Evidence-Based Practice

The overall purpose of evidence-based practice is to optimize exercise program outcomes. The parameters of an exercise program include frequency, intensity, time, and type (or the F.I.T.T. principle). Each parameter contributes to the overall energy expenditure of an exercise program. Scientific research has demonstrated a relationship between optimal exercise training and improved health outcomes, including better cardiovascular fitness, lower risk of coronary artery disease, and a decrease in all-cause mortality, obesity, dyslipidemia, type 2 diabetes, and colon cancer. Thus, the United States Surgeon General, the American College of Sports Medicine (ACSM), and the American Heart Association (AHA) have all recommended a minimum energy expenditure goal of 1,000 calories per week.

Yet, one shortcoming to this broad, one-size-fitsall recommendation is a lack of consideration for individual differences in body mass. This oversight may lead to a potentially significant over- or underestimation of energy expenditure goals for an individual. Overestimation of the energy expenditure goals of an individual may result in unrealistic goals, and therefore increase the risk for injury, burnout, or decreased exercise-program adherence. Conversely, underestimating the energy expenditure goals for an individual may result in less-than-ideal training adaptations, which also could lessen exercise program adherence. Indeed, research has also shown that exercise programs with energy expenditure (14 and 23 kilocalories per kilogram per week) goals based on individual differences in body mass resulted in significant improvements to cardiorespiratory fitness and other risk factors for chronic diseases, including dylipidemia, body composition imbalances, and risk of type 2 diabetes. An evidencebased approach will consider the individual (e.g., differences in body mass) and integrate the best research to improve the quality of exercise programming and limit training unresponsiveness.

Evidence-based practice has its origins in the field of medicine beginning in the 1990s. The impetus for evidence-based practice was the idea that clinical decisions should be based on the highest quality research evidence. This approach seems intuitive; nevertheless, at the time, it was new territory for medicine and clinical practice. In 2000, it was estimated that only approximately 15%–40% of clinical decisions were based on research evidence. Because the evidence base in any field is dynamic and constantly evolving, proponents of incorporating evidence-based practice into the medical field deemed it necessary for practitioners to integrate the latest and highest quality research evidence into daily practice. Evidence-based practice spread from the field of medicine to other health fields, including the fitness and exercise-science disciplines.

Five steps are involved with applying evidencebased practice to the design of an exercise program:

For the best results in an evidence-based practice, each of the five steps need to be followed and evaluated for effectiveness.

Background questions are intended to uncover information regarding physical activity/exercise and some target adaptation or health outcome. Foreground questions should be designed to provide insight into specific exercise programming guidelines that will optimize achievement. For instance, a background question may ask about general health concerns associated with physical inactivity. One answer to this question would be the fact that cardiovascular disease (CVD) is linked with physical inactivity and also the leading cause of mortality in the United States. An example of a foreground question may be: What are the risk factors that best predict CVD? A follow-up foreground question could be: How can these risk factors be modified? Answers to these foreground questions might reveal that dyslipidemia, impaired fasting-blood glucose, and obesity are all substantial risk factors for CVD. Furthermore, it might be identified that the overall energy expenditure of the exercise program is an important priority in terms of risk-factor reduction. In this instance, the fitness practitioner would move onto step two of evidence-based practice in search of an answer to the question: What should be the overall energy expenditure goal of the program for the individual for which the exercise program will be designed?

Fitness practitioners have three primary sources of evidence from which to draw information to answer the question(s) generated in step 1: academic preparation, professional experience and expertise, and scientific research. In the search to locate the best evidence, fitness practitioners should consider two main factors: the potential bias of the source and its timeliness. In this regard, each source has various strengths and weaknesses.

PROFESSIONAL EXPERIENCE AND EXPERTISE. The professional experience and expertise of fitness practitioners can be an extremely powerful source of evidence. Indeed, a fitness practitioner with 20 years of experience in the design, implementation, and supervision of exercise programs with a wide array of individuals undoubtedly has learned many valuable lessons. In turn, this collective experience can be readily applied to present and future exercise program design. However, the professional experience and expertise of fitness practitioners can also be susceptible to bias. For instance, it is possible that fitness practitioners completely ignore newer exercise guidelines and research, instead continuing to rely on archaic principles learned from their own education decades earlier. It is also common for fitness practitioners to develop a sense of authority from their own previous experience that can supersede new research findings on exercise programming.

SCIENTIFIC RESEARCH. Research constitutes the source of evidence least predisposed to bias. Fitness practitioners can easily use the Internet and search databases such as PubMed and Google Scholar to locate fitness and exercise-science peer-reviewed journal articles. The best strategy to minimize bias is to remove the human element and let the scientific data speak for itself. Although the interpretation of scientific data can be biased, research evidence per se is less biased than academic preparation and professional experience and expertise. Accordingly, it is optimal if exercise program design is most influenced by scientific research evidence.

The third step in evidence-based practice is to critically appraise the evidence gathered in step 2. It is important for fitness practitioners to determine the validity of the evidence. Fitness professionals should also determine the applicability of the results to be sure the results from a study are generalizable to the individual for whom the exercise program is being deigned. For example, if a fitness professional identified a study performed with middle-aged men that examined the effectiveness of high-intensity interval training (HIIT) on cardiorespiratory fitness, those findings would not be applicable to older adult women.

When critically appraising the research evidence as it pertains to exercise-program design, fitness practitioners need to recognize that not all evidence is equal in terms of its quality ( Figure 1 ). The highest levels of evidence are considered to be systematic reviews of randomized controlled trials (Level 1a) and individual randomized controlled trials (Level 1b). On the other end of the spectrum, expert opinion, textbooks, and practical experience are given Level 5 rankings. In this hierarchy, the source of evidence that is least susceptible to bias (i.e., a systematic review of randomized controlled trials) is acknowledged as the best quality. In contrast, the source of evidence most susceptible to bias (i.e., expert opinion and practical experience) is assigned the lowest quality.

The last step of evidence-based practice requires fitness practitioners to periodically evaluate the first four steps. Research changes on a regular basis and will dictate the need to update exercise program design. Additionally, the individuals for whom fitness practitioners design exercise programs will constantly change. Therefore, background and foreground questions will differ and require additional rounds of questioning as well as locating and critically appraising evidence.

Lance C. Dalleck, PhD