Descripciones y Diagramas de Procesos

The first seminal meta-analysis that systematically and quantitatively evaluated the evidence was conducted by Dishman and colleagues (1998), who investigated the effectiveness of workplace health promotion programmes on physical activity, physical fitness and health-related outcomes. The review included studies published between 1972 and 1997 carried out among healthy employees and based on randomised controlled trial (RCTs) and controlled trial (CT) designs. Outcome measures included physical activity and physical fitness assessments (i.e., self-reported time spent in physical activity), biological indicators, such as cardiorespiratory fitness, muscle strength and flexibility, body composition), and other health-related outcome measures (i.e., general health, fatigue, cholesterol, blood pressure and musculoskeletal disorders). Of the selected 26 studies, 15 were RCTs and 11 were CTs. The authors found that the average effect size was positive but small (r = .11, 95% CI: -.20 to .40), even if the effects varied because of the heterogeneity of measurements and differences in study design. The effects were smaller in experimental than in non-experimental designs and the few studies that used an experimental design yielded small or no effects. Only 10% of the reviewed studies reported large effect size (i.e., larger than .40), suggesting that the programme was successful in changing the outcomes from a control level of 50% before the intervention to 70% after the intervention (Dishman et al., 1998, p. 348). Moreover, very few studies were deemed of high methodological quality. Methodological flaws of the studies included lack of accurate reporting on pre- and post- test measures and procedures involved as well as limitations of the instruments used for

collecting data about physical activity (i.e., self-reported or maximum oxygen consumption). Dishman and colleagues concluded that there was no evidence for a positive effect of interventions on physical activity outcomes, partly due to the scientific limitations and to poor research design (Dishman et al., 1998). This conclusion is slightly in contrast with those of Shepard (1996), and the difference in conclusions with Dishman et al.’s review depends on the fact that Shepard did not use meta-analytic techniques to evaluate the effectiveness of the studies.

Another systematic review by Proper et al. (2003) analysed the quality and results of the literature, published between 1980 and 2000, about physical activity promotion in the workplace focusing on physical activity, physical fitness, and health related outcomes. The concept of physical fitness encompassed health-related fitness, including cardiorespiratory fitness, muscle flexibility, muscle strength, and body weight and body composition. Other health outcomes included general health, fatigue, musculoskeletal disorders, blood pressure, and blood serum lipids. The authors conducted a qualitative evaluation of the literature, since a meta-analysis was not possible due to heterogeneity of studies’ design and results (Proper et al., 2003). A total of 26 studies was analysed, of these 15 were RCTs and 11 were non-randomised controlled trials. Eight studies (5 RCTs and 3 CTs) evaluating the effect of an intervention on physical activity behaviour were selected. Among these, two methodologically sound RCTs (deemed of “high- quality” according to the rating system developed by the authors) reported that participants in the experimental condition had significantly increased their exercise behaviour and energy expenditure in comparison to the control group (Proper et al., 2003, p. 113). Like in Sherman’s (1996) review, the authors concluded that the evidence of effectiveness with regards to physical activity was strong and consistent in that studies showed positive, significant effects in the experimental conditions. Strong evidence was found also for effects on musculoskeletal disorders. However, for the other health-related outcomes, the evidence was judged inconclusive (for cardiorespiratory fitness, muscle flexibility and strength, body weight, body composition, general health), limited (for fatigue), or no evidence (for blood serum lipids and blood pressure outcomes). The conclusions drawn in Proper et al.’s 2003 review were not consistent with Dishman and

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colleagues’ study (1998). The authors recognised that this could be explained by the fact that the reviews differed in terms of methodology (Proper and colleagues used a qualitative appraisal of studies based on a rating scheme).

Marshall (2004) analysed the literature published between 1998 and 2004 and included in the review 32 studies, five of which were RCTs, six randomised trials, seven quasi-experimental trials with a control condition, and the others were non-experimental cohort studies with no control condition (Marshall, 2004). Effect size calculations were computed only from six out of 32 selected studies, because the others did not provide enough information. Marshall found that the average effect size for studies promoting physical activity through motivational prompts was .34; for a workplace exercise programme it was .37; for a study which used individual counselling and for single risk factor intervention programmes it was .40; and for intervention programmes addressing various health risk factors it was .24 (Marshall, 2004, p. 62). The author commented that these effect size estimates were larger than those reported in Dishman and colleagues’ review (1998), but were based on a smaller sample of studies (only six), which implied that results should have been interpreted with caution. In line with Dishman et al.’s conclusions, Marshall suggested that the evidence supporting the effectiveness of workplace physical activity interventions was little, and lamented the paucity of few high-quality, methodologically sound studies (Marshall, 2004). Similar conclusions were drawn by Badland and Shofield (2004), who concluded that “little basis exists to demonstrate sustainable increases in health-related physical activity levels when using the workplace as a platform for intervention” (Badland & Schofield, 2004, p. 9).

Different results were found in a 2005 literature review (Matson-Koffman et al., 2005), which focused on policy and environmental interventions promoting physical activity and nutrition. The authors conducted a comprehensive evaluation of the literature published between 1972 and 2003. Twelve studies targeting physical activity in the workplace were included in the review. Of these, two were published before 1990 and 10 after 1990. Overall the authors suggested that the reviewed studies reported overall positive results. One study, published before 1990 (Wilbur & Garner, 1984), reported that participation in a large comprehensive programme - Johnson & Johnson’s

Live for Life programme - was associated with a significant increase in energy expenditure (Matson-Koffman et al., 2005) but for a short period of time. Unlike Proper et al. (2003), Matson-Koffman and colleagues reported positive results of in reducing participants’ cholesterol level and systolic blood pressure. Consistent with Proper et al.’s and Shepard’s reviews, Matson-Koffman et al. concluded that policy and environmental interventions could increase levels of physical activity even though for a short term (Matson-Koffman et al., 2005). These conclusions contrasted with those presented in another contemporaneous systematic review, which focused on environmental changes in the workplace on physical activity, and concluded that the evidence was inconclusive (Engbers et al., 2005).

Another noteworthy systematic review of the literature about workplace physical activity interventions effectiveness was conducted by Dugdill et al. (2008). The authors included 38 papers, published between 1996 and 2007, representing 33 interventions including seven specifically aimed at influencing stair walking, four aimed at increasing walking to and from the workplace and the rest were multi-component studies.

With regards to stair walking, the results of the studies were judged inconsistent as both positive and negative effects were reported. Authors concluded that there was limited evidence of the effectiveness of interventions influencing stair walking (Dugdill et al., 2008), when these interventions used ineffective means of promotion. This result was in line with those reported in another previous narrative review, which focused on interventions aimed at increasing stair climbing in the workplace (Eves & Webb, 2006). This was confirmed also by a contemporaneous study conducted in an NHS setting in the U.K. (Blake, Lee, Stanton, & Gorely, 2008). Authors reported no statistically significant differences in stair climbing or descent through the introduction and removal of promotional posters (Blake et al., 2008).

Interventions aimed at increasing walking to and from workplace showed overall positive and significant results, suggesting that they contributed to a significant behaviour change (Dugdill et al., 2008). Multi-component interventions included a combination of counselling, motivational interviewing, health checks, screening, health promotion messages, information, led activity sessions, and active travel. The reviewers

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found that workplace counselling was effective in changing behaviour, whereas the evidence for health promotion messages and information was inconclusive (Dugdill et al., 2008). Overall, Dugdill and colleagues concluded that the workplace physical activity interventions showed good potential in influencing physical activity behaviour.

More recently, two meta-analyses on the effectiveness of workplace health promotion interventions on physical activity were conducted (Abraham & Graham- Rowe, 2009; Conn et al., 2009) showing comparable results and producing a methodologically sound and quantitatively supported evaluation of the evidence, which has not yet been updated. Abraham and Graham-Rowe (2009), with the aim to update Dishman et al.’s (1998) study, investigated the literature published between 1997 and 2007. The authors included in the review 37 evaluations reporting the results of about 55 interventions; 10 of these were present also in Dishman et al.’s review. The authors were able to calculate 57 effect sizes from 37 evaluations selected (because different papers provided more than one outcome measure).

Overall Abraham and Graham-Rowe discovered that worksite interventions had a small positive effect on physical activity level (d = .20), with considerable heterogeneity between the studies. However, the estimates varied little between studies conducted before (d = .17) and after 1997 (d = .22). They also found that fitness outcome measures were smaller in effect than self-reported physical activities (.13 versus .23). Abraham and Graham-Rowe concluded that worksite interventions targeting physical activity (and specifically walking or step counting) were more effective than those targeting general lifestyle changes, but when fitness outcomes were considered, the evidence of effectiveness was weaker. However, the authors suggested that if the effects, albeit small, were replicated across the population (and maintained) “the average increase in population fitness is likely to have considerable health and economic impacts” (Abraham & Graham-Rowe, 2009, p. 140).

Similar findings were reported in the other meta-analysis by Conn and colleagues (2009) who offered a more extensive review of studies, by including papers published from 1969 through 2007 (Conn et al., 2009). The authors evaluated results from 138 studies and reports finding overall significant effects on physical activity, fitness, lipids

and anthropometric measures (i.e., BMI) and also for psychological indicators, such as mood and perceived quality of life. For physical activity, the average effect size was .21 (similar to Dishman et al.’s and Abraham & Graham-Rowe’s reviews), for fitness it was .57, for lipids .13, for other anthropometric measures it was .08, and for mood and quality of life were .13 and .23 respectively. According to Conn et al., these findings supported the argument that some interventions might improve physical activity, but due to the highly significant heterogeneity of the estimated effects, results had to be interpreted with caution (Conn et al., 2009).

The estimates of effect sizes for physical activity in both Abraham and Graham- Rowe’s (2009) and Conn et al.’s (2009) reviews were in line with those estimated in Dishman et al.’s review (1998) and were consistent with those previously reported in other systematic reviews about community-based and general physical activity interventions in community settings, which were associated with small effects (Baker et al., 2011; Foster et al., 2005; Hillsdon et al., 2004; Hillsdon & Thorogood, 1996).

More recently, three other systematic reviews investigated some specific aspects of physical activity in the workplace, finding similar results compared to the previously reported meta-analyses. For example, one systematic review focused on interventions to reduce sitting (Chau et al., 2010). The lack of sufficient information for conducting a meta-analysis (only six studies met the inclusion criteria) and the fact that the reduction of time spent sitting was a secondary objective, the authors concluded that there is insufficient evidence to conclude that interventions aimed at reducing time spent sitting were effective (Chau et al., 2010). Another systematic review dealt with the integration of short bouts of physical activity into organisational routine (Barr-Anderson, AuYoung, Whitt-Glover, Glenn, & Yancey, 2011). The authors reviewed 11 unique worksite interventions, which showed significant but modest improvements in physical activity. However, the results on other outcomes (e.g., work performance) were judged inconsistent suggesting that the effect of short exercise bouts on work performance outcomes was mixed (Barr-Anderson et al., 2011).

Another systematic review and meta-analysis investigated the effectiveness of physical activity and nutritional programmes in the workplace (Hutchinson & Wilson,

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2011). The authors analysed the literature published between 1999 and 2009 and reviewed a total of 29 studies, grouped according to different theoretical frameworks theoretical framework on which the interventions were based (i.e., health education, cognitive-behavioural, motivation enhancement, social influence, exercise). The authors found that theoretical approaches reported overall small effects. Larger effects were found in interventions that used motivation enhancement and in studies that focused on one health behaviour and in RCTs (Hutchinson & Wilson, 2011).

The effectiveness of workplace physical activity interventions on other health- related outcomes (such as body fat and BMI) showed moderate results, as well. For example, two recent meta-analyses investigated the effects of workplace physical activity and nutrition interventions on body weight, BMI and other related measures finding similar results (Anderson et al., 2009; Verweij, Coffeng, van Mechelen, & Proper, 2011). In Anderson and colleagues’ review (2009), which analysed the literature published between 1966 and 2005, the pooled results extracted from six RCTs showed that employees decreased of 2.8 pounds in weight (95% CI: 4.60 to 1.00) and .50 in BMI (95% CI: .80 to .20) when compared to controls at 6 to 12-months follow-up (Anderson et al., 2009). The authors concluded that there is “strong evidence of a consistent, albeit modest, effect” (Anderson et al., 2009, p. 355). Verveij et al. analysed the literature published between 1980 and 2009 and focused only on studies based on RCT design. They evaluated the following outcomes: body weight, BMI, and body fat percentage (calculated from a sum of skin-folds). In total twenty-two studies were selected and analyses were conducted separately for each outcome. For interventions targeting physical activity and dietary behaviours, the pooled results from nine studies showed that the mean difference in body weight in nine studies was -1.19 kg (95% CI: -1.64 to .74), in BMI in six studies it was -.34 kg/m2 _{(95% CI: -.46 to -.22), and body fat}

percentage was -1.12% (95% CI: -1.86 to -.38). However, for interventions focusing only on physical activity, there quality of evidence was judged low and inconsistent for all outcomes measured (body weight, BMI and body fat percentage). Consistent with Anderson et al.’s review, Verveij and colleagues concluded that there was moderate evidence suggesting that workplace interventions promoting both physical activity and

dietary behaviour can significantly reduce body weight, BMI and body fat percentage (Verweij et al., 2011).

Another recent systematic review analysed workplace physical activity studies carried out in Europe and published up to December 2009. The authors found moderate evidence of effectiveness for physical fitness outcomes with exercise training interventions and for physical activity outcomes with active commuting interventions, but these interventions were considered promising approaches to promote physical activity in the workplace (Vuillemin et al., 2011).