With research studies so easy to find on the Internet, fitness professionals are regularly bombarded by clients asking for interpretations.

Unfortunately, reading and interpreting scientific articles can get frustrating when terminology is unfamiliar and writing styles are wordy or awkward. Scientific journals try to communicate research findings as clearly as possible, but journals often use a highly stylized voice that makes it difficult for the applied professional to grasp the meaning of published studies.

Fitness professionals with a good grasp of common research methods and terminology (see Table 1) have a better chance of helping clients to make sense of scientific writing. The explanations that follow should make it easier for you to translate researchers’ conclusions into plain English:

What Does “Significant” Mean?

The term “significant”—or more correctly “statistical significance”—in a research study refers to the likelihood that certain test scores will occur. This in turn helps researchers understand whether their results are credible.

In exercise science research, statistical significance is typically stated at one of two probability (


) levels:


≤ 0.05 or


≤ 0.01. Think of


≤ 0.05 as saying 95 times out of a 100 you will get this result (and 5 times out of a 100 you can get a chance result).

What’s the Difference Between Primary and Secondary Research?

Primary research starts with a research question (i.e., an unsolved problem the researcher is trying to unravel). This type of investigation follows a detailed process—the scientific method—that enables the researcher to develop a hypothesis and create an experiment to test it (see Figure 1). (Sometimes more than one question is posed.)

Before a primary research study is published in a journal, it goes through a strict peer review, in which two or more specialists in the field critically examine the article and recommend whether it should be accepted for publication. Many primary research journals now include a practical-applications section that synthesizes the useful insights gleaned from the study. This section usually appears at the end of the article.

By contrast, a secondary research study—such as a literature review or meta-analysis—collates, summarizes and analyzes existing research. Secondary research also goes through peer review before scientific journals will publish it.

Understanding Titles and Abstracts

Internet searches usually yield two categories of titles for research studies: the authoritative titles published in journals, and the “clickbait” headlines on articles summarizing the research. Researchers often spend an inordinate amount of time choosing their article’s title, which often provides a great glimpse into what the study is all about. Clickbait titles are another animal altogether: Designed mainly to generate online advertising revenue, they rarely have much to do with quality research. Be on guard for these sensational headlines as you conduct Internet research, and make sure your clients can distinguish between clickbait headlines and authoritative titles.

After the title, most research journal articles begin with an


—a brief summary of the purpose, methods, results and main conclusions of the study. Ideally, and most of the time, the abstract is a standalone synthesis of the entire paper and is easily accessed through Internet searches. However, as fitness pros have no doubt realized, reading complete research articles online sometimes requires paying a fee. A system like this that prevents Internet users from accessing full article content without a paid subscription to the webpage host (or without direct payment for access to the article) is called a “paywall.” Students and faculty at universities have library resources that bypass paywall systems.

What Are the Main Research Classifications?

Research is conducted in five basic categories:

1. Historical Research

This research explores past events for clues that can help us anticipate or explain future events. For example, improving our understanding of research into high-intensity exercise injuries has helped the fitness industry design safe and effective high-intensity programs for specific populations.

2. Descriptive Research

This research often collects information through data review, surveys, interviews or observation. In essence, descriptive research describes the way things are. A paper reviewing previously reported research is considered descriptive research. The feature on the health benefits of exercise, “35 Ailments, One Prescription: MOVE!,” in this issue of

IDEA Fitness Journal

is another example. Often, new ideas and theories are discovered and presented via the descriptive process.

3. Correlational Research

This research attempts to determine the relationship between two or more variables. The degree of the relationship is expressed as a correlation coefficient. For example, a researcher may try to determine the relationship between cardiorespiratory fitness and self-esteem in college women. As variables become more positively related, the correlation draws nearer to +1.00 (range is 0.0 to ±1.0). Unrelated variables produce a correlation near 0.0. If the correlation is near -1.00, the variables are inversely related. Eating and hunger, for example, have an inverse correlation: The more we eat, the less hunger we feel.

4. Causal-Comparative Research

This research hunts for cause-effect relationships between two or more groups. For instance, researchers may compare the body composition of people who have trained only with free weights with that of people who have trained only with exercise machines. Researchers do not manipulate variables: They investigate how training with free weights versus exercise machines affects body composition.

Obviously, because factors such as diet, training program and aerobic conditioning can affect body composition, causal-comparative research must be reviewed scrupulously to see how these other factors were controlled.

5. Experimental Research

This research starts with a hypothesis (maybe several)—an educated guess about how things work. Scientists then conduct an experiment to confirm or reject the hypothesis.

For instance, much of my latest research has been exploring the physiological effects of high-intensity interval training (HIIT). This happens in three key steps:

  • First, I randomly select study groups from a population of healthy active men and women.
  • Second, I choose the exercise programs to be tested (different work-to-rest intervals in HIIT), making sure the study controls all relevant factors (e.g., no other exercise programs are running during the testing; there is no change in diet; subjects are not taking supplements; and the health and fitness levels of subjects are similar, etc.).
  • Third, I measure the effect of the different work-to-rest HIIT programs by analyzing specific variables such as kilocalorie expenditure, oxygen consumption, fat utilization, excess postexercise oxygen consumption, heart rate, blood pressure and postexercise lactate levels for each program.

Experimental research demands lots of time and resources, but it often produces the soundest evidence of cause-effect relationships. Experimental research should have a control group (subjects who do not get the treatment being studied). In my HIIT training research, for instance, steady-state exercise is the control trial, providing a benchmark against which to measure the test results.

Table 1: Definition of Common Research Terms

These are some of the common terms you may see when evaluating research:

Dependent vs. Independent Variables

Dependent variables are direct outcomes of independent variables (the former “depend” on the latter). Researchers investigate changes in a dependent variable that result from manipulating an independent variable.

In the HIIT study example, I could measure changes in kilocalorie expenditure (dependent variable) triggered by different work-to-rest interval protocols (independent variable).

Internal Validity

Internal validity describes how well a researcher designs the study. Establishing internal validity requires using very detailed methods (e.g., controlling certain variables), so that other researchers can replicate and validate the findings.

External Validity

External validity describes the degree to which the results of a study can be generalized; in other words, how well the results can be applied to groups outside the experimental setting.

Anatomy of a Primary Research Study Publication

Starts with a title and abstract.

Has an introduction where the authors summarize the research question(s) and hypothesis.

Includes detailed methods and procedures that state who and how many subjects participated, how and why they were selected, how they were tested, what equipment was used, and what kind of statistical design the study employed.

Has a “results” section with a straightforward recounting of the statistical outcomes.

Flows right into the discussion and conclusion sections, which explain, discuss and conclude the meaning of the study findings.

Is published in a peer-review journal.

A Fitness Instructor’s Checklist for Interpreting Research

Here is a 10-point checklist for interpreting research and gauging its credibility and scope:

  1. Is the study published in a peer-review journal?
  2. Who is the study population (e.g., men, women, age, fitness level, etc.)?
  3. How big is the sample size? Note: Many experimental studies are very timely, so researchers often complete a statistical power analysis to verify the authenticity of the study.
  4. Did the researchers control variables in the study methods?
  5. Was there a control group?
  6. What type of research is this:historical, descriptive, correlationalor experimental?
  7. Are the researchers overstatingthe result? Research results often support a hypothesis, but they rarely prove the hypothesis.
  8. Did an outside group with a vested interest in the research fund the study? Or did any of the research- ers’ have an affiliation that could suggest a conflict of interest? If so, it doesn’t necessarily meanthe research is biased, but it would be prudent to read more studies on the topic.
  9. Do the researchers seem to have an agenda? Some researchers are biased due to personal preferences, and you may observe this in the writing.
  10. Do the researchers acknowledge the study’s limitations (found in the discussion section)?

Source: Smith 2015.


Smith, J.A. 2015. Ten questions to ask about scientific studies. Accessed Oct. 25, 2015. http://reatergood.berkeley.edu/article/item/10_questions_to_ask_about_scientific_studies.

Len Kravitz, PhD

Len Kravitz, PhD is a professor and program coordinator of exercise science at the University of New Mexico where he recently received the Presidential Award of Distinction and the Outstanding Teacher of the Year award. In addition to being a 2016 inductee into the National Fitness Hall of Fame, Dr. Kravitz was awarded the Fitness Educator of the Year by the American Council on Exercise. Just recently, ACSM honored him with writing the 'Paper of the Year' for the ACSM Health and Fitness Journal.

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