The Åstrand-Ryhming test/method under the magnifying glass

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1 The Åstrand-Ryhming test/method under the magnifying glass A review of research articles Dan Andersson IDROTTSHÖGSKOLAN I STOCKHOLM D-uppsats i Idrott 2004

2 D-UPPSATS I IDROTT POÄNG (10 POÄNG) VID MAGISTERUTBILDNING I IDROTT 2004 PÅ IDROTTSHÖGSKOLAN I STOCKHOLM The Åstrand-Ryhming test/method under the magnifying glass A review of research articles Dan Andersson Handledare: Peter G. Schantz

3 Abstract Aim: Validity studies of the Åstrand-Ryhming test/method are somewhat contradictory and the need of a review of the accumulated results is urgent. The aim of this study was to interpret and evaluate scientific results about the internal and external validity as well as the reproducibility of the Åstrand-Ryhming test (1954) and the Åstrand-Ryhming test (1960) and, if motivated, suggest presumptive modifications. In accordance with the aim the following questions were formulated: (1) Is the test valid? (2) For whom is it valid? (3) Is it reproducible? (4) For whom is it reproducible? (5) Is there a scientific base for suggesting modifications of the test? Method: Initially the characteristics and bases of the two tests/methods were sorted out. Subsequent to that a search for appropriate articles was conducted. The search resulted in 14 articles that had a title including Åstrand or Åstrand-Ryhming. Each article was evaluated and scrutinized. Uncertainty or lack of key information reduced the credibility of the article. Results and conclusion: Based on the limited number of articles that were a part of this review it is not possible to decide whether or not the Åstrand-Ryhming test/method is valid. Consequently it is not possible to decide for which population the test is valid. It is additionally not possible to decide if the Åstrand-Ryhming test/method is reproducible or for whom the test is reproducible. It is most likely possible to improve the accuracy of the estimations by means of modifying the Åstrand-Ryhming test/method. Suggestions of modifications include: (1) An elimination of the maximal treadmill test data (which is integrated in the 1960 nomogram), (2) A recommendation of new guidelines for the selection of workload, (3) That each test subject, prior to the initial test, conducts a pre-test, in order to get acquainted with the laboratory environment, the test equipment, and the testing procedures. (4) The introduction of a correction factor for obese individuals and (5) The construction of (a) new age correction factors and (b) separate age correction factors for the two sexes. 2

4 Contents Abstract Page 2 Record of figures and tables Page 4 1. Introduction Page 5 2. Aim and questions Page 7 3. Method Page 8 4. Background Page Characteristics of the Åstrand-Ryhming test (1954) Page Construction of the nomogram Page Material and methods Page Validity Page Characteristics of the Åstrand-Ryhming test (1960) Page Material and methods Page Adjustment of the original nomogram Page Correction factor for age Page Accuracy of prediction Page Results Page The articles Page An overview of the articles Page Group 1, with focus on validity Page Group 2, with focus on modification Page Discussion Page Question 1: Is the test valid? Page Question 2: For whom is it valid? Page Question 3: Is it reproducible? Page Question 4: For whom is it reproducible? Page Question 5: Is there a scientific base for suggesting modifications of the test? Page Conclusion Page 70 References Page 71 3

5 Record of figures and tables Record of figures Figure 1 The 1954 nomogram (Åstrand & Ryhming, 1954) Page 13 Figure 2 The relationship between pulse rate (Åstrand & Ryhming, 1954) Page 14 Figure 3 Mechanical efficiency when cycling (Åstrand & Ryhming, 1954) Page 15 Figure 4 Maximal oxygen intake calculated (Åstrand & Ryhming, 1954) Page 17 Figure 5 Heart rates in relation to oxygen uptake (Åstrand, P.-O., 1952) Page 17 Figure 6 The 1960 nomogram (Åstrand, I., 1960) Page 22 Figure 7 Correction factor for the nomogram (Åstrand, I., 1960) Page 26 Figure 8 Deviation in % between predicted and (Åstrand, I., 1960) Page 28 Figure 9 Individual predictions of maximal oxygen (Jessup et al, 1974) Page 36 Figure 10 Comparison between direct determined (Teräslinna et al, 1966) Page 41 Figure 11 A plot of the differences of the estimated (Wisén et al, 1995) Page 45 Figure 12 Maximal oxygen intake estimated with the (Wisén et al, 1995) Page 45 Figure 13 The Legge-Banister nomogram (Legge and Banister, 1986) Page 48 Figure 14 Maximal oxygen intake calculated (Legge and Banister, 1986) Page 50 Figure 15 Nomogram for workload selection (Terry et al, 1977) Page 53 Figure 16 Figure for ranking research articles about the Åstrand-Ryhming Page 57 Figure 17 Figure for ranking the Åstrand-Ryhming test/method. Page 62 Record of tables Table 1 Error of methods when maximal (Åstrand & Ryhming, 1954) Page 18 Table 2 Average values of maximal heart rate (Åstrand, P.-O., 1952) Page 20 Table 3 Number of subjects in the different (Åstrand, I., 1960) Page 23 Table 4A An overview of the articles, questions 1-9 Page 30 Table 4B An overview of the articles, questions Page 31 Table 5 Correlation coefficients, standard error (Cink et al, 1981) Page 33 Table 6 Comparison of predicted and measured (Jessup et al, 1977) Page 34 Table 7 Comparison among the predicted maximal (Jetté et al, 1979) Page 37 Table 8 Åstrand, Sjöstrand and directly measured maximal (Kasch, 1984) Page 38 Table 9 Raw values for the observed maximal oxygen (Macsween, 2001) Page 40 Table 10 Data from the 31 test subjects (Teräslinna et al, 1966) Page 41 Table 11 Means and standard deviations for estimated (Williams, 1975) Page 43 Table 12 Estimated reliabilities of additional test days (Williams, 1975) Page 43 Table 13 Correlation coefficients and standard error (Siconolfi et al, 1982) Page 51 Table 14 A comparison between the two nomograms Page 55 4

6 1. Introduction Knowledge about an individual s capacity for cardiovascular work is of interest, e.g., when selecting people for special tasks in the military service or in heavy industrial work. It is also of great interest for coaches, athletes and exercise scientists. An individual s capacity for physical work is dependent mainly upon the supply of oxygen to the working muscles. In order to determine the aerobic capacity you will have to conduct a test, maximally or submaximally. Measuring VO 2 max directly demands sophisticated equipment, highly skilled technicians, time and money. It is also, for a large number of subjects, associated with discomfort and/or pain. For these reasons it is desirable to have a valid substitute for assessing VO 2 max that could be used by exercise and fitness programs in industry, hospitals, universities, schools, YMCAs, clubs, and recreation departments. 1 The Åstrand-Ryhming test/method is an example of such a substitute. The procedure is simple and no sophisticated laboratory equipment is needed. The test is widely used and several researchers have evaluated and scrutinized the test. The test does not require an all out effort, and is for the majority of individuals not associated with discomfort or physical pain. However, validity studies are somewhat contradictory and the need of a review, with an interpretation of the accumulated results, is urgent. Such a review will shed new light over the test and have potential impact on both medical care and the physiological testing of the highperformance athlete. For this reason I have chosen to position the Åstrand-Ryhming test/method under the magnifying glass. Initially it is important to sort out the characteristics and bases of the two tests; the Åstrand Ryhming test (1954) and the Åstrand-Ryhming test (1960). For a general discussion about the test and further information about advantages, disadvantages and validity see Åstrand & Rodahl (1986) or Legge and Banister (1986). 2, 3 1 Kasch, F.W. (1984) The validity of the Åstrand and Sjöstrand submaximal tests. The Physician and Sports medicine, 54, page Åstrand, P.-O. & Rodahl, K. (1986) Textbook of work physiology. Physiological Bases of exercise. 3 rd Edition. New York: McGraw-Hill Book Company, page

7 When approaching scientific literature about The test one quickly realizes that the tests from 1954 and from 1960 have a wide variety of names such as the Åstrand test, the Åstrand- Ryhming test and the Å-R test. In order to be distinct and to differentiate between them the following definitions concerning the tests/methods will be used in this essay. 4 The Åstrand-Ryhming test (1954) = the test with the accompanying nomogram described by P.-O. Åstrand, and I. Ryhming in the article from The Åstrand-Ryhming test (1960) = the test with the accompanying nomogram described by I. Åstrand in her thesis from The Åstrand-Ryhming test/method = if it is uncertain which of the test/nomogram that has been investigated or when writing about the test in general. 3 Legge B.J., Banister E.W. (1986) The Åstrand-Ryhming nomogram revisited. J Appl Physiol, 61 (3), page P.-O. Åstrand and I. Ryhming married each other in the 1950 s. As a consequence I. Ryhming became I. Åstrand. 5 Åstrand, P.-O. & Ryhming, I. (1954) A nomogram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol, 7, page Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm

8 2. Aim and questions Aim To interpret and evaluate scientific results about the internal and external validity as well as the reproducibility of the Åstrand-Ryhming test (1954) and the Åstrand-Ryhming test (1960) and, if motivated, suggest presumptive modifications. Questions 1. Is the test valid? 2. For whom is it valid? 3. Is it reproducible? 4. For whom is it reproducible? 5. Is there a scientific base for suggesting modifications of the test? 7

9 3. Method This essay is a review of research articles. To find relevant articles one has to conduct a search. It is important to be aware of that another selection method is likely to have resulted in the sorting out of different research articles and possibly, dissimilar or conflicting answers. Due to a large number of hits a restriction was made, see below. The selection method was conducted in the following manner: Step 1 A search was made on PubMed ( on the following words: astrand ergometer cycle test = 11 hits. astrand ergometer bicycle test = 10 hits. astrand test = 90 hits. astrand ryhming nomogram = 10 hits. astrand rhyming nomogram = 4 hits. In total: 125 hits. The following results were excluded due to the large amount of hits: ergometer bicycle test = 1475 hits. ergometer cycle test = 1558 hits. bicycle ergometer = 2480 hits. cycle ergometry = 2185 hits. In total: 7698 hits. Step 2 Was a closer examination together with Dr Schantz and resulted in a sorting out of 45 relevant articles (out of the abovementioned 125 hits). 8

10 Step 3 Which of these 45 articles has a title including Åstrand or Åstrand-Ryhming? The answer is 15. However one of them, Pollock M.L., Linnerud A.C. (1971) Observations of the Åstrand- Rhyming nomogram as related to the evaluation of training. Am Correct Ther J, 25 (6), page was excluded due to the aim. Consequently 14 articles remained. 1. Cink R.E., Thomas T.R. (1981) Validity of the Åstrand-Ryhming nomogram for predicting maximal oxygen intake. Br J Sports Med, 15 (3), page Cullinane E.M., Siconolfi S., Carleton R.A., Thompson P.D. (1988) Modification of the Åstrand-Ryhming submaximal bicycle test for estimating VO 2 max of inactive men and women. Med Sci Sports Exerc, 20 (3), page Jessup G.T., Riggs C.E., Lambert J., Miller W.D. (1977) The effect of pedalling speed on the validity of the Åstrand-Ryhming aerobic work capacity test. J Sports Med, 17 (4), page Jessup G.T., Terry J.W., Landiss C.W. (1975) Prediction of workload for the Åstrand-Ryhming test using stepwise multiple linear regression. J Sports Med, 15 (1), page Jessup G.T., Tolson H, Terry J.W. (1974) Prediction of maximal oxygen intake from Åstrand-Ryhming test, 12-minute run, and anthropometric variables using stepwise multiple regression. Am J Phys Med, 53(4), page Jette M. (1979) A comparison between predicted VO 2 max from the Åstrand procedure and the Canadian Home Fitness Test. Can J Appl Sport Sci, 4 (3), page Kasch, F.W. (1984) The validity of the Åstrand and Sjöstrand submaximal tests. The Physician and Sports medicine, page 47-51, 54. 9

11 8. Legge B.J., Banister E.W. (1986) The Åstrand-Ryhming nomogram revisited. J Appl Physiol, 61(3), page Macsween A. (2001) The reliability and validity of the Åstrand nomogram and linear extrapolation for deriving VO 2 max from submaximal exercise data. J Sports Med, 41 (3), page Siconolfi S.F., Cullinane E.M., Carleton R.A., Thompson P.D. (1982) Assessing VO 2 max in epidemiological studies: a modification of the Åstrand-Ryhming test. Med Sci Sports Exerc, 14 (5), page Teräslinna P., Ismail A.H., MacLeod D.F. (1966) Nomogram by Åstrand and Ryhming as a predictor of maximum oxygen intake. J Appl Physiol, 21(2), page Terry J.W., Tolson H., Johnson D.J., Jessup G.T. (1977) A workload selection procedure for the Åstrand-Ryhming test. J Sports Med, 17 (4), page Williams, L. (1975) Reliability of predicting maximal oxygen intake using the Åstrand-Ryhming nomogram. Res Quart, 46, page Wisén A.G., Wohlfart B. (1995) A comparison between two exercise tests on cycle; a computerized test versus the Åstrand test. Clin Physiol, 15 (1), page Each article will be scrutinized and the credibility will be evaluated. The credibility depends on the entirety of the study. The entirety of the study depends on if it have been conducted and presented in a systematic and logical manner. Uncertainty and/or lack of key information will reduce the credibility of the article. When dissecting the articles the following questions were used as tools: 1. Which nomogram did the author/authors examine? 2. Was the first test excluded? 10

12 3. Which cycle ergometer was used? 4. Have they stated that they have checked the calibration of the ergometer? 5. Which were the workloads during submaximal work? 6. Pedalling speed? 7. How many submaximal tests with each person were conducted? 8. How many subjects were used? 9. How old were the subjects? 10. How many were men and how many were women? 11. Did they calculate BMI on the test subjects? 12. If BMI wasn t calculated - which was the BMI using their reported values for mean weight and height? 13. How did they correct the values - age correction or heart rate correction? 14. What was the subjects health status? 15. Were they trained or untrained? 16. Which activity was used when determining submaximal VO Which activity was used when determining maximal VO 2? 18. Did they report the criteria of reaching maximal VO 2? 11

13 Validity & reproducibility (reliability) A valid measure is one, which is measuring what it is supposed to measure. 7 Validity consists of internal and external validity. The internal validity of a study refers to the accuracy of the research in determining the relationship between the dependent and independent variables (the integrity of the experimental design). The external validity is to what extent the research results can apply to a wider range of situations. If a result of a test/measure repeatedly is identical or closely similar the reproducibility (reliability) is high. Envision that a scientist is interested in quantifying obesity. By systematically and carefully measuring the size of the feet (with a well calibrated instrument) data is collected. This is probably not going to make him/her any wiser. Determining BMI is probably a more valid measure. However, this must be done systematically; a mere glance in order to estimate BMI will lead to low reliability and low validity. Validity implies reliability; a valid measure has to be reliable, but a reliable measure does not have to be valid. 8 In a diagram, comparing for example determined max VO 2 with estimated max VO 2, it is essential that a line of identity, an ideal line, is drawn (e.g. figure 4). The line of identity represents perfect correlation (r = 1.0). With a line of identity included you can compare your regression line with the ideal line. If a line of identity is not included it is easy to be misled and assume that the presented values are better than they are (e.g. figure 9). Consequently you can have a high r-value but an incorrect (with respect to the ideal line) slope of the line (i.e. distant from the ideal line), implying over- or underestimation. Parameters such as standard deviation (SD) and correlation coefficients (r) are interesting but blunt; the SD is based on average values and is merely correct with respect to the average values. The r-value is also an insufficient measure of a method s validity. 7 Gunnarson R. Validitet och reliabilitet [Dept of Prim Health Care Göteborg University - Research methodology web site]. March 13, Available at: Accessed June 26, Ibid. 12

14 4. Background 4.1. Characteristics of the Åstrand-Ryhming test (1954) The Åstrand-Ryhming test (1954) with its accompanying nomogram for calculation of aerobic capacity submaximally was presented in 1954 (figure 1). 9 It is based on the relationship between pulse rate during work and actual oxygen intake in % of a subject s maximal aerobic capacity = a certain amount of oxygen is required for each workload (figure 2). FIGURE 1 9 A nomogram is a graphic representation that consists of several lines marked off to scale and arranged in such a way that by using a straightedge to connect known values on two lines an unknown value can be read at the point of intersection with another line. 13

15 FIGURE Construction of the nomogram Research from Åstrand 10 and Ryhming 11 together with the investigations of Wahlund 12 concerning mechanical efficiency constitutes cornerstones in the attempts at creating a nomogram. Wahlund investigated men of various physical fitness and detected a pretty constant mechanical efficiency when cycling on a cycle ergometer. 469 men were tested; the investigation covered patients with various diagnoses or symptoms of heart or lung diseases (n = 376) and ordinary healthy subjects (n = 40) as well as moderately trained healthy subjects (n = 26) and athletes (n = 27). 10 Åstrand, P.-O. (1952) Experimental Studies of Physical Working Capacity in Relation to Sex and Age. Thesis. Munksgaard, Copenhagen. 11 Ryhming, I. (1953) A modified Harvard Step test for the evaluation of physical fitness. Arbeitsphysiologie, 15, page Wahlund, H. (1948) Determination of the physical working capacity. Acta Med. Scandinav. Suppl Thesis. Stockholm. 14

16 The possibility to estimate oxygen uptake from workload within a range of + 8% in two-thirds of the cases was reported. 13 Wahlund used a Krogh cycle ergometer with a pedalling rate of 60 rpm. To control the velocity a speedometer was used. The men being tested were instructed to keep a pace corresponding to 5 m/s. Åstrand and Ryhming has shown that the oxygen uptake can be indicated from work level within a range of + 6% in two thirds of the subjects. Identical values for mechanical efficiency were obtained for men and women (figure 3). 14 A wide scattering of the subject s mechanical efficiency, i.e. from %, will not change the shape of the nomogram but simply result in more errors when predicting maximal aerobic capacity. FIGURE 3 13 Wahlund, H. (1948) Determination of the physical working capacity. Acta Med. Scandinav. Suppl Thesis. Stockholm, page Åstrand, P.-O. & Ryhming, I. (1954) A nomogram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol, 7, page

17 Material and methods Åstrand and Ryhming used the Krogh cycle ergometer. According to Åstrand, P.-O. (personal communication) the ergometer was calibrated with controlled weights. 15 When constructing the nomogram 27 male and 31 female well-trained subjects in the age of years were used as a basis (figure 4). 16 All of them were students at the Gymnastiska Centralinstitutet, Stockholm (G.C.I., College of physical education). The maximal oxygen intake was determined in maximal tests on the treadmill or on the cycle ergometer. In addition to this between three and five submaximal tests were conducted on several days. Subjects not reaching a steady state between 125 and 170 bpm were excluded. 17 Within these limits there is normally an almost linear increase in metabolism with heart rate. 18 The submaximal tests were a cycle test (900 kg m/min for women and 1200 kg m/min for men) where the O 2 intake was determined. The pedalling frequency when testing the subjects submaximally was 50 rpm. 19 Heart rates from 140 to 220 bpm were recorded at an oxygen uptake of 3.0 litres/min. A heart rate of 180 bpm represented an oxygen uptake of 2.0 litres/min for some women and as much as 5.0 litres/min for some men. The scattering results probably depend on differences in the subject s maximal aerobic power. 20 When the males were exercising at 50 % of their maximal oxygen uptake, their heart rates were on the average 128 bpm and when exercising on 70 % of their maximal aerobic power, the average heart rates were 154. For women the results were 138 and 164 bpm respectively (figure 5). The SD was 8-9 bpm. The findings in the above mentioned experiments made it possible to include scales in a nomogram with work levels (cycle test) and body weights (step test). When reading horizontally from the scale work level to the scale with O 2 intake the 15 Personal communication with Åstrand, P.-O., 1/ Åstrand, P.-O. & Ryhming, I. (1954) A nomogram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol, 7, page Eriksson, M. & Larsson, B., (2001) Ergometri konditionstest på cykel en undersökning av hur Åstrandstestet utvecklades och används idag. C-essay from Idrottshögskolan, Stockholm, page Åstrand, P.-O. & Ryhming, I. (1954) A nomogram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol, 7, page Ibid. 20 Åstrand, P.-O. & Rodahl, K. (1986) Textbook of work physiology. Physiological Bases of exercise. 3 rd Edition. New York: McGraw-Hill Book Company, page

18 actual energy output can be obtained. Together with information about the subject s heart rate it is possible to estimate the maximal oxygen uptake (figure 1). Maximal heart rate was not a parameter in the 1954 study. 21 FIGURE 4 FIGURE 5 21 Personal communication with Åstrand, P.-O., 1/

19 Validity Åstrand & Ryhming plotted the aerobic capacity calculated from the nomogram against the actual determined aerobic capacity. For two-thirds of the cases the difference (standard deviation) will be less than 6.7 % for men and 9.4 % for women. With a lower rate of work, 600 and 900 kg m/min for women and men respectively, the standard deviation was higher, 14.4% for women and 10.4% for men (see table 1). 22 TABLE 1 22 Åstrand, P.-O. & Ryhming, I. (1954) A nomogram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol, 7, page

20 The validity of the nomogram was controlled by comparing maximal oxygen intake calculated from the nomogram with the direct determined maximum using 18 well-trained male subjects, years of age. The standard deviation was less than 7 %. 23 For 31 females and 28 males between the ages of years, the maximal oxygen uptake was calculated from both heart rate and O 2 intake when doing a cycle test (600 and 900 kg/min), and from heart rate and O 2 intake when doing a step test. These two values were compared and the standard deviation was 9.5 % and 7.3 % respectively. The prediction of a subjects maximal VO 2, from submaximal data can, when using the nomogram correctly, be made with a standard deviation of less than + 10 %. 24 According to the authors the nomogram is based on results from experiments with healthy men and women between the ages of years. The validity when testing younger or older people or patients with diseases is not known. When determining maximal oxygen uptake Åstrand and Ryhming uses different testing equipment such as the cycle ergometer and the treadmill. 25 This can be due to the fact that in his thesis from 1952, Experimental Studies of Physical Working Capacity in Relation to Sex and Age, P.-O. Åstrand detected no difference between the maximal values obtained during cycling and running (table 2). 26 However, this might cause problems considering that the direct determined maximal oxygen uptake attained in various types of exercise such as cycling and running is likely to result in different values depending on whether or not you are an ordinary subject or a specially trained subject. 27 In addition to this, running on a treadmill produces higher maximal oxygen uptake than cycling on an ergometer (on the average some 4-8 %) Åstrand, P.-O. & Ryhming, I. (1954) A nomogram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol, 7, page Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age.. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page Åstrand, P.-O. & Ryhming, I. (1954) A nomogram for calculation of aerobic capacity (physical fitness) from pulse rate during submaximal work. J Appl Physiol, 7, page Åstrand, P.-O. (1952) Experimental Studies of Physical Working Capacity in Relation to Sex and Age. Thesis. Munksgaard, Copenhagen, page Åstrand, P.-O. & Rodahl, K. (1986) Textbook of work physiology. Physiological Bases of exercise. 3 rd Edition. New York: McGraw-Hill Book Company, page Ibid. 19

21 P.-O. Åstrand states in an interview from 2000 that when testing the subjects submaximally a higher pulse rate was detected in the first test compared to subsequent tests. 29 This was presumed to be a result of anxiety. 30 According to P.-O. Åstrand the subjects first had to get acquainted with the experimental procedures. The first determinations with each subject were therefore excluded and not used for the calculations of values. 31 The exclusion is not to be found in the article from Journal of Applied Physiology, where the nomogram originally was presented, but merely in P.-O. Åstrand s dissertation Experimental studies of physical working capacity in relation to sex and age from 1952 and in the c-essay by Eriksson & Larsson Ergometri konditionstest på cykel - en undersökning av hur Åstrandstestet utvecklades och används idag. 32, 33 Therefore, anyone who reproduces P.-O. Åstrand s and I. Ryhming s procedure from the article in Journal of Applied Physiology might be doing it inadequately. TABLE 2 29 Eriksson, M. & Larsson, B., (2001) Ergometri konditionstest på cykel en undersökning av hur Åstrandstestet utvecklades och används idag. C-essay from Idrottshögskolan, Stockholm, page Ibid. 31 Åstrand, P.-O. (1952) Experimental Studies of Physical Working Capacity in Relation to Sex and Age. Thesis. Munksgaard, Copenhagen, page Ibid. 33 Eriksson, M. & Larsson, B., (2001) Ergometri konditionstest på cykel en undersökning av hur Åstrandstestet utvecklades och används idag. C-essay from Idrottshögskolan, Stockholm, page

22 Furthermore, it is difficult to find out whether or not a test subject has participated in one or several studies. This implies that the same person might have been (1) a part of the construction of the nomogram and (2) a part of Åstrand s and Ryhming s own validity study of the same nomogram. If this is the case Åstrand and Ryhming might have circle-validated themselves. 34 In the interview from 2000, which is to be found in the above named c-essay, P.-O. Åstrand states that he neither has any notes left nor the memory of how the division was made Characteristics of the Åstrand-Ryhming test (1960) I. Åstrand adjusted and improved the original nomogram from 1954 and expanded the possibility to use her nomogram as a predictor of aerobic capacity with special reference to age and sex, see figure Material and methods Determinations of oxygen uptake and heart rate at submaximal and maximal work for physically active female and male subjects were used as the basis for the calculations. When constructing the nomogram I. Åstrand used 44 female and 100 male subjects as test subjects. The subjects were: housewives, years of age, draymen years of age, males years of age who were members of a health club in Philadelphia, USA, males years of age who participated in a physical training program (moderate training for 5-6 weeks). She also used data from the Åstrand-Ryhming test from 1954 (29 male and 32 female students), making it a total of 205 subjects. The subjects from 1954 were all students at Gymnastiska Centralinstitutet, Stockholm (G.C.I., College of physical education). For number of subjects in the different materials and in various age groups see table Eriksson, M. & Larsson, B., (2001) Ergometri konditionstest på cykel en undersökning av hur Åstrandstestet utvecklades och används idag. C-essay from Idrottshögskolan, Stockholm, page Ibid. 36 Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page Drayman = somebody who drives a vehicle for a brewery 21

23 FIGURE 6 22

24 TABLE 3 In her investigations I. Åstrand used the Krogh and the von Döbeln cycle ergometer. The ergometers were calibrated. 38 According to Eriksson & Larsson the submaximal tests, with one exception, were executed in the same way as in the construction of the first nomogram. 39 The only exception was that I. Åstrand used both the Krogh and the von Döbeln cycle ergometer. In the nomogram from 1954 only the Krogh ergometer was used. According to P.- O. Åstrand (personal communication) these two ergometers result in identical results, i.e. a given work load demands the same oxygen intake. 40 The work was performed on at least 2 days with light and heavy loads each day. On the last experimental day the subjects attempted to reach their maximal levels with regard to oxygen uptake. 41 The work period was usually 5-10 min. An exception to this was when the subjects 38 Personal communication with Åstrand, P.-O., 1/ Eriksson, M. & Larsson, B., (2001) Ergometri konditionstest på cykel - en undersökning av hur Åstrandstestet utvecklades och används idag. C-essay from Idrottshögskolan, Stockholm, page Personal communication with Åstrand, P.-O. 23/ Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page

25 were working on the maximal load - when doing this the work period was sometimes limited to 2-3 min. The values used for oxygen uptake and heart rate refer to the last minutes of work on each load and are usually mean values obtained either from determinations on two or more occasions, or from two or more successive determinations on the same occasion. An exception to this are the determinations of oxygen uptake made at maximal work, whereby the highest value was used if it differed from the other determinations by more than 0,08 l/min. 42 To establish the degree of strain the blood lactate concentration was measured. The values indicate that the subjects worked at or close to their maximum Adjustment of the original nomogram The nomogram from 1954 was adjusted by means of: (1) A correction of the mechanical efficiency, since the mechanical efficiency is considerably lower at lower loads, e.g. at 300 kpm/min than at 900 kpm/min. 43 The error becomes relatively large when using the lower loads if this is not being considered. The use of lower loads is necessary for certain populations, e.g. older individuals. This was put into practice by changing the relationship between the workload scale and the VO 2 scale. (2) The construction of separate workload scales for the two sexes, since there is a difference in oxygen uptake at a certain workload between males and females. However, the net mechanical efficiency is the same. 44 There was also a small difference in oxygen uptake between younger and older subjects at a specific workload. It did not however justify different scales for the two groups; instead a mean value for all age groups was used. 45 A finding when constructing the nomogram was that a better agreement between measured and predicted maximal oxygen uptake was obtained if the subjects used relatively high 42 Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page Ibid. 44 Ibid. 45 Ibid. 24

26 workloads. 46 Thus, there is a small systematic difference in the maximal oxygen uptake calculated from low and high work loads. 47 It was recommended that only pulse rates between 125 and 170 bpm should be used for calculations Correction factor for age Older people do not reach maximal pulses as high as younger people, thus an age correction factor was introduced (figure 7). However, I. Åstrand states that it is possible that the proposed age correction factors are too low causing underestimation when using the presented values. 48, 49 The correction factor is applicable on both males and females. 50 The material used for determining the correction factor is relatively small. 51 Irma Åstrand expresses that the original idea with the nomogram was that it should be easy to handle and that too many correction factors might - in fact - limit the use of the nomogram Accuracy of prediction The accuracy of the nomogram is somewhat higher when using relatively higher loads and when applying the nomogram on well-trained, younger persons than to the whole material (SD = + 10% in comparison with the whole material, + 15%), see figure The reason for this difference is probably that the physical education students represent a selected group of subjects with a comparatively large oxygen uptake capacity. Moreover, they have had more severe physical training than the other subjects. Physical training does not only increase the 46 Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page Ibid, page Ibid, page The Åstrand-Ryhming test/method has often been accused of suffering from underprediction, see chapter 7, Results and discussion, for a discussion about underestimation. 50 Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page Ibid. 52 Personal communication with I. Åstrand, 23/ Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page

27 maximal oxygen capacity, but also changes the individual slopes of the curves for heart rate and oxygen uptake. This means that the nomogram might have had a slightly different appearance if another original material had been used. 54 FIGURE 7 Can higher accuracy be gained when performing repeated tests with the same subjects? In a study from 1958 by I. Åstrand on inexperienced persons (draymen, n = 81) some of them (n =11) had, at a certain workload (900 kpm/min), lower values for several physical parameters on the second experimental day. 55 Usually the values for heart rate, oxygen intake, pulmonary ventilation and blood lactate concentration for a given work load were lower on the second experimental day than on the first; mechanical efficiency was accordingly higher. 56 Åstrand continues: In many cases the difference in oxygen intake and in heart rate from day one to day two was 0.2 litres/min. and 15 or more beats/min. respectively. 57 However, the average difference was not statistically significant Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page Åstrand, I. (1958) The physical work capacity of workers years old. Acta Physiologica Scandinavica 42, page Ibid, page Ibid. 58 Ibid. 26

28 When the original nomogram was constructed the first determinations with each subject were excluded and not used for the calculations of values. In the study on draymen (1958), that was a part of designing the second nomogram, the first determinations with each subject were also excluded consequently. Thus, it is likely that this was done in all of the different studies that were a part of constructing the modified nomogram. 59 This is confirmed by I. Åstrand and P.- O. Åstrand (personal communication). 60 According to I. Åstrand the higher mechanical efficiency on the second test day, in comparison with on the first test day, can be explained with lower tension/nervousness among the test subjects. 61 In the original nomogram the sole testing advice used when testing the subjects submaximally was the cycle ergometer. When testing the subjects maximally both the cycle ergometer and the treadmill were used. In the modified nomogram from 1960 I. Åstrand choose only to use the cycle ergometer. Data from the original nomogram was however included in the shaping of the modified nomogram. This means that some of the testing results, of which the modified nomogram is based upon, also derive from tests conducted on the treadmill. I. Åstrand emphasizes that the method of measuring work load and heart rate submaximally in order to determine a persons aerobic capacity only gives a hint of a subjects aerobic capacity. For exact information one has to measure the aerobic work capacity directly However, this is not stated in all of the articles. 60 Confirmed by I. Åstrand (23/6-2003) and P.-O. Åstrand (1/2-2004) in personal communication. 61 Åstrand, I. (1958) The physical work capacity of workers years old. Acta Physiologica Scandinavica 42, page Åstrand, I. (1960) Aerobic work capacity in men and women with special reference to age. Acta Physiologica Scandinavica, vol. 49, supplementum 169. Thesis. Stockholm 1960, page

29 FIGURE 8 28

30 5. Results 5.1. The articles This chapter aims to introduce each article, mainly with respect to the questions presented in chapter 3. The 14 articles about the Åstrand-Ryhming test/method can more or less be divided into one of the following two groups depending on the aim: group 1, with focus on validity and group 2 with focus on modification. Group 1, focus on validity 1. Cink R.E., Thomas T.R. (1981), 2. Jessup G.T., Riggs C.E., Lambert J., Miller W.D. (1977) 3. Jessup G.T., Tolson H., Terry J.W. (1974) 4. Jetté, M. (1979) 5. Kasch, F.W. (1984) 6. Macsween, A. (2001) 7. Teräslinna P., Ismail A.H., MacLeod D.F. (1966) 8. Williams, L. (1975) 9. Wisén, A.G., Wohlfart B. (1995) Group 2, focus on modification 1. Cullinane E.M., Siconolfi S., Carleton R.A., Thompson P.D. (1988) 2. Jessup G.T., Terry J.W., Landiss C.W. (1975) 3. Legge B.J., Banister E.W. (1986) 4. Siconolfi S.F., Cullinane E.M., Carleton R.A., Thompson P.D. (1982) 5. Terry J.W., Tolson H., Johnson D.J., Jessup G.T. (1977) An overview of the articles If the authors haven t stated which nomogram they have examined and not mentioned any correction factors for age it was assumed that they investigated the original nomogram, i.e. the Åstrand-Ryhming nomogram (1954). A hyphen (-) in the following two tables (4A & 4B) implies that the answer is not to be found in the article or that it is difficult to interpret what the authors suggest. 29

31 TABLE 4A, An overview of the articles, questions 1-9 Questions Articles Which nomogram? Exclusion of the first test? Which cycle ergometer? Was the ergometer calibrated? Workload, submax work? Pedalling speed? Number of submax tests? How many subjects were used? Age of the subjects? Cink et al (1981) 1960 No Monark - 75/100/150 W 50 rpm 1 51 (40) years Jessup et al (1977) 1954 No Schwinn Ergometric Yes - 50 & 80 rpm years Jessup et al (1974) 1954 No Monark Yes years Jetté (1979) 1960 No Monark years Kasch (1984) 1960 No Monark rpm years Teräslinna et al (1966) 1960 No Monark kpm/min 50 rpm years Williams (1975) Wisén et al (1995) Jessup et al (1975) 1954 No No Monark and Cat Eye Ergociser Monark, yes Cat Eye, not possible 1954 No Monark Yes 450 kpm (starting point) College-age - 50 rpm years 600 kpm (starting point) years Legge and Banister (1986) Siconolfi et al (1982) Terry et al (1977) Åstrand & Ryhming 1954 I. Åstrand No Quinton (QI-854) Yes 1960 No Philbin Yes Various work loads 64 =300 kpm =600 kpm (starting point) 50 rpm 1954 No Monark Yes 600 kpm Yes Krogh Yes 1960 Yes Krogh & von Döbeln Yes = kpm = kpm Various work loads 2/3 (1Å-R-test) years 50 rpm years 1 (if the desired HR was reached) years 50 rpm years 50 rpm > years 63 The article by Cullinane et al (1988) and by Macsween (2001) is not included in table 4A and table 4B due to the fact that they did not conduct any trials. 64 Various work loads, 50 W incremental steps, each lasting 3 minutes at a pedal rate of 90 rpm to 80% of a subjects age-predicted VO 2 max. 30

32 TABLE 4B, An overview of the articles, questions Questions Articles Sex of the test subjects? Did they calculate BMI? BMI, using reported figures? Correction of values? Health status? Training status? Activity, submax VO 2? Activity, max VO 2? Criteria of reaching max VO 2? Cink et al (1981) No 23.6 Age correction - Various physical fitness Cycle ergometer Cycle ergometer Yes Jessup et al (1977) No Cycle ergometer Cycle ergometer - Jessup et al (1974) No Students of phys.ed. Cycle ergometer Treadmill - Jetté (1979) No Age correction - Sedentary Cycle ergometer Treadmill Yes Kasch (1984) No 24.5 Age correction Healthy - Cycle ergometer Cycle ergometer Yes Teräslinna et al (1966) No No figures were reported Age correction Healthy Members of a fitness program Cycle ergometer Cycle ergometer Yes Williams (1975) No No figures were reported - - Students of phys.ed. Cycle ergometer - - Wisén et al (1995) No Age correction Healthy Various physical fitness Cycle ergometer - - Jessup et al (1975) No Students of phys.ed. Cycle ergometer Treadmill - Legge and Banister (1986) No No figures were reported physical Various fitness Cycle ergometer Cycle ergometer Yes Siconolfi et al (1982) At least 10 & /age decade No No figures were reported - Healthy Mainly inactive Cycle ergometer Cycle ergometer Yes Terry et al (1977) No Students of phys.ed. Cycle ergometer Treadmill - Åstrand & Ryhming Healthy Well trained Cycle ergometer Cycle ergometer & Treadmill Yes I. Åstrand Healthy Physically active Cycle ergometer Cycle ergometer 66 Yes 65 Legge and Banister merely states that the subjects were medically examined prior to beginning the study. 66 Data from the original nomogram was however included in the 1960 nomogram. Consequently some of the testing results derive from tests conducted on the treadmill. 31

33 Group 1, with focus on validity Cink et al (1981) evaluated the predicted VO 2 max from the Åstrand-Ryhming test (1960) using the cycle ergometer as the sole exercise mode. 67 They followed the recommended submaximal test protocol with a pedalling speed of 50 rpm using two sets of correction factors (1) Age correction by I. Åstrand (1960) and (2) Age correction by von Döbeln et al. 68 Cink et al used a Monark ergometer (although they have not stated that they have checked the calibration, but they have stated that the seat height was adjusted so that the subjects knee was slightly flexed when the ball of the foot rested on the pedal at the lowest point in a revolution). BMI was not calculated in the study; using the authors reported figures for mean weight and height resulted in a BMI of men between the ages of years conducted two tests, one submaximal and one maximal. The subjects were of various physical fitness. It is not stated whether or not the subjects were healthy. The maximal test was conducted after the submaximal test. A pedalling speed of 60 rpm was used and the workload was 25 W for the first two minutes. The workload was increased by 25W every minute until the subject was exhausted. The criteria of reaching maximal VO 2 were: exhaustion, ECG changes, marked dyspnoea, confusion, pallor, or pain in the chest, arms or jaw. The result indicate roughly that 2/3 of the VO 2 max measurements elicited during a maximal cycle ergometer test will be within L min -1 (r = 0.76) or 5.7 ml kg -1 min -1 (r = 0.83) of the VO 2 predicted from the Åstrand-Ryhming test (1960), see table It was concluded that there was no significant difference between the measured and the predicted means. A diagram showing the correlation between the directly determined maximum oxygen uptake and the prediction of maximum oxygen uptake is missing. 67 Cink R.E., Thomas T.R. (1981). Validity of the Åstrand-Ryhming nomogram for predicting maximal oxygen intake. Br J Sports Med, 15 (3), page von Döbeln, W., Åstrand, I., Bergström, A. (1967). An analysis of age and other factors related to maximal oxygen uptake. J Appl Physiol, 22, page When converting weight in pounds to weight in kg multiplied the pounds and when converting height in inches to height in cm multiplied the inches. Figures for conversion were found on 70 The usual measure of linear association is the Pearson correlation coefficient, symbolized by an r. 32

34 TABLE 5 Jessup et al (1977) investigated the effect of pedalling speed on the validity of the Åstrand- Ryhming test (1954). 71 Research had suggested that perceived exertion was reduced at higher pedalling speeds for equivalent power outputs. The purpose of the study was to determine the validity of the Åstrand-Ryhming test (1954) administered at 50 and 80 rpm. The cycle ergometer was a calibrated Schwinn Ergometric (an electronic cycle ergometer) and was used in all tests, submaximal as well as maximal. BMI was not calculated in the study; using the authors reported figures for mean weight and height resulted in a BMI of male volunteer subjects between the ages of years performed on consecutive days (a) the Åstrand-Ryhming test (1954) administered at 50 rpm; (b) the Åstrand-Ryhming test (1954) administered at 80 rpm; and (c) a maximum oxygen intake determined at the end of a maximal graded exercise test. The graded exercise test consisted of performing consecutive six-minute work bouts at 300, 600, 900 and 1200 kpm, or until the exercise heart rate reached 180 bpm, at which point the subject was pushed to maximum aerobic power by increasing the pedal speed and resistance. The criterion of reaching max VO 2 is lacking as well as information about the subjects health- and training status. 71 Jessup G. T., Riggs C. E., Lambert J., Miller W. D. (1977) The effect of pedalling speed on the validity of the Åstrand-Ryhming aerobic work capacity test. J Sports Med, 17 (4), page

35 TABLE 6 The results revealed a correlation coefficient of r = 0.64 and r = 0.63 for the Åstrand- Ryhming test (1954) administered at 50 and 80 rpm, respectively. This can be compared with the Åstrand-Ryhming test (1954) with an r = 0.71 and with the Åstrand-Ryhming test (1960) with an r = The correlation between the test conducted at 50 rpm compared with the test conducted on 80 rpm was r = See table 6 for a comparison of predicted and measured scores by different investigators. Jessup et al (1974) compared the prediction of maximal oxygen intake with simple regression models, the Åstrand-Ryhming test (1954) and a 12-Minute Run with multiple regression 72 According to Åstrand & Rodahl the oxygen uptake varies with pedal frequency, see Åstrand, P.-O. & Rodahl, K. (1986) Textbook of work physiology. Physiological Bases of exercise. 3 rd Edition. New York: McGraw- Hill Book Company, page 365. The discrepancy probably depends on that Jessup et al (1977) and Åstrand & Rodahl (1986) have examined different types of cycle ergometers, i.e. the mechanically braked cycle ergometer and the electromechanically braked cycle ergometer. 34

36 models in young volunteer subjects. 73 They used 40 volunteer male college students enrolled in physical education activity courses. The men were between the ages of years with a mean of 19.5 years. Simple regression techniques such as the Åstrand-Ryhming test/method and the 12-minute Run were administered approximately one week apart and compared with multiple regression models. When testing the students submaximally a calibrated Monark and standard procedures were used. The maximal test was the Balke treadmill test. 74 BMI was not calculated; using the authors reported figures for mean weight and height resulted in a BMI of The data was analysed with a computer program that performed a stepwise multiple linear regression (UCLA BIMED 02R). The individual correlations between max VO 2 and prediction from the Åstrand-Ryhming test/method was r = 0.64 (figure 9). Information about the subjects health- and training status and criteria of reaching max VO 2 are lacking. Jette (1979) compared the predicted maximal oxygen consumption derived from the Canadian Home Fitness Test (CHFT) 75 and the Åstrand-Ryhming test (1960) to the observed VO 2 max determined from a progressive multi-stage treadmill test sedentary subjects between the ages of years old (35 men and 29 women) were used as test subjects. The tests were conducted on two different occasions. On occasion 1: CHFT and the Åstrand-Ryhming test (1960) with a minimum of 30 minutes in between the two tests, occasion 2: maximal VO 2 test using a multi-stage treadmill test. 73 Jessup, G.T., Tolson H, Terry J.W., (1974) Prediction of maximal oxygen intake from Åstrand-Ryhming test, 12-minute run and anthropometric variables using stepwise multiple regression. Am J Phys Med, 53 (4), page For additional information about the Balke treadmill test see Åstrand, P.-O. & Rodahl, K. (1986) Textbook of work physiology. Physiological Bases of exercise. 3 rd Edition. New York: McGraw-Hill Book Company, page The Canadian Home Fitness test is a safe, simple, self-administered fitness test. It is a steptest - the steps are 20.3 cm high. For further information about the CHFT see Åstrand, P.-O. & Rodahl, K. (1986) Textbook of work physiology. Physiological Bases of exercise. 3 rd Edition. New York: McGraw-Hill Book Company, page Jette M. (1979) A comparison between predicted VO 2 max from the Åstrand procedure and the Canadian Home Fitness Test. Can J Appl Sport Sci, 4 (3), page