ACSM'S Health & Fitness Journal:
doi: 10.1249/FIT.0000000000000035
COLUMNS: Research Bites

Research Bites

Yoke, Mary M.A., M.M.

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Mary Yoke, M.A., M.M., is a full-time faculty member in the Kinesiology Department of the Indiana University School of Public Health. Previously, she was an adjunct professor at Adelphi University for 22 years, where she authored or coauthored numerous group exercise research studies. She is the author of 4 texts on fitness; she has presented in 11 countries and throughout the United States on a wide variety of health/fitness topics and has obtained 23 certifications. Her research interests include behavior change, positive psychology, and group fitness and personal training efficacy.

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It seems that one of the most important tasks for fitness professionals is to help get people moving. We need to start making a dent in the obesity epidemic, and one way to do this is to motivate the general public to sit less and move more. There is mounting evidence that constant sitting is harmful to health, causing metabolic alterations that can increase the risk of morbidity and mortality (2,6). Furthermore, decreased energy expenditure is an outcome of inactivity, which then leads to the potential for further weight gain. Levine and colleagues (8) state that “in order to reverse obesity, we need to develop individual strategies to promote standing and ambulating time by 2.5 hours per day.” Proper et al. (9) write that “exchanging just 30 minutes of sitting time for more active leisure would have a profound impact on population levels of overweight and obesity.” So what are some strategies that can be used to get people more active?

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Andersen et al. (1), in a 2013 randomized controlled trial, explored the effect of regular encouraging emails on office workers’ cardiovascular health and physical activity patterns. A total of 160 inactive employees participated in the study; these workers sat 90% of their work time before the intervention. Participants were randomly assigned to either a control group or an intervention group that received supportive emails once per week for 10 weeks. The email group was encouraged to form small groups with coworkers and to walk the stairs for 10 minutes every day. How well did this work?

Results showed that 83% of the participants in the email group performed an average of 3.3 stair-climbing sessions per week, and this significantly improved their cardiovascular fitness over the control group by 1.5 mL/kg per minute (there was a 6% improvement in the email group vs. a 2% improvement in the control group). Also, a participation rate of 83% reflects a relatively high adherence. A majority of the participants opted to exercise with coworkers, and 72% reported sweating while stair walking, but not to the extent that it was bothersome. Nearly 23% of the exercisers reported that they were bothered by sweating; the study’s authors suggest that an alternative form of exercise may be preferable for these individuals. In addition, 26% of the email group participants said they would definitely continue stair walking in the future, whereas 53% reported that they might continue. These positive results should be considered in the context that this was a minimal, low-cost, easy-to-administer intervention. The employer did not have to invest in a fitness facility, equipment, or regular instructor. Employees most likely viewed the activity as simple, sociable, readily available, functional, and familiar. Another potentially important factor in the success of the program was the perceived support of the employer in promoting the 10 minutes of daily activity, possibly altering the social climate and accepted norm in the workplace.

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The take-home message is that regular (once per week) email-based encouragements to form groups and do daily 10-minute stair-walks are a feasible way of getting sedentary employees to move and thereby improve their cardiovascular health and well-being!

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Knee osteoarthritis is an increasingly common cause of disability and reduced ability to work, particularly as one gets older. Numerous studies have validated the idea that appropriate cardiovascular and muscle-strengthening exercises are very beneficial in managing arthritic pain and maintaining joint function. Unfortunately, people with arthritis tend to be inactive and do not receive the benefits of movement and therefore have an increased risk of poor health outcomes. A study by Lee et al. (7) identified modifiable risk factors for inactivity in adults with knee osteoarthritis. These risk factors were obesity/overweight, inadequate dietary fiber intake, severe knee dysfunction, and knee pain.

A total of 1,089 participants (average age, 66 years) with knee osteoarthritis were assessed using an Actigraph accelerometer for four or more days. Of these, 49% were completely inactive, which meant that they did not perform any 10-minute bouts of moderate to vigorous activity during the monitoring period. In all, only 1 out of 10 adults fully adhered to ACSM- and government-recommended physical activity levels. A significant relationship was found between obesity/overweight and inactivity, as well as between a low-fiber diet and inactivity. Interestingly, a diet lacking in adequate fiber intake also has been shown to be related to inactivity in other studies (e.g., Gillman et al. (3)). Poor dietary fiber intake may be representative of an unhealthy diet and unhealthy lifestyle overall. Not surprisingly, knee pain and dysfunction also were significantly related to decreased movement in study participants, although analysis found that a greater proportion of inactivity was explained by obesity/overweight and unhealthy eating behaviors than by specific knee issues.

For fitness professionals, the bottom line is that increasing efforts must be made to reach those with knee osteoarthritis, encouraging them to become more active, reduce body weight, and eat a higher-quality diet. Water exercise, walking, and appropriate strength exercises have been shown to be particularly effective and well tolerated in those with knee osteoarthritis.

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Two recent research articles shed more light on Zumba, the overwhelmingly popular, Latin-inspired, global group exercise dance phenomenon. The first article, by Hausken and Dyrstad (4), compared intensity in Zumba with other modalities — spinning and running (two different running protocols were measured). To assess intensity, heart rate monitors, accelerometers, and rating of perceived exertion were used in all trials. The 35 college-aged participants were all asked about their levels of experience with Zumba, spinning, and the two running protocols and were then classed as less experienced or more experienced. More experienced participants were defined as having performed Zumba, spinning, and running more than eight times each. A notable finding is the significant difference in energy expenditure and intensity between experienced and inexperienced participants in Zumba. For example, beginner participants averaged 70% of HRmax during the 60-minute Zumba class, approximately 10% to 15% less than those with more experience. Accelerometer counts also were significantly different between the two groups. The main reason for the difference, according to the authors, is that less experienced participants use a smaller range of motion and have not yet acquired the skill to maximize the dance-oriented moves. No such difference was found between beginners and more experienced participants in spinning exercise or in running. In addition, Zumba was perceived to be 19% to 23% less exhaustive than either spinning or the 2 running protocols. This also may be because of the skill required to fully invest in Zumba movements, with the result being a lowered intensity. Spinning and running, on the other hand, can be performed at higher intensities even without a high degree of skill. The authors state that, if maximal calorie burning is desired, beginner participants should choose a simpler modality such as spinning or running.

A second article, by Inouye et al. (5) in 2013, examined injury rates among 49 Zumba participants in 5 Zumba classes taught by different instructors. The average age of the participants was 44 years, and they had been taking approximately 3 Zumba classes per week for an average of 12 months. Approximately 29% of the participants (14 of 49) reported 21 prior Zumba-related injuries. The most common injuries were to the knee (42%), followed by the ankle/foot, shoulder, elbow, calf, lower back, neck, thigh, and muscle pain. Significantly, those who participated in Zumba classes four or more times per week had the highest rates of injury. The authors write that Zumba should be supported by the fitness and health care industries because it has helped motivate many participants to move, and there are nearly 14 million participants in 185 countries worldwide. However, the fact that one in four Zumba participants may experience an injury is worrisome. Suggestions for reducing injuries include better training for Zumba instructors (the 1-day class required to obtain a Zumba license spends little-to-no time on injury prevention strategies), fitness certification for Zumba instructors, longer warm-up periods, the use of proper footwear (not running shoes), cross-training, picking an appropriate class (e.g., Zumba Gold for older adults), and reducing the frequency of Zumba classes to three or less per week. Zumba is advertised as a dance party — easy, fun, and effective — and can be a workout that feels like a celebration. Hopefully, this feel-good system of upbeat movement to music will continue to flourish but, at the same time, address the need for injury prevention.

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1. Andersen LL, Sundstrup E, Boysen M, Jakobsen MD, Mortensen OS, Persson R. Cardiovascular health effects of internet-based encouragements to do daily workplace stair-walks: a randomized controlled trial. J Med Internet Res. 2013; 15 (6): e127.

2. Dunstan DW, Barr ELM, Healy GN, Salmon J, Shaw JE, Balkau B, Magliano DJ, Cameron AJ, Zimmet PZ. Television viewing time and mortality: the Australian diabetes, obesity and lifestyle study. Circulation. 2010; 121: 384–91.

3. Gillman MW, Pinto BM, Tennstedt S, Glanz K, Marcus B, Friedman RH. Relationships of physical activity with dietary behaviors among adults. Prev Med. 2010; 32: 295–301.

4. Hausken K, Dyrstad SM. Heart rate, accelerometer measurements, experience and rating of perceived exertion in Zumba, interval running, spinning, and pyramid running. J Exerc Physiol. 2013; 16 (6): 39–50.

5. Inouye J, Nichols A, Maskarinec G, Tseng C-W. A survey of musculoskeletal injuries associated with Zumba. Hawaii J Med Public Health. 2013; 72 (12): 433–36.

6. Katzmarzyk PT, Church TS, Craig CL, Bouchard C. Sitting time and mortality from all causes, cardiovascular disease, and cancer. Med Sci Sports Exerc. 2009; 41 (5): 998–1005.

7. Lee J, Song J, Hootman J, Semanik PA, Chang RW, Sharma L, van Horn L, Bathon JM, Eaton CB, Hochberg MC, Jackson R, Kwoh CK, Mysiw WJ, Nevitt M, Dunlop DD. Obesity and other modifiable factors for physical inactivity measured by accelerometer in adults with knee osteoarthritis. Arthritis Care Res (Hoboken). 2013; 65 (1): 53–61.

8. Levine JA, Vander Weg MW, Hill JO, Klesges RC. Non-exercise activity thermogenesis: the crouching tiger hidden dragon of societal weight gain. Arterioscler Thromb Vasc Biol. 2006; 26: 729–36.

9. Proper KI, Cerin E, Brown WJ, Owen N. Sitting time and socio-economic differences in overweight and obesity. Int J Obes (Lond). 2007; 31: 169–76.

© 2014 American College of Sports Medicine.


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