distinguished writing award: 2003 research consortium graduate student award winner
TRANSCRIPT
2003 RESEARCH CONSORTIUMGRADUATE STUDENT AWARD WINNER
Factors Influencing Physical ActivityAmong Adults With Physical DisabilitiesMaria Kosma, Bradley J. Cardinal*, and JeffMcCubbin, Oregon State University
The benefits of physical activity and/or exercise for inI dividuals with disabilities have been reported by an
abundance of studies and governmental agencies (Centersfor Disease Control and Prevention, 1999; Guthrie, 1999).Some of the benefits include increased health-related fitness, movement skills, and independent functioning, prevention of obesity and other health-related conditions,decreased anxiety and depression, and increased positivemood, self-esteem, and self-confidence. Unfortunately, toofew people with disabilities enjoy those benefits, becausetoo few are active on a regular basis. For example, a 1997survey (Healthy People, 2010), reported that only 12% ofthe adult population with disabilities participated in physical activityof moderate intensity, 5 days per week for 30 mineach day. Although these data do not seem to differ drastically from the data of the same age-range nondisabled population (16% participating in the recommended activity),there is a much higher percentage of adults with disabilities (56%) who do not participate in any leisure-time physical activity compared with adults without disabilities (36%).
The social minority model, which serves to at least partially regulate the physical activity behavior of individualswith disabilities, recognizes certain psychosocial factorsthat may decrease physical activity motivation (Kosma etaI., 2002). Therefore, it is essential to identify importantmotivational concepts and principles associated with active living (Durstine et aI., 2000). Given the limited theorydriven empirical evidence toward the identification ofmotivational strategies among this population segment,the purpose of this study was to explore the most influential (motivational) factors in physical activity for adults withphysical disabilities based on the transtheoretical model(TM; Prochaska & DiClemente, 1983).
The TM is a contemporary action-oriented model thatrecognizes ways to increase physical activity behavior. Themajor dimensions of the TM are stages of change (i.e.,physical activity intention and behavior), processes ofchange (i.e., 10 cognitive and behavioral strategies to increase physical activity), self-efficacy (i.e., perceived selfconfidence to overcome barriers toward physical activity),and decisional balance (i.e., perceived pros and cons toward exercise). Classifying individuals within a corresponding stage regarding physical activity intention andbehavior may facilitate the development of interventionprograms. Specifically, in this study there was an attemptto determine the most important exercise motivationalstrategies that can be used in intervention programs.
ROES: March 2003 Supplement
This was a national, cross-sectional survey of adults withphysical disabilities. The degree to which different independent variables (processes of change, decision balance,self-efficacy, and physical activity barriers) may affect exercise stages of change was examined. A press release anda flyer were used as study dissemination sources for participant recruitment. Study participation was voluntary.
Research questions:
1. Which cognitive, behavioral, and environmental factors (i.e., processes of change, self-efficacy, decisionalbalance, and exercise barriers) mostly affect stages ofchange (i.e., a physical activity indicator)?
2. In which stages of change are participants more accurately classified as a means to direct effective intervention programs?
On the basis of statistical power analysis (i.e., statisticalpower = .80, medium effect size [ES = .25], and a = .05;Kraemer & Thiemann, 1987), 200 participants wereneeded for the internal validity of the study. Initially, 411individuals volunteered to participate in the survey. Fromthe 334 individuals who responded to the survey (response rate = 81.3%), 322 participants (women = 62.1%,men = 37.3%; Mage = 52.5 years) qualified to remain inthe study. The most prevalent disability categories werepostpolio (17.7%), multiple sclerosis (11.8%), and spinal cord injury (10.9%). Most of the participants (91.9%)were Caucasians.
In this study, self-report standardized measures of exercise stages of change (Reed et al., 1997), processes ofchange(Marcus et al., 1992), self-efficacy (Marcus et al., 1994), decisional balance (Marcus et al., 1994), and exercise barriers(Zhu, 2001) were distributed to the study participants. Participants were asked to fill out the questionnaires and return them to the principal investigator in a self-addressedprepaid envelope. A total of four mailings were conductedthrough the university's Survey Research Center.
The Statistical Package for Social Sciences (SPSS) version 11 was used to analyze the data. Two direct discriminant function (DDF) analyses were conducted to identifyinfluential factors toward physical activity. In the first DDFanalysis, the behavioral and cognitive processes of changewere tested as two distinct higher order constructs (5 cognitive and 5 behavioral strategies). In the second DDFanalysis, each of the cognitive and behavioral processes of
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change was evaluated separately for their contribution toclassification within the stages of change.
The a priori criterion for an accepted canonical correlation (i.e., the relationship between the combined scoresof the independent variables and stages of change) was ~.33 (Tabachnick & Fidell, 2001). Therefore, from the fourdiscriminant functions (i.e., combined scores of the independent variables) produced in the initial DDF analysis, only the first two functions were statistically (Wilk'sLambda, = .394, X2 [20] = 294.3, P< .001; Wilk's Lambda,= .766, X2 [12] = 84.4, P< .001) and practically (r\ = .70;r2
= .44) significant. In the first discriminant function, thestructure coefficients (i.e., correlation between each predictor and the corresponding discriminant function) revealed that behavioral processes of change were the mostimportant influential factors (r =.85), followed by self-efficacy (r= .66), decisional balance (r= .54), and cognitiveprocesses (r= .33). In the second discriminant function,barriers (r = .71) and cognitive processes (r = .59) werethe most significant predictors. The stage-of-change classification probabilities after weighting for group size indicated that the most stable stages were maintenance (89.6%),precontemplation (68.9%), and contemplation (51.7%),whereas the least stable stage was preparation (0%).
Similarly, in the second DDF analysis the first two discriminant functions were statistically (Wilk's Lambda, =
.310, X2 [52] = 365.9, P< .001; Wilk's Lambda, = .662, X2 [36]= 128.9, P< .001) and practically (r\ =.71; r2 = .50) significant. In the first discriminant function, the structure coefficients showed that behavioral processes, self-efficacy,and decisional balance were the most important stageof-ehange predictors. In the second discriminant function, the cognitive processes of change and exercisebarriers were the most influential factors. The classification accuracy within the stages of change indicated thatmaintenance (89%), precontemplation (70.5%), andcontemplation (55.2%) were the most stable stages. In thissecond DDF analysis, classification accuracy was distributed more evenly across the stages than in the first DDFanalysis. Specifically, 23.8% of cases in the preparationstage were correctly classified.
This is the first study to examine physical activity motivational factors for adults with physical disabilities on thebasis of the full TM. Results indicated that the behavioralprocesses of change, self-efficacy, and decisional balancewere very important to physical activity participation. Barriers toward physical activity and the cognitive processesof change were also very important to physical activity en-
hancement. These results are in agreement with currentevidence that behavioral and cognitive processes of changeare both important in physical activity initiation and maintenance for the nondisabled population (Wallace &Buckworth, 2001) .
In the second DDF analysis, structure coefficients identified certain processes of change that can influence physical activity involvement. In particular, practitioners andscholars in adapted physical activity can use such exerciseintervention techniques as anxiety release, successfulexperiences, commitment to active lifestyles, environmental cues, contingent-based reinforcement, awareness ofphysical activity benefits, as well as barrier identificationand elimination. Additionally, cognitive, emotional, andenvironmental consequences following physical activityand/or inactivity can act as triggers toward active lifestyles.As a whole, classification accuracy within the stages ofchange after controlling for group size was satisfactory (i.e.,67.1 % above chance accuracy in the first DDF analysis and69.9% above chance accuracy in the second DDF analysis). These results suggest that the aforementioned factors are very important toward physical activity initiationand enhancement. The results also support the constructvalidity of the stages-of-ehange measure. However, the waythe preparation stage is conceptualized and measured,as well as the relationship with the study predictors, mayneed some refinement.
It is important to keep certain study limitations in mind.First, this was a cross-sectional study, and, therefore, developmental trends in exercise behavior cannot be observed. Longitudinal designs are recommended in orderto examine the stability of different physical activity predictors across time. Second, actual physical activity behavior was not measured in this study. Future studies shouldmeasure both physical activity and stages of change tobetter establish the concurrent validity of the results.Third, this study managed to capture mainly active Caucasians with unequal group sizes across the differentstages of change, restricting the generalizability of theresults. Therefore, the study needs to be replicated withparticipants equally representing all stages of change. Itis also recommended that researchers examine differentage groups from diverse ethnic backgrounds and functional levels. Following the attempt of this project, futurestudies should try to develop physical activity motivationalstrategies based on theory-driven contemporary modelsaimed at understudied diverse populations. This studywas funded by NIDRR, USDE (CFDA No. 84.133b-9).
*Denotes Fellow status in the AAHPERD Research Consortium (as of December 2002).
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