Monday, April 19, 2010

FitBits - Review of Exercise Related Research - April, 2010

Some good fitness studies that might make us think. I want to mention my personal support for the Bulgarian Squat, a great alternative to standard squats and a great exercise for rehabbing the knee following an injury.

Exercise ETC's
Review of Exercise Related Research
April 15, 2010

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

Can Running Lead to Heart Disease?

It's widely accepted that physical exercise offers vast benefits from improved cardiovascular health and disease prevention to improved athletic performance. Every once in a while, however, researchers are stumped by anomalies that appear to challenge that prevailing belief. Many of these anomalies occur among elite athletic populations who many assume to possess the lowest risk of disease and disability.

For instance, in a recent presentation to the American College of Cardiology it was reported that long-distance runners may have a higher risk for coronary plaque build-up. Calcified plaque in the coronary arteries is, of course, the primary mechanism responsible for heart attacks.

Researchers measured the volume of calcified plaque in the coronary arteries of 25 long-distance runners and 23 symptomatic heart patients using computed tomography angiography or CT scan. The runners had raced at least one marathon per year for 25 years.

Surprisingly, the volume of calcified plaque in the arteries of long-distance runners was 60% greater than the symptomatic controls, although there were no symptoms amongst any runners. Researchers speculate that long-term systemic inflammation may be responsible as a consequence of frequent vigorous exercise. What does this mean for elite marathoners?

Although this study might result in speculation that excessive endurance exercise results in higher disease risk, there are other factors to consider; the primary factor being lower mortality amongst long-distance runners. However, this information could be useful to long-distance runner who might now focus on managing inflammation better through nutrition and supplementation.

Schwartz J, et al (2010) Does long-term endurance running enhance or inhibit coronary artery plaque formation? A prospective multidetector CTA study of men completing marathons for least 25 consecutive years. American College of Cardiology. 1271-330.

The Biomechanics of the Bulgarian Squat

The use of a Bulgarian Squat, or Rear Leg Elevated Split Squat (RLESS) in place of a traditional 2-leg Squat is gaining popularity amongst strength & conditioning coaches. Although eliminating the Conventional Squat is controversial, there a number of valuable points that may convince one that the benefits outweigh the risks. The single leg variations may be better for performance improvement while simultaneously reducing risk for injury to the low back when lifting even moderate resistances.

To test the theory of better performance, a recent study published in the Journal of Sports Rehabilitation compared lower-body EMG activity during the Bulgarian Squat to a two-leg Squat in eleven female intercollegiate athletes.

Using EMG, researchers measured muscle activity during 3 squats to parallel using 85% of the participants' 3 repetition maximum load in each exercise.

It was determined that the Bulgarian Squat produced greater EMG activity in both the gluteus medius and hamstrings compared to the 2-leg squat; two commonly weak or undertrained muscles. The Squat, on the other hand, produced greater EMG activity in the quadriceps. However, because quadriceps activity was higher and hamstring activity lower, the 2-leg Squat produces a higher quadriceps-to-hamstring ratio. This is important with respect to stability at the knee. A more even ratio would produce lower strain on ligaments such as the ACL and potentially strengthen the joint in a way that reduces risk for ACL injury.

This study continues to reinforce the need to continue evaluating the role of the loaded bi-lateral squat, and supports the value of including the RLESS in training programs.

McCurdy, K. ET al (2010) Comparison of Lower Extremity EMG Between the 2-Leg Squat and Modified Single-Leg Squat in Female Athletes. JSR. 19(1):

Does "Healthy" Food Make You Eat More?

Perceptions often determine reality. It's unfortunate that much of our society has been conditioned to perceive what is good and healthy for us as also that which is "not fun" or "comfortable." Consequently, many people cringe when hearing talk of physical exertion or glutton-free nutrition. Now, a recent study suggests that simply perceiving and consuming a food that is "healthy" may lead to increased hunger and overeating.

College students were asked to sample a protein bar and were told either that they were testing "a new health bar," or a "chocolate bar that is very tasty and yummy with a chocolate-raspberry core." Some time afterward researchers questioned the students about their hunger. Interestingly, hunger was rated higher by those who consumed the bar labeled as "healthy."

Moreover, a control group who did not receive anything to eat, but who did examine the bars, was also asked to rate their hunger at the later time. The controls reported hunger at the same level as those who had eaten the bar labeled as "tasty and yummy."

In a second study, researchers used bread instead of a protein bar, and labeled the bread in a similar manner. Afterwards, participants were offered pretzels. The participants who ate the bread labeled as "low-fat and nutritious" also ate more pretzels.

The third component of the study provided a choice of two protein bars, randomly labeled as healthy or tasty. In this case, ratings of hunger were similar between groups indicating that the power to choose may be as important as perceived deprivation.

In any weight loss program it is important to understand the psychological and emotional relationships people have with food. Avoid labeling foods with the understanding that people may be more likely to overeat later if they perceive to be depriving themselves of satiety.

HealthDay. Calling a Food 'Healthy' May Make You Hungrier. Friday, April 2, 2010.

Asymptomatic Hip Injuries in Hockey Players

Finding ways to predict, prevent and treat injuries are the three major challenges of sports medicine. One specific area of interest is in detection of asymptomatic injuries. It is believed that a fairly high percentage of athletes participate in sport with underlying injuries or degenerative conditions that go undetected because they do not produce symptoms. In a recent example, researchers reported that more than two-thirds of hockey players tested presented with asymptomatic hip or pelvic injuries on MRI.

Researchers used high-resolution MRIs to create images of the hips and pelvis of 39 current intercollegiate and professional hockey players. Although only 3 participants had indicated experiencing minimal pain at the time of the MRI, 28 of the participants had irregularities on their images. Hip labral tears were present in 21 participants, while 12 images showed muscle strains and 2 indicated tendinosis.

It's important to learn from studies such as this that although people may present as functional and pain-free they may not be truly injury free. As such, exposure to high intensity, impact-based, or complex movements during exercise may result in more severe acute injuries. Because we don't have access to specific diagnostic information in prevention, as Personal Fitness Professionals we are learning to make certain assumptions based on the likelihood of commonly underlying asymptomatic injuries.

By assuming there is an injury present we are encouraged to make alternative exercise selections that reduce the risk of injury to joints such as the knees, hips, and spine, and keep our clients progressing toward their goals. This becomes increasingly important as the average first-time client is more overweight, de-conditioned and has a longer prior injury history than ever before.

March 14, 2010. American Orthopedic Society for Sports Medicine. New Study Finds 70 Percent of Able-bodied Hockey Players Have Abnormal Hip and Pelvis MRIs. Press Release Online

1 comment:

Janice Ladden said...

Hi, after reading your FitBits, I agree with you that there are a high number of ordinary people who participate in managed and supervised physical exercises without knowing they have other injuries. I had a minor head injury which caused stiff neck. I ignored it expecting it to go away and decided to continue with my university exercise regimen. Good thing a physical therapist, (Dallas,
noticed my posture and our family GP then diagnosed it as whip lash, thus preventing further possible injuries. Hence, the importance of making alternative exercise selections.