FitBits
Exercise ETC's Monthly Research Review
February 15, 2008

Compiled by Chris Marino, MS, CSCS
Director of Education, Exercise ETC

One Step Closer to
Understanding Fatigue

Understanding and conquering muscle fatigue is one of the greatest challenges for physiologists in the 21st century. Preserving the strength of muscle contractions during prolonged effort has broad implications from improving outcomes in chronic disease management to increasing athletic performance.

In an exciting report, scientists from Columbia University claim that they have uncovered a new link in the battle to understand fatigue... Calcium. By assessing the cause of congestive heart failure (CHF) researchers hypothesized that calcium channels leak in response to an overload of flight-or-fight hormones. To test their hypothesis they formulated a new drug based on some of the properties in calcium-channel blockers. The drug was tested on mice.

The mice were first exercised to exhaustion and evaluated for calcium-channel leakage, which was confirmed. The mice were re-tested following administration of the new drug. Interestingly, the mice ran for up to 20% longer than previously.

To confirm this effect in human skeletal muscle, researchers at Appalachian State University biopsied the thigh muscles of cyclists after consecutive daily 3-hour bike rides. Columbia researchers evaluated the samples and again, confirmed their hypothesis. They also reported that calcium-channel leakage had stopped within a few days after the last bike ride.

The drug is scheduled to undergo human testing shortly. If it is successful it will represent one of the largest breakthrough treatments for chronic diseases that cause fatigue and will be another temptation for athletes who are motivated to win.

Gina Kolata (2008) Finding May Solve Riddle of Fatigue in Muscles. The New York Times. Feb 12.

Bellinger, A.M., et al (2008) Remodeling of ryanodine receptor complex causes "leaky" channels: A molecular mechanism for decreased exercise capacity Proceedings of the National Academy of Sciences. 105: 2198-2202.

Squats & Deadlifts vs
the Stability Ball:
Which Are Better for the Back?

Over the past decade, the Swiss Ball (SB) has become a popular tool for developing the “core” in fitness programs. But is it more effective than traditional squats and deadlifts for strengthening the back?

Researchers at Appalachian State University compared trunk muscle activation during SB exercises to that experienced during squats and deadlifts. Nine previously resistance-trained men were tested for 1 repetition maximum in the squat and deadlift. Then, three isometric SB exercises were evaluated: the quadruped hip extension, bridge-feet on the ball, and back extension. Muscle activation in longissumus and multifidus was assessed.

During the SB exercises, muscle activation in the back extensors was greatest in the back extension, followed by the bridge, and finally the quadruped. None of the SB exercises, however, recruited the back extensors better than the deadlift or squat when performed at moderately high intensities.

Because strength and hypertrophy are best achieved with muscle activation of greater than 60% of maximum, the researchers suggest that the SB exercises are deficient at building these characteristics. None achieved this minimum intensity.

Interestingly, the authors neglect to address previous findings that strength & hypertrophy, although desirable, have not been correlated with back health. Stuart McGill, renowned expert on the biomechanics of back pain and injury reports in his book Low Back Disorders that endurance, not strength, is necessary for a healthy back. According to McGill, some individuals who have back pain may require exercises that spare them from excessive spinal compression. Such exercises would exhibit less muscle activation, such as the SB exercises in this study. McGill recommends activities such as the quadruped birddog exercise because it allows the individual to begin at a much lower and safer intensity for building endurance in the spine.

Nuzzo, J.L., et al (2008) Trunk Muscle Activity During Stability Ball and Free Weight Exercises. Journal of Strength & Conditioning Research. 22(1): 95-102.

Lowest Sugars
May NOT Be Better For Diabetics

Type 2 Diabetes affects over 21 million Americans. The disease is characterized by the inability to self-regulate blood glucose and insulin, which can result in complications such as vascular damage, neuropathy, heart disease, and more. Health organizations such as the American Diabetes Association strive to promote exceptional blood glucose control amongst diabetics to prevent early disability and death due to the condition. Unfortunately, the current position on controlling blood sugar in diabetics may now require revision.

A federal study of over 10,000 diabetics was stopped suddenly last week when researchers recognized a trend toward increasing fatalities in the experimental group. The goal was to lower HbA1c levels to <6%, or "normal." HbA1c or Hemoglobin A1c is a protein used to measure blood glucose. The study divided diabetic participants into two groups. One was required to follow an extremely rigid plan requiring frequent blood glucose checks, medications and some used intensive insulin therapy.

The second group was provided greater flexibility and attempted to maintain HbA1c between 7.0% and 7.9%. Participants in this group checked glucose only a couple times a day and were prescribed less medication.

Surprising to researchers, there were fifty-four more deaths occurring in the group adhering to rigid blood glucose control. Although the cause is merely speculative, researchers believe that lowering glucose more slowly might reduce the risk experienced by participants in this trial.

Individuals with Type 2 Diabetes are being encouraged to speak with their physician to discuss possible changes to their treatment.

Gina Kolata (2008) Diabetes Study Partially Halted After Deaths. The New York Times. Feb 7.

Is It The Grapes Or The Alcohol?

The preventive benefits of drinking 1 to 2 glasses of red wine daily are acknowledged by some health authorities. However, questions remain as to whether equal benefits are obtainable from other alcoholic beverages. Supporters of red wine consumption would suggest that grape extracts or polyphenols are responsible for the health benefits. A recent study might have you believe otherwise.

Canadian researchers compared the effects of red wine on the vascular and nervous systems to those of ethanol. Thirteen participants consumed red wine, ethanol or water on three occasions. Hemodynamics, sympathetic nervous system activity and arterial diameter were assessed.

Blood pressure was unchanged. Heart rate increased by ~6 bpm after 2 servings of red wine. Cardiac output dropped slightly after 1 serving of either ethanol or wine and increased after 2 servings of wine. Muscle sympathetic nerve activity was increased with 2 servings but not 1 serving of either. Arterial dilation increased after 1 and 2 servings of either.

The results of this study suggest that red wine and ethanol are equally effective at improving vascular and nervous system function. Regardless of the potential health benefits, one must be conscious of the additional risk assumed by consuming caloric beverages. Consequential weight gain would eliminate any benefits obtained from drinking alcohol daily.

Spaak, J. et al (2008) Dose-related effects of red wine and alcohol on hemodynamics, sympathetic nerve activity, and arterial diameter. Am J Physiol Heart Circ Physiol 294: H605-H612.


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