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Tuesday, July 27, 2010

Grouping Exercises Saves Times While Providing Equal Benefits

The benefits of the multiple mini-circuit method of performing resistance exercise have been described previously in this blog. It involves doing a set of each of 2-5 exercises in a grouping, then repeating the cycle 3 or more times before going on to the next exercise grouping. The advantages include:
  • A lot of exercise can be done in a given time period.
  • Each muscle group has adequate recovery time.
  • Heart rate remains high, affording some aerobic conditioning.
  • The body becomes accustomed to intermittent high-intensity exertions, relevant to many sports.
A recent article by Robbins at al. in the Journal of Strength and Conditioning Research (vol. 24, no. 7, pp. 1782-1789, 2010) provides research support for this exercise method.

Study Method
18 physically trained men performed the following two exercises:
  • Bench Pull - lie face down on a bench and perform a rowing movement to raise a barbell lying under the bench
  • Bench Throw - Perform an explosive bench press movement throwing the bar upwards, using a specially designed machine that catches the barbell so it does not fall back down on the lifter
On one day they first did 3 sets of bench pulls followed by 3 sets of bench throws for a total of about 20 minutes of exercise. On another day, they alternated sets of bench pull and bench press, accomplishing 3 sets of each, for a total of about 10 minutes of exercise.

Even though the alternating sets took half as much time as performing 3 sets of one exercise followed by 3 sets of the other exercise, the subjects were able to handle as much weight for as many repetitions of each exercise in both types of routines. In addition, measures such as bench press throw height, peak power, peak velocity, and muscle electrical activity were the same for both routines.

Bottom Line
While saving a lot of time, performing exercises in groupings worked the muscles as well as doing all sets of each exercise before going on to the next exercise. Thus, the grouping method enables a full workout to be performed in much less time or allows more work to be done in a given amount of time.

NOTE: Our descriptions of exercise programs are for educational purposes and do not constitute recommendations. Anyone embarking on a physical exercise program must be in good enough health to safely do so. Fitness to exercise can best be determined by a physician's clearance.

Monday, July 12, 2010

Spending More Time Outdoors Benefits Health

The increased availability of in-home entertainment systems such as TV's, computers, sound systems, and video games along with perceived discomforts and even dangers of spending time outdoors has prompted Americans to spend more time indoors. The U.S. government has estimated that the average American spends 90% of his/her time indoors. But that may be deleterious to our health. A recent article in the Harvard Health Letter (July 2010) details the following benefits of spending more time outdoors:
  1. Your Vitamin D levels will go up - Sunlight hitting your skin begins the process of the body's manufacture of biologically active Vitamin D. Fifteen minutes of sun exposure on bare skin can result in the manufacture of far more Vitamin D than you can get in any supplement pill. An increasing number of studies have shown the association of high Vitamin D levels with various health benefits including protection against osteoporosis, cancer, depression, heart attack and stroke. The northern latitudes get less direct sun exposure than southern latitudes and some forms of cancer are more common in the northern vs. the southern states. As we age, our ability to manufacture Vitamin D from sun exposure drops considerably. People with darker skin also generate less Vitamin D from a given amount of sun exposure. While there is an ongoing controversy about whether sun exposure without sunscreen causes more benefit from Vitamin D production than danger from skin cancer, the Harvard Health Letter recommends some limited daily unprotected sun exposure along with protection against the sun when outdoors for long periods or during the middle of the day in summer.
  2. You will get more exercise - Physical exercise has been shown to have a very wide range of health benefits. People tend to be more sedentary when spending time indoors. When outdoors, people tend to spend more time in physically active pastimes such as walking, biking, gardening, and playing sports. Children are more active outdoors as well. A study using GPS units found that children were more than twice as active when outdoors than indoors.
  3. Your mood will improve - The kind of light you get outdoors tends to elevate mood, and light-therapy has been used to treat people who tend to become depressed during the long winter months. The increased physical activity associated with spending more time outdoors also has a mood-enhancing effect. Exercising in a natural setting has even more positive effect on mood and self-esteem, as a British study has shown.
  4. Your focus may improve - A study has shown that children with Attention Deficit Hyperactivity Disorder do better on a test of concentration after walking through a park than when walking through residential or downtown neighborhoods.
  5. You may heal faster - A University of Pittsburg study showed that surgical patients experienced less pain and stress and needed less medication when exposed to natural light. Even a window view of a natural setting seemed to promote recovery better than a view of buildings.
It's clear that the evidence in favor of spending more time outdoors is quite solid. So find an outdoor activity you enjoy and get out there.

Friday, July 2, 2010

Can Mental Imagery Improve Physical Strength?

Mental imagery involves envisioning oneself performing a physical activity without actually doing it. It is currently used by many high-level athletes to enhance their physical performance. While the method is well-accepted for maintaining focus and consistency of technique, its use has recently been examined for improving strength as well.

Study Method
In a study by Lebon, Collet and Guillot in the Journal of Strength and Conditioning Research (vol. 26, no. 6, pp. 1680-1687, 2010) male college athletes who had not been weight training were put on a program of bench-press and leg-press training 3 times per week for 4 weeks. The only difference between the training groups was that the imagery group visualized doing each exercise during the between-set rest periods while the control group performed another thought task.

Both groups improved in strength and the number of repetitions they could perform with 80% of the maximal weight they could lift during pre-training tests. However, the imagery group improved 26% in leg press strength vs. 21% in the control group. Repetitions with 80% of pre-training max increased 92% in the imagery group vs. 79% in the control group. Both between-group differences were statistically significant. There were no differences between training groups as to changes in bench-press performance and neither group showed any significant increases in muscle-size.

Bottom Line
It is known that the strength gains resulting from the first few weeks of training are largely due to neuromuscular adaptations rather than muscle-size increases. Mental imagery may enhance the neuromuscular component of strength change and thus the most applicable to novice lifters. It is not clear why the method was effective for the leg press but not the bench press.