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The initiation and maintenance of exercise behavior: A learning theory conceptualization
C/mm/ Psycholop Reoiew, Vol. 8, pp. 345-353, Printed in the USA. All rights reserved.
1988 Copyright
027%7358/88 $3.00 + .OO 0 1988 Pergarnon Press plc
THE INITIATION AND MAINTENANCE EXERCISE BEHAVIOR: A LEARNING THEORY CONCEPTUALIZATION
OF
Laura A. Lees judith A. Dygdon The Chicago School of Professional
Psychology
ABSTRACT.
Current popular interest in health maintenance and physical fitness raises this new question for clinical psychology to address: What variables account for the fact that some individuals will initiate an exercise program and continue, while others will discontinue shortly aftir program initiation? While considerable theoretical and empirical work regarding the benefits derived from exercise exists, the question raised above has not yet been considered. Since clinical psychologists will most likely be called upon to satisfy the role qf facilitating the acquisition and maintenance of exercise behaviors for their clients, a conceptualization of how such behavior patterns evolve is crucial. This paper presents a learning theory conceptualization as to how exercise becomes a routine behavior for some. Implications for clinical intervention, derived from this conceptualization, are also discussed.
Popular
interest
in health
maintenance
and physical
fitness
behaviors
has in-
creased dramatically in recent years. Evidence of such current interest is presented in the results of a nationwide survey (Pacific Mutual Life Insurance Company, 1978). Respondents to this survey overwhelmingly endorsed “good health” as the most important factor in their lives. Many factors considered essential to a satisfying life were endorsed far less than “good health”; among these factors were “satisfying employment: “favorable living environment,” and “high standard of living.” It is most interesting to note that respondents to this survey were reported to believe that health status could be improved by smoking cessation, nutritious eating, stress control, and regular exercise. This apparent popular belief, that physical fitness is correlated with health status, appears to be well supported by empirical data. Numerous studies point to a relationship between exercise and the prevention of problems in the physical
Appreciation is expressed to Jeffrey C. Grip for his helpful suggestions on an earlier version of this manuscript. Requests for reprints should be addressed to: Laura A. Lees; The Chicago School of Professional Psychology; 806 South Plymouth Court; Chicago, IL 60605. 345
346
L. A. Lees a&J. A. Dygafon
health domain, such as coronary heart disease, blood pressure elevation, and obesity (Haskell, 1984; Cooper, Pollack, Marin, &White, 1976; Morris, Pollard, Everitt, & Chave, 1980). Other studies argue the existence of relationships between exercise and the prevention of problems in the mental health domain, such as anxiety and depression (Sime, 1984; Reiter, 1981; Griest et al., 1978). Taken together, data from the variety of studies reviewed above suggest that most people see exercise as important, and that this view is reasonable in light of considerable evidence that there is a relationship between exercise and health. Interestingly, other data suggest that far fewer individuals actually engage in regular exercise than report believing that exercise is important (Ribisl, 1984; Haskell, 1984; Pacific Mutual Life Insurance Company, 1978). This finding suggests that there exists a group of individuals who want to become exercisers but have not added this behavior to their personal repertoires. It seems quite appropriate for psychology, as a science of behavior, to address the issue of why this discrepancy exists between the numbers of individuals who report believing that exercise is important, and the number of individuals who actually engage in regular or routine exercise. Psychology has contributed to the development of strategies to facilitate the improvement of other potential “health-engendering” behaviors (e.g., smoking cessation, weight control). It seems that a psychological conceptualization of exercise initiation and maintenance stands to contribute, generally, to the understanding of how such behaviors are acquired, and specifically, to the facilitation of the acquisition of such behaviors for individuals who desire to do so. Some authors (e.g., Ribisl, 1984; Haskell, 1984) have suggested that the discrepancy between the numbers of individuals who report believing that exercise is important, and the number of individuals who actually engage in regular exercise, is due to the fact that some individuals who recognize that exercise is important simply do not know how to begin. It appears quite likely that this explanation accounts for some portion of this discrepancy. The intervention required to facilitate the acquisition of exercise behaviors for these individuals is clear. A basic educational model which identifies activities that contribute to improved physical status is a necessary first step. However, it seems likely that another portion of the discrepancy between individuals who report believing that exercise is important but do not engage in it, and individuals who do engage in regular exercise, is accounted for by those individuals who, unlike the group addressed by Ribisl (1984) and Haskell (1984), know how to begin an exercise program, but discontinue shortly after initiation. Intervention for this group is not as clear, and a psychological conceptualization of why some continue an exercise program once initiated, while others discontinue, is not immediately forthcoming. It is precisely this issue which the remainder of this paper addresses. In this endeavor, an appeal is made to the learning theories as a model for understanding this phenomenon. BASIC DEFINITIONS
Before entering into a detailed theoretical conceptualization of exercise initiation and maintenance, some definitions of what is meant by exercise and exercise maintenance in this paper are in order. In this paper, “exercise” refers to a regular series of specific movements designed to strengthen or develop bodily muscles and
The Initiation and Maintenance oj Exercise Behavior
347
endurance. This includes any one of, or any combination of, physical activities such as: mobile or stationary bicycle riding, jogging, rope jumping, swimming, aerobic dancing, and static exercises that work specific muscle groups (e, g., floor exercises, weight training). In this paper, “regular exercise,” or “maintenance of exercise behaviors,” refers to participation in exercise according to some nonrandom schedule. In addition, this paper excludes from its purview exercise behavior which can be considered “addictive” (i.e., individuals who appear to be dependent upon exercise) or “occupational” (i.e., competitive athletes in training) since these behaviors may differ significantly in form or function from “regular exercise” as it is defined above. While many fitness experts recommend participation in exercise for up to 90 minutes (this period includes the warm-up phase; aerobic stimulus phase; intermediate cool-down phase; anaerobic phase; for example, weight training, static exercises; and final cool-down phase) three times per week (Ribisl, 1984), the definitions used in this paper are not limited by this factor. For many regular exercisers, this activity takes place in a fitness facility, but the definitions employed in this paper are not limited to activities which take place within a formal structure. THEORETICAL CONCEPTUALIZATION In attempting to use the learning theories to explain the development of regular exercise, a pure operant model is initially most appealing. In other words, to state that exercise behaviors are present in an individual’s behavioral repertoire because they are reinforced, makes conceptual sense. Before initiating an attempt to identify the stimuli that might serve as reinforcers, it is reasonable to investigate from where these operants might come. An observational learning hypothesis can readily be used to explain this. Potential models of exercise behavior who are reinforced for that behavior can easily be found in current mainstream American society. The media, for example, present many exercise models. Examples of exercisers who report positive feelings of stimulation after exercise, or who report that their good health status, or shapely bodies, follow exercise, are plentiful in television programming. In addition, radio, television, and the print media present numerous “tacts,” that is, verbal representations of environmental stimuli, behaviors, or relationships between or among them (Skinner, 1957), outlining the following reinforcing contingencies: that exercise eventually produces healthy and attractive bodies; that people who exercise feel good afterwards; and that people who exercise are called conscientious, intelligent, or disciplined by society. Furthermore, separate from contacts with exercise models in the media, many individuals personally encounter others who exercise and consequently have attained obvious physical benefits, or who report other advantageous short- or long-term consequences. In sum, it is clear that learning through the observation of models or through verbal representations of the positive events that follow exercise may well account for an individual’s initiating exercise behavior. It is, however, unreasonable to expect that new exercise behaviors will be maintained in the absence of response contingent reinforcement for the new exerciser. At this point, an appeal to the literature on endogenous opioids, and the suggested role they play as reinforcing stimuli, becomes attractive. However, the
348
results
L. A. Lees and J, A. Dyp-don
of studies
investigating
this hypothesis
are equivocal,
and the precise
mech-
anisms through which these substances may exert such reinforcing effects have yet to be determined (see Steinberg & Sykes, 1985). Some authors (i.e., Carr et al., 1981) report that, within certain limits, opioid release increases as participation in exercise increases. Therefore, the possibility exists that the reinforcing effects of opioids are only realized when these substances are released in sufficient quantity. If this is the case, the new exerciser who does not have the ability (i.e., muscle strength, aerobic capacity) to exercise with the intensity, or for the duration, necessary to release sufficient amounts of opioids may not experience this reinforcing effect. Taking this into consideration, there must be other reinforcing stimuli involved early on in maintaining exercise behaviors. For this reason, a “more external” operant hypothesis is required before a comprehensive conceptualization of the factors that maintain exercise behavior can be formulated. It is clear that not all exercise initiators maintain this behavior. It appears quite likely that those exercise initiators who do not maintain this new behavior are those
who meet
with no reinforcement
for the behavior.
The
first step,
then,
in
developing an operant explanation for exercise behavior, is the identification of reinforcers delivered to the new exerciser. It is at this point some difficulties for an operant explanation of the maintenance of exercise emerge. What stimuli can be seen as potential “exercise reinforcing stimuli” in the new exerciser’s situation? For those new exercisers who engage in these behaviors in a fitness facility, or in less structured environments but with other people present, occasional verbal praise from staff members, or other exercisers, can be seen as a reinforcing stimulus. Undoubtedly, such a stimulus contingently follows exercise behavior for many new exercisers. However, it is difficult to conceive of verbal praise as an extremely potent reinforcer for most, or as a stimulus which occurs with great frequency. As such, verbal praise, in and of itself, seems unlikely to be successful in maintaining such a high cost, or difficult, behavior as exercise, especially “new exercise .” Physical health and body appearance improvements were discussed in relation to the reinforcers a potential exerciser might observe an exercise model might attain. One might initially speculate that these stimuli serve to reinforce exercise behavior. However, this explanation quickly loses its appeal since these events are far removed in time from initial exercise behaviors. The possibility that other stimuli, which follow the initial exercise behavior more closely in time, have been conditioned to these more distal stimuli exists; precisely what those stimuli are is difficult, at this level, to discriminate. However, this explanation becomes more attractive with further expansion. One way to proceed in the search for potential reinforcing stimuli is to identify what events typically follow exercise. In fact, what follows exercise most consistently, is simply proprioceptive feedback from the muscles, tendons, and joints involved in the exercise, indicating their use. It would appear that, in the case of this feedback is perceived possibly as pain, exercise, especially new exercise, discomfort, or at least fatigue. Most would concur in labeling this fatigue an aversive stimulus. While certainly not part of the definition of “punishment,” many would expect an aversive stimulus to function as a punisher. Yet fatigue does not always appear to suppress exercise behavior. This phenomenon would appear to be problematic for a learning theory explanation of exercise behavior. On closer inspection, however, it may provide the connection mentioned above between
The Initiation and Maintenanceof Exercise Behavior
349
stimuli which follow exercise closely in time, and the seemingly positive, and conceivably reinforcing, health and appearance benefits attained after exercise has continued for some time. Dulany (1968) p resented data indicating that apparently aversive stimuli can function as positive reinforcers under certain conditions. In Dulany’s work, subjects were told that the receipt of a mild aversive stimulus would indicate that they had done a task correctly. In fact, under these conditions, subjects increased the frequency with which they engaged in tasks that produced the aversive stimulus. 1977) have interpreted these results from a Dulany and others (e.g., Bandura, social learning theory perspective, arguing that the information a stimulus carries overrides its reinforcement or punishment value. It appears, however, that this phenomenon can be explained, perhaps more parsimoniously, by arguing that the aversive stimulus became a conditioned reinforcer when the relationship between the appearance of that stimulus and correct performance was tacted for subjects. Extrapolating this explanation to the experiences of a new exerciser, we can say that when the relationship between mild muscle fatigue and improvement in physical condition is tacted for the new exerciser, muscle fatigue comes to function as a conditioned positive reinforcer. Upon returning to the question of why some new exercisers continue, while others quit, it is reasonable to speculate that those who continue have experienced, and learned from, the verbal representations described above, while those who quit, have not. The explanation outlined above makes the consideration of muscle fatigue functioning as a positive reinforcer quite acceptable. It is conceivable, however, that the natural environment may place the stimulus of muscle fatigue in another classical conditioning paradigm that may thwart the effects of the conditioning described above. New exercisers are likely to experience considerable muscle soreness some time after engaging in exercise behavior, and this late-occurring soreness is likely to be more intense, and possibly more aversive, than the physiological feedback experienced immediately after exercise. That is, although the new exerciser is told that the proprioceptive feedback that comes with exercise precedes eventual physical improvement, he/she observes that it precedes considerable soreness that comes a day or two later. It is possible that after a few trials in which fatigue precedes even more aversive late-occurring soreness, fatigue would come to serve as a punishing stimulus unless steps were taken to alter the nature of this association. It seems reasonable to hypothesize, then, that, just as the tatting of the relationship between immediate muscle fatigue and improvement in physical condition is critical to the maintenance of exercise behavior, so too is the tatting of the relationship between late-occurring soreness and improvement in physical condition. The preceding explanations allow muscle fatigue, which occurs immediately after exercise, to function as a positive reinforcer and suggest how a conditioning paradigm that would produce an opposite effect could be avoided. However, these explanations rapidly lose their appeal as the intensity of the aversive stimuli involved increases. While it seems plausible that one can alter the valence of an aversive stimulus by offering a verbal representation indicating that the presence of that stimulus signals, in essence, that good things are happening, it seems quite unlikely that such a procedure would succeed when the aversive stimulus becomes intense pain. In these cases, such an attempt should fail. Consistent with this would be the prediction that new exercisers who meet with extreme discomfort,
350
L. A. Lees andJ. A. Dygdon
either immediately after exercising, or some short time afterwards, will most likely discontinue. In accord with this prediction, it is interesting to note that many authors (e.g., Martin & Dubbert, 1984) stress the importance of graduated exercise for new exercisers, lest they tackle difficult tasks early on and discontinue. Conceivably, this recommendation comes from the casual observation of the principle suggested above at work. It appears reasonable that muscle soreness comes to function as a positive reinforcer. However, it remains a conditioned reinforcer. This is a critical point, in that as a conditioned reinforcer it would be expected to “lose in the pull for behavior” when in opposition with a more potent reinforcer that would follow a competing behavior. A learning theory conceptualization of exercise behavior must address why a new exerciser would choose, on a given occasion, to exercise, rather than engage in any of a variety of behaviors that might offer more potent reinforcement (e. g., why an individual might choose to exercise rather than accept an invitation to have dinner with friends). Conceivably, no conflict is experienced in these situations by individuals for whom “good physical appearance” is a very potent reinforcer because of their learning history. However, for others, another set of behaviors, separate entirely from the class of responses called “exercise,” may be prerequisite to the acquisition of exercise behaviors. Perhaps the new exerciser who maintains exercise behaviors possesses another set of skills that allow for the scheduling of daily activities such that situations offering conditioned reinforcement for exercise, and situations offering more potent reinforcement for other behaviors, never compete.
CLINICAL
IMPLICATIONS
The preceding discussion presents many evocative arguments. Clearly, a learning theory explanation of the development of regular exercise behavior seems plausible. While it seems initially reasonable to offer clinical applications derived from these theoretical arguments, it is critical to point out that all of the issues presented above are empirical questions, and research designed to test their usefulness must be conducted before clinical rules are derived. Nevertheless, at this juncture, some speculation can be offered regarding the sorts of intervention efforts these theoretical formulations might suggest, should support for these hypotheses eventually be attained. Prior to discussing clinical implications, it is essential to note that only qualified professionals (i.e., the exercise physiologist) should prescribe exercise programs for clients wanting to initiate exercise behavior. The role of the clinical psychologist is to then facilitate the adherence to and maintenance of that exercise prescription. If the notion that proprioceptive feedback experienced immediately after exercising comes to function as a positive reinforcer by virtue of verbal tacts stating that these stimuli precede noticeable physical improvement, then clinicians, in attempting to intervene on behalf of clients who wish to engage in regular exercise, would be wise to ensure that their clients are exposed to such tacts frequently Similarly, tacts stating that the muscle and early in their exercise programs. soreness which occurs some time after exercise and precedes noticeable physical improvement should be presented frequently and early; thus avoiding a situation in which the new exerciser is told that proprioceptive feedback upon exercising precedes something desirable (i.e., eventual physical improvement), but observes
The Initiation and Maintmame of Exercise Beftavior
351
that it is more immediately followed by discomfort. In addition, following the model outlined above, a clinician would want to ensure that a client’s exercise program is well planned such that he/she does not attempt tasks that are too difficult, and hence likely to produce significant pain: that is, a stimulus unlikely to be made to function as a positive reinforcer. The last point raised in this paper appears to be one most likely to be overlooked by clinicians attempting to facilitate the acquisition of exercise behaviors. Such an oversight seems likely because the last class of behaviors this paper encourages clinicians to address have, in fact, nothing to do with exercise, per se. However, if empirical work demonstrates that individuals, on a given occasion are more likely to choose to engage in a behavior that is followed by a more potent reinforcer when a discriminative stimulus signaling its availability competes with one signaling conditioned reinforcement for exercise, then clinicians will need to evaluate their clients’ abilities to schedule daily activities such that situations offering conditioned reinforcement for exercise never compete with situations offering more attractive reinforcers for other behaviors. If these skills are absent from a client’s repertoire, then they will need to be acquired before success at developing regular exercise can be expected. An additional issue is raised by, but not directly addressed in, the preceding discussion and may be of considerable relevance to clinicians dealing with the sorts of interventions discussed above. While attention in this paper has been focused on an explanation of exercise maintenance, no attention has been devoted to exercise choice, or why an individual would choose to engage in exercise behaviors when alternative behaviors might provide access to the same ultimate reinforcers. For example, if we assume that improved physical appearance is the ultimate reinforcer in the case of a given individual, then diet regulation may provide similar access. Conceivably, the personal learning histories of individuals who at least attempt exercise are filled with the experiences described in this paper as responsible for the initiation of exercise (e.g., exposure to successful exercisers, tacts identifying the contingency between exercise and good physical appearance, etc.). Similarly, the personal learning histories of individuals who choose alternative behaviors to gain access to the same, long-term, reinforcers may contain experiences in which the alternative behaviors are associated with the reinforcing stimuli. This point, in and of itself, is straightforward and rather unexciting. It can be useful, however, in the case in which some intervention is necessary for an individual who is using an “exercise alternative” (e.g., diet regulation) to an excessive or dangerous degree. If in a case like this there was good reason to believe that the maintaining reinforcer was “good physical condition” or some other stimulus that exercise might produce, a constructionally oriented behaviorist might seek to modify the maladaptive behavior by assisting the individual in adding exercise to his/her repertoire (e.g., Goldiamond, 1984). Intervention planning, in this case, might be facilitated by using the hypotheses offered in this paper. More speci~cally, if one assumed that the learning history of the individual in question was deficient in examples in which exercise behavior provided access to “good physical condition,” then the first phase of treatment would be directed toward remedying these deficiencies. Subsequent phases, then, should be directed toward the establishment of conditioned reinforcers for discreet exercise behaviors and the development of the scheduling skills discussed above. (Of course, our treatment of this example is not meant to encourage clinicians to replace every
352
L. A. Lees andJ. A. Dygdon
maladaptive behavior that might be maintained by some sort of physical improvement with exercise. It is certainly possible that, in this hypothetical case, excessive diet regulation was maintained by other, possibly social, consequences that would have produced excessive exercise, had exercise been introduced. As always, a careful behavioral analysis in which critical maintaining stimuli are identified is necessary prior to embarking upon any treatment plan). CONCLUSION
In summary, this paper argues that a learning theory based explanation of the acquisition and maintenance of exercise behavior is quite plausible, but that the most reasonable learning theory explanation is not one which is immediately apparent. The hypotheses offered in this paper are clearly testable, and their evaluation is required before the clinical implications suggested can be applied. Researchers attempting to evaluate this model are encouraged to study different types of exercise (e.g., aerobic training, weight training, etc.) independently. While the model proposed in this paper would appear generalizable across exercise modalities, differences in response topography, training modes, and ensuing physiological changes necessitate separate consideration until such generalizability is demonstrated. REFERENCES Bandura, A. (1977). Social learning theory. Englewood Cliffs, NJ: Prentice-Hall. Carr, D. B., Bullen, B. A., Skrinar, G. S., Arnold, M. A., Rosenblatt, M., Beitens, I. Z., Martin, J. B., & McArthur, J. W. (1981). Physical conditioning facilitates the exercise-induced secretion of beta-endorphin and beta-~ipotropin in women. The tiw ~~~~a~dJour~~ o~Medi~~~, 305, 560563. Cooper, K. H., Pollack, M., Marin, R., White, S., Linnerud, A., &Jackson, A. (1976). Physical fitness levels vs selected coronary risk factors. Journal theAmerican Medical Association, 236, 166169. Dulany, D. E. (1968). Awareness, ruies, and propositional control: A confrontation with S-R behavior theory. In T R. Dixon and D. L. Horton (Eds.), T/e&i ~e~~~o~.and genera! 6&z&r iheocy (pp. 340-387). Englewood Cliffs, NJ: Prentice-Hall. Goldiamond, 1. (1984). Training parent trainers and ethic&s in nonlinear analysis of behavior. In R. F. Dangle and A. Polster (Eds.), Parent training: Foundations $mearch and practice (pp. 504-546). New York: Guilford Press. Griest, J. H., Klein, M. H., Eischens, R. R., Faris, J,, Gurman, A. S., & Morgan, W. P. (1978). Running through your mind.Journal ofPsychosomatic Research, 22, 259-294. Haskell, W. L. (1984). Overview: Health be&its of exercise. InJ. D. Matarazzo, S. M. Weiss, J. u&al h&h: A ~~book of ~~lt~en~~e~~t and A. Herd, N. E. Miller, & S. M. Weiss (Eds.), I3efK1 disease prevention (pp. 409-423). New York: John Wiley & Sons. Martin, J. E., & Dubbert, P. M. (1984). Behavioral management strategies for improving health and fitness. Journal of Cardiac Rehabilitation, 4, 200-208. Morris, J, N., Pollard, R., Everitt, M. G., & Chave, S. P. W. (1980). Vigorous exercise in leisure time: Protection against coronary heart disease. Lancet, 8206, 1207-1210. Pacitic Mutual Life Insurance Company (1978). E xercise. In Health ~~n~~~ce: 4 na~~~~~~~s.urveyof thebarriers towards better health and ways ~~Q~e?co~~~~them.Oakland, CA: Pacific Mutual Life Insurante Co. Reiter, M. (1981). Effects of physical exercise program on selected mood states in a group of women over a,ge 65 (Doctoral dissertation, Columbia University, 1981). Dissertation Abstracts International, 42, (University Microfilms No. 81-23283). Ribisl, P. M. (1984). Developing an exercise prescription for health. In J. D. Matarazzo, S. M. Weiss, J. S. Herd, N. E. MiIIer. & S. M. Weiss (Eds.), ~e~Ll~ora~h&h: A f~ndbook cf health en~n~e~~t and d~sea~~~Teventio~(pp. 448-466). New York: John Wiley & Sons.
of
The Initiation and Maintenance of Exercise Behavior
353
Sime, W. E. (1984). Psychological benefits of exercise training in the healthy individual. In J. D. Matarazzo, S. M. Weiss, J. A. Herd, N. E. Miller, & S. M. Weiss (Eds.), Behavioral health: A handbook ofhealth enhancementanddiseaseprevention (pp. 488-508). New York: John Wiley & Sons. Skinner, B. F. (1957). Verbalbehavior. Englewood Cliffs, NJ: Prentice-Hall. Steinberg, H., & Sykes, E. A. (1985). Introduction to symposium on endorphins and behavioral processes; review of the literature on endorphins and exercise. Pharmacolo~ Biochemistry ~9 Behavior, 23. 857-862.
1988 Copyright
027%7358/88 $3.00 + .OO 0 1988 Pergarnon Press plc
THE INITIATION AND MAINTENANCE EXERCISE BEHAVIOR: A LEARNING THEORY CONCEPTUALIZATION
OF
Laura A. Lees judith A. Dygdon The Chicago School of Professional
Psychology
ABSTRACT.
Current popular interest in health maintenance and physical fitness raises this new question for clinical psychology to address: What variables account for the fact that some individuals will initiate an exercise program and continue, while others will discontinue shortly aftir program initiation? While considerable theoretical and empirical work regarding the benefits derived from exercise exists, the question raised above has not yet been considered. Since clinical psychologists will most likely be called upon to satisfy the role qf facilitating the acquisition and maintenance of exercise behaviors for their clients, a conceptualization of how such behavior patterns evolve is crucial. This paper presents a learning theory conceptualization as to how exercise becomes a routine behavior for some. Implications for clinical intervention, derived from this conceptualization, are also discussed.
Popular
interest
in health
maintenance
and physical
fitness
behaviors
has in-
creased dramatically in recent years. Evidence of such current interest is presented in the results of a nationwide survey (Pacific Mutual Life Insurance Company, 1978). Respondents to this survey overwhelmingly endorsed “good health” as the most important factor in their lives. Many factors considered essential to a satisfying life were endorsed far less than “good health”; among these factors were “satisfying employment: “favorable living environment,” and “high standard of living.” It is most interesting to note that respondents to this survey were reported to believe that health status could be improved by smoking cessation, nutritious eating, stress control, and regular exercise. This apparent popular belief, that physical fitness is correlated with health status, appears to be well supported by empirical data. Numerous studies point to a relationship between exercise and the prevention of problems in the physical
Appreciation is expressed to Jeffrey C. Grip for his helpful suggestions on an earlier version of this manuscript. Requests for reprints should be addressed to: Laura A. Lees; The Chicago School of Professional Psychology; 806 South Plymouth Court; Chicago, IL 60605. 345
346
L. A. Lees a&J. A. Dygafon
health domain, such as coronary heart disease, blood pressure elevation, and obesity (Haskell, 1984; Cooper, Pollack, Marin, &White, 1976; Morris, Pollard, Everitt, & Chave, 1980). Other studies argue the existence of relationships between exercise and the prevention of problems in the mental health domain, such as anxiety and depression (Sime, 1984; Reiter, 1981; Griest et al., 1978). Taken together, data from the variety of studies reviewed above suggest that most people see exercise as important, and that this view is reasonable in light of considerable evidence that there is a relationship between exercise and health. Interestingly, other data suggest that far fewer individuals actually engage in regular exercise than report believing that exercise is important (Ribisl, 1984; Haskell, 1984; Pacific Mutual Life Insurance Company, 1978). This finding suggests that there exists a group of individuals who want to become exercisers but have not added this behavior to their personal repertoires. It seems quite appropriate for psychology, as a science of behavior, to address the issue of why this discrepancy exists between the numbers of individuals who report believing that exercise is important, and the number of individuals who actually engage in regular or routine exercise. Psychology has contributed to the development of strategies to facilitate the improvement of other potential “health-engendering” behaviors (e.g., smoking cessation, weight control). It seems that a psychological conceptualization of exercise initiation and maintenance stands to contribute, generally, to the understanding of how such behaviors are acquired, and specifically, to the facilitation of the acquisition of such behaviors for individuals who desire to do so. Some authors (e.g., Ribisl, 1984; Haskell, 1984) have suggested that the discrepancy between the numbers of individuals who report believing that exercise is important, and the number of individuals who actually engage in regular exercise, is due to the fact that some individuals who recognize that exercise is important simply do not know how to begin. It appears quite likely that this explanation accounts for some portion of this discrepancy. The intervention required to facilitate the acquisition of exercise behaviors for these individuals is clear. A basic educational model which identifies activities that contribute to improved physical status is a necessary first step. However, it seems likely that another portion of the discrepancy between individuals who report believing that exercise is important but do not engage in it, and individuals who do engage in regular exercise, is accounted for by those individuals who, unlike the group addressed by Ribisl (1984) and Haskell (1984), know how to begin an exercise program, but discontinue shortly after initiation. Intervention for this group is not as clear, and a psychological conceptualization of why some continue an exercise program once initiated, while others discontinue, is not immediately forthcoming. It is precisely this issue which the remainder of this paper addresses. In this endeavor, an appeal is made to the learning theories as a model for understanding this phenomenon. BASIC DEFINITIONS
Before entering into a detailed theoretical conceptualization of exercise initiation and maintenance, some definitions of what is meant by exercise and exercise maintenance in this paper are in order. In this paper, “exercise” refers to a regular series of specific movements designed to strengthen or develop bodily muscles and
The Initiation and Maintenance oj Exercise Behavior
347
endurance. This includes any one of, or any combination of, physical activities such as: mobile or stationary bicycle riding, jogging, rope jumping, swimming, aerobic dancing, and static exercises that work specific muscle groups (e, g., floor exercises, weight training). In this paper, “regular exercise,” or “maintenance of exercise behaviors,” refers to participation in exercise according to some nonrandom schedule. In addition, this paper excludes from its purview exercise behavior which can be considered “addictive” (i.e., individuals who appear to be dependent upon exercise) or “occupational” (i.e., competitive athletes in training) since these behaviors may differ significantly in form or function from “regular exercise” as it is defined above. While many fitness experts recommend participation in exercise for up to 90 minutes (this period includes the warm-up phase; aerobic stimulus phase; intermediate cool-down phase; anaerobic phase; for example, weight training, static exercises; and final cool-down phase) three times per week (Ribisl, 1984), the definitions used in this paper are not limited by this factor. For many regular exercisers, this activity takes place in a fitness facility, but the definitions employed in this paper are not limited to activities which take place within a formal structure. THEORETICAL CONCEPTUALIZATION In attempting to use the learning theories to explain the development of regular exercise, a pure operant model is initially most appealing. In other words, to state that exercise behaviors are present in an individual’s behavioral repertoire because they are reinforced, makes conceptual sense. Before initiating an attempt to identify the stimuli that might serve as reinforcers, it is reasonable to investigate from where these operants might come. An observational learning hypothesis can readily be used to explain this. Potential models of exercise behavior who are reinforced for that behavior can easily be found in current mainstream American society. The media, for example, present many exercise models. Examples of exercisers who report positive feelings of stimulation after exercise, or who report that their good health status, or shapely bodies, follow exercise, are plentiful in television programming. In addition, radio, television, and the print media present numerous “tacts,” that is, verbal representations of environmental stimuli, behaviors, or relationships between or among them (Skinner, 1957), outlining the following reinforcing contingencies: that exercise eventually produces healthy and attractive bodies; that people who exercise feel good afterwards; and that people who exercise are called conscientious, intelligent, or disciplined by society. Furthermore, separate from contacts with exercise models in the media, many individuals personally encounter others who exercise and consequently have attained obvious physical benefits, or who report other advantageous short- or long-term consequences. In sum, it is clear that learning through the observation of models or through verbal representations of the positive events that follow exercise may well account for an individual’s initiating exercise behavior. It is, however, unreasonable to expect that new exercise behaviors will be maintained in the absence of response contingent reinforcement for the new exerciser. At this point, an appeal to the literature on endogenous opioids, and the suggested role they play as reinforcing stimuli, becomes attractive. However, the
348
results
L. A. Lees and J, A. Dyp-don
of studies
investigating
this hypothesis
are equivocal,
and the precise
mech-
anisms through which these substances may exert such reinforcing effects have yet to be determined (see Steinberg & Sykes, 1985). Some authors (i.e., Carr et al., 1981) report that, within certain limits, opioid release increases as participation in exercise increases. Therefore, the possibility exists that the reinforcing effects of opioids are only realized when these substances are released in sufficient quantity. If this is the case, the new exerciser who does not have the ability (i.e., muscle strength, aerobic capacity) to exercise with the intensity, or for the duration, necessary to release sufficient amounts of opioids may not experience this reinforcing effect. Taking this into consideration, there must be other reinforcing stimuli involved early on in maintaining exercise behaviors. For this reason, a “more external” operant hypothesis is required before a comprehensive conceptualization of the factors that maintain exercise behavior can be formulated. It is clear that not all exercise initiators maintain this behavior. It appears quite likely that those exercise initiators who do not maintain this new behavior are those
who meet
with no reinforcement
for the behavior.
The
first step,
then,
in
developing an operant explanation for exercise behavior, is the identification of reinforcers delivered to the new exerciser. It is at this point some difficulties for an operant explanation of the maintenance of exercise emerge. What stimuli can be seen as potential “exercise reinforcing stimuli” in the new exerciser’s situation? For those new exercisers who engage in these behaviors in a fitness facility, or in less structured environments but with other people present, occasional verbal praise from staff members, or other exercisers, can be seen as a reinforcing stimulus. Undoubtedly, such a stimulus contingently follows exercise behavior for many new exercisers. However, it is difficult to conceive of verbal praise as an extremely potent reinforcer for most, or as a stimulus which occurs with great frequency. As such, verbal praise, in and of itself, seems unlikely to be successful in maintaining such a high cost, or difficult, behavior as exercise, especially “new exercise .” Physical health and body appearance improvements were discussed in relation to the reinforcers a potential exerciser might observe an exercise model might attain. One might initially speculate that these stimuli serve to reinforce exercise behavior. However, this explanation quickly loses its appeal since these events are far removed in time from initial exercise behaviors. The possibility that other stimuli, which follow the initial exercise behavior more closely in time, have been conditioned to these more distal stimuli exists; precisely what those stimuli are is difficult, at this level, to discriminate. However, this explanation becomes more attractive with further expansion. One way to proceed in the search for potential reinforcing stimuli is to identify what events typically follow exercise. In fact, what follows exercise most consistently, is simply proprioceptive feedback from the muscles, tendons, and joints involved in the exercise, indicating their use. It would appear that, in the case of this feedback is perceived possibly as pain, exercise, especially new exercise, discomfort, or at least fatigue. Most would concur in labeling this fatigue an aversive stimulus. While certainly not part of the definition of “punishment,” many would expect an aversive stimulus to function as a punisher. Yet fatigue does not always appear to suppress exercise behavior. This phenomenon would appear to be problematic for a learning theory explanation of exercise behavior. On closer inspection, however, it may provide the connection mentioned above between
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stimuli which follow exercise closely in time, and the seemingly positive, and conceivably reinforcing, health and appearance benefits attained after exercise has continued for some time. Dulany (1968) p resented data indicating that apparently aversive stimuli can function as positive reinforcers under certain conditions. In Dulany’s work, subjects were told that the receipt of a mild aversive stimulus would indicate that they had done a task correctly. In fact, under these conditions, subjects increased the frequency with which they engaged in tasks that produced the aversive stimulus. 1977) have interpreted these results from a Dulany and others (e.g., Bandura, social learning theory perspective, arguing that the information a stimulus carries overrides its reinforcement or punishment value. It appears, however, that this phenomenon can be explained, perhaps more parsimoniously, by arguing that the aversive stimulus became a conditioned reinforcer when the relationship between the appearance of that stimulus and correct performance was tacted for subjects. Extrapolating this explanation to the experiences of a new exerciser, we can say that when the relationship between mild muscle fatigue and improvement in physical condition is tacted for the new exerciser, muscle fatigue comes to function as a conditioned positive reinforcer. Upon returning to the question of why some new exercisers continue, while others quit, it is reasonable to speculate that those who continue have experienced, and learned from, the verbal representations described above, while those who quit, have not. The explanation outlined above makes the consideration of muscle fatigue functioning as a positive reinforcer quite acceptable. It is conceivable, however, that the natural environment may place the stimulus of muscle fatigue in another classical conditioning paradigm that may thwart the effects of the conditioning described above. New exercisers are likely to experience considerable muscle soreness some time after engaging in exercise behavior, and this late-occurring soreness is likely to be more intense, and possibly more aversive, than the physiological feedback experienced immediately after exercise. That is, although the new exerciser is told that the proprioceptive feedback that comes with exercise precedes eventual physical improvement, he/she observes that it precedes considerable soreness that comes a day or two later. It is possible that after a few trials in which fatigue precedes even more aversive late-occurring soreness, fatigue would come to serve as a punishing stimulus unless steps were taken to alter the nature of this association. It seems reasonable to hypothesize, then, that, just as the tatting of the relationship between immediate muscle fatigue and improvement in physical condition is critical to the maintenance of exercise behavior, so too is the tatting of the relationship between late-occurring soreness and improvement in physical condition. The preceding explanations allow muscle fatigue, which occurs immediately after exercise, to function as a positive reinforcer and suggest how a conditioning paradigm that would produce an opposite effect could be avoided. However, these explanations rapidly lose their appeal as the intensity of the aversive stimuli involved increases. While it seems plausible that one can alter the valence of an aversive stimulus by offering a verbal representation indicating that the presence of that stimulus signals, in essence, that good things are happening, it seems quite unlikely that such a procedure would succeed when the aversive stimulus becomes intense pain. In these cases, such an attempt should fail. Consistent with this would be the prediction that new exercisers who meet with extreme discomfort,
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either immediately after exercising, or some short time afterwards, will most likely discontinue. In accord with this prediction, it is interesting to note that many authors (e.g., Martin & Dubbert, 1984) stress the importance of graduated exercise for new exercisers, lest they tackle difficult tasks early on and discontinue. Conceivably, this recommendation comes from the casual observation of the principle suggested above at work. It appears reasonable that muscle soreness comes to function as a positive reinforcer. However, it remains a conditioned reinforcer. This is a critical point, in that as a conditioned reinforcer it would be expected to “lose in the pull for behavior” when in opposition with a more potent reinforcer that would follow a competing behavior. A learning theory conceptualization of exercise behavior must address why a new exerciser would choose, on a given occasion, to exercise, rather than engage in any of a variety of behaviors that might offer more potent reinforcement (e. g., why an individual might choose to exercise rather than accept an invitation to have dinner with friends). Conceivably, no conflict is experienced in these situations by individuals for whom “good physical appearance” is a very potent reinforcer because of their learning history. However, for others, another set of behaviors, separate entirely from the class of responses called “exercise,” may be prerequisite to the acquisition of exercise behaviors. Perhaps the new exerciser who maintains exercise behaviors possesses another set of skills that allow for the scheduling of daily activities such that situations offering conditioned reinforcement for exercise, and situations offering more potent reinforcement for other behaviors, never compete.
CLINICAL
IMPLICATIONS
The preceding discussion presents many evocative arguments. Clearly, a learning theory explanation of the development of regular exercise behavior seems plausible. While it seems initially reasonable to offer clinical applications derived from these theoretical arguments, it is critical to point out that all of the issues presented above are empirical questions, and research designed to test their usefulness must be conducted before clinical rules are derived. Nevertheless, at this juncture, some speculation can be offered regarding the sorts of intervention efforts these theoretical formulations might suggest, should support for these hypotheses eventually be attained. Prior to discussing clinical implications, it is essential to note that only qualified professionals (i.e., the exercise physiologist) should prescribe exercise programs for clients wanting to initiate exercise behavior. The role of the clinical psychologist is to then facilitate the adherence to and maintenance of that exercise prescription. If the notion that proprioceptive feedback experienced immediately after exercising comes to function as a positive reinforcer by virtue of verbal tacts stating that these stimuli precede noticeable physical improvement, then clinicians, in attempting to intervene on behalf of clients who wish to engage in regular exercise, would be wise to ensure that their clients are exposed to such tacts frequently Similarly, tacts stating that the muscle and early in their exercise programs. soreness which occurs some time after exercise and precedes noticeable physical improvement should be presented frequently and early; thus avoiding a situation in which the new exerciser is told that proprioceptive feedback upon exercising precedes something desirable (i.e., eventual physical improvement), but observes
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that it is more immediately followed by discomfort. In addition, following the model outlined above, a clinician would want to ensure that a client’s exercise program is well planned such that he/she does not attempt tasks that are too difficult, and hence likely to produce significant pain: that is, a stimulus unlikely to be made to function as a positive reinforcer. The last point raised in this paper appears to be one most likely to be overlooked by clinicians attempting to facilitate the acquisition of exercise behaviors. Such an oversight seems likely because the last class of behaviors this paper encourages clinicians to address have, in fact, nothing to do with exercise, per se. However, if empirical work demonstrates that individuals, on a given occasion are more likely to choose to engage in a behavior that is followed by a more potent reinforcer when a discriminative stimulus signaling its availability competes with one signaling conditioned reinforcement for exercise, then clinicians will need to evaluate their clients’ abilities to schedule daily activities such that situations offering conditioned reinforcement for exercise never compete with situations offering more attractive reinforcers for other behaviors. If these skills are absent from a client’s repertoire, then they will need to be acquired before success at developing regular exercise can be expected. An additional issue is raised by, but not directly addressed in, the preceding discussion and may be of considerable relevance to clinicians dealing with the sorts of interventions discussed above. While attention in this paper has been focused on an explanation of exercise maintenance, no attention has been devoted to exercise choice, or why an individual would choose to engage in exercise behaviors when alternative behaviors might provide access to the same ultimate reinforcers. For example, if we assume that improved physical appearance is the ultimate reinforcer in the case of a given individual, then diet regulation may provide similar access. Conceivably, the personal learning histories of individuals who at least attempt exercise are filled with the experiences described in this paper as responsible for the initiation of exercise (e.g., exposure to successful exercisers, tacts identifying the contingency between exercise and good physical appearance, etc.). Similarly, the personal learning histories of individuals who choose alternative behaviors to gain access to the same, long-term, reinforcers may contain experiences in which the alternative behaviors are associated with the reinforcing stimuli. This point, in and of itself, is straightforward and rather unexciting. It can be useful, however, in the case in which some intervention is necessary for an individual who is using an “exercise alternative” (e.g., diet regulation) to an excessive or dangerous degree. If in a case like this there was good reason to believe that the maintaining reinforcer was “good physical condition” or some other stimulus that exercise might produce, a constructionally oriented behaviorist might seek to modify the maladaptive behavior by assisting the individual in adding exercise to his/her repertoire (e.g., Goldiamond, 1984). Intervention planning, in this case, might be facilitated by using the hypotheses offered in this paper. More speci~cally, if one assumed that the learning history of the individual in question was deficient in examples in which exercise behavior provided access to “good physical condition,” then the first phase of treatment would be directed toward remedying these deficiencies. Subsequent phases, then, should be directed toward the establishment of conditioned reinforcers for discreet exercise behaviors and the development of the scheduling skills discussed above. (Of course, our treatment of this example is not meant to encourage clinicians to replace every
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maladaptive behavior that might be maintained by some sort of physical improvement with exercise. It is certainly possible that, in this hypothetical case, excessive diet regulation was maintained by other, possibly social, consequences that would have produced excessive exercise, had exercise been introduced. As always, a careful behavioral analysis in which critical maintaining stimuli are identified is necessary prior to embarking upon any treatment plan). CONCLUSION
In summary, this paper argues that a learning theory based explanation of the acquisition and maintenance of exercise behavior is quite plausible, but that the most reasonable learning theory explanation is not one which is immediately apparent. The hypotheses offered in this paper are clearly testable, and their evaluation is required before the clinical implications suggested can be applied. Researchers attempting to evaluate this model are encouraged to study different types of exercise (e.g., aerobic training, weight training, etc.) independently. While the model proposed in this paper would appear generalizable across exercise modalities, differences in response topography, training modes, and ensuing physiological changes necessitate separate consideration until such generalizability is demonstrated. REFERENCES Bandura, A. (1977). Social learning theory. Englewood Cliffs, NJ: Prentice-Hall. Carr, D. B., Bullen, B. A., Skrinar, G. S., Arnold, M. A., Rosenblatt, M., Beitens, I. Z., Martin, J. B., & McArthur, J. W. (1981). Physical conditioning facilitates the exercise-induced secretion of beta-endorphin and beta-~ipotropin in women. The tiw ~~~~a~dJour~~ o~Medi~~~, 305, 560563. Cooper, K. H., Pollack, M., Marin, R., White, S., Linnerud, A., &Jackson, A. (1976). Physical fitness levels vs selected coronary risk factors. Journal theAmerican Medical Association, 236, 166169. Dulany, D. E. (1968). Awareness, ruies, and propositional control: A confrontation with S-R behavior theory. In T R. Dixon and D. L. Horton (Eds.), T/e&i ~e~~~o~.and genera! 6&z&r iheocy (pp. 340-387). Englewood Cliffs, NJ: Prentice-Hall. Goldiamond, 1. (1984). Training parent trainers and ethic&s in nonlinear analysis of behavior. In R. F. Dangle and A. Polster (Eds.), Parent training: Foundations $mearch and practice (pp. 504-546). New York: Guilford Press. Griest, J. H., Klein, M. H., Eischens, R. R., Faris, J,, Gurman, A. S., & Morgan, W. P. (1978). Running through your mind.Journal ofPsychosomatic Research, 22, 259-294. Haskell, W. L. (1984). Overview: Health be&its of exercise. InJ. D. Matarazzo, S. M. Weiss, J. u&al h&h: A ~~book of ~~lt~en~~e~~t and A. Herd, N. E. Miller, & S. M. Weiss (Eds.), I3efK1 disease prevention (pp. 409-423). New York: John Wiley & Sons. Martin, J. E., & Dubbert, P. M. (1984). Behavioral management strategies for improving health and fitness. Journal of Cardiac Rehabilitation, 4, 200-208. Morris, J, N., Pollard, R., Everitt, M. G., & Chave, S. P. W. (1980). Vigorous exercise in leisure time: Protection against coronary heart disease. Lancet, 8206, 1207-1210. Pacitic Mutual Life Insurance Company (1978). E xercise. In Health ~~n~~~ce: 4 na~~~~~~~s.urveyof thebarriers towards better health and ways ~~Q~e?co~~~~them.Oakland, CA: Pacific Mutual Life Insurante Co. Reiter, M. (1981). Effects of physical exercise program on selected mood states in a group of women over a,ge 65 (Doctoral dissertation, Columbia University, 1981). Dissertation Abstracts International, 42, (University Microfilms No. 81-23283). Ribisl, P. M. (1984). Developing an exercise prescription for health. In J. D. Matarazzo, S. M. Weiss, J. S. Herd, N. E. MiIIer. & S. M. Weiss (Eds.), ~e~Ll~ora~h&h: A f~ndbook cf health en~n~e~~t and d~sea~~~Teventio~(pp. 448-466). New York: John Wiley & Sons.
of
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Sime, W. E. (1984). Psychological benefits of exercise training in the healthy individual. In J. D. Matarazzo, S. M. Weiss, J. A. Herd, N. E. Miller, & S. M. Weiss (Eds.), Behavioral health: A handbook ofhealth enhancementanddiseaseprevention (pp. 488-508). New York: John Wiley & Sons. Skinner, B. F. (1957). Verbalbehavior. Englewood Cliffs, NJ: Prentice-Hall. Steinberg, H., & Sykes, E. A. (1985). Introduction to symposium on endorphins and behavioral processes; review of the literature on endorphins and exercise. Pharmacolo~ Biochemistry ~9 Behavior, 23. 857-862.