J. (1963): Physical Fillless Acilievemelll ill SelecledPhysical Education Programs. Albany, NY: University of the Slateof New York.23. MichaeJ. E. D. jnr and Horvath, S. M. (1965): J. Appl. Physiol.,20, 263.24. Askew, N. R. (1966): Res. Quarl. Amer. Assoc. Hlth Phys. Educ.,37, 451.

Nutrition and physical fitness of white, coloured, and bantu high-school children

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Nutrition and physical fitness of white, coloured, and bantu high-school children

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