I have a couple of thoughts on this first article. First, this was only a 4-week study, so we don't how this might work over the long term (but the findings are concerning). More importantly, however, there are antioxidants that both protect against cellular damage and increase insulin sensitivity, including cinnamon and alpha lipoic acid.
While we want to increase insulin sensitivity, we also want to avoid getting cancer and keep our immune systems strong
And on the last study, static stretching BEFORE an event or even a training session is almost never a good idea. Warm up before and then stretch after.
Antioxidants Inhibit Improvements in Insulin Sensitivity
Reactive Oxygen Species (ROS), more commonly known as Free Radicals (FR) are believed to be partly responsible for the cellular damage that accelerates aging. Thus, controlling FR activity is at the forefront of longevity research. Antioxidant supplements, which have been studied extensively in this area, have been linked to reduced FR activity, potentially reducing the progression of age-associated diseases and disorders.
Interestingly, although controlling FR activity is perceived to be helpful in most circumstances, there is one instance where it may not be…with exercise. Exercise increases FR activity, however, in this situation FR's appear to be responsible for many of the benefits achieved via exercise by inhibiting cellular damage. Therefore, inhibiting FR activity through antioxidant supplementation may not be advisable for people who exercise.
In a study published this week in the Proceedings of the National Academy of Sciences, researchers concluded that antioxidant supplementation inhibits improvements in insulin sensitivity with exercise. A group of 39 young men were exercised for a 4-week period, approximately half of whom used a combination of 1000mg Vitamin C and 400IU Vitamin E daily. Baseline and post-exercise measures of insulin sensitivity were collected.
Participants who used antioxidant supplements experienced no improvement in insulin sensitivity with exercise, whereas the non-antioxidant group improved significantly. Fortunately, a month after ceasing Vitamin supplementation insulin sensitivity returned to normal in the latter group.
The increasing prevalence of insulin resistance is quickly leading to an epidemic of Type II Diabetes around the world. As exercise is believed to be the most effective natural treatment for insulin resistance, both diabetics and pre-diabetic individuals should be wary of taking antioxidants if they are beginning an exercise program. Instead, the researchers recommend advocating for diets high in fruits and vegetables so that optimal antioxidant intake can be achieved without supplementation.
Kahn, C.R., et al (2009) Antioxidants prevent health-promoting effects of physical exercise in humans. Proceedings of the National Academy of Sciences. ePub online.* * *
Weighing-In Enhances Weight Maintenance
The biggest challenge for individuals who have lost a considerable amount of weight is often not the initial weight loss, but the maintenance of weight loss. Previous research has identified exercise to be the primary factor in whether or not someone regains weight. However, continued support is also recognized as important for successful weight maintenance. In a recent study published in the Journal of the Canadian Medical Association, researchers determined that a simply bi-weekly weigh-in along with regular phone calls is sufficient to optimize consistency with exercise and diet and prevent weight regain.
Two hundred women who had recently lost more than 5% of their original bodyweight were assigned to one of two groups. The first group received nutrition education and supervised exercise by nutritionists and exercise physiologists, while the second group received phone support from nurses along with a bi-weekly weigh-in. Some participants were educated in the use of high-carbohydrate eating, while others were encouraged to eat a diet high in mono-unsaturated fats.
Following the two-year intervention, it was determined that both groups had maintained an equivalent amount of weight. Interestingly, participants were more compliant for weigh-ins than for regular supervised exercise. Type of diet did not affect weight loss or regain.
Given the increased costs of the extensive intervention, the researchers concluded that less expensive monitoring and support could be as beneficial in weight maintenance. This could be essential for hospital and government-based programs that develop interventions for low-income populations. The practical lesson for exercise professionals is that people who lose weight may benefit from regular weigh-ins, and frequent contact may further facilitate successful long-term weight management and compliance.
Dale, K.S., et al (2009) Determining optimal approaches for weight maintenance: a randomized controlled trial. CMAJ.* * *
Many Running Injuries Attributed to Weak Hips
Statistics indicate that between 65% and 80% of all recreational and competitive runners experience some type of overuse injury annually. Such injuries include patellofemoral knee pain, illiotibial band syndrome, shin splints, Achilles tendinopathy, plantar fasciitis, and stress fractures. The vast majority of such injuries, ~80% affect the lower-leg, with nearly 40% occurring at the knee. Unfortunately, science and medicine have yet to truly understand the mechanisms behind such injuries.
Researchers recently reviewed the literature over a 28 year span from 1980 to 2008 and concluded that two mechanisms appear to underlie all lower-leg injuries. First, a small number of studies implicated "atypical foot pronation mechanics." Pronation, which occurs during the stance phase of gait as the foot flattens causing internal rotation of the tibia and femur, is essential to generating energy for the next stride. However, excessive or insufficient pronation leads to poor energy production and consequently to excessive motion about the foot and knee.
Second, and more prominent, researchers uncovered a growing number of studies that suggest "inadequate hip muscle stabilization" leads to a majority of overuse injuries. Because the hip muscles, specifically the gluteus medius, minimus and maximus stabilize the leg during gait, poor strength or conditioning of these muscles results in excessive stress at and below the knee.
Recent studies have shown that improving hip muscle strength reduces the incidence of knee pain in runners. With running season in full-swing throughout the country along with races every weekend there's not a better time to encourage runners to maintain their strength training programs.
Ferber, R., et al (2009) Suspected Mechanisms in the Cause of Overuse Running Injuries: A Clinical Review. Sports Health. May/June* * *
Static Stretching Before Golf Impairs Performance
The benefits of pre-exercise stretching have been questioned in recent years. The controversy stems from findings that static stretching temporarily impairs a muscles capacity to produce force rapidly. Although this might not be problematic for low intensity exercise, individuals participating in vigorous athletics may experience an increased risk of injury following a static stretching warm-up.
Golf is not often perceived as a vigorous sport. However, the golf swing is considered one of the most vigorous movements performed in all athletics, generating extraordinarily high amounts of force. Because the golf swing requires an optimal range of motion through the shoulders, hips, and spine many golfers have taken to stretching before competition to "loosen-up." Unfortunately, this may be placing them at high risk of injury, and now researchers suggest it might impair performance as well.
Researchers at Austin State University compared the effects of static and dynamic warm-up on a variety of golf measures: club-head speed, drive distance, drive accuracy, and consistency of ball contact. Fifteen young male golfers with a handicap of 5 or lower performed a dynamic warm-up, and static stretching followed by a dynamic warm-up. The dynamic warm-up consisted of 10 swings with a Momentus training club, followed by 15 full-swings with a golf club progressing from lighter to heavier clubs. The static stretching protocol included 20-minutes of golf-specific stretches held for 10 seconds each, repeated 3 times bilaterally.
Following the warm-ups participants hit 10 balls with a driver at a driving range, with 1 minute recoveries between shots. Following the static stretching protocol, participants had reduced club-head speed and consequently hit for shorter distances. In addition, accuracy was reduced by >30%, and ball contact consistency was down >15%.
This study supports the progressive philosophy of a dynamic warm-up protocol. However, the researcher suggests that static stretching may remain useful away from the range or golf course to improve golf-specific flexibility.
Gergley, Jeffrey C. (2009) Acute Effects of Passive Stretching During Warm-up on Driver Clubhead Speed, Distance, Accuracy, and Consistent Ball Contact in Young Male Competitive Golfers. JSCR. 23(3): 863-867.
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