ACSM'S Health & Fitness Journal:
doi: 10.1249/01.FIT.0000257710.99739.6f

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Bracko, Michael R. Ed.D., FACSM

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Michael R. Bracko, Ed.D., FACSM, is an exercise physiologist and director of the Institute for Hockey Research and the Occupational Performance Institute in Calgary, Canada. He is an associate editor for ACSM's Health & Fitness Journal® and works in three areas: 1) sports physiology, where he conducts research on the performance characteristics of female ice hockey players, teaches high performance skating, and serves as physiologist for the University of Alberta Women's Hockey Team and the U.S. Deaf Olympic Men's Ice Hockey Team; 2) the health and fitness industry, by contributing to SELF Magazine's online Forum and by presenting at health and fitness meetings such as the ACSM's Health & Fitness Summit & Exhibition; and 3) as an occupational physiologist, in the areas of injury prevention, ergonomics, workstation stretching, and prework warm-up.

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Vigorous Activity Improves Grades

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The purpose of this study was to investigate the effect of physical education class enrollment and physical activity on grades in math, science, English, and world studies on 214 sixth grade children. Subjects participated in a physical education class during the first or second semester. Physical activity outside the physical education class was estimated using the 3-day physical activity recall, asking participants about activities for three consecutive days.

Physical activity was scored according to "no activity," "some activity," or "activity that meets Healthy People 2010 guidelines." Healthy People 2010 guidelines are as follows: moderate activity for 30 minutes/day to 5 days/week and vigorous activity for 20 minutes/day for 3 days/week. Academic achievement was based on grades in the above-mentioned classes. An observer who recorded time spent in an activity and student and teacher behavior during the class assessed activity levels in physical education classes.

The results of the study show that there was no effect on grades according to first or second semester physical education class enrollment, physical education enrollment, or moderate physical activity. However, students who engaged in vigorous physical activity at a level that met or exceeded the Healthy People 2010 guidelines achieved higher grades compared with students who did not perform vigorous activity.

The authors conclude that grades were not affected specifically by participating in physical education class, but regular, vigorous activity did improve grades (1).

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Diagnosis and Prognosis of Low Back Pain

In this review article, the authors reported findings on the evaluations and prognosis of low back pain. Low back pain is very common, costly, and debilitating; however, the cause is usually unknown. Some hypotheses about the cause of low back pain include weak trunk extensors, psychological stress, hamstring inflexibility, poor trunk muscle control, and poor posture.

The common methods of evaluation (X-rays and magnetic resonance imagings [MRIs]) usually cannot identify a cause for the pain. The literature indicates that X-rays and MRIs are "unrewarding" for approximately 85% of patients with low back pain.

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Prognosis for chronic low back pain rarely has been studied and is unknown. Acute low back pain has been investigated, and it has an excellent prognosis because up to 90% of cases recover within 6 weeks. The literature indicates that people will return to work within 4 weeks despite continued pain and disability (2).

The authors conclude that low back pain has been an enigma for decades and that it is not possible to identify the cause of low back pain in most cases. A review of diagnostic tools such as X-rays and MRI show that they are not useful in the diagnosis of low back pain. It seems to be most prudent to reevaluate patients who do not respond rapidly to treatment (2).

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Does Oxygenated Water Improve Exercise Performance?

This study, from Vienna, Austria, investigated the effect of oxygenated water on cycle tests and lactate levels. Twenty men, divided into two groups, performed bike ergometer tests every 2 weeks for 6 weeks (four tests). All subjects performed four-bike tests. Between tests 1 and 2, group 1 drank 1.5 L of oxygenated water everyday. Group 2 drank control water. After week 2/test 2, there was a "wash-out" period where subjects did not drink experimental or control water. After week 4, there was another test followed by group 1 drinking control water and group 2 drinking oxygenated water. The final test was performed in week 6.

The results indicate that V˙O2max did not differ between oxygenated water and control water groups. Measures of lactate were significantly different in favor of the oxygenated water group, but only after the first test. Tests 2, 3, and 4 did not show significant differences. The authors conclude that consuming oxygenated water does not enhance aerobic performance or lactate kinetics (3).

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Relationship Between Physical Activity and Sick Leave

The purpose of this study was to investigate the dose-response relationship between moderate and vigorous physical activity and sick leave in a working population in the Netherlands. Data were used from three large Dutch databases. Physical activity was measured in four ways: (1) frequency of moderate-intensity activity for 30 minutes a day, (2) frequency of vigorous activity for 20 minutes per session (both of these were derived from the Centers for Disease Control/American College of Sports Medicine recommendations), (3) total amount of moderate-intensity activity in minutes per day, and (4) total amount of vigorous activity in minutes per day. Sick leave as assessed by asking how many days were missed due to illness in the last 2 months.

The results of the study indicate that there were no differences in sick leave duration between those who met the moderate-intensity activity recommendations and those who did not. From two of the databases, sick leave in workers meeting the vigorous intensity activity recommendations was significantly lower than those who were not vigorously active. There was no dose-response relationship between frequency and duration of moderate-intensity physical activity and sick leave duration.

Based on two other databases, a dose-response relationship was found between frequency of vigorous intensity activity (up to 3 times/week) and sick leave duration. Workers who did no vigorous activity had the most sick days, whereas those who were vigorously active 3 days/week had the fewest sick days. However, those who reported a frequency greater than 3 days/week of vigorous activity experienced more sick days (perhaps related to sports injuries).

The authors conclude that there are important health and economical aspects of worksite-based exercise programs. However, careful consideration should be given to the intensity of activity and the number of days per week of activity (4).

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1. Coe, D. P., J.M. Pivarnik, C.J Womack, et al. Effect of physical education and activity levels on academic achievement in children. Medicine & Science in Sports & Exercise® 38(8):1515-1519, 2006.

2. Refshauge, K.M., and C.G. Maher. Low back pain investigation and prognosis: a review. British Journal of Sports Medicine 40(6):494-498, 2006.

3. Leibetseder, V., G. Strauss-Blasche, W. Marktl, and C. Ekmekcioglu. Does oxygenated water support aerobic performance and lactate kinetics? International Journal of Sports Medicine 27(3):232-235, 2006.

4. Proper, K. I., S.G. van den Heuvel, E.M. De Vroome, V.H. Hildebrandt, and A.J. Van der Beek. Dose-response relation between physical activity and sick leave. British Journal of Sports Medicine 40(2):173-178, 2006.

© 2007 American College of Sports Medicine


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