Influence of Self-Efficacy on Compliance to Workplace Exercise

Mette Merete Pedersen 0 1 Mette Kreutzfeldt Zebis 0 1 Henning Langberg 0 1 Otto Melchior Poulsen 0 1 Ole Steen Mortensen 0 1 Jette Nygaard Jensen 0 1 Gisela Sjgaard 0 1 Thomas Bredahl 0 1 Lars Louis Andersen 0 1 0 H. Langberg Institute of Sports Medicine Copenhagen, Copenhagen University Hospital , Bispebjerg, 2400 Copenhagen, Denmark 1 O. S. Mortensen Department of Occupational and Environmental Medicine, Copenhagen University Hospital , Bispebjerg, 2400 Copenhagen, Denmark Background Continuous neck and shoulder pain is a common musculoskeletal complaint. Physical exercise can reduce pain symptoms, but compliance to exercise is a challenge. Exercise-specific self-efficacy has been found to be a predictor of participation in preplanned exercise. Little is known about the influence of exercise-specific selfefficacy on compliance to workplace physical exercise. Purpose To determine the influence of exercise-specific self-efficacy on compliance to specific strength exercises during working hours for laboratory technicians. Methods We performed a cluster-randomized controlled trial, including laboratory technicians from two industrial production units in Copenhagen, Denmark. The participants were randomized to supervised specific strength exercises for the neck and shoulder muscles for 20 minutes three times a week (n 0 282) or to a reference group (n 0 255). The participants answered baseline and follow-up questions regarding self-efficacy and registered all exercises in a diary. Results Overall compliance to exercises was 45 %. Compliance in company A (private sector) differed significantly between the three self-efficacy groups after 20 weeks. The odds ratio of compliance was 2.37 for moderate versus low self-efficacy, and 2.93 for high versus low self-efficacy. No significant difference was found in company B (public sector) or in the intervention group as a whole. Conclusion We did not find self-efficacy to be a general statistically significant predictor of compliance to exercises during 20 weeks, but found self-efficacy to be a predictor of compliance in a private sector setting. Workplace-specific differences might be present and should be taken into account. - Musculoskeletal pain is one of the most common and costly health problems in Europe and North America [1, 2]. In Denmark, musculoskeletal disorders comprises half of all work-related disorders [3], and continuous neck and shoulder pain is one of the common complaints [1, 2]. Targeted physical exercise for working adults can have positive effects on neck and shoulder pain symptoms [47]. However, compliance to exercises is challenging for many employees, and studies comprising interventions during working hours have reported moderate compliance at best [8, 9]. To target health-promoting strategies more efficiently, it is important to identify characteristics associated with low compliance. Self-efficacy has been stated a key predictor of human behavior and describes a person's beliefs in his or her own abilities to make a behavioral change [1013]. Selfefficacy is defined as: People's judgments of their capabilities to organize and execute courses of action required to attain designated types of performances. It is concerned not with the skills one possesses, but rather with judgments of what one can do with whatever skills one possesses [14]. The self-efficacy theory states that confidence in one's ability to conduct a given task or behavior is strongly related to one's actual ability to perform that behavior [14]. Selfefficacy varies in different domains of functioning and should therefore be used in a domain-specific manner [11, 15]. Exercise self-efficacy has been found to correlate positively with initiation and maintenance of physical exercises especially in the early and middle stages of a preplanned program [1624] and to be a predictor of general physical activity during leisure time [17, 20, 22, 25]. Additionally, participating in physical activity can improve exercise selfefficacy and subsequently lead to further participation in physical activity [12, 26]. However, little is known about the influence of exercise self-efficacy on compliance to physical exercise in different workplace settings. Our study determines the influence of exercise-specific self-efficacy on compliance to specific strength exercises for laboratory technicians at two different workplaces from the private and public sector, respectively. We hypothesize that: at both workplaces, (1) individuals with a low initial exercisespecific self-efficacy are less compliant than those with a high initial exercise-specific self-efficacy and that (2) specific strength exercises enhance exercise-specific self-efficacy. Material and Methods We performed a cluster-randomized controlled trial (RCT) in Copenhagen, Denmark (for full methodological description, see Zebis et al. [27]). The present paper includes a prospective observational study on the exercise group within the clusterRCT, as well as an intention-to-treat analysis on changes in exercise self-efficacy (hereafter, self-efficacy) in the exercise and control groups. We recruited subjects from two industrial production unitsa private sector company (A) and a public sector company (B)in February 2009. Company A was characterized by having strong leadership commitment to social responsibility and health-enhancing activities at work, in particular, regarding physical exercise, and to communicate their strategy to the workers. Many workers performed various leisure time physical activities. Company B, in contrast, did not demonstrate any special leadership involvement in these areas, but they accepted the study to be conducted at the workplace. At both workplaces, the subjects were laboratory technicians performing monotonous and repetitive work. In both companies, the participants were randomized on a cluster level to two different intervention groups: specific strength exercises (SSE) and reference (REF). This cluster randomization resulted in two groups (SSE, n0 282; REF, n0 255) that were comparable with regard to age, height, and weight. The reference group had a higher proportion of men than the exercise group, which was controlled for in the analysis (for more details, see Zebis et al. [27]). The SSE group consisted of 196 in company A and 86 in company B, and the REF group consisted of 167 in company A and 88 in company B. The analysis of the prospective observational part of the study included the 268 participants of the exercise group who had accepted participation at baseline, and who were not excluded from the study throughout the 20-week study period. The analysis of the cluster-RCT part of the study included participants in the exercise and reference groups who replied to the baseline and follow-up questions regarding selfefficacy. The local ethical committee (HC2008103) approved the study protocol, which was registered in ClinicalTrials.gov (NCT01071980). We informed the p (...truncated)