Stepping High, Not Faster, for Better Aerobic Fitness
When step-class teachers pump up the speed of stepping along with the volume, it not only makes it harder to follow the routine, it puts people at risk of orthopedic injuries. The Aerobic and Fitness Assn. of America recommends a cadence of 118 to 128 beats per minute, not the 125 to 133 beats a minute that one survey found is often taught. But keeping step classes safe doesn’t sacrifice fitness, according to a recent study of 30 women at Southwest Texas State University in San Marcos.
Unlike previous research that looked at the body’s response to simply stepping up and down from a bench, this study monitored volunteer students as they moved their arms and stepped on and off 6- and 8-inch benches in a choreographed routine, just as they would in an aerobic dance step class. Their responses were also measured when they worked out at two different cadences, of 125 and 130 beats per minute.
The researchers found that the intensity of the workout was not affected by the cadence, but it did increase when the height of the step was increased a mere two inches. Heart rate, for instance, rose by 10 beats per minute on average. Taller and more fit people may need the higher bench to get the most from step exercise, report the researchers.
Journal of Strength and Conditioning Research 2002, 16 (2), 242-249
Intelligence, Length of Breast-Feeding Linked
Several studies have shown that breast-feeding is positively associated with intellectual development in young children, but now researchers have taken a look at what happens when breast-fed babies grow up.
Information on a very large group of children born in Denmark between 1959 and 1961, all of whom were breast-fed for different periods of time, gave researchers the unique opportunity to track the IQ scores of about 3,000 of them as young adults.
The researchers found a “robust” association between the length of time a baby was breast-fed and his or her intelligence as an adult. Babies who were switched to formula after less than a month didn’t score as high on IQ tests as those who nursed for two months. Those breast-fed less than one month had an average adult IQ of 99.4. Those nursed two to three months scored 101.7.
And the longer a child was breast-fed the smarter he or she was--that is, up to a point, which seemed to be about nine months. Those who nursed for four to six months had an average adult IQ of 102.3; those who nursed for six to nine months had an average IQ of 106. After nine months, the average IQ was 104.
Because of the large numbers of people in the study, the researchers were able to statistically eliminate factors that might have an impact on IQ, such as the mother’s age, education and social status.
Among several theories to explain the link to intelligence is that breastfeeding may be an indication of how much time a mother spends interacting with a child after the first year.
Another explanation is that there are substances in breast milk, like the fatty acid DHA, that were not in infant formula or cow’s milk in the early 1960s. DHA (docosahexanenoic acid) is believed to have a role in transmitting nerve signals in the brain. Today’s formulas contain a precursor to DHA.
Journal of the American Medical Assn., Vol. 287 (18): 2365-2371
Fibromyalgia May Be Disturbed Reaction to Stress and Pain
More is known about what fibromyalgia syndrome isn’t than what it is. It’s not arthritis, because the joints don’t hurt--the muscles do. It’s not chronic fatigue syndrome, even though that, too, is a condition that causes generalized pain.
There is growing evidence that fibromyalgia is a disturbance in the body’s reaction to stress and pain that involves a complex interplay of abnormal hormonal responses. Oregon Health & Science University researchers in Portland recently reported that women with fibromyalgia have a defect in growth hormone secretion and suggest that a drug long used to treat myasthenia gravis may correct it.
In the study, 20 women with fibromyalgia and 10 healthy women walked quickly on a treadmill until they were exhausted. Growth-hormone levels went up in the healthy women but not in those with fibromyalgia. However, when the women were given the stress test again after taking Mestinon, a drug that inhibits the hormone somatostatin, those with fibromyalgia had an increase in the growth hormone similar to that of the healthy women. The women could have abnormally high levels of somatostatin, which inhibits their ability to secrete the needed growth hormone.
“It may be that in the past these women had so much stress or trauma that they overstressed their stress response and their reaction has diminished,” says Robert Bennett, professor of medicine at OHSU, who conducted the study.
Arthritis & Rheumatism Vol 46 (5): 1344-1350
Specialists Heat Up a Safe Alternative to Back Surgery
When all else fails to remedy chronic disc-related low back pain, some people turn to surgery as a last resort. Five years ago, two back specialists who favor nonsurgical treatment for back pain devised a therapy called IDET (intradiscal electrothermal treatment) that they believed offered a safe alternative. Two studies confirmed the short-term success of the therapy for people with very specific kinds of disc problems, and this month the third study--a two-year follow-up of 58 people--has been published.
The researchers who developed the therapy found that two-thirds of those with disc problems improved 50% and maintained the improvement for two years. When the therapy was effective, the patients’ pain continued to diminish over the years, and their functional ability improved.Intradiscal electrothermal treatment involves the insertion, using a needle, of a tiny tube into the outer wall of the disc. At the end of the tube is a heating element that reaches about 170 degrees. The heat toughens and seals the disc and destroys abnormal nerve endings. A local anesthetic is used for the procedure.
“People who were too uncomfortable to do rehabilitation exercises can do them after IDET, and that may be responsible for the improvement,” says Jeffrey A. Saal, associate clinical professor in the department of functional restoration at Stanford University Medical Center. “IDET buys people some time as well. If we can stop the degeneration for a few years, it might stop itself.”
Saal says he and brother Joel Saal have performed the treatment on about 2,000 people and that about 40,000 people have had the procedure worldwide. The therapy was approved by the FDA in 1998.
An editorial commenting on the study points out that an important next step is to compare the therapy to two other treatments, surgery and steroid injections.
SPINE Vol 27 (9):
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Dianne Partie Lange can be reached at DianneLange@ cs.com.
