Background

Lack of physical activity (or sedentarity) is associated with an increased risk of health problems and chronic diseases such as obesity, type 2 diabetes, cardiovascular disease, cancer, osteoporosis, and depression [1]. Adoption of regular physical activity is strongly recommended for the prevention and treatment of obesity and associated co-morbidities, with national guidelines recommending a combination of endurance, strength, and flexibility training [1–3].

Fitness trainers are a resource for the general public to obtain exercise information, exercise prescription, and guidance. Fitness trainers, often called personal trainers, specialize in the assessment of an individual's fitness level and the design and supervision of exercise programs tailored to individual fitness goals such as weight reduction [4]. Credentialing of fitness trainers is offered through many fitness organizations, and their requirements range from brief online courses to university degrees and/or stringent certifying examinations [5–7]. In 2006, there were approximately 235,000 fitness workers, including fitness trainers, registered in the United States and these numbers are expected to increase by 27% between 2006 and 2016 [4]. However, accessibility to fitness trainers depends on an individual's financial ability to pay for access to the facility and/or the trainer for advice.

The integration of fitness trainers into primary care has been studied. A review of eighteen studies examining physician-to-trainer 'exercise referral schemes' found that they have a small effect on increasing physical activity level in patients [8]. Another review of exercise interventions in primary care revealed that interventions performed by allied health professionals, including exercise specialists, may be more effective than those delivered by a physician alone, potentially due to the enhanced ability of health professionals to provide a more intensive intervention than time-constrained physicians [9]. Indeed, a survey of 500 physicians revealed that they rate themselves as ineffective at helping patients remain physically active and felt too hampered by time constraints to provide effective exercise counseling [10]. Finally, the 2006 Canadian guidelines for management of obesity recommend that inter-professional teams include exercise specialists [11].

Concurrently, there is an increased focus by national research granting agencies on the uptake and use of research findings [12, 13]. This process is commonly called knowledge translation (KT), implementation, dissemination, diffusion, or knowledge transfer [13]. KT is defined as 'a dynamic and iterative process that includes synthesis, dissemination, exchange and ethically-sound application of knowledge to improve health, provide more effective health services and products and strengthen the healthcare system' [14]. However, research is not often translated for use in practice, and studies are underway to determine effective interventions for KT.

The Cochrane Effective Practice and Organization of Care (EPOC) Group reports systematic reviews of studies designed to determine effective means for transferring knowledge to healthcare professionals [15]. KT strategies identified in EPOC reviews that have been shown to improve uptake of evidence-based knowledge include practice reminders (14% change in practice), educational meetings (11 to 20%), local opinion leaders (10%), audit and feedback (5%), printed educational materials (5%), and educational outreach (5%) [16]. Unfortunately, no reviews have been identified that target fitness trainers, and it is unclear how or to what extent fitness trainers integrate research findings in their practice.

In summary, although fitness trainers are publicly available to work with individuals to enhance physical activity, there is wide variability in the requirements for certification, including the knowledgebase and ongoing learning. Concurrently, studies are underway to improve fitness among the public, but effective strategies to transfer knowledge into practice is limited to healthcare providers.

The overall aim of this systematic review was to explore approaches or channels for translating scientific evidence-based knowledge to fitness trainers. Specific research questions were: Where do fitness trainers get their evidence-based information? What types of interventions are effective for translating evidence-based knowledge for use by fitness trainers? What are the barriers and facilitators to the use of evidence-based information by fitness trainers in their practice?

Methods

Search Protocol

The search strategy incorporated key terms related to fitness trainers (e.g., personal/fitness/exercise, trainer/instructor/leader/professional) and KT (e.g., dissemination, transfer, implementation) [17]. Given the authors' perception that KT to fitness professionals may be limited, a broad search strategy favoring high sensitivity was used (see Figure 1). The following databases were searched to May 2009: Medline, EMBASE, PsycINFO, Sport Discus, CINAHL, Scholars Portal Physical Education interface, and the Cochrane Central Register of Controlled Trials (second quarter, 2009). Additionally, the reference lists of included citations (n = 2) and excluded citations directly pertaining to fitness trainers (n = 9) were examined to search for other relevant publications. These eleven studies were also entered into Pubmed to search for related articles and to crosscheck publications by all study authors. Results were combined and duplicates removed.

Figure 1
figure 1

Medline search strategy.

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Selection process

The criteria for determining eligibility are described in Table 1. Two authors (DS, MH) independently screened titles and abstracts of all identified citations and, for relevant citations, assessed their eligibility for inclusion. Two authors (DS, MH) independently extracted data of included studies using a standardized form. Quality appraisals, including risk of bias, were based on the Critical Appraisal and Skills Program criteria for qualitative, descriptive, and observational studies [18]. Inconsistencies between reviewers were resolved by consensus at screening, eligibility assessment, and data abstraction.

Table 1 Criteria for study inclusion
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Synthesis process

Data from standardized forms were entered into an Excel database. Data synthesis was guided by the three research questions. For quantitative studies, we reported the results for outcomes as described in the paper aligned to one or more of the research questions. A similar approach was used to report qualitative data as described by the authors. Given the paucity of studies identified, we did not conduct a meta-analysis for similar quantitative outcomes or meta-qualitative analysis to identify themes across studies.

Results

Of 626 unique citations identified in the search strategy, and an additional eight studies retrieved through alternative methods, two studies were eligible for inclusion (see Figure 2). One study employed a survey design and the other a qualitative methodology. Of the 93 citations excluded after articles were reviewed, 51 were not studies, 33 were not about fitness trainers (e.g., three teachers, six athletic trainers, eight general public, 16 healthcare professionals), and nine did not measure how fitness trainers currently obtain/use evidence-based information (see Table 2).

Figure 2
figure 2

Flow diagram for screening process.

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Table 2 Characteristics of excluded studies (n = 42)
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Question one: Where do fitness trainers get their evidence-based knowledge?

Hare and colleagues surveyed a group of 325 American College of Sports Medicine registered fitness professionals working across a range of environments to assess their attitudes, perceptions, and beliefs regarding obesity [19]. Of 25 survey items, one item asked respondents to identify what sources of information they use to obtain knowledge on weight control information. Participants identified textbooks (81%), college class notes (80%), scientific journals (79%), workshops/seminars (78%), past experience (51%), colleagues (49%), and mass media (20%). Participants holding a Doctorate degree (14%) were less like to use mass media as a source of information than those holding a Master's degree or less (86%) (p = 0.04). Participants holding a Master's or Doctorate degree (61%) were more likely to use scientific journals as source of information than those with a Bachelor's degree or less (39%) (p = 0.008). Limitations include the potential for response bias with 66% response rate and the absence of a priori identification of units of analysis. Strengths were having an explicit description of the survey development and validation process, appropriate recruitment of participants, and clear reporting of results.

Forsyth and colleagues conducted a qualitative study to examine the knowledge, approaches, and attitudes of fitness instructors dealing with clients seeking weight loss advice [20]. A purposive sample of 10 fitness instructors in New Zealand, with qualifications ranging from none to Master's level preparation, was interviewed. A wide range of knowledge and competency concerning weight control and exercise prescription was found among the participants. All rated keeping current with knowledge as important. Preferred knowledge resources included word of mouth (networking with peers), followed by internet, fitness magazines, seminars, and research papers. Less educated participants were more likely to use the internet and reported difficulty determining accuracy and credibility of information. Limitations included insufficient description of the data analysis process and lack of author reflection regarding personal bias and relationship with participants. Despite limitations, this study provides a clear statement of research aims, used an appropriate study methodology to accomplish the objectives, and provided a rich description of results.

Question two: What types of interventions are effective for translating evidence-based knowledge to fitness trainers?

No studies identified addressed this question.

Question three: What are the barriers and facilitators to the use of evidence-based knowledge by fitness trainers in their practice?

No studies identified specifically addressed this question. However, as noted above, education level was identified as a factor influencing knowledge sources and could be considered as a barrier or facilitator to finding research-based evidence for use in practice.

Discussion

This is the first known systematic review of KT strategies used by fitness trainers. The principal finding is the lack of literature related to this important question. In fact, included studies were limited to description of sources of information used by fitness trainers, and none evaluated interventions for KT to fitness trainers. Furthermore, both studies targeted fitness trainers' perspectives on body weight control issues, and KT was not one of the main objectives.

The most common sources of information used by fitness trainers were textbooks, networking with colleagues, scientific journals, seminars, and mass media [19, 20]. These sources reflect a range of quality of the information with only one source, scientific journals, likely to include evidence-based information to inform practice [21]. Textbooks and course notes are considered to be of lower quality given the often absence of peer review and the time delays in publishing, rendering some knowledge out of date quickly. As well, textbooks and notes were likely to be further out-dated for the majority of participants, as the 325 surveyed by Hare et al. had been employed for a mean of 10.3 years [19]. From a KT perspective, systematic reviews or practice guidelines that synthesize evidence from multiple studies are identified as the 'unit of knowledge' for moving evidence into practice [13]; however, none of the participants in the two studies specifically identified having used either of these sources of evidence-based knowledge.

Both studies also suggested that fitness trainers with higher levels of education (e.g., graduate degrees) are more likely to use scholarly sources of evidence compared to those with lower levels of education who are more likely to rely on mass media, including the internet [19, 20]. Of concern is that those using the internet were also described as having difficulty discerning the credibility and quality of information sources [20]. The implication of educational level as a factor influencing choice of information sources is difficult to determine, given that there are little data on the educational qualifications of fitness trainers working with the public. Another study examining current knowledge of 115 health fitness professionals working in fitness facilities in Southern California found that three held Master's degrees (3%), 22 held bachelor's degrees in exercise science (19%), nine held other bachelor's degrees (8%), and the majority (70%) held less than a bachelor's degree [22]. In comparison with the study by Hare et al. in which 61% of participants held postgraduate university degrees and worked across a range of environments including hospitals, rehabilitation clinics, and universities. Therefore, it is challenging to determine what proportion of these individuals are actively involved in providing individual exercise counseling, thereby making it difficult to extrapolate our findings to the fitness trainer population at large.

Unfortunately, our systematic review did not identify any KT intervention studies evaluating outcomes such as knowledge uptake, intention to use research in practice, use of evidence in practice, or fitness trainer satisfaction with KT interventions. As one example of KT to fitness trainers, the Somerset Health Authority in the UK has contracted a team of accredited sport and exercise scientists at the University of Gloucestershire to: ensure quality of advice from leisure providers; provide workshops for fitness professionals on current research-based knowledge to safely deal with lower risk patients; be a consultancy service; and provide bimonthly newsletters focused on information dissemination [23]. However, no formal evaluation was reported in the literature regarding the impact of these KT interventions on knowledge uptake, intention to use or actual use of the evidence in practice, or fitness trainer satisfaction with the KT strategies.

While data are available regarding KT interventions to healthcare providers [16], it is unclear whether or not these interventions would also be effective with fitness trainers. Compared to healthcare providers, fitness trainers do not have standardized levels of educational preparation, and it is unclear whether their practice is motivated by other factors (e.g., marketing their services, maintaining their clientele, client satisfaction). Given that one of the most common sources of information for fitness trainers is networking with peers, interventions such as communities of practice and/or using local opinion leaders may be more appealing KT approaches worth evaluating.

There are several limitations and strengths that should be considered when interpreting the findings from our systematic review. With only two studies identified, it is possible some studies were missed due to poor indexing in databases [24]. The search strategy was intended to be broad in nature and comprehensive in that we used a variety of approaches and data sources. Therefore, given the search methods and screening process using two independent reviewers, it is unlikely that many, if any, were missed. Another limitation is the descriptive nature of the available studies failing to provide highest quality evidence in support of any conclusions. Finally, we were unable to assess for publication bias due to small number of studies [25]. In addition to the rigorous and systematic methods used, another strength of our review was having an inter-professional research team with expertise in KT (DS), library sciences (RS), kinesiology (MH, DP, KA), and personal training/exercise physiology (MH, KA).

Summary

In conclusion, there is insufficient evidence to determine how fitness trainers attain new evidence-based knowledge and incorporate this knowledge into their practice. There is no known evidence examining effective strategies to translate knowledge for this group of fitness experts. Therefore, given fitness trainers' role in advising the general public, their accessibility, and the emerging evidence-based guidelines on best practices related to the use of exercise and nutrition interventions, further research is needed to ensure that fitness trainers, working with the public, integrate new research knowledge into their fitness assessment and exercise guidance.