Metabolic Response to the Half-Mile AAHPERD Functional Fitness Walk Test in Older Adults

Transcription

1 Journal of Aging and Physical Activity, 1996, 4, O 1996 Human Kinetics Publishers, Inc. Metabolic Response to the Half-Mile AAHPERD Functional Fitness Walk Test in Older Adults Blanche Evans, David Hopkins, and Tracey Toney The purpose of this study was to determine the metabolic stress of a selfpaced half-mile walk test incorporated in the AAHPERD functional fitness assessment for older adults. Forty-three subjects, aged 57 to 75, completed a half-mile walk on an indoor track (IT) and during a treadmill simulation (TS) of the track walk. Treadmill data indicated that subjects exercised at a mean V02 of 14.7 ml. kg-'. min-i and mean heart rate (b. min-i) of 129. A significant difference (p I.05) was found between IT and TS on rating of perceived exertion. Results indicate that older subjects selected a pace that stressed their cardiorespiratory system without producing severe fatigue or medical complications. Therefore, the half-mile walk test appears to be a safe test that may be incorporated in functional fitness testing. However, its ability to determine functional capacity needs further study. Key Words: oxygen uptake, field tests, heart rate, RPE Historically, the older population has been neglected in the development of measurement and evaluation tools for fitness-related activity. There is a need for a safe and easily administered field test of fitness to provide feedback and motivation to the older adult. In June 1986, an ad hoc committee of the American Alliance of Health, Physical Education, Recreation and Dance (AAHPERD) was charged with developing a functional fitness assessment for individuals over the age of 60 years (Clark, 1989). This test development was important as it represented an attempt to assess a different component of fitness in this age group, functional fitness, and therefore represented a new direction for testing. In the AAHPERD test, functional fitness was operationally defined as "an individual's capacity to meet ordinary and unexpected demands of daily life safely and effectively" (Clark, 1989, p. 66). This definition indicated the need for an assessment that was practical and closely related to activities normally encountered by the older adult. In addition, the assessment was designed to require inexpensive equipment, to be drug independent, and to involve no more risk than encountered in everyday life (Clark, 1989; Flatten, 1989). Test items included in the functional fitness assessment measure agilityjdynamic balance, The authors are with the Department of Physical Education, Indiana State University, Terre Haute, IN

2 Metabolic Response to Half-Mile Walk 81 cardiorespiratory endurance, flexibility, muscular strength and endurance, and motor control and coordination. A more detailed description of the procedures for administering each item is included in the Methods section. Furthermore, individual test items have been described by Clark (1989) and included in a test manual by Osness et al. (1990). Recently, the reliability of each test item was reported for males and females by Shaulis, Golding, and Tandy (1994). Because the test battery is relatively new, little research has been reported on the physiological demands of the functional fitness assessment as a whole or on individual test items. Of particular interest are the physiological requirements that might be expected of older individuals who complete the cardiorespiratory endurance component of the assessment, the half-mile walk. This test involves walking as fast as comfortably possible for one half of a mile. The instructions to participants emphasize that the activity is restricted to walking, is self-paced, and should be discontinued if discomfort is experienced (Clark, 1989; Osness et al., 1990). Previously, the level of cardiorespiratory fitness or aerobic power in the older adult has been most commonly assessed using laboratory exercise tests. Treadmill tests have been the most popular mode for measuring aerobic power in the elderly; however, cycle ergometers have also been used (Siconolfi, Cullinane, Carleton, & Thompson, 1982; Sidney & Shephard, 1977). Because laboratory tests may prove to be stressful for the older adult, competitive timed field tests that involve walking a set distance have become popular and have been used to estimate aerobic power (Kline et al., 1987). However, for some older individuals, the competitive nature of that activity may prove to be undesirable. An alternative to these types of tests is the AAHPERD functional fitness half-mile walk, which is performed in a noncompetitive environment. Since the half-mile walk test may be self-administered and self-monitored, it is important to ensure that the participants respond to the instructions and intent of the test with a level of activity that is appropriate for determining their functional capacity yet is not considered potentially harmful. Therefore, the purpose of this study was to determine the metabolic demands imposed by the AAHPERD functional fitness halfmile, self-paced walk test for older adults. Methods SUBJECTS The participants were male and female volunteers over 55 years of age who were recruited from the community by use of flyers and newspaper advertisements. Upon arriving at the gymnasium on one of two advertised testing days, they participated in the five tests inciuded in the AAHPERD functional fitness assessment. At this time, they also were informed of an additional test opportunity, a treadmill walk that would simulate the physiological stress encountered during their half-mile walk test. Seventy-one individuals completed the AAHPERD functional fitness assessment. However, only 43 of these 71 participants chose to participate in the treadmill walk. Accordingly, data analyses are restricted to those 43 individuals who participated in both tests. All participants who completed the functional

3 82 Evans, Hopkins, and Toney fitness assessment were allowed an opportunity to participate in the treadmill walk. Of the 28 functional fitness assessment participants not included in the treadmill walk, 21 were not interested in attempting the test. Seven participants who began the treadmill walk terminated the test early and were not included in the data analyses. The reasons participants elected to stop the treadmill test varied. Several subjects indicated they had difficulty breathing while wearing a face mask and were uncomfortable. Other subjects indicated that they felt the speed was faster than their pace for the track walk. Their treadmill speeds were recalculated and found to be identical to the treadmill speed initially selected. Even though participants had prior practice with treadmill walking, the elevated treadmill walking surface combined with the breathing apparatus may have resulted in subjects having a perception of an increased walking pace. All participants were informed of the test procedures, the risks, and the benefits during group meetings prior to the functional fitness assessment and in one-on-one conferences at the treadmill walk session. Each participant signed informed consent documents in accordance with university internal review board policy and the recommendations of the American College of Sports Medicine (ACSM) (1991). Descriptive statistics for the 43 treadmill walk participants as a group and for males (n = 17) and females (n = 26) are presented in Table 1. Self-reported medical problems obtained from written questionnaires for the participants are summarized in Table 2. Over one-half of the participants reported problems with arthritis. The other most frequently reported problems were difficulty with hearing, poor vision, joint pain, and shortness of breath. These problems are commonly reported by older individuals and did not interfere with subjects' participation in any part of the functional fitness assessment or treadmill walk. TESTS Participants were asked to appear on one of two test days for completion of the AAHPERD functional fitness test battery. The five items included in the assessment are described in the following paragraphs. The order for testing each Table 1 Descriptive Statistics of Participants and Half-Mile Walk Time (Means and Standard Deviations) Total group Males Females (n = 43) (a = 17) (n = 26) Variable M SD M SD M SD Age (years) Height (cm) Weight (kg) Percent body fat Walk time (s)

4 Metabolic Response to Half-Mile Walk 83 Table 2 Self-Reported Medical Problems (n = 42)a Medical problem Number reported Percent reported Arthritis Difficulty in hearing Joint pain Difficulty with vision Shortness of breath Low back problems Dizziness/balance problems Indigestion Chest pain/palpitations Lung disease Diabetes Gout Asthma Leg pain Anemia Arteriosclerosis "No report for one subject. component and specific test instructions are described in the test manual (Osness et al., 1990). The trunkpeg flexibility test (sit-and-reach test) was performed without shoes with the participant seated on the floor, legs extended, toes pointed up, feet 12 in. apart, and heels against a 20-in. line marked on the floor. With the hands placed one on top of the other, participants slowly reached forward along a yardstick taped to the floor between the legs with the 20-in. point on the yardstick even with the heels and the 20-in. reference line, and the zero point toward the participant. A hand was placed on the knees so they could not be raised throughout the two practice trials or the two test trials. The score for each test trial was recorded to the nearest 112 in. The agilityjdynarnic balance test began with the participant seated in a chair. Two cones were placed behind the chair at spots 6 ft to the side and 5 ft behind it. On the "ready, go" signal, the participant stood, walked to the right (between the cone and the chair), walked around the cone, returned to the chair, sat down, raised the heels 112-in., and repeated the movement to the left side. One trial was the time, recorded to the nearest second, required to complete two circuits. Two trials were administered with 30 s rest between trials. The coordination test used three unopened soda cans placed on a 30-in. strip of tape on a table. Marks were placed at 5-in. intervals beginning in. from the tape edge. The soda cans were placed on the the first, third, and fifth marks from the right side of the tape. The participant was seated in front of the table. Upon a signal, the participant, holding the can on the first mark with the thumb up, placed the can upside down on the second mark, followed by using

5 84 Evans, Hopkins, and Toney the same procedure for the second and third cans. Then, subjects returned the cans to their original marks by grasping the can with the thumb down and putting it upright. One trial was successfully completing this procedure two times without stopping. The score was the best time of two trials timed to the nearest 0.1 s. The muscular strengthlendurance assessment was performed with the participant seated in a chair, eyes focused ahead, feet flat on the floor. The dominant arm was straight and relaxed. A 4-lb (women) or 8-lb (men) weight was placed in the dominant hand. The participant performed a biceps curl through the full range of motion for a practice trial. Following a l-min rest, the participant completed as many repetitions as possible in 30 s. The maximal number of full repetitions performed in the 30 s was the score. The half-mile walk was performed at the end of the battery of tests on an indoor, 118-mile, oval tartan track. Participants were given standard instructions indicating that the walk was to be completed as quickly as possible using a brisk but comfortable pace, that the pace should allow completion of the walk without undue fatigue or discomfort, and that the walk was noncompetitive. The time to complete four laps (112 mile) was recorded in seconds (Table 1). In addition, pulse rate and rating of perceived exertion (RPE) were determined immediately postwalk by trained personnel. The pulse rate was monitored for 15 s, beginning within 10 to 15 s postwalk. Immediately after the pulse rate was taken, the RPE was recorded. Verbal instructions were given for the use of the Borg 6-20 point scale (Borg, 1962) prior to the track walk. Before leaving the functional fitness assessment area, participants who volunteered to complete the simulated treadmill walk were given a description of the test and instructions to maintain similar food, medication, smoking, and caffeine use as they had for the functional fitness tests. Each participant was given a card with an assigned laboratory test date and time. The time between the track walk and the treadmill walk was at least 1 week. Participants were given an opportunity after the functional fitness assessment and prior to the laboratory test session to walk on the treadmill until they felt comfortable. Subjects walked until they could release the handrails, maintain their balance, and walk at their track walk pace. A number of participants had prior experience with treadmill walking and required no practice. On the day of the laboratory test, a series of questionnaires pertaining to health and medical history were completed. Three skinfold measurements, using sex-specific sites (Pollock, Schmidt, & Jackson, 1980) were recorded for each individual in order to obtain estimates of percent of body fat. A half-mile walk on a treadmill that simulated the average speed of the track walk was then completed. The treadmill speed was determined by using the total time required to complete the track walk and the distance of the walk (112 mile). Immediately prior to the treadmill walk, participants were seated in a chair on the treadmill, and resting blood pressure (BP), heart rate (HR), and oxygen uptake (VO,) measures were obtained. After 5 min of seated rest, they began walking on the treadmill while the speed was increased during the first 30 s of the walk from 53.6 m - min-' to their calculated speed. The duration of the treadmill walk corresponded to the duration of their track walk. Measures of V02, minute ventilation (VE), and respiratory exchange ratio (RER) were recorded every 30 s throughout the treadmill walk, using a Sensormedics Horizon I1 metabolic cart (Sensormedics Corporation, Anaheim, CA) and a Hans Rudolf

6 Metabolic Response to Half-Mile Walk 85 face mask. The concentrations of oxygen and carbon dioxide were measured using electronic gas analyzers calibrated prior to each test with medically tested gases. HR and RPE were recorded each minute during the walk. ECG was monitored continuously using a 12-lead configuration and a Quinton Q-2000 electrocardiograph. The means of the values obtained during the last 2 min of the exercise were used in data analyses. In addition, blood pressure was measured at 2-min intervals throughout the treadmill exercise, at the end of the exercise, and at 1 min postexercise. STATISTICAL ANALYSIS The metabolic response to the simulated track walk was summarized using descriptive statistics. A one-way MANOVA was conducted to determine significant differences between males and females on the dependent variables. A significant omnibus F was followed by one-way ANOVAs to identify specific differences between males and females. Based on the ANOVA findings, the data for males and females were pooled for further comparison. A dependent t test was used to compare RPE responses to the indoor track and treadmill walks. All tests were conducted at the.05 level of significance. Results The means and standard deviations of the variables assessed during the treadmill walk are presented in Table 3 for the total group, males, and females. The omnibus F for the MANOVA showed significant differences (p I.05) between males and females for the dependent variables. Follow-up ANOVAs identified significant differences (p I.05) between males and females for variables related to body size and percent fat. As expected, men were taller and heavier, had less fat, had higher V02 values, and walked faster than females. HR and RER values were similar; therefore, the data for males and females were pooled for these comparisons. A comparison of RPE values between the track and treadmill walks is presented in Table 4. The dependent t test results indicated that the mean RPE Table 3 Means and Standard Deviations of Variables Assessed During Simulation Walk on the Treadmill Variable Total group Males Females (n = 43) (n = 17) (n = 26) V, (L. min-i) VOz (ml. kg-'. mid) METs RER HR (b - mi&)

7 86 Evans, Hopkins, and Toney Table 4 Comparison of RPE Values Between Track and Treadmill Walks (n = 43) Variable M SE Diff SE diff t value RPE track RPE treadmill value for the treadmill walk was significantly higher (p I.05) compared with the mean RPE value for the track walk. Discussion With the growing popularity of the AAHPERD functional fitness assessment for older adults, questions have been raised regarding the validity, reliability, physiological demand, and safety of the individual test items. Recent investigations have provided insight into the reliability of each test item for both males and females (Shaulis et al., 1994). The present investigation determined the metabolic and perceived exertion responses of older adults to the half-mile walk. The findings indicate that participation in this test results in physiological and perceived stress that is well within the demand that would be encountered during daily living and recreational activities. Mean and peak ventilation values were well below estimated mean values of 75 L. min-' in males and 50 L. min-' in females at a frequency of 50 breaths1 min, which have been reported to result in shortness of breath in one group of older exercising individuals (Shephard, 1978). The peak ventilation for males was 55 L. min-' with a frequency of 33 breathslmin and for females 34 L. mid and 34 breathslmin. None of the participants reported shortness of breath during or after either the track walk or the treadmill walk. The mean V02 and HR values (Table 3) for the treadmill walk for males and females indicated that the participants were exercising at a level that would be expected to be safe. Similar V02 and HR values have been reported for older adults walking at a self-selected speed with and without hand-held weights (VOz ml. kg-'. min-i = 13.2 to 15.7; HR b. min-i = 124 to 135) and while walking at 70% of heart rate reserve with and without hand-held weights (V02 ml. kg-' min-' = 15.7 to 16.4; HR b. mix1 = 135 to 140) (Evans, Potteiger, Bray, & Tuttle, 1994). No complications were reported during exercise in that investigation or in the present investigation. It appears that older adults select a walking pace that is reasonable, safe, and well within the physiological demands required for daily living and recreational activities, and at an HR within recommended exercise intensities for older adults (ACSM, 1993). Activities with similar MET values have been reported and include croquet, table tennis, hiking, and bowling, which are common daily and lifetime activities (ACSM, 1995). However, the participants do not appear to respond at or near their functional capacity. Actual measurement of V0,max would be needed to determine the validity of this test prior to its use as a submaximal test of functional capacity.

8 Metabolic Response to Half-Mile Walk 87 The mean RER of 1.06 indicates a level of stress not represented by the RPE, HR, or VO, values and, therefore, appears to be aberrant. For a similar intensity of exercise reported in another study (Evans et al., 1994), the RER values ranged from 0.90 to It is possible that an equipment problem went undetected; however, analyzers were calibrated prior to each treadmill walk and postwalk for most tests. Only one other explanation seems remotely possible. older individuals tend to have poor circulation and a slower cardiac response to work that leads to a greater accumulation of lactic acid at submaximal work efforts (Shephard, 1978; Stamford, 1988), which could have influenced the RER values. However. blood lactate concentrations were not determined. and the level of work does not appear to be of sufficient intensity to result in such a response. In addition, the VE values are reasonable and coincide with values reported for older adults exercising at a similar exercise intensity (Evans et al., 1994). The participants in this study did not perceive the half-mile track and treadmill walks to be difficult. The RPE values reported for the two walks fall at a level of work rated as light and between light and somewhat hard (Borg, 1962). Similar RPE values have been reported during walking with hand-held weights in a group of older adults (Evans, Potteiger, Bray, & Tuttle, 1994). In that study, the RPE values ranged from 9 to 11 units for walking with hand-held weights at a self-selected constant speed, and from 10 to 12 units while exercising at 70% heart rate reserve with hand-held weights. Even though the treadmill walk was found to be significantly harder than the track walk, the difference was small, less than one unit. This response is not unexpected even though subjects were walking at the same mean speed during the treadmill and track walks. Participants were unable to vary their speed during the treadmill walk, and gas collection equipment was worn. In addition, walking on a treadmill may be considered a novel activity for this group. Peace et al. (1983) reported higher energy cost values for treadmill walking compared with floor walking for older adults. Future research should include a local rating of perceived exertion, as some subjects verbally reported leg fatigue immediately following the walks. Systolic and diastolic blood pressure readings changed in an expected direction and magnitude from rest to exercise during the treadmill walk. Mean systolic blood pressure values at rest were k 17.7 mmhg with a range of 100 to 180 mmhg, while the mean values during exercise increased approximately 30 mmhg to with a range of 138 to 240. For individuals who began the test with high blood pressure readings, blood pressure did not increase more than for those beginning with low readings. None exceeded the discontinuation point of 250 mmhg recommended by the ACSM (1991). Diastolic values changed minimally in the participants. The mean diastolic blood pressure at rest was 77.9 f 9.4 mmhg with a range of 60 to 100 mmhg, while during exercise the mean value was 80.2 f 12.1 mmhg with a range of 58 to 108 mmhg. The increase for diastolic blood pressure during exercise was approximately 10 mmhg. The ACSM (1991) recommends discontinuation of the test if diastolic values reach 120 mmhg. The discontinuation value for this study was more conservative at 110 mmhg. None of the participants reached the recommended points for stopping the test. In conclusion, the cardiorespiratory endurance component of the functional fitness assessment for older adults (Osness et al., 1990) appears to be well

9 88 Evans, Hopkins, and Toney tolerated by the age group for whom it was developed. Participants completed the half-mile walk well within recommended tolerance levels and showed no adverse reactions or complications. They reported that they enjoyed participating in the functional fitness assessment and the treadmill walk test. Their only negative comments focused on the lack of norms for test items. With the publication of norms and activity guidelines based on assessment results, older adults will be able to compare their results and determine functional fitness status quite easily with minimal risk. However, the ability of the test to determine functional capacity in this age group needs further study. References ACSM. (1991). Guidelines for exercise testing and prescription (4th ed.). Philadelphia: Lea & Febiger. ACSM. (1993). Resource manual for guidelines for exercise testing and prescription (2nd ed.). Philadelphia: Lea & Febiger. ACSM. (1995). ACSM's guidelines for exercise testing and prescription (5th ed.). Baltimore: Williams & Wilkins. Barry, A.J., Daly, J.W., Pruett, E.D.R., Steinmetz, J.R., Page, H.F., Birkhead, N.C., & Rodahl, K. (1966). The effects of physical conditioning on older individuals: I. Work capacity, circulatory-respiratory function, and electrocardiogram. Journal of Gerontology, 21, Borg, G. (1962). Physical performance and perceived exertion. Lund, Sweden: Gleerup. Clark, B.A. (1989). Tests for fitness in older adults: AAHPERD fitness task force. JOPERD, 60(3), Evans, B.W., Potteiger, J.A., Bray, M.C., & Tuttle, J.L. (1994). Metabolic and hemodynamic responses to walking with hand weights in older individuals. Medicine and Science in Sports and Exercise, 26, Flatten, K. (1989). Fitness evaluation and programming for older adults. JOPERD, 60(3), 63. Kline, G.M., Porcari, J.P., Hintermeister, R., Freedson, P.S., Ward, A., McCarron, R.F., Ross, J., & Rippe, J.M. (1987). Estimation of VO, max from one mile track walk, gender, age and body weight. Medicine and Science in Sports and Exercise, 19, Osness, W.H., Adrian, M., Clark, B., Hoeger, W., Raab, D., & Wisnell, R. (1990). Functional fitness assessment for adults over 60 years (a field based assessment). Reston, VA: American Alliance for Health, Physical Education, Recreation and Dance. Pearce, M.E., Cunningham, D.A., Donner, A.P., Rechnitzer, P.A., Fullerton, G.M., & Howard, J.H. (1983). Energy cost of treadmill and floor walking at self-selected paces. European Journal of Applied Physiology, 52, Pollock, M.L., Schmidt, D.H., & Jackson, A.S. (1980). Measurement of cardiorespiratory fitness and body composition in the clinical setting. Comprehensive Therapy, 6, Shaulis, D., Golding, L.A., & Tandy, R.D. (1994). Reliability of the AAHPERD functional fitness assessment across multiple practice sessions in older men and women. Journal of Aging and Physical Activity, 2, Shephard, R.J. (1978). Physical activity and aging. Chicago: Yearbook Medical.

10 Metabolic Response to Half-Mile Walk 89 Siconolfi, S.F., Cullinane, E.M., Carleton, R.A., & Thompson, P.D. (1982). Assessing VO, max in epidemiologic studies: Modification of the Astrand-~~hrnin~ test. Medicine and Science in Sports and Exercise, 14, Sidney, K.H., & Shephard, R.J. (1977). Maximum and submaximum exercise tests in men and women in the seventh, eighth, and ninth decades of life. Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology, 43(2), Stamford, B.A. (1988). Exercise and the elderly. Exercise and Sport Sciences Reviews, 16,