The use of the ventilatory anaerobic threshold for the development of exercise guidelines

Comput. Bid Med. Vol. 19. No. 5. pp.307-317. Printed in Great Britain

1989

001Cr4825/89 $3.00 + .I0 C 1989 Pergamon Press plc

THE USE OF THE VENTILATORY ANAEROBIC THRESHOLD FOR THE DEVELOPMENT OF EXERCISE GUIDELINES KENNON

FRANCIS

Division of Physical Therapy. Room B41 SHRP Building, University of Alabama at Birmingham, Birmingham. AL 35294, U.S.A. (Receioed 14 December 1988; in wised form 10 March 1989: received for publication 22 March 1989) Abstract-The general interest in the application of exercise testing to evaluate the work capacity or change in the functional ability of individuals has resulted in the development of a variety of noninvasive tests and test parameters such as the anaerobic threshold. This paper presents a computer program written in BASIC that determines the anaerobic threshold from expired respiratory gases collected from an incremental exercise test. Results are summarized in tabular as well as graphical format. The use of the incremental exercise test in conjunction with this computer program will provide another means of efficiently determining the exercise capability of the patient Anaerobic threshold

Exercise prescription

Microcomputers

Analysis

Physical work capacity tests, sometimes called “stress tests”, have gained widespread application in clinical practice as valuable noninvasive measurement tools for the determination of cardiovascular endurance. Stress tests that measure the cardiorespiratory adjustments and tissue utilization of oxygen to increasing work loads have gained widespread popularity because of the assumption that an organic abnormality or functional inadequacy is more apt to become apparent when the individual is subjected to functional stress than at rest when the demand is minimum [1,2,7,12,15]. An assessment of the cardiovascular system during exercise enables the clinician to determine an individual’s present capacity for conducting aerobic activities as well as changes in capacity that might have occurred as a result of training or disuse. Knowing the energy requirements of exercise and the corresponding physiologic adjustments made by an individual to the stress of exercise, a sound basis can be provided for formulating a fitness program as well as for evaluating a subject’s functional status before and during an exercise training program [ll, 133. The general interest in the application of exercise testing to evaluate the physical work capacity or change in the functional ability of an individual has motivated the development of a variety of discriminative test parameters that can be used in test conditions. One such parameter is maximal oxygen uptake (irO2max). 002max is considered to be the best indicator of functional aerobic capacity and functional cardiorespiratory fitness. 002max expresses the ability of the cardiorespiratory system to transport oxygen to active tissues and of those tissues to use it [l, 21. Cardiopulmonary fitness depends on the coordinated function of the cardiovascular, pulmonary, blood and muscle systems, which collectively is called the “oxygen transport system”. To perform effectively during exercise, the heart must pump large quantities of blood to the working muscles with optimal oxygen extraction and utilization. Another test parameter that is increasingly being used in conjunction with vO2max to assess the capacity of the cardiovascular system and tissue metabolism is the aerobicanaerobic transition point called the “anaerobic” or “lactate” threshold (AT) [4,17,21,23]. 307

KENNON FRANCIS

308

Any exercise that involves moderately intense muscular activity demanding sustained energy release for time periods greater than 5min mandates a high rate of high energy adenosine triphosphate (ATP) turnover. The energy required for the continual phosphorylation of ADP to ATP is provided by the aerobic breakdown of nutrients such as carbohydrates, fats and proteins. Unless a steady rate can be achieved between oxidative phosphorylation and the energy requirements of the activity, an anaerobic-aerobic energy imbalance develops, resulting in a build-up of lactic acid and hydrogen ions hastening the time to fatigue. Several investigators [8,9,20,22] have suggested that the AT reflects these subtle changes in cellular metabolism and may be a more sensitive indicator of circulatory and metabolic adaptations to exercise than the more traditional means of using an arbitrary fraction of an individual’s VO2max. Hence the AT is ideally suited for the characterization of an individual’s endurance capacity as well as for the determination of the optimal training intensity [23]. Traditionally, training prescriptions based on a percentage of V02max do not distinguish between work above or below the point of accumulation of blood lactate. Consequently, exercise performed at a specific intensity within the commonly used range of 50-80% of V02max may result in dissimilar work stresses in individuals with different thresholds for accumulation of lactic acid but similar values of V02max [22]. A number of investigators believe that a more uniform training stress may be imposed if work is equated on the basis of the AT [8,9,16,20]. The delineation of the AT during an incremental work test can be easily performed in a clinical setting by monitoring changes in ventilatory parameters. The detection of AT using ventilatory parameters is based on two assumptions: (a) that the increase in blood lactic acid is related to changes in the aerobic-anaerobic supply of ATP [IS]; (b) that the AT arises simultaneously with an increase in blood lactic acid above basal resting values [19]. In an incremental exercise stress test to exhaustion, ventilation first increases linearly with respect to oxygen uptake reflecting adequate supply of oxygen to the exercising muscle. As the work load is increased, there is a point at which local oxygen supply in muscle becomes inadequate, typically in the range of 50-70% of an individual’s maximal oxygen uptake or aerobic capacity (V02max) [l]. As a result, the rate of ATP generation from aerobic mechanisms is insufficient, resulting in a shift to anaerobic metabolism, thereby elevating blood levels of lactic acid and increasing ventilation more rapidly than oxygen consumption. The point at which this curvilinear increase in ventilation occurs with respect to the work load is called the ventilatory anaerobic threshold or “VAT” [1,4,10,19]. BRUCE

PROTOCOL

FOR

THE DETERMINATION CAPACITY

OF WORK

The committee on exercise of the American Heart Association [l] and the American College of Sports Medicine [12] agree that multistage exercise testing (with successively increasing work loads) accompanied by continuous ECG monitoring and periodic blood pressure determination is the most informative type of testing procedure for evaluating the physical work capacity or change in the functional ability. Efforts toward achieving objectivity and reliability in testing have resulted in the development of a variety of protocols and testing procedures that use a variety of ergometers. A national survey of 1400 exercise-testing facilities has shown that the treadmill is the most widely used mode of testing (71%), followed by the cycle ergometer (17%) and steps (12%) [25]. Of the treadmill protocols, the Bruce multistage treadmill test [S] was the most widely used, with over 65.5% of the facilities reporting its use [14,25]. The Bruce test protocol (Table 1) involves walking or running on a motor driven treadmill in 4 incremental stages starting at 1.7 miles/h at a 10% slope (Table 1). The slope increases 2% and the speed increases at 0.8-0.9 miles/h at 3min intervals [S]. Heart rate and blood pressures are recorded at specified intervals throughout the test. The initial workload of stage I exercise raises the energy expenditure to about 3-4 METS. (One MET

Development of exercise guidelines

309

Table 1. The Bruce test: varying speed and grade treadmill test Energy requirements Test phase

Duration (min)

METS

I II III IV

3 3 3 3

5 6-7 8-10 10-12

(mlisin) 16-18 23-25 28-34 35-42

Speed (mph) 1.7 2.5 3.4 4.2

Grade % 10 12 14 16

unit is equal to resting oxygen consumption, about 3Sml/kg of body weight/min.) Even though the speed and gradient are increased every 3 min, as subsequent exercise stages are entered, the weight-adjusted oxygen uptake increases almost linearly with time. EXERCISE

PRESCRIPTION

To be most effective, an exercise prescription must give specific, written instructions for the intensity, duration, and frequency of exercise [l]. A computer can easily generate an exercise prescription using the results of a Bruce treadmill protocol and the resting heart rate. Intensity of training is determined from the VAT and the corresponding MET and heart rate values associated with VAT point. These values are useful for translating an exercise prescription into actual work levels using a variety of exercise modalities such as cycling, walking, swimming, running, and recreational games and sports as shown in Table 2 [ 133. Guidelines for training intensity are usually presented in both formats. The patient is advised to monitor his heart rate periodically to insure the training heart rate is maintained at the prescribed level. An exercise prescription is only applicable for a 12 week period. The patient should consult with the clinician at the end of this period for adaptation of guidelines. FREQUENCY

AND

DURATION

There is general agreement that exercise training should be conducted three or four times weekly for consistent results [ 1,6]. Programs with fewer sessions are less effective in Table 2. Approximate metabolic equivalents of prescribed and recreational activities MET* range

Prescribed activity

Recreational activity

2-4

Walking at 2-3 mph Cycling (ergometer) at 150-300 kg Swimming, using float board

Strolling Light stretching exercise Bicycling at 6mph

5-6

Walking-jogging at 4 mph Cycling (ergometer) at 450-600 kg Swimming, treading water

Light calisthenics Golf Bicycling at 8 mph

7-8

Walking-jogging at 5 mph Cycling (ergometer) at 750-900 kg Swimming, doing crawl at 30 yd/min

Noncompetitive tennis, badminton Hiking Bicycling at 11-12 mph

9-10

Jogging-running at 5.5-6 mph Cycling (ergometer) at 1050kg Swimming, doing crawl at 40 yd/min

Vigorous calisthenics Rope skipping Cross-country skiing Bicycling at 13 mph

11-12

Jogging-running at 7 mph Cycling (ergometer) at 1200-l 350 kg Swimming, doing crawl at 50 yd/min

Team sports, e.g. basketball, soccer Handball

13-14

Running at 8 mph Cycling (ergometer) at 1500-1650 kg

Vigorous team sports Cross-country skiing Vigorous rope skipping

15-16

Running at 10 mph Cycling (ergometer) at 1800 kg

Sustained performance at levels of highly trained athlete

‘1 MET unit is equal to resting oxygen consumption, about 3.5 ml O,/kg/min. CBM

19:5-B

Data For JOHN DDE

7.35

172

25.12

AGE:

= 18.18

149

SUmnary Data for JOHN DOE DATE: 12/12/88 ---______________-_____________________________--_ WORK STAGE MINUTES HR VE ----___-__ _______ ____ ____ I 5 100 26 ; 115 27.5 I 1.5 120 25.6 I 2 122 26 I 2.5 123 32 I 3 130 36 I 3.5 132 35 I 4 135 42 II 4.5 140 45 II 5 145 52 II 5.5 155 67 II 6 165 83 II 6.5 170 99 III 7 172 115 III

Ventilatory Break pomt

Heart rate break point =

45

DATE: 12/12/88

CARDIOVASCULAR FITNESS LEVEL: GOOD

MAXIMUM HEART RATE =

MAX VC2 (METS) =

MAX VO2 (ML/KG/MIN) =

SUBJECT WEIGHT (LBS) : :55

Summary

:.:

Y

RECREATIONAL ACTIVITY: NON-COMPETATIVE TENNIS, BADMINTON, HIKING, BICYCLING AT 11 - 12 MPH _____________________

PRESCRIBED ACTIVITY : WALK/JOG, 12 MIN MILE, CYCLING (ERGOMETER1 AT 750 - 900 KGM, SWIMMING (CRAWL AT 30 YDIMIN)

IN ORDER TO DERIVE THE GREATEST BENEFIT FROM AN EXERCISE PROGRAN YOU SHOULD EXERCISE A MINIMUM OF 3 TO 4 TIMES A WEEK USING THE TARGET HEART RATE OF 149 BEATS/MINUTE WHILE PERFORMING ONE OF THE FOLLOWING ACTIVITIES:

EXERCISE GUIDELINES

Development of exercise guidelines

311

achieving and maintaining physical fitness and optimal body weight composition. The duration of each session depends on the intensity and type of exercise. Most studies suggest that 30-40min of exercise at the proper training intensity is optimum [l, 61. Balke [3] suggests that the exercise period should consume 10% of the daily caloric consumption. For example if the daily caloric consumption is equal to 3000 kcal, and using the equivalent of lkcal/hour/kg body weight = 1 MET, a 75 kg patient with a prescribed training intensity of 8 METS would have to exercise for 30min.

COMPUTER

PROGRAM

The computer program (see Appendix 1) was written in Microsoft Basic for the PC microcomputer. The program requires the use of the Bruce treadmill test protocol and the input of exercise heart rates and minute ventilation (irE) values derived from expired gases. Heart rate and irE should be recorded at 30s intervals throughout the test period. If a laboratory is not using a computerized automated system for determination of VE, a semiautomated program has been reported [lo] that will determine &E from expired gases. The following program determines the VAT from entered data (lines looO-2380) using the breakpoint routine described by Orr et al. [17]. Linear regression (lines 730-940) is used to determine the appropriate heart rate at the calculated VAT. The plotting routine of Spain [24] is used to graph the relationship of heart rate or ventilatory equivalents and work. The exercise prescription (lines 3600-3720) is developed using the guidelines outlined by Hanson et al. [13]. Figure 1 presents a sample printout of the results and exercise prescription developed by the program. SUMMARY Exercise training is a useful therapeutic intervention for most normal, untrained adults, and for many patients with an established risk of cardiovascular disease. Health care professionals should be familiar with appropriate evaluation methods and recommendations for establishing an exercise program. The use of the microcomputer to devise exercise guidelines based on fitness assessment test makes it easier for the patient to adopt a practical regimen for health enhancement. Because of the attractiveness of the anaerobic threshold in assisting the clinician in the differential diagnosis of disorders of the cardiorespiratory coupling to cellular respiration, and in developing and evaluating exercise therapies, the inclusion of the anaerobic threshold as a routine test parameter is becoming more popular. The use of the incremental exercise test in conjunction with this computer program provide another means ofefficiently determining exercise capacities and guidelines for the patient. REFERENCES 1. American College of Sports Medicine Guidelines for Graded Exercise Testing and Exercise Prescription, Lea and Febiger, Philadelphia (1986). 2. P. 0. Astrand, Quantification of exercise capability and evaluation of physical capacity in man, Prog. cardiouas. Dis. 19, 51 (1976). 3. B. Balke, Prescribing physical activity, Sports Medicine, A. J. Ryan and F. Allman, Eds, pp. 505-523. Academic Press, New York (1974). 4. W. L. Beaver, K. Wasserman and B. J. Whipp, A new method for detecting anaerobic threshold by gas exchange, J. appl. Physiol. 60, 2020 (1986). 5. R. A. Bruce, Principles of exercise testing, Exercise Testing and Exercise Training in Coronary Heart Disease, J. P. Naughton and H. K. Hellerstein, Eds, pp. 45-63. Academic Press, New York (1973). 6. R. A. Bruce, Functional aerobic capacity, exercise and aging, Principles of Geriatric Medicine, R. Andres, E. L. Bierman and W. R. Haxxard, Eds, pp. 87-103. McGraw-Hill, New York (1985). 7. R. A. Bruce, Maximal exercise testing: prognostic values for assessment of coronary heart disease risk, Postgrad. Med. 70, 161 (1981). 8. J. Davis, F. Whipp and K. Wasserman, Anaerobic threshold alteration caused by endurance training in middle-aged men, J. appf. Physiol. 46, 1039-1046 (1979). 9. J. Dwyer and R. Bybee, Heart rate indices of the anaerobic threshold, Med. Sci. Sports Exercise IS, 72-76 (1983). 10. K. T. Francis, Anaerobic Threshold, Comput. Biol. Med. 19, 1 (1989). 11. K. T. Francis, Prescribing exercise programs using the microcomputer, MD Comput. 4, 19-24 (1987). 12. Guidelines for exercise testing: a report of the American College of Cardiology/American Heart Association

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Task Force on Assessment of Cardiovascular Procedures, J. Am. CoU. Cardiol. 8, 725 (1986). 13. P. G. Hanson, M. D. Giese and R. J. Corliss, Clinical guidelines for exercise training, Postgrad. Med. 67, 120 (1980). 14. T. Jopke, Choosing and exercise testing protocol, Physician Sports Med. 9, 141 (1981). 15. E. B. Larson and R. A. Bruce, Health benefits of exercise in an aging society, Arch Znt. Med. 147,353 (1987). 16. V. Katch, A. Weltman, S. Sady and P. Freedson, Validity of the relative percent concept for equating training intensity, Eur. J. appl. Physiol. 39, 219-227 (1978). 17. G. W. Orr, H. J. Green, R. L. Hughson and G. W. Bennett, A computer linear regression model to determine ventilatory anaerobic threshold, J. appl. Physiol. 52, 1349 (1982). 18. W. N. Stainsby, Biochemical and physiological basis for lactate production, Med. Sci. Sports Exercise 18, 341 (1986). 19. K. Wasserman, Determinants and detection of anaerobic threshold and consequences of exercise above it, Circulation 76, 29-39 (1987). 20. K. Wasserman, The anaerobic threshold measurement to evaluate exercise performance, Am. Rev. resp. Dis. 129, Suppl. ~35 (1984). 21. K. Wasserman, B. J. Whipp, S. N. Koyal and W. L. Beaver, Anaerobic threshold and respiratory gas exchange during exercise, J. appl. Physiol. 35, 236 (1973). 22. A. Weltman, V. Katch, S. Sady and P. Freedson, Onset of metabolic acidosis (anaerobic threshold) and maximal oxygen uptake, J. Sports Med. Phys. Fitness 19, 135-142 (1979). 23. P. Vago, J. Mercier, M. Ramonatxo and C. Prefaut, Is ventilatory anaerobic threshold a good index of endurance capacity? Int. 1. Sports Med. 8,190(1987). 24.J. D. Spain, BasicMicrocomputer Models in Biology, p. 345. Addison-Wesley, Reading, MA (1982). 25. R. J. Stuart and M. H. Ellestad, National survey of exercise stress testing, Clinical application and predictive capacity, Chest 77, 94 (1980).

APPENDIX 3 KEY OFF: REM CLEAR IBM HELP SCREEN FROM SCREEN 4 CLS:PRINT SPC(4O);:SW%=POS(O)+39:CLS 5 BS%=40: REM DETERMINES THE SIZE OF THE BOX G PRINT:PRINT:PRINT 7 S$&" :GOSUB 25 8 S$="EXERCISE PRESCRIPTION USING ":GOSUB 30:S$="":GOSUB 30 10 S$="THE VENTILATORY ANAEROBIC THRESHOLD":GOSUB 30:S$="":GOSUB 30 11 5$="1989 BY":GOSUB 30:S$="KENNON FRANCIS":GOSUB 30 12 S$="":GOSUB 30 13 ZOSUB 35 14 LOCATE 20,25:PRINT "PRESS SPACE BAR TO CONTINUE." 15 4$ = INKEY$ 17 IF INKEY$ ="" THEN 17 20 SOTO 50 25 PRINT TAB((SW%-BS%-2)/2);CHR$(201);STRING$(BS%,205);CHR$(187):RETURN ' PRINT TOP OF BORDER 30 PRINT TAB((SW%-BS%-2)/2);CHR$(186);TAB((SW%-LEN(S$))/2);S$;TAB(SW%/2+BS%/2); ,HR$(186):RETURN 'PRINT STRING INSIDE BORDER 35 PRINT TAB((SW%-BS%-2)/2);CHR$(200);STRING$(BS%,205);CHR$(188):RETURN 'PRINT BOTTOM OF BORDER 50 KEY OFF: CLS 60 ZLEAR: REM SET ALL VARIABLES TO 0 80 DEF SEG=O: POKE 1047,64: DEF SEG: ' FORCE UPPERCASE LETTERS ONLY 100 CLS: DEF FN ROUND(X) = INT (X * 100 + .5) / 100 110 DIM FG(30): DIM VI(30) 120 DIM FS(30): DIM FD(30): DIM X1(30) 123 IF SG = 3.5 THEN SG$ = "11" 130 DIM X(100), Y(lOO), Z (loo), A(lOO), B(lOO), C(lOO), D(100) 140 DIM Vl(20): DIM V2(20): DIM V3(20): DIM V4(20): DIM VO(20): DIM RQ(20) 150 DIM VB(20): DIM VC(20): DIM VA(20): DIM OE(20): DIM OC(20): DIM MI(20) 160 DIM TG(20): DIM WE(20): DIM VK(20) : DIM HR(20): DIM WW(20): DIM X2(100) 172 I______________________________ 173 ' PATIENT DATA ENTRY ROUTINE 174 I______________________________ 180 PRINT "BRUCE MAXIMAL EXERTIONAL TREADMILL TEST" PRINT 190 PRINT "I=~====P====EII==III=DPIIEII~P~~~~=================": 200 INPUT "ENTER SUBJECT NAME: ";NA$ 210 PRINT : INPUT "ENTER DATE (DD/MM/W): ";DT$ 220 PRINT : INPUT "ENTER SUBJECT WEIGHT (LBS): ";LB 230 PRINT : INPUT "ENTER SUBJECT AGE: ";AGE 240 PRINT : INPUT "ENTER SUBJECT SEX (M/F): ";SEX$ 250 LK = LB / 2.2: REM WEIGHT CONVERSION TO KG 270 CLS:INPUT"ENTER LAST MINUTE OF BRUCE TEST ";RS 280 RY = RS"'2’ NO OF 30 SECOND PERIODS 290 PR~NT:INPUT"ENTERANY ADDITIONAL SECONDS (ENTER 0 IF NONE) 1';RV 300 I

Development ofexerciseguidelines 310 IF RV = > 60 THEN BEEP: GOT0 270 320 IF RV < 30 THEN RV = 0 330 IF RV =>30 AND RV < 60 THEN RV = 30: RY = RY + 1 350 ’ 390 !______________________ 400 ’ DATA entry routine 410 I_______________________ 420 CLS 430 ’ 440 ’ 450 PRINT"Data entry" 460 PRINT"--______________________-______" 470 SG$ = "I": SG = .5 VE" 480 PRINT"WORK STAGE MINUTES HR ____I) 490 PRINT"______-___ __-_______ 500 KR = 8:N =RY 510 FOR I = 1 TO RY 520 LOCATE KR.5:PRINT SG$ 530 LOCATE KR,16:PRINT SG 540 LOCATE KR,27:INPUT A(I):' THIS IS HEART RATE 550 LOCATE KR,37:INPUT B(1) :'THIS IS VE 560 KR = KR tl 580 IF SEX$ ="M" THEN VI(I) = 3.88 +(.056 * (~~tt'60)) 590 IF SFX$ ="F" THEN VI(I) = 1.06 +(.056 "c(SG "60)) 600 IF I = 6 THEN SG$ = "11" 610 IF I = 12 THEN SG$ = "III" 620 IF I = 18 THEN SG$ = "IV" 630 IF I => 24 THEN SG$ = "V" 640 SG = SGt.5 650 VO = FN ROUND (VI(I)): VM = FN ROUND (VI(I)/3.5) 660 MH = A(I) 665 IF KR = 20 THEN GOSUB 960 670 NEXT I 680 IF VM < 4 THEN FL$ = "POOR" 690 IF VM =>4 AND VM <7 THEN FL$ = "LOW" 700 IF VM =>7 AND V?l(11 THEN FL$ = "AVERAGE" 710 IF VM =>ll AND VM <14 THEN FL$ = "GOOD" 720 IF VM =>14 THEN FL$ = "EXCELLENT" 730 1________________________ 731 ’ Regression routine 732 1___________________-____ 740 CLS:BEEP 750 N = RS: JJ = 0: KK = 0: LL = 0:MM = 0 : R2 = 0 760 FOR I = 1 TO RY 770 53 = JJ + VI(I) 780 KK = KK + A(1) 790 LL = LL + (VI(I))_2 800 MM = MM + ( A(I))-2 810 R2 = R2 t A(1) * VI(I) 820 NEXT I 830 B2 = (N"'R2- KK "JJ)/ (N * LL - 55-2) 840 29 = B2 850 ~2 = (KK - ~2 ~CJJ)/ N 860 Z8 = A2 930 GOT0 990 931 1________________________ 940 'SUBROUTINE FOR CLEARING SCREEN 941 1________________________ 950 ' 960 FOR K = 6 TO 20: LOCATE K,l:PRINT STRING$ (80,32);:NEXT 970 KR = 8 980 RETURN 990 ’

991 ~_____________________-__~__~~~~-~----

1000 'Determinationof breakpoint routine 1040 N = RY: ' ry is the number of collections 1050 LOCATE 10,lO :PRINT"working...." 1060 PRINT 1070 FOR I = 1 TO N 1080 X(I) = VI(I) 1090 Y(I) = B(I) 1100 NEXT I 1110 XBAR=O!

313

314

KENNON FRANCIS 1120 YBAR=O! 1130 ’ 1140 FOR I=1 TO N 1160 XBAR=XBAR+X(I) YBAR=YBAR+Y(I) 1170 1180 NEXT I 1190 XBAR=XBAR/N 1200 YBAR=YBAR/N 1210 TSS=O! 1220 SXX=O! 1230 SXY=O! 1240 FOR I=1 TO N Y(I)=Y(I)-YBAR 1250 TSS=TSS+Y(I)>tY(I) 1260 1270 SXX=SXX+(X(I)-XBAR)-2 1280 SXY=SXY+(X(I)-XBAR)"Y(I) 1290 NEXT I 1300 Bl=SXY/SXX 1310 BO=YBAR-Bl"XBAR 1320 RSSS=TSS-Bl"SXY 1330 SE=SQR(RSSS/(SXX"(N-2))) 1390 XMIN=X(l) 1400 IN%=1 1410 IN%=IN%+l 1420 IF X(IN%)=XMIN GOT0 1410 1430 IF X(IN%)XMAX THEN XMAXZ=XMAX:XMINZ=XMAX:XMAX=X(IN%):GOTO 1500 1480 XMAXZ=X(IN%) 1490 XMINZ=X(IN%) 'find the second point from each end 1500 FOR I=IN%+l TO N 1510 IF X(I)XMAX THEN XMAX2=XMAX:X?+AX=X(I):GOTO 1550 1540 IF X(I)>XMAXZ THEN XMAXZ=X(I) 1550 NEXT I 1560 1570 1580 A=XMINZ 1590 B=XMAX2 1600 C=(3!-SQR(5!))/2! 1610 Vl=A+C*(B-A) 1620 V2=B-C*(B-A) 1630 TOL=.Ol 1640 XO=A 1650 GOSUB 2070 1660 FA=RSS 1670 XO=B 1680 GOSUB 2070 1690 FB=RSS 1700 XO=Vl 1710 GOSUB 2070 1720 FVl=RSS 1730 xo=v2 1740 GOSUB 2070 1750 FV2=RSS 1760 IF FVl>=FV2 GOT0 1870 B=V2 1770 FB=FV2 1780 V2=Vl 1790 FVZ=FVl 1800 Vl=AtC*(B-A) 1810 XO=Vl 1820 GOSUB 2070 1830 FVl=RSS 1840 IF VZ-Vl
Development of exercise guidelines 1910 VZ=B-C*(B-A) 1920 xo=v2 1930 GOSUB 2070 1940 FVZ-RSS 1950 IF VZ-Vl
315

316

KENNONFRANCIS 2580 X-VAL= VI(I) 2590 IF CE = 1 THEN YVAL = B(I) 2600 IF CE = 2 THEN YVAL = A(I) 2610 GOSUB 2920 2620 NEXT I 2630 LOCATE 25, 12 :PRINT"press to continue" 2640 A$ = INKEY$: IF A$ ="" THEN 2640 2650 SCREEN 2,0,0: SCREEN O,O,O 2660 CLS: GOT0 2390 2670 ' plotting routine 2680 SCREEN 1.1: CLS LINE (45,160) - (319,160) 2690 LINE (50,0)-(50.160): 2700 FOR I = 10 TO 160 STEP 15 LINE (46,1)-(49,I):NEXT I 2710 2720 FOR I = 50 TO 319 STEP 25 LINE (1,161)-(1,163):NEXT I 2730 2740 LOCATE 1,23-LEN(TTL$)/2: PRINT TTL$; 2750 LOCATE 24,23_LEN(XLAB$)/2:PRINT XLAB$; 2760 Z = LEN(YLAB$) 2770 FOR I = 1 TO Z: LOCATE (10-Z/2)+1,1: 2780 PRINT MID$(YLAB$,I,l);:NEXT I 2790 YMAX$ = STR$(YMAX): LOCATE 2,6-LEN(YMAX$): PRINT YMAX$; 2800 YMID$ = STR$((YMAX+YMIN)/2):LOCATE 11,6-LEN(YMID$): PRINT YMID$; 2810 YMIN$ = STR$(YMIN): LOCATE 21,6-LEN(YMIN$): PRINT YMIN$; 2820 XMIN$ = STR$(XMIN): LOCATE 22,6: PRINT XMIN$; 2830 XMID$ = STR$((XMAX+XMIN)/2):LOCATE 22,24-LEN(XMID$):PRINT XMID$; 2840 XMAX$ =STR$wlAx): LOCATE 22,40-LEN(XMAX$):PRINT XMAX$; 2850 IF CE = 3 THEN YMID$ = STR$(O): LOCATE 11,6-LEN(YMID$): PRINT YMID$; 2860 RETURN 2920 ’ Plot an 11+11 at xval,yval 2930 IX = 50 + 25O"(XVAL-XMIN)/(XMAX-XMIN) 2940 IY = 160 - lSO~~(YVAL-YMIN)/(YMAX-YMIN) 2950 LINE (IX-l,IY-1) - (IX+l,IY+l) 2960 LINE (IX+l,IY-1) - (IX-1,IYtl) 2970 RETURN 2980 CLS:LOCATE 10, 35:PRINT"bye bye": END 2990 t 3000 FOR K = 6 TO 20: LOCATE K,l:PRINT STRING$ (80,32);:NEXT 3010 KR=7 3020 RETURN 3030 I____________________-______ 3031 ’ Data summary routine 3035 1___________________________ 3040 CLS 3050 PRINT"Summary Data for 'I;NA$;:PRINT" DATE: ";DT$ 3060 PRINT"_______________________-_____-_________-________________~~ 3070 SG$ = "I": SG = .5 3080 PRINT"WORK STAGE MINUTES VE" HR 3090 PRINT"_____-____ _______ _______(I 3100 KR = 5:N =RY 3110 FOR I = 1 TO RY 3120 LOCATE KR,5:PRINT SG$ 3130 LOCATE KR,16:PRINT SG 3140 LOCATE KR,27:PRINT A(I):' THIS IS HEART RATE 3150 LOCATE KR,37:PRINT B(1) :'THIS IS VE 3160 KR = KR +1 3170 IF KR = 20 THEN GOSUB 3730 3180 IF SEx$ = ~~F*~ THEN VI(I) = 1.06 t (.56 *(sG*~o)) 3190 IF I = 6 THEN SG$ = "11" 3200 IF I = 12 THEN SG$ = "III" 3210 IF I = 18 THEN SG$ = "IV" 3220 IF I =>24 THEN SG$ = "V" 3230 SG = SG+.S 3240 NEXT I 3250 PRINT: PRIN~"______________________-_____-_____~~_____~_____~_____~~_~ 3260 LOCATE 23, 12 :PRINT"press to continue" 3270 A$ = INKEY$: IF A$ ="'ITHEN 3270 3280 CLS 3290 PRINT"SunrmaryData For I';NA$;:PRINT" DATE: ";DT$ 3300 PRINT"_______________________________________________~~ 3310 PRINT:PRINT"SUBJECTWEIGHT (LBS) :";LB;:PRINT" AGE: ";AGE 3320 PRINT:PRINT"MAxvo2 (ML/KG/MIN) = 11;vo

Development of exercise guidelines

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PRINT:PRINT~.X vo2 (METS) = '1;w PRINT:PRINT"MAXIMUMHEART RATE = ";MH PRINT:PRINT"CARDIOVASCULARFITNESS LEVEL: 'I; FL$ FX = FN ROUND (28 +(Z9 * X0)) PRINT:PRINT"Heartrate break point = 'I;INT (FX) PRINT:PRINT "Ventilatory Break point = 'I;FN ROUND (X0);" liters/min" LOCATE 20, 12 :PRINT"press to continue" PRINT"______--___-___-_-__-______________-__-~__~-~_~" A$ = INKEY$: IF A$ ="" THEN 3470 IF VM< 5 THEN VP$ = "WALK AT 2-3 MPH, CYCLE ERGOMETER AT 150-300 KGM, SWIM USING A FLOAT BOARD" 3490 IF V-M<5 THEN VZ$ = "LIGHT STRETCHING EXERCISE, BICYCLING AT 6 MPH" 3500 IF VM> 4 AND VM< 7 THEN VP$ = "WALK/JOG AT 4 MPH, CYCLE (ERGOMETER AT 450-600 KGM, SWIMMING - TREAD WATER" 3510 IF VM> 4 AND VM< 7 THEN VZ$ = "LIGHT CALISTHENICS, GOLF, BICYCLING 8 MPH" 3520 IF VM> 7 AND V-M<9 THEN VP$ = "WALK/JOG: 12 MIN MILE, CYCLE ERGOMETER Q 750 to 900 KGM, SWIM (CRAWL AT 30 YD/MIN)" 3530 IF VM> 7 AND VM< 9 THEN VZ$ = "NON-COMPETATIVETENNIS, BADMINTON, HIKING, BICYCLING AT 11 - 12 MPH" 3540 IF VM> 8 AND VM< 11 THEN VP$ = "WALK/JOG @ 10 MIN MILE, CYCLE ERGOMETER Q 1050 KGM, SWIM (CRAWL AT 40 yd/min)" 3550 IF VM> 8 AND VM< 11 THEN VZ$ = "VIGOROUS CALISTHENICS, ROPE SKIPPING, BICYCLING AT 13 MPH" 3560 IF VM>lO AND VM< 13 THEN VP$ = "WALK/JOG (8.5 MIN MILE), CYCLING (ERGOMETER) AT 1,200 KGM, SWIMMING (CRAWL AT 50 yd/min)" 3570 IF VM>lO AND VM< 13 THEN VZ$ = "TEAM SPORTS SUCH AS BASKETBALL, SOCCER, HANDBALL" 3580 IF VM>13 THEN VP$ = "WALK/JOG @ 7.5 MIN MILE), CYCLE ERGOMETER Q 1500 KGM,SWIM (CRAWL AT 50 yd/min)" 3590 IF VM>13 THEN VZ$ = "VIGOROUS TEAM SPORTS, VIGOROUS ROPE SKIPPING" 3600 CLS:PRINT"EXERCISEGUIDELINES" 3620 PRINT"_-____-_--______-____" 3630 PRINT:PRINT"IN ORDER TO DERIVE THE GREATEST BENEFIT FROM AN EXERCISE PROGRAM" 3640 PRINT"YOU SHOULD EXERCISE A MINIMUM OF 3 TO 4 TIMES A WEEK USING THE" 3650 PRINT'ITARGETHEART RATE OF ";INT (FX);:PRINT"BEATS/MINUTEWHILE PERFORMING" 3660 PRINT"ONE OF THE FOLLOWING ACTIVITIES: fl 3670 PRINT:PRINT "PRESCRIBED ACTIVITY :":PRINT VP$ 3680 PRINT:PRINT "RECREATIONAL ACTIVITY:":PRINT VZ$ 3690 PRINT"---_---__---__--___-_" 3700 LOCATE 23, 12 :PRINT"press to continue" 3710 A$ = INKEY$: IF A$ ="'ITHEN 3710 3720 GOT0 2390 3730 'SUBROUTINE FOR CLEARING SCREEN 3740 LOCATE 23, 12 :PRINT"press to continue" 3750 A$ = INKEY$: IF A$ ="" THEN 3750 3760 FOR K = 5 TO 20: LOCATE K,l:PRINT STRING$ (80.32);:NEXT 3770 KR = 5 3780 RETURN About the AUthOC-KENNON FRANCIS received his Ph.D. in biochemistry from Auburn University in 1973, and has taught at the University of Alabama at Birmingham since 1974. He is currently a full professor in the Division of Physical Therapy, where he teaches exercise physiology, pursues his primary research in physiological concepts of health promotion, and devotes himself to his favourite pastime, microcomputers. He is an editor for computer applications for the Journal of Physical Therapy and Clinical Management in Physical Therapy. He has just published a book titled Computer Applications in Physical Therapy. 3330 3340 3350 3360 3370 3380 3450 3460 3470 3480