High-Heeled Shoes may Affect Long Term Muscle Efficiency and Function

While high-heeled shoes may be a fashionable choice of footwear for many women, habitual use of these shoes increases the risk of muscle fascicle strains and comprised muscle efficiency.  The structure of the shoe forces the foot into a plantar-flexed position.  This unnatural positioning of the foot shortens the medial gastrocnemius muscle fascicles and increases Achilles tendon stiffness.

Researchers at University of Jyväskylä in Finland and the Griffith University in Queensland, Australia studied 19 women, 9 of whom habitually wore heels (at least 40 hours per week over a minimum of 2 years) and 10 of whom rarely wore heels (less than 10 hours per week).  In addition to altering the length and stiffness of lower extremity muscles, habitual wear of high-heeled shoes increased the muscle activation of the tibialis anterior and soleus when walking in heels.  This increased level of activation is associated with decreased muscle efficiency.   When walking barefoot, the high-heeled shoe group exhibited higher muscle activation of the medial gastrocnemius during the stance phase of walking.  This trend indicates a chronic response to compensate for the altered muscle-tendon function.

Bottom line: It may be wise to limit the use of high-heeled shoes to special occasions in order to prevent chronic damage to the muscles and tendons that contribute to walking.

Read more about this study here.

ACL Injuries and Muscle Strength in Girls at Puberty

There are many theories and a vast medical and scientific literature exploring why girls who play sports experience more ACL injuries than boys.  A recently published review in the journal Sports Medicine authored by researchers from the University of Wollongong in Australia focused on changes in the relative strength of hamstring and quadriceps muscle at the time of puberty.  The evidence suggests that in girls during puberty the growth in size and strength of the hamstring muscle group seems to lag behind that of the quadriceps muscle group. This lag is not present in boys.

These observations have been made from retrospective studies (looking backwards at injuries) and scientists put the highest value on prospective studies (which look forward) in order to avoid bias.  However, the evidence seems strong enough to suggest that training which develops a greater balance between the hamstrings and quadriceps might be useful as a component of programs to help avoid ACL injuries in girls at puberty.

Read more about this review here.

Exercise and Breast Cancer Risk

It is now known that physical activity reduces the risk of breast cancer but the exact relationship between “dose” and timing of exercise  - particularly in relation to menopause – is less well defined.   A new study from the Department of Epidemiology at the University of North Carolina was recently published on-line in the journal Cancer.

The study examined these relationships in more than 1500 women with breast cancer and 1200 controls who did not in the Long Island Breast Cancer Study Project

The results indicated that exercise had no preventative effect when the onset of breast cancer prior to menopause was examined.  However, lifetime exercise was strongly related to cancer-free survival when breast cancer onset after menopause was examined. Child-bearing women who had exercised between 10-19 hours per week prior to and after menopause experienced a 30% reduction in the risk of breast cancer.  Surprisingly, exercise intensity did not seem to affect the relationship.  The data indicated that substantial postmenopausal weight gain may eliminate the benefits of regular exercise.

These results are strong evidence that exercise and weight maintenance are powerful factors in the prevention of breast cancer.

Read more about the study here.

Marathon Runner Deaths Remain Relatively Low Despite Large Increases in Participation

In 2000, 299,000 marathon runners lined up at starting lines all over the United States.  By 2009, the number of marathon runners had increased to over 473,000.  Researchers at the Johns Hopkins School of Medicine performed an epidemiological analysis of the 3.7 million marathon participants in this ten-year span and identified 28 runners who died either during the marathon or in the 24 hours following the race.  These deaths included 6 women and 22 men.

Over the entire decade, the overall death rate was 0.75 deaths per 100,000 finishers, with a rate of 0.98 for men and 0.41 for women.   Half of the deaths occurred in participants older than 45 years of age.  And, of this older group almost all deaths were the result of myocardial infarction/atherosclerotic heart disease.  It is reasonable that these causes of death would be more likely to affect men rather than women since men have a much higher risk for cardiovascular disease.  The different death rates for men and women likely reflect the known larger risk of heart disease in men.

Training for a marathon is a physical challenge that requires planning and care.  A thorough physical exam to rule out potentially life threatening heart disease is a wise precaution, particularly for older first-time marathoners.

See the full abstract here.

Thanks for Joining us on Mother’s Day!

On Mothers’ Day - Sunday May 13 - the University of Washington’s Women’s Sports Medicine and Lifetime Fitness Program and UW Sports Medicine Clinic held a 5k Walk/Run in Seattle’s beautiful Seward Park. 

There was no entry fee, no timing, no competition, just a great time for families to kick off Mom’s special day in a healthy way.

Pictures of the event can be viewed here.

If you missed the event this year, save the date for Mothers’ Day 2013 – Sunday May 12, 2013 – and plan to join other families to celebrate the mothers in  your family.

Reducing Cholesterol when you are Overweight

The power of exercise as medicine is getting more and more attention.  In a recent study in the Journal of Obesity (www.hindawi.com/journals/jobes), a group of scientists from the West Virginia University School of Medicine summarized all studies in the literature where the effect of exercise and diet on lipid lowering was compared to the control condition of usual care or no treatment in overweight and obese adults.  This kind of study (known as a meta-analysis) can be extremely powerful since it combines many more subjects than is usually possible to include in a single study.

The analysis of more than 859 men and women with body mass index  ≥25 kg/m² showed that exercise and diet were effective in reducing several important components of the lipid profile including total cholesterol, low-density lipoprotein cholesterol, and triglycerides. One important measure – high density lipoprotein cholesterol was not affected.

The findings of the study are clinically important because they imply that the exercise performed by study participants reduced the risk of death from heart disease by up to 8%. This is one more piece of strong evidence that reaching for your running shoes before – or at least at the same time as – you reach for the pill bottle might be a very wise move.

Read the abstract here and learn more about the types of exercise and the subjects studied here.

 

Age and Gender Affect Sport-Related Concussion Symptoms and Outcomes

High school football players have made the news frequently in the past year regarding the unreasonably high rate of concussions.  Steps have been taken on both a government and school level to start improving how such injuries are evaluated.  However, girls have remained an under-served group when it comes to sport-related concussions.

Researchers at Michigan State University studied 296 athletes of different ages and genders over a two year period.  They measured the baseline neurocognitive performance of athletes and then repeated the same measurements on several days in the two weeks following the occurrence of a concussion.  They discovered that, on average, female athletes performed worse on visual memory tests and reported more symptoms as compared to their male counterparts in the two weeks post-concussion.  In addition, when comparing the effects of age on memory following the incidence of a concussion, high school athletes performed worse than college athletes in both visual and verbal memory.

The high incidence of sport-related concussions is of great concern over all ages and genders.  However, based on this research, perhaps it is time to take extra precaution when it comes to younger athletes and female athletes who are participating in contact sports.

 Read the abstract here.

Can Aerobic Training and Strength Training Complement Each Other?

The effect of concurrent training, which combines both strength and aerobic exercise, has been debated in the past.  A controversy exists as to whether the combination of the two forms of exercise in a training regimen is likely to enhance one’s overall increase in strength as compared to a regimen of only strength training.  It is an especially important issue for those hoping to maximize their performance.

A recent paper in the International Journal of Sport Medicine from the Federal University of Rio Grande do Sul in Brazil, described research on 44 women in 4 different exercise groups.  The first group combined strength running with running; the second combined strength training with interval running training; the third combined strength training with cycling; and the fourth group only performed strength training.  Each group trained for 11 weeks, twice a week.  The researchers found no significant difference between groups when comparing initial and final measurements of maximal strength in knee extension, bench press and leg press exercises, endurance in knee extension and bench press exercises, and isometric and isokinetic peak torque of knee extension.  The absence of significant difference in strength based on the presence of aerobic training suggests that there is no interference effect when adding in aerobic exercise to a strength training regimen.

This research suggests that,if you are trying to maximize your performance for an event or sport that focuses on strength, you will not detract from your training by supplementing your workouts with aerobic exercise.

Read the abstract of the paper here.