ACSM'S Health & Fitness Journal:
doi: 10.1249/FIT.0b013e318201ceb6
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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. Men's Deaf Olympic Ice Hockey Team; 2) the health and fitness industry, by contributing to fitness magazines, consulting, presenting at health and fitness meetings such as ACSM's Health & Fitness Summit & Exposition; and 3) as an occupational physiologist in the areas of back injury prevention, ergonomics, workstation stretching, and prework warm-up.

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PUBLIC SCHOOL BETTER FOR FITNESS THAN HOME SCHOOL

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The purpose of this study was to compare physical activity levels and dietary intake of public school versus home school children. The effects of parental and home influences also were examined. Thirty-six matched pairs of public school and home school children aged 7 to 11 years participated in this study. Each participant wore an activity monitor and recorded his or her dietary intake for seven consecutive days. The students were measured on physical activity (New Lifestyles-1000 medical-grade activity monitors) and nutrition (dietary intake for seven consecutive days).

The results of this study showed that public school students had significantly more total steps (86,789 ± 19,976 vs. 76,410 ± 24,018) and more weekday steps (13,406 ± 3,258 vs. 10,790 ± 3,572) than did the home school students. Weekend steps were not significantly different between the groups. Public school students had significantly greater total time spent in moderate to vigorous physical activity (MVPA) and weekday MVPA time compared with the home school students (308.72 ± 102.26 minutes vs. 218.67 ± 96.88 minutes and 47.29 ± 14.80 minutes vs. 31.40 ± 14.08 minutes). Weekend MVPA time was not significantly different between the groups. There were no significant differences in total energy intake between any of the children, child/parent, or parent group comparisons.

These results indicate that public school students are more physically active than home school students. This may be of interest to personal trainers looking to market themselves to home school parents as a way of introducing physical education into a home school curriculum (2).

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SPORTS BRA DESIGN

In this study, the researchers investigated whether a sports bra designed to elevate and compress the breasts could decrease exercise and bra discomfort experienced by women with large breasts compared with a standard sports bra. Twenty women (mean age, 31 years; range, 19 to 44 years) who were professionally sized to wear a C+ bra cup were recruited. All of the subjects were fitted by one experienced bra fit assessor using a professional bra fitting criteria. Subjects were premenopausal, not breast-feeding, and not pregnant. Subjects ran on a treadmill for 3 minutes in three randomly ordered bra conditions: 1) a commercially available sports bra (New Legend sports bra, Berlei; Pacific Brands, Victoria, Australia), 2) an experimental bra that provided both compression and elevation, and 3) a placebo bra. The experimental bra provided breast elevation by using 1-cm thick foam pads placed in the inferior or lateral aspect of the bra cup. The size and the shape of the pads changed in accordance with breast mass and functioned to increase the stiffness of the inferior lateral aspect of the cup.

The subjects were evaluated on the following variables: vertical breast displacement and velocity, bra fit comfort, exercise-induced breast discomfort, and bra preference. The results indicate that exercise-induced breast discomfort and bra discomfort were significantly less for the experimental bra compared with the sports bra and placebo bra. This reduction in discomfort was achieved through greater breast elevation and compression, with no differences found in vertical breast displacement or vertical breast velocity. The researchers suggest that the results of this study can help in the design of sports bras so that women with large breasts can exercise in more comfort, which will encourage them to be physically active (3).

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OPEN VERSUS CLOSED KINETIC CHAIN LEG EXERCISES

This study investigated the effect of open and closed kinetic chain exercises on the activity of the vastus medialis oblique (VMO) and vastus lateralis (VL) as they relate to patellofemoral pain syndrome rehabilitation and prevention. Twenty-two subjects (11 men and 11 women; mean age, 25.6 years) were tested with surface electromyography to calculate VMO:VL ratio during three different quadriceps strengthening exercises: 1) double leg squat with isometric hip adduction (squatting to 45 degrees leaning against a wall while compressing a folded pillow between the knees), 2) single leg knee extension exercise with no weight while seated on a table, and 3) forward lunge to 45 degrees with no weight.

The results of the testing showed that the double leg squat had a significantly greater activation of the VMO compared with the knee extension and lunge. The knee extension and double leg squat had significantly greater activation of the VL compared with the lunge. The double leg squat and lunge exercises showed significantly greater VMO:VL ratio than the knee extension, but there was no difference between double leg squat and lunge. The authors suggest that the lunge would be useful in the initial stages of rehabilitation, with the double leg squat being used in the later stages of rehabilitation.

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CIRCUIT TRAINING BETTER FOR FITNESS

In this study from Italy, the researchers investigated the effects of three different exercise protocols on body composition, strength, and blood lactate for 12 weeks. The exercise protocols included: 1) control; 2) endurance, running at 65% of heart rate reserve, 30 to 40 minutes day−1, 3 days week−1; 3) circuit low intensity, 8 minutes running at 65% of heart rate reserve followed by three sets of 15 repetitions of five weight training exercises for the upper body, trunk, and legs, repeating protocol for 50 minutes total exercise time; and 4) circuit high intensity, 3 minutes of running at 65% of heart rate reserve then 1 minute of running at 75% of heart rate reserve repeated twice, then three sets of 20 repetitions of five weight training exercises for the upper body, trunk, and legs, repeating protocol for 50 minutes total exercise time.

There were 40 subjects (mean age, 56 years) with 10 subjects in each group. The authors referred to the subjects as being overweight and middle-aged with large waistlines. The subjects were measured on the following variables before and after training: body weight, percent body fat (skinfolds), waistline measurement, blood lactate during a cycle test, six repetitions of maximum horizontal leg press, and underhand cable pulldowns.

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The results of the study showed that the circuit-high-intensity group had the greatest reduction in body weight, percent fat mass, waistline, and blood lactate response, and greater improvements in six repetitions of maximum horizontal leg press, and underhand cable pulldowns. These results seem to follow the trend of higher intensity exercise being popular and beneficial to both trained and untrained clients (4).

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References

1. Irish SE, Millward AJ, Wride J, Haas BM, Shum GLK. The effect of closed-kinetic chain exercises and open-kinetic chain exercise on the muscle activity of vastus medialis oblique and vastus lateralis. J Strength Cond Res. 2010;24(5):1256-62.

2. Long DE, Gaetke LM, Perry SD, Abel MG, Clasey JL. The assessment of physical activity and nutrition in home schooled versus public schooled children. Pediatr Exerc Sci. 2010;22:44-59.

3. McGhee DE, Steele JR. Breast elevation and compression decrease exercise-induced breast discomfort. Med Sci Sports Exerc. 2010;42(7):1333-8.

4. Paoli A, Paccelli F, Bargossi AM, Marcolin G, Guzzinati S, Neri M, Bianco A, Palma A. Effects of three distinct protocols of fitness training on body composition, strength and blood lactate. J Sports Med Phys Fitness. 2010;50:43-51.

© 2011 American College of Sports Medicine

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