Minimalist Shoes, Wearable Trackers and Weekend Warriors, Football Head Impacts and Balance and More from the Journal Medicine & Science in Sports & Exercise

Are Minimalist Shoes Effective for Strengthening Foot Muscles in Runners?

As the main point of contact with the ground, the foot plays a vital role in how humans move. The complex structure of the foot includes 26 bones, more than 20 muscles, many ligaments and various types of soft tissue. These features allow the foot to provide rigid support or flexibility, depending on the situation. Weakness of the basic foot muscles (those small muscles located solely within the foot that do not cross the ankle joint) has been associated with a variety of foot injuries. Strengthening these muscles may help prevent injuries.

In this research, the investigators measured the effects of walking in minimalist footwear or performing specific foot strengthening exercises on the size and strength of some of these basic foot muscles. A total of 57 runners participated over a period of eight weeks in one of these randomly assigned conditions: minimalist shoe walking, foot muscle strengthening or a control situation. Serial measurements of foot muscle strength and size were made during the study. The research showed that walking in minimalist shoes results in strength gains and muscle size increases; the same was found in the group that performed the foot exercises. While minimalist shoes have mostly been associated with running, the general public and/or people who suffer from a variety of painful foot conditions may benefit from walking in minimalist shoes.

For more information, view the abstract or contact the investigator.

Using Wearable Trackers to Re-examine Health Implications of Physical Activity Patterns Among Weekend Warriors

The Physical Activity Guidelines for Americans recommend at least 150 to 300 minutes of moderate-to-vigorous activity per week, yet little guidance is given as to how best achieve this amount of weekly activity. Do those who participate in activity most days of the week have similar mortality benefits to those who only exercise on a few days?

In this population-based study of 3,438 adults over age 40, investigators used physical activity trackers, worn for a week, to classify individuals who did their weekly activity only one-two days per week (Weekend Warriors). The compared mortality rates for those Weekend Warriors over a period of about six years against rates for similar individuals who did their activity more frequently each week. Both the Weekend Warriors and the more frequently active participants had similarly lower mortality rates than individuals in this large study group who were more sedentary – even after results were adjusted for overall activity per week. Physical activity was related to decreased mortality rate, even among those who were active only one or two days per week.

For more information, view the abstract or contact the investigator.

Does Female Teen-Aged Development Change Hip and Knee Landing Biomechanics: Are there Implications for Knee Injury?

Knee injuries in adolescent females, including anterior cruciate ligament (ACL) rupture, are increasing in frequency. One of the suspected causes is poor landing technique characterized by ‘knock-knee’ posture. Pubertal development is associated with rapid growth of the long bones and surrounding soft tissue and is thought to be an underlying contributor to poor knee and lower limb biomechanics. Yet, no previous studies have investigated the effects of female pubertal development stages on knee and hip biomechanics during a single-limb landing task.

In this study of 93 healthy and physically active girls, the investigators grouped subjects according to pre-pubertal, early/mid-pubertal and late/post-pubertal development stages. All girls had their hip and knee biomechanics recorded with three-dimensional (3-D) motion analysis and force-plate technology while they completed a single-limb landing task. This experimental task was designed to mimic the mechanism of traumatic sporting knee injuries. Girls at latter stages of puberty were heavier, taller and landed with higher 3-D knee forces in comparison to girls at earlier stages of development.These findings indicate that pubertal-related growth may contribute to higher rates of female adolescent knee injury.

For more information, view the abstract or contact the investigator.

A Season of Football Head Impacts Does Not Affect Balance

There is considerable public concern about the effects of repetitive football head impacts on a player’s brain health. Many studies suggest a link between head impacts and poorer health. Safe and efficient walking and balance are critical for activities of daily living and can reflect a person’s overall health.

In this study, investigators evaluated 34 collegiate football players who wore head impact sensors and compared their walking and balance to 13 cheerleaders before and after a single season at two different colleges. Surprisingly, there was no worsening of walking or balance performance in the football players over the course of the season compared to their status before a season or compared to the cheerleaders. The helmet sensor data showed that these players, on average, were exposed to 538 impacts over the course of the competitive season. However, neither the number of impacts nor the force of the impacts had much influence on walking or balance performance measures in the athletes. The conclusion of this study is that repetitive football head impacts did not affect walking or balance performance over a single season. The possible effects of these impacts over multiple seasons or in later life remain unknown.

For more information, view the abstract or contact the investigator.

Higher protein intakes may help your endurance performance

Protein typically has been thought of as a nutrient important for strength sports and growing larger muscles. However, research suggests that a higher protein intake could give you an edge in your endurance performance as well. In this research, investigators studied a group of 10 volunteers—well-trained male runners, average age 28 years. The runners were provided with different diets on three separate occasions during a four-day controlled training period. Each of the diets provided adequate carbohydrate (metabolic fuel), but different amounts of protein. Using an amino acid ‘tracer’ (the building block of protein) that is slightly heavier than normal amino acids, the researchers measured how the body used the dietary protein to support recovery. They also measured any changes in the athletes’ strength or exercise performance at the beginning and end of the controlled diets—these performance-based measures are, arguably, the most important consideration for athletes.

The findings suggest that a higher protein intake than typically consumed among endurance athletes allowed more protein to be retained to support recovery. The results also showed that the athletes were generally stronger and faster over when tested in a 5-km time trial. Thus, during training, consuming protein at levels of 1.2-2.0 grams per kilogram body weight per day may be more effective for maintaining their protein metabolism and exercise performance.

For more information, view the abstract or contact the investigator. 

After bariatric surgery, increase in habitual physical activity is associated with reversibility of type 2 diabetes

Bariatric surgery is considered as an effective treatment for weight loss in severe obesity. A lessening of type 2 diabetes also is often achieved following the surgery. In this study, the investigators examined the influences of self-reported habitual physical activity on skeletal muscle insulin sensitivity and fat deposits after bariatric surgery. Subjects were 36 severely obese patients, including 18 with and 28 without diabetes. All subjects were followed for six months after surgery.

On average, they lost 22.9 percent of body weight. Their self-reported habitual physical activity level increased after surgery. Improvement in skeletal muscle insulin sensitivity, an indicator of better insulin function and reduced risk for type 2 diabetes, was found only in patients who reported having increased their physical activity after surgery! The increase in self-reported physical activity also was associated with loss of visceral fat mass (deeper belly fat), improvement in liver metabolism and reduced inflammation. Thus, habitual physical activity should be encouraged for these patients. It may improve insulin function, reduce internal abdominal fat, and further improve the metabolic health benefits of bariatric surgery.

For more information, view the abstract or contact the investigator.