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PE 850: Primary vs. Secondary

Research Methods in Exercise Science

Primary Sources

Primary Source materials document original work.

The following are examples of the types of information contained in scientific primary sources:

  • Reports of scientific discoveries
  • Results of experiments
  • Results of clinical trials

Primary Sources materials tend to be published in scholarly scientific journals, like the Journal of Applied Physiology (also available in print at the library).

These types of articles tend to describe the specific instance of a test or series of tests, often on human and non-human animals.


This study sought to determine whether participants in taijiquan classes would report increases in mindfulness greater than that of a comparison group, and whether changes in mindfulness were associated with improvements in mood, perceived stress, self-regulatory self-efficacy, and sleep quality. The study design was quasi-experimental with repeated measures. The study was set in a midsized public university. Students aged 18-48 years old enrolled in 15-week courses of either taijiquan (n=76) or special recreation (control group, n=132). Chen-style taijiquan classes were offered 2 times per week for 50 minutes each time. Self-report of mindfulness (Five Facet Mindfulness Questionnaire), mood (Four Dimensional Mood Scale), perceived stress (Perceived Stress Scale), self-regulatory self-efficacy (Self-regulatory Self-Efficacy Scale), and sleep quality (Pittsburgh Sleep Quality Index). Increases in total mindfulness scores occurred only in the taijiquan group, not in the control group. All well-being variables showed a pattern of improvement in the taijiquan group, with either stability or decline over time in the control group. Increases in mindfulness were significantly correlated with improvements on all well-being measures and with sleep quality. Relative to a recreation control group, taijiquan classes for college students are associated with increased mindfulness and improved sleep quality, mood, and perceived stress, but not self-regulatory self-efficacy. Randomized control design studies are needed to substantiate the causal role of taijiquan exercise in the development of mindfulness and associated improvements in well-being.


Caldwell, Karen, et al. "Changes in Mindfulness, Well-being, and Sleep Quality in College Students through Taijiquan Courses: A Cohort Control Study." Journal of alternative and complementary medicine (New York, N.Y.) 17.10 (2011): 931-8. AIDS and Cancer Research Abstracts; Biological Sciences. Web. 24 Jan. 2013.

Secondary Sources

Secondary source materials contain commentary on, or discussion about, primary sources.

The following are examples of the types of information contained in scientific secondary sources:

  • Analysis and interpretation of research results
  • Analysis and interpretation of scientific discoveries

An example of a journal which contains secondary source materials is the Journal of Physical Education, Dance and Recreation (also available in print form through the library).

These types of articles often generalize and interpret the findings from primary source articles as they may apply to a larger, generally described population.


The National Sleep Foundation recommends that adults get seven to nine hours of sleep per day. However, nearly 25 percent of people in the United States are not getting enough sleep, and insufficient sleep has been shown to contribute to chronic diseases such as diabetes, cardiovascular disease, and obesity. Exercise is already known to improve the quality of sleep, and a team of researchers from Appalachian State University wanted to see whether the timing of exercise makes a difference. They found that working out in the morning can maximize benefits. The researchers studied the effects of exercise timing on the sleep patterns of six male and three female subjects. Each participant spent 30 minutes on a treadmill on three separate occasions at predetermined times: 7 a.m., 1 p.m., and 7 p.m. At night, participants wore a sleep-monitoring headband to measure their quality of sleep. The results showed that exercise at 7 a.m. produced the greatest improvements in sleep quality compared to the other two workout times. When subjects exercised in the morning, they spent 85 percent more time in light sleep, and 75 percent more time in deep sleep, and they also had a 20 percent increase in sleep cycle frequency. This study, which was presented at the 58th Annual Meeting of the American College of Sports Medicine, shows that exercisers could gain even greater benefits from physical activity if they work out in the morning.

"Morning exercise improves sleep at night." JOPERD--The Journal of Physical Education, Recreation & Dance 82.9 (2011): 3+. Academic OneFile. Web. 24 Jan. 2013.