Advances in Physical Education
2012. Vol.2, No.1, 1-9
Published Online February 2012 in SciRes (http://www.SciRP.org/journal/ape) http://dx.doi.org/10.4236/ape.2012.21001
Dynamic Activity-Related Incentives for Physical Activity
Julia Schüler, Sibylle Brunner
University of Zurich, Zurich, Switzerland
Received December 7th, 2011; revised January 15th, 2012; accepted January 21st, 2012
The present studies adopted the theoretical framework of activity- and purpose-related incentives (Rheinberg,
2008) to explain the main tenance of physica l activity. We hypothesized tha t activity-related incentiv es (e.g.,
“fun”) increase more than purpose-related inc entives (e.g., “health”) between the initiation and maintenance
phase of physical activ ity. Additionally, change in activ ity-related inc entives was h ypothesiz ed to be a be tter
predictor of ma int e nance of physical activi ty than change in purpose-related incentive s. Two correlative field
studies with rehabilitation patients (Study 1) and Nordic Walkers (Study 2) were conducted to test the hy-
potheses. Participants’ incen tives of physical activity were measured at the beginning of exercising and two
weeks (Study 1; T2) and three months (Study 2; T2) later. At T2, participants were asked for their current
physical activity. Both studies showed a greater change of activity-related incentives than purpose-related
incentives. Furthermore, change in activity-related incentives was more predictive of the maintenance of
physical activity than chang e in purpose-related incentives. The results showed the important role of activi-
ty-related incentives in maintenance of physical activity. The theoretical contribution to physical activity
maintenance research and practical implications for health promotion programs were discussed.
Keywords: Physical Activity; Behavior Maintenance; Motivation; Incentives
Introduction
While people are generally aware of the favorable health
benefits associated with regular physical activity, exercise and
sport (Blair & Connelly, 1996), many people fail to persist in
being physically active and performing sport and exercise be-
havior. A high percentage of individuals who initiate physical
activity fail to maintain this behavior and drop-out within the
first six months (50% according to Wing, 2000: p. 85). Thus,
researchers are interested in the factors that contribute to the
adherence of physical activity (see Dishman, 1994; Markland &
Hardy, 1993) and suggest different determinants such as goals
(e.g., Duda, 1989), commitment to physical activity (Scanlan,
Carpenter, Schmidt, Simons, & Keeler, 1993), self-efficacy
beliefs (Schwarzer, 1992) and perceived satisfaction with re-
ceived outcomes of physical activity (Rothman, 2000).
In the present paper, we suggest that incentives might be
partly responsible for the maintenance of physical activity. In
contrast to previous approaches on related concepts such as
personal exercise incentives (e.g., Duda & Tappe, 1989) and
exercise motivation (Markland & Hardy, 1993), our approach is
strongly based on the classical concept of incentives in motiva-
tional psychology1 (e.g., Atkinson, 1957; Beckmann & Heck-
hausen, 2008; Vroom, 1964) and on an extension of the classi-
cal concept (Rheinberg, 2008). Here, incentives are defined as
stimuli that refer to affective goal-states and thereby stimulate
goal-directed behavior (Beckmann & Heckhausen, 2008). At
first sight the incentive concept seems to be related to research
on outcome expectancies. Most expectancy-based theories draw
on the idea that “people’s actions are greatly affected by their
beliefs about the probable outcomes of those actions” (Scheier
& Carver, 1987: p. 170; for the domain of physical activity see
Anderson, Wojcik, Winett, & Williams, 2006). They therefore
understand expectancies as anticipations of desired or undesired
future states. These outcome expectancies lead, for example, to
an optimistic orientation that helps people to strive effectively
for their goals (Scheier & Carver, 1987). Although the out-
come expectancy concept shares some characteristics with in-
centives, for example the fact that they both have motivating
functions, they are quite different in their defining features. In
terms of classical expectancy-value models in motivation psy-
chology (Atkinson, 1957), outcome expectancies represent the
general belief that it is worth striving for a goal and initiating
goal-directed actions. They are cognitive evaluations of the
probability of goal-attainment (e.g. it is highly probable); how-
ever, nothing is said about the valence and the content of the
expected outcome. This is addressed by the value component of
the expectancy-value model, which defines the future state (fun,
health) and defines whether it is desirable (health) or undesir-
able (illness). In summary, theoretically expectancies and in-
centives are both important reasons for individuals to behave in
a certain kind of way (e.g., performing sports regularly), but are
conceptually different. Two further reasons for relying on the
concept of incentives rather than on outcome expectancies are
that empirical investigation of the latter yield mixed results
regarding how strong and for whom outcome expectancies
predict physical activity (e.g., Williams, Anderson, & Winett,
2005, for a review) and that the concept of incentives allows
activity- and purpose-related incentives to be distinguished,
which is the most important aspect of our research question.
In accordance with Rothmans’ (2000: p. 64) statement that
“the psychological factors that enable people to adopt a new pat-
tern of behavior are not necessarily those that help them to sus-
tain that behavior over time”, we assume that incentives that
1Note that the term “incentive” is not used here in the sense of an ex-
ternal reward (as is the case in research on the undermining of intrinsic
motivation; e.g., Deci, 1971), but is defined as a situational characteris-
tic that promises the satisfaction of a need.

J. SCHÜLER ET AL.
stimulate the initiation of physical activity differ from those that
are responsible for its maintenance. In other words, incentives for
being physically active are dynamic rather than static. To empiri-
cally test this assumption, we refer to the concept of activity- and
purpose-related incentives proposed by Rheinberg (2008). When
asked for their incentives of physical activity, individuals often
mention “fun”, “enjoyment”, “social affiliation”, “health”, “im-
proving appearance” or “loosing body weight” (e.g., Markland &
Ingledew, 2007). According to the definition of incentives, all
examples represent positive, affective goal-states that stimulate a
person to engage in physical activity. Besides this common cha-
racteristic, however, for example “f un” versu s “he alth” obvio usly
differ and it is these differences upon which we focus in analyz-
ing their role in the initiation and maintenance of physical active-
ity. Since one striking difference between “fun” and “health” lies
in the fact that the former is related to the physical activity itself
and the latter to the outcome of being phy sically active, we adopt
the classification suggested by Rheinberg (2008) according to
which incentives are classified as activity-related and purpose-
related.
Following a more detailed introduction to the concepts of ac-
tivity- and purpose-related incentives, we will deduce two hypo-
theses which assume that the activity-related and purp ose - re la te d
incentives differentially increase over time between initiation
and maintenance phase of physical activity and that these in-
creases ha ve varying p ower in the pr ediction of lo ng-term m a i nt e -
nance of physical activity.
Activity-Related and Purpose-Related Incentives
Incentive approaches in motivation psychology take into ac-
count that individuals are not only passively driven by needs
and motives but are also able to anticipate positive future states
(e.g., Atkinson, 1957; Beckmann & Heckhausen, 2008) and
direct their behavior towards these states. Traditional research
on motivation postulates that anticipated future states lie in the
result of an action (Atkinson, 1957; McClelland, 1985; Vroom,
1964): An action such as regularly exercising is attractive and
meaningful if the consequences of the action, for instance im-
proved health, are attractive. This also applies to the Extended
Cognitive Model (Heckhausen & Rheinberg, 1980) in which
incentives are located at the end of an action course. Since this
model is not able to explain behavior that is performed without
or with less pronounced purpose-related incentives, such as
being physically active without aiming to improve health, or
riding a bicycle without a destination, Rheinberg (2008) ex-
tended the original model by acknowledging that while pur-
pose-related incentives are important, they are not the only type
of incentives for human behavior. He assumed a second source
of incentives which lies in the action itself; so-called activi-
ty-related incentives. With respect to physical activity, people
may exercise because it is fun, because they enjoy the move-
ments and the feeling of muscular power, or because of other
positive experiences. We assume that a detailed analysis of
activity- and purpose-related incentives for physical activity,
respectively, will help to shed light on the phenomena of be-
havior initiation and maintenance.
The terms activity- and purpose-related incentives are con-
ceptually similar to the terms intrinsic and extrinsic motivation
(e.g., Deci & Ryan, 1985, 2000). One reason for nevertheless
choosing the terms “activity-” and “purpose-related incentives”
is that the terms intrinsic and extrinsic are used with different
foci by different authors within, for example, self-determination
theory (SDT) research (Deci & Ryan, 2000), interest research
(Sansone & Smith, 2000), and motivation research (Heck- hau-
sen & Heckhausen, 2008; Shah & Kruglanski, 2000) (for a
summary of different meanings of “intrinsic” see Rheinberg,
2008). The most important reason for using the terms “activi-
ty-” and “purpose-related incentive” is that these terms most
clearly focus on the very feature which we assume to be the key
difference between incentives such as “fun” and “health” and
thus best explain the differential effects of activity- and pur-
pose-related incentives on maintenance of physical activity.
This difference comprises the temporal distance from the activ-
ity itself. For example, the activity-related incentive “fun” is
very closely temporally related to the activity and is experi-
enced directly during the course of action itself. In contrast,
purpose-related incentives such as “health” are by definition
separated from the activity, constituting a consequence which is
experienced when th e activity has been terminated. We assume
that this difference regarding the temporal distance from the
activity is accompanied by two effects that will be explained in
the following section.
Differential Changes in Activity- and
Purpose-Related Incentives
We assume that incentives are not “stable characteristics of
person-environment interactions” (McClelland, 1985: pp. 180-
181) but are rather subject to dynamic change from the initia-
tion to the maintenance phase of behavior. And we expect ac-
tivity- and purpose-related incentives to differentially change
over time. A change in activity-related incentives is plausible
due to the very nature of such incentives: Most activity-related
incentives (e.g., having fun, feeling good whilst performing a
perfect movement) require affective and somatic experience of
the activity itself and can therefore only develop when the ac-
tivity is repeatedly performed over a certain length of time.
They often involve body sensations or psychological sensations
and are thus hard to anticipate upon first beginning to exercise.
This theorizing was supported in the sport domain by McAuley,
Wraith and Duncan (1991) who pointed out that external rea-
sons such as improvement of physical appearance might be the
reason for adopting exercise behavior and physical activity, but
that intrinsic reasons might become more salient across the time,
because people’s skills and physical conditioning improve and
enable more enjoyment of physical activity. These considera-
tions are further supported by current research on intrinsic mo-
tivation, interest, and flow-experience which suggesting that
some incentives are inherent in the activity itself and are likely
to be discovered in long-term interaction with the activity (Deci
& Ryan, 1985; Csikszentmihalyi, 1990; “expertise effect of
flow” by Rheinberg, 2008).
While due to our line of argumentation activity-related in-
centives existentially depend upon the activity, purpose-related
incentives require less experience of the activity itself, given
that they are more explicit from the very onset and are therefore
more easily anticipated. It is, for example, common knowledge
that exercising and physical activity improves health and regu-
lates body weight. We hypothesized that purpose-related incen-
tives would increase less from the initiation to the maintenance
phase than activity-related incentives. Based on this sum of
theoretical and empirical evidence, we deduce our first hy-
pothesis that incentives are dynamic and change from the initia-
2

J. SCHÜLER ET AL.
tion to the maintenance phase of an activity, with activity-re-
lated incentives such as “fun” increasing more than purpose-
related incentives such as “health”.
The idea that incentives change across the time was proposed
in a broader sense by organismic integration theory which is an
SDT subtheory (Deci & Ryan, 1985). It postulates that much
behavior is not intrinsically, but extrin sically motivate d. This is
especially true after early childhood when social pressure and
demands require doing activities that are not interesting (Ryan
& Deci, 2000). Therefore, during childhood socialization as
well as across the life span, processes of internalization and
integration of extrinsic demands into the self enable a more
self-regulated (rather than externally regulated) behavior. For
example, individuals take in external regulation (introjection),
identify with a behavior’s value (identification) or they inte-
grate external regulations with the aspects of their self (integra-
tion). However, also the highest transformation of externally-
regulated into self-regulated behavior is a form of extrinsic
motivation and thus still differs from intrinsic motivation (in
terms of doing the activity for its own sake).
Other concepts related to our idea of the dynamicity of in-
centives stems from researchers examining changes in the sali-
ence of different sorts of incentives across time. Although these
researchers differed in the labeling and conceptualization of
“incentive”, the phenomena they investigated are rather similar.
Liberman and Trope (1998; Trope & Liberman, 2003), for ex-
ample, analyzed temporal changes in abstract incentives (“high-
level construals”) and concrete incentives (“low-level constru-
als”) and Pennington and Roese (2003) found that promotion
incentives (“promotion goal importance”) increased with tem-
poral distance whereas prevention incentives (“prevention goal
importance”) remained stable over time.
While previous research focused on the change of behavior
regulation through internalization or integration or on weight-
ing of and interplay between positive and negative incentives
(Prochaska et al., 1994) or on the salience of incentives across
time (Liberman & Trope, 1998) as reported above, the present
paper divided incentives into the two categories activity- and
purpose-related incentives, observed their variation across time,
and analyzed their effects on maintenance of physical activity.
To summarize, the present paper adheres to the notion that
incentives are not stable but differ across time and further as-
sumes that the differentiation between activity- and purpose-
related incentives is an important concept that enhances the pre-
dictability of behavior maintenance.
The Differential Predictive Power of
Activity- an d Purpose-Related Incentives
The second hypothesis derived from theoretical considera-
tions on activity- and purpose-related incentives concerns the
effects of incentive changes on the maintenance of physical
activity. We assume that physical activity is more likely to be
maintained by those individuals for whom activity-related in-
centives increase during physical activity, than by those par-
ticipants for whom purpose-related incentives increase. The
rationale behind this assumption is based upon the difference in
temporal distances from the activity. The positive quality of
activity-related incentives, such as having fun or enjoying
movements, is very closely temporally related to the activity
itself and thus functions as a direct reward for activity per-
formance. According to the principle of operant conditioning
(Skinner, 1938), this should enhance the probability of the ac-
tivity being repeated. In contrast, individuals whose activity-
related incentives do not increase from the initiation to the
maintenance phase miss out on an important source of motiva-
tion and are subsequently more endangered when it comes to
disengaging from the behavior. Unlike activity-related incen-
tives, purpose-related incentives, such as “health” or losing
body-weight, are often long-term effects that can seldom be
experienced immediately following physical activity. Due to
the less intense temporal relationship between purpose-related
incentives and the activity, the rewarding effect of these incen-
tives should thus be much weaker than that of activity-related
incentives (for the effects of time-association between action
and reward see Tarpy & Sawabini, 1974; Shanks & Dickinson,
1991). To summarize, we postulate that an increase in activi-
ty-related incentives predict the maintenance of physical activi-
ty better than an increase in purpose-related incentives.
The Present Research
We postulate greater increases in the activity-related incen-
tives, as for example “fun” than in the purpose-related incen-
tives, as for example “health” from the initiation phase to the
maintenance phase of physical activity (Hypothesis 1). Fur-
thermore, increases in activity-related incentives are hypothe-
sized to be a better predictor of maintenance of physical activity
than increases in purpose-related incentives (Hypothesis 2).
Two studies tested these hypotheses. The studies were corre-
lational field studies with performers of fitness sports whose
physical activity incentives were measured as predictors of
physical activity. Besides these common characteristics, both
studies theoretically and methodologically complement one
another in three important ways. First, Study 1 focused on the
incentives of rehabilitation patients participating in physical
activity courses provided by a rehabilitation centre and Study 2
measured incentives among middle-aged Nordic walkers. With
using different study samples we aimed to support the genera-
lizability of the study results. The second difference between
the two studies was the time interval of data collection. In
Study 2, data were collected on two occasions, registering in-
centives two weeks apart. Study 2 extended this time period by
measuring incentives with a three-month interval and predicted
the maintenance or cessation of physical activity six months
after its initiation. The third but very important aspect distin-
guishing the studies is how we assessed the incentives. In Study
1 the incentive “fun” as a prototype of an activity-related incen-
tive and “health” as a purpose-related incentive prototype were
presented and participants rated how much the incentives fit to
their person. Study 2 aimed at extending the incentive measure
by adding incentives from the achievement, affiliation and
power domain that were gained by an expert rating.
Study 1
In Study 1 incentives for health-related physical activity were
measured using a questionnaire administered on two separate
occasions; in the last week of a health-oriented physical activity
course that was integrated in a rehabilitation program and two
weeks later after participants had left the rehabilitation center.
Participants were thus accompanied from their initiation of
physical activity up to the time when they either maintained or
disengaged from exercising.

J. SCHÜLER ET AL.
Due to practical reasons we had to use a brief measure of in-
centives and thus choose the incentives “fun” and “health” as
representative activity- and purpose-related incentives for the
initiation and maintenance of physical activity. We investigated
whether incentive changes predicted actual physical activity by
asking participants whether they had maintained their recom-
mended frequency of physical activity over a set period of time
(“optimal exercisers”) or had exercised less than recommended
(“suboptimal exercisers”). This criterion of physical activity was
selected due to our assumption that no patient would completely
quit the recommended physical activity program due to a high
level of internal pressure (physical activity is needed to reduce
pain) and a high level of external pressure (recommendation of
physical activity by a person of authority; external control of
compliance after two weeks) but that patients would vary in the
amount of physical activity performed. According to our first
hypothesis, the activity-related incentive “fun” should increase
more compared to the purpose-related incentive “health” within
the two-week period for the maintainers but not for suboptimal
performers. According to our second hypothesis, the change in
“fun” should be a better predictor for optimal exercising versus
suboptimal exercising than the change in “health”.
Method
Participants and Pr oce dure
Forty-seven mal e and 20 female participants of a health physi-
cal activity program in a rehabilitation clinic were contacted and
asked to participate in a study on “motivation and experiences of
physical activity”. Patients with different diagnoses including
arthrosis, low back pain, and fibr omyalgia, aged between 24 and
79 years (M = 55.04, SD = 11.97), who participated in a three-
week health program in the clinic took part in the present study.
For each participant, physiotherapists compiled an individual
physical activity program co nsisting of various training element s
such as aqua-fit, cycling, or swimming. The physiotherapists
highly recommended continuing this physical activity program
after being discharged from the rehabilitation clinic. Participants
were recruited during the final week of the progra m by a female
experimenter who explained the data collection procedure in
detail and who directly answered any ensuing questions. The
study consisted of two parts. Fi rst, participants completed a ques-
tionnai re at the beginning of the final physical ac tivity lesson ( T1)
and returned it to the experimenter. The questionnaire comprised
baseline measures of the incentives “fun” and “health” and also
asked for details on the specific physical activity program that
had been individually arranged for each participant. Two weeks
after the end of the health physical activity program (T2), par-
ticipants were contacted via mail and asked to respond to ques-
tions concerning their current incentives and physical activity.
Incentive Assessment
The two incentives “fun” and “health” were assessed using
the two statements “My reason for being physically active is
fun” and “My reason for being physically active is health”. Par-
ticipants rated the degree to which the statements personally
applied to them (1: not at all - 5: very much). Incentive changes
were assessed by using difference scores that is by subtracting
T1 ratings from T2 ratings separately for “fun” and “health”.
Assessment of Physical Activity
In order to evaluate whether a participant had continued to
perform the recommended physical activity program after hav-
ing been discharged from the clinic, we compared the physical
activity reported at T2 with the recommendations made by the
physiotherapists. Recommendations were assessed by asking
participants at T1 about the customized physical activity pro-
gram which had personally been recommended to them for
continued performance by the physiotherapist. Two weeks after
finishing the clinic physical activity program (T2), participants
were asked about their current physical activity. Based on this
information, participants were subsequently divided into two
groups: optimal exercisers (N = 42) who reported performing
the recommended physical activity program and suboptimal
exercisers (N = 25) who reported performing less than the
recommended physical activity program. As expected, none of
the patients reported having completely quit the physical activi-
ty program.
Results
Preliminary Analyses
Preliminary analyses revealed no significant impact of age,
clinical diagnosis, or recommended physical activity. Men and
women did not differ in any of the relevant variables and sex
did not influence the results reported below. So data were col-
lapsed for the following analyses.
Descriptive Statistics and Intercor relations between
Variables
“Fun” and “health” incentive-changes scores were not signi-
ficantly associated (Pearson correlation, r = .20, n.s.). Changes
in the “fun” incentive (M = –.02, SD = .79) were significantly
correlated with the dichotomous variable optimal exercise ver-
sus suboptimal exercise (Spearman’s rho, r = .31, p < .05), indi-
cating that the higher the positive change of “fun”, the more
likely the participant was to continue their personally recom-
mended physical activity program. Change in the “health” in-
centive (M = –.05, SD = .60) was not significantly associated
with optimal physical activity versus suboptimal physical activi-
ty (Spearman’s rho, r = –.08, n.s.).
Incentive Change in Optimal and Suboptimal Exercisers
Given our assumption that incentives would differentially
change for optimal exercisers and suboptimal exercisers, the
incentive changes are illustrated separately for each of these
two groups in Figures 1(a) (optimal exercisers) and 1(b) (sub-
optimal exercisers). The optimal exercisers are characterized by
an increase in “fun” (T1: M = 4.31, SD = .78; T2: M = 4.50, SD
= .59) and a relatively stable “health” incentive (T1: M = 4.62,
SD = .58; T2: M = 4.55, SD = .63). Statistical significance of
the difference between the changes in “fun” and “health” incen-
tives was tested by comparing the incentive- change indexes
(difference score) in a repeated-measure analysis of variance.
The incentive-change index for “fun” (M = .19, SD = .09) was
significantly higher than the index for “health” (M = –.07, SD
= .09), F(1,41) = 4.52, p < .05.
Figure 1(b) shows that suboptimal exercisers are characterized
by a decrease in the activity-related incentive “fun” (T1: M =
4.28, SD = .94; T2: M = 3.93, SD = 1.25) and a relatively stable
purpose-related incentive “health” (T1: M = 4.68, SD = .69; T2:
M = 4.72, SD = .46). The repeated-measure analysis of variance
showed significantly greater decreases in the “fun” incentive-
change index (M = –.35, SD = .19) than the “health” incen-
tive-change index (M = .05, SD = .12), F(1,24) = 5.21, p < .05.
4

J. SCHÜLER ET AL.
1a) Incentiv e chan ge in o ptimal exercisers
3.5
4
4.5
5
initiationmaintenance
incentive ratings
fun health
(a)
1b) Incentive chang e in sub optimal exercisers
3.5
4
4.5
5
initiation maintenance
incentive rat ings
fun health
(b)
Figure 1.
Change in the incentives “fun” and “health” from the initia-
tion (T1) to the maintenance (T2) phase of physical activity
for optimal exercisers (N = 42), see Figure 1(a) and subop-
timal exercisers (N = 25), see Figure 1(b).
Effects of Incentive Change on the Maintenance of
Physical Activity
A step-wise binary logistic regression analysis was conducted
to test whether change in the “fun” incentive or the “health”
incentive was a better predictor of becoming an optimal versus
suboptimal exerciser. The two types of incentive changes (dif-
ference scores) were entered into the regression equation in a
forward step-wise manner in order to investigate the influence of
each variable on the dependent variable. The constant was en-
tered first followed by the independent variable which correlated
most highly with the dependent variable and then the final vari-
able. In this way, variables with low predictive power were iden-
tified and subsequently eliminated from the regression equa-
tion (criterion: Wald statistic). Step-wise binary linear regression
analysis thus indicated which of the two incentive changes best
predicted whether a participant showed optimal or suboptimal
physical activity and which incentive change might be excluded
from the regression equation because it did not account for addi-
tional variance. It was shown that change in the “fun” incentive
should be included as predictor in the regression model (Wald (1)
= 6.67, p < .05; B = 1.0, Se = .39), whereas change in the
“health” incentive did not explain any additional variance in
physical activity and was subsequently excluded. The chi-square
test of model fit (chi-square = 7.95, p < .01) indicated a signifi-
cantly better goodness of fit for the model which included
change in the “health” incentive (M odel 2) than the model which
contained only the constant (Model 1). Model 2 explained
15.5% of variance in the dependent measure (Nagelkerke’s
R-square = .155) that is optimal versus suboptimal exercising.
Brief Discussion Study 2
Study 1 confirmed our hypotheses in a sample of participants
of a rehabilitation physical activity program. Participants who
continued to perform their recommended physical activity pro-
gram two weeks after discharge (optimal exerciser) showed a
different pattern of incentive change than those participants who
exercised less than recommended (suboptimal exercisers). In
accordance with our hypothesis, optimal exercisers were charac-
terized by a greater positive change in the “fun” incentive than
the “health” incentive. Suboptimal exercisers were characterized
by a decrease in the “fun” incentive and a relatively stable level
of the “health” incentive. As postulated in our second hy pothesi s,
change in the “fun” incentive also proved to be a significant pre-
dictor of optimal versus suboptimal physical activity, whereas
change in the “health” incentive lacked predictive power. These
results confirmed the stronger effect of the activity-related incen-
tive “fun” on the maintenance of phy sical activity. However, one
might criticize that the two-week period is too short to measure
changes in incentives and behavior adequately. Another limita-
tion is the single item measure of activity- and purpose-related
incentives. Study 2 addressed these issues.
Study 2
Study 2 used a longitudinal design to examine whether incen-
tive change predicts the long-term maintenance of physical ac-
tivity. According to the Transtheoretical Model (Prochaska &
DiClemente, 1983, 1992), the different phases through which in-
dividuals progress when they change their health-related be-
havior (see above) can be defined by time criteria. The mainte-
nance phase is assumed to begin when an individual has main-
tained the behavior change for a period of six months. To fulfill
this time criterion, Study 2 accompanied Nordic-walker begin-
ners in their walking activity from their very first lesson in Nor-
dic walking (beginning of the action phase) up to the six-month
marker of the maintenance phase.
One aim of Study 2 was to replicate the results found in
Study 1. We expected that the “fun” incentive would increase
more than the “health” incentive between the initiation and the
maintenance phase and expected that the change in the “fun”
incentive would be a better predictor of maintenance than the
change in the “health” incentive.
Furthermore, we extended the activity- and purpose-related
incentive measure by referring to other important domains of
human life rather than fun and health. In order to systemize and
reduce the variety of incentives, we refer to dispositional theo-
ries on motivation (e.g., McClelland, 1985) which focus on the
achievement, power and the affiliation domain. We created an
incentive questionnaire in Study 2 that comprises activity- and
purpose-related achievement, power, affiliation incentives and
some further incentives. Again, we hypothesized that activi-
ty-related incentives increased more during the course on being
physically active and better predict maintenance of physical
activity than purpose-related incentives.

J. SCHÜLER ET AL.
Method
Participants and Pr oce dure
Sixty-eight participants with a mean age of 44.41 years (SD
= 8.60, range from 29 - 65 years) were recruited from local
Nordic walking courses to take part in a study on “first experi-
ences in Nordic walking”. Most participants were female (N =
60). The Nordic walking courses were affiliated with a local
Nordic Walking Association that offered courses explicitly to
beginners with no prior knowledge of Nordic walking. The
Nordic walking fitness instructors confirmed that all partici-
pants had been correctly classified as beginners.
Participants were recruited in their very first lesson by a fe-
male experimenter who explained that data would be collected
in three phases in order to obtain a realistic rating of experiences
in the first Nordic Walking course. Participants who agreed to
take part in the study received a first take-home booklet to be
immediately completed upon arriving at home after the first
physical activity lesson (T1) and returned via mail. Of 72 be-
ginners who indicated an interest in participating in the study, 68
returned the questionnaire within one week. The questionnaire
included baseline measures of incentives and informed the par-
ticipants that the next phase of data collection would be at the
end of the course. At the end of the three-month Nordic walking
course (12 weekly lessons; T2), participants once again com-
pleted a questionnaire on their incentives for participating in
Nordic walking. Fitness instructors additionally informed the
participants about upcoming opportunities for participating in
Nordic walking (e.g., Nordic walking routes; further courses)
and that they would be contacted three months later by the ex-
perimenter with a further questionnaire on their Nordic walking
activities. Six months after beginning the course, participants
were contacted via mail and were questioned with respect to
their current Nordic walking activities (T3). After returning the
final questionnaire, participants were debriefed about the re-
search question and hypotheses.
Incentive Assessment
“Fun” and “health” incentives were assessed using ratings of
the statements “I do Nordic walking because it is fun/it im-
proves my health” (1: not at all - 5: very much). Again, incen-
tive change was measured by subtracting ratings at T1 from
ratings at T2.
The items of the extended incentive measure were the result of
a two-step procedure. First, two experts on motivation research
who are highly familiar with the concept of activity- and pur-
pose-related incentives, and the theoretical concept of achieve-
ment, power and affiliation motives generated activity- and pur-
pose-related incentives for the achievement, power and affiliation
domain independently from each other. Secondly, the two best
fitting items of each category were chosen by the experts dis-
cussing the items in detail. The activity-related incentive scale
comprises two incentives for the achievement, affiliation and
power domain (e.g., achievement: I do Nordic Walking/because I
like to experience progress; affiliation: because I enjoy spending
time with my friends; power: because I experience a sense of
power) and a further item that we expected to be important but
did not fit in one of the categories (because I get absorbed by the
activity). Participants rated their agreement to each of the seven
statements using a 5-point scale from 1 (not at all) to 5 (very
much). The scale was sufficiently reliable (T1: α = .67; T2: α
= .71). The mean across all items was computed (T1: M = 3.31,
SD = .63; T2: M = 2.90, SD = .54). The purpose-related incentive
scale also comprises two items for each of the categories. An
example for a purpose-related achievement incentive is “I do
Nordic walking because I want to be better than others”. An ex-
ample for purpose-related affiliation incentives is “I do Nordic
walking because we often have a night out after the physical
activity lessons” and an example for purpose-related incentives in
the power domain is “I do Nordic walking because I want to
impress others”. Again, a further incentive that people reported
when being asked for their reasons of physical activity was added
(“I do Nordic walking because I want to lose body-weight”). A
purpose-related incentive score was computed by calculating the
mean (T1: M = 3.22, SD = .68, α = .62; T2: M = 2.83, SD = .62, α
= .71). Activity- and purpose-related incentive change indexes
were calculated by subtracting ratings at T1 from ratings at T2
(difference scores as in the previous studies).
Assessment of Drop-Out versus Maintenanc e
Nordic walking maintenance and drop-out were measured by
simply asking participants whether they still performed Nordic
walking sports or whether they had dropped out six months
after having commenced the course (T3). Forty-nine of the 68
participants (72.1%) indicated that they still regularly per-
formed Nordic walking (at least once a week) and 19 partici-
pants indicated that they had quit Nordic walking sports.
Results
Preliminary Analyses and Descriptive Statistics
Women and men did not differ with respect to any of the
study variables. Participants’ age also had no significant impact
on the results, so that data were pooled for the following analy-
ses. Changes in activity-related incentives (M = –.09, SD = .58)
and purpose-related incentives (M = –.07, SD = .55) were sig-
nificantly correlated (Pearson’s r = .67, p < .001) and activity-
as well as purpose-related incentives were associated with the
maintenance versus drop-out variable (activity-related incentive:
Spearman’s rho = –.38, p < .01, for purpose-related incentive:
Spearman’s rho = –.25, p < .05), indicating that the higher par-
ticipants’ incentive changes were, the less likely they would
drop out of Nordic Walking sports.
A similar correlation pattern was found for “fun” and “health”.
Changes in the incentives “fun” (M = –.15, SD = .65) and
“health” (M = –.23, SD = .69) were significantly associated
(Pearson’s r = .42, p < .01). Both incentives were significantly
related to the maintenance versus drop-out variable (Spearman’s
rho for fun = –.59, p < .01, for health = –.36, p < .01).
Incentive Changes in Maintainers and Drop-Outs
Given our assumption that incentives would differentially
change for maintainers and drop-outs, Table 1 illustrates des-
criptive statistics for activity- and purpose-related incentives at
T1 and T2 and change indexes separately for each of the two
groups. The changes in “fun” and “health” in maintainers and
drop-outs were very similar to the change in activity- and pur-
pose-related incentives, except that they were higher. Main-
tainers reported more fun (T1: M = 4.76, SD = .56; T2: M =
4.34, SD = .37) as well as health incentives (T1: M = 4.90, SD
= .31; T2: M = 4.82, SD = .44) than drop-outs (activity: T1: M
= 4.68, SD = .48; T2: M = 3.95, SD = .85 ; purpose: T1: M =
4.79, SD = .41; T2: M = 4.16, SD = .96). For maintainers the
fun incentive increased, but decreased for drop-outs.
6

J. SCHÜLER ET AL.
Table 1.
Descriptive Statistics for activity- and purpose-related incentives at T1
and T2 and incentive-change indexes for participants who maintained
Nordic walking (N = 49) and those who dropped out (N = 19) ( Study 2).
T1 T2 Incentive change
M SDM SD M SD
Maintainers
Activity-re l ated incentiv e 3.35 .563.40 .62 .05 .43
Purpose-related incentive 2.95 .562.96 .62 .00 .47
Drop-outs
Activity-re l ated incentiv e 3.21 .812.67 .61 –.48 .56
Purpose-related ince nt ive 2.77 .482.47 .50 –.34 .52
On a descriptive level, the group of maintainers showed a
higher incentive-change index for activity-related incentives (M
= .05, SD = .51) compared to the incentive-change index for
purpose-related incentives (M = .01, SD = .53). However, a re-
peated-measure analysis of variance revealed that the differences
were not significant, F(1,48) = .20. In contrast, for drop-outs the
activity-related incentives (M = –.44, SD = .61) decreased sig-
nificantly more than the purpose-related incentives (M = –.30,
SD = .53), F(1,18) = 9.91, p < .01.
The “fun” and “health” incentive change for maintainers and
drop-outs was comparable to the incentive change of optimal
and suboptimal exercisers in Study 1 (e.g., illustrated in Figure
1). The incentive change for “fun” (M = .08, SD = .45) was mar-
ginally higher than the incentive-change index for “health” (M =
–.08, SD = .53), F(1,48) = 3.35, p = .07. Drop-outs were mainly
characterized by a decrease in “fun” (M = –.74, SD = .73) and
“health” (M = –.63, SD = .90) incentives that did not signifi-
cantly differ (F(1,18) = .20, p = .63).
Effects of Incentive Change on the Maintenance of Physical
Activity versus Drop-Out
Similar to Study 1, a step-wise binary logistic regression
analysis was used to examine whether activity- and purpose-
related incentive changes predicted Nordic-walking mainte-
nance or drop-out six months after initiation of the physical
activity. The activity-related incentive change predicted exer-
cise in Nordic-walking maintenance and was thus included in
the regression model (Wald (1) = 8.55, p < .01; B = –1.61, Se
= .55). In contrast, change in purpose-related incentives failed
to reach significance and was thus excluded due to a lack of
predictive power. The chi-square test of model fit (10.17, p
< .01) indicated a highly significant difference in the goodness
of fit for the model which included change in activity-related
incentives (Model 2) compared to the model which contained
only the constant (Model 1) (Nagelkerke’s R-square = .20).
Similar to the activity- and purpose-related incentive mea-
sure, the change in the “fun” incentive was found to predict
physical activity maintenance and was included in the regres-
sion model (Wald (1) = 13.62, p < .001; B = –3.12, Se = .84).
The change in the “health” incentive was thus excluded from
the regression equation. The chi-square test of model fit (26.45,
p < .001) indicated a highly significant difference in the good-
ness of fit for the model which included change in the “fun”
incentive (Nagelkerke’s R-square = .46).
Brief Discussion Study 1
The present study accompanied Nordic walkers from the ini-
tiation phase up to the maintenance phase (six months later) of
physical activity. In line with Study 1, results revealed different
patterns of incentive change for those participants who main-
tained Nordic walking behavior and those who dropped out after
six months. For maintainers, the “fun” incentive increased str-
onger than the “health” incentive. Conversely, for drop-outs,
“fun” decreased more (but not significantly) than “health”. On a
descriptive level maintainers showed a greater increase in activ-
ity-related incentives than in purpose-related incentives. Con-
versely, drop-outs were characterized by a stronger decrease in
activity- compared to purpose-related incentives. A binary logis-
tic regression analysis again confirmed our second hypothesis:
change in activity-related incentive change was included in the
regression equation as a significant predictor of maintenance
versus drop-out, whereas change in purpose-related incentives
was excluded due to a lack of predictive power.
General Discussion
Based on considerations that the experience of physical ac-
tivity might change individuals’ incentives (see also Rothman,
2000), we empirically demonstrated and thus conclude that
incentives of physical activity are not static but rather change
over time. This idea of dynamicity corresponds to the postulate
of modern health theories of behavior change, that the course of
complex human action consists of qualitatively different action
phases in which different variables—in our case incentives—
are active (Prochaska & DiClemente, 1983; Rothman, 2000;
Schwarzer, 1992). As an extension of previous theoretical con-
siderations, we postulated that not only the dynamic change in
incentives but also the differentiation between two types of
incentives must be considered when it comes to predicting be-
havior maintenance. According to Rheinberg’s (2008) differen-
tiation between activity- and purpose-related incentives, stimuli
which incite goal-directed behavior (in our case physical activi-
ty) are either related to the physical activity itself (e.g., fun) or
to the result of the activity (e.g., health). We assumed that these
two types of incentives differentially change over time and
differentially influence physical activity. Since activity-related
incentives are dependent on the experience of the activity and
are discovered in interaction with it (Csikszentmihalyi & Ra-
thunde, 1992), they were expected to increase more strongly
than purpose-related incentives, which are more salient from
the very beginning and thus have a lower change potential (Hy-
pothesis 1). Two studies with elderly rehabilitation patients and
middle-aged Nordic walkers empirically confirmed this hy-
pothesis. For optimal exercisers (Study 1) and Nordic-walking
maintainers (Study 2), the “fun” incentive (as a representative
of activity-related incentive) increased more strongly than the
“health” incentive (representative of purpose-related incentive)
between the initiation and the maintenance phase of physical
activity. Using a broader incentive measure, Study 2 revealed
that the activity-related incentives of drop-outs decreased. Un-
expectedly, the increase of activity-related incentives in main-
tainers was not significant.
In line with the principles of operant conditioning, the re-
warding power of activity- and purpose-related incentives
prompted us to hypothesize that activity-related incentives such
as “fun” would be stronger predictors of physical activity than
purpose-related incentives such as “health” (Hypothesis 2).
According to the regularities of operant conditioning, activi-
ty-related incentives are more closely temporally related to the

J. SCHÜLER ET AL.
activity than purpose-related incentives and were thus assumed
to have a stronger rewarding effect on the maintenance of beha-
vior. In line with this assumption, the change in activity-re-
lated incentives predicted optimal exercising versus suboptimal
exercising in Study 1 as well as maintenance versus drop-out in
Study 2, whereas change in purpose-related incentives failed to
account for a significant amount of maintenance variance. It is
noteworthy that we found a consistent pattern of results for both
hypotheses using different samples and partially different mea-
sures of incentives.
Our results provide initial evidence supporting our theoretical
considerations and contributing to the fields of intrinsic motiva-
tion research and classical motivation research. Using the con-
cept of activity- and purpose-related incentives (Rheinberg,
2008), and in doing so focusing on temporal distance from the
activity as the most important differentiating characteristic of
incentives, the terms “intrinsic” and “extrinsic” are given a dif-
ferent focus than has been applied in previous intrinsic motiva-
tion research (Deci & Ryan, 1985). With the help of this focus,
we were able to enhance the predictability of physical activity
maintenance.
However, because our research focus was on the examination
of activity- and purpose-related incentives, we did not consider
further variables that might be important variables for sport and
exercise adherence such as (changes in) self-efficacy or inten-
tion. Another limitation are our study samples. We tested very
different samples in order to enhance the confidence in the
generalizability of data. However, the majority of rehabilitation
patients in the first study were male, whereas the majority of
Nordic walkers in Study 2 were female and therefore it cannot
be empirically excluded that gender and type of sport are con-
founded. Future studies are needed which replicate the study
results for men and women, different age groups (e.g., children,
adolescents) and different types of sports (e.g., competitive
versus recreational sports) and address the limitations of the
present studies.
The results of the present studies allow important conclusions
for practical interventions to be drawn. For example, according
to our results, health campaigns that aim to motivate individuals
to adopt physical activity by generating activity-related incen-
tives, such as, for example, having fun or feeling great while
being physically active, will be less effective. For many people,
working out is not fun in the beginning and exercising often
does not feel good. Instead, fun and other positive qualities of
exercising typically emerge in later phases when the activity has
been performed for a certain amount of time. Promising fun
from the very onset may frustrate individuals and facilitate drop-
out behavior because of unsatisfied expectancies (Rothman,
2000). Beginners rather need a realistic preview of the physical
activity experience and self-regulatory strategies, such as action
planning (Sniehotta, Scholz, & Schwarzer, 2005) and other ac-
tion control strategies (Kuhl & Beckmann, 1985) such as vividly
visualizing the positive consequences of physical activity in
order to overcome the critical phase of being an beginner of
physical activity. Once individuals have started to exercise, they
require good conditions (e.g., challenge-skill balance; positive
feedback) in order to discover activity-related incentives such as
“fun” while performing the physical activity.
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