Research Summaries

Weight Training and Bone Adaptation

Weight training has long been known to have a positive effect on bone density, however little is known as to the specific dynamics behind this process. Researchers at the University of Southern California, Las Angeles, recently conducted a study in order to gather more insight on bone adaptation, a.k.a. osteogenic response, to weight training. The researchers split 20 young women into an exercise group and a control group (12 exercise, 8 control). The exercise group performed knee extension and flexion exercises for both legs, but limited it to only concentric contractions on one leg and eccentric contractions on the other. Subjects exercised in this manner 3 times a week for 18 weeks and were tested for muscle strength, body composition and mid- femur bone density both before and immediately after the training period. While both legs showed significant strength increases, only the eccentrically trained leg showed increased mid- femur bone density and mid- thigh lean mass. This led researchers to conclude that the eccentric contractions were more osteogenic than concentric contractions, possibly because of the higher force productions associated with eccentric muscle contractions.

Effective Methods of Fat Loss

While it is well-known among more progressive trainers and exercisers that a combination of diet, aerobic and strength training is the best plan of attack when trying to win the battle of the bulge, a study conducted by famed sports sciences researcher William Fleck, Ph.D. at Penn State University showed just how well this works in comparison to two other popular methods of fat loss. The study placed 35 overweight men into one of 3 groups - diet only, diet and aerobics, and a combination of diet, aerobics and strength-training. After 12 weeks, the subjects were tested for weight loss, lean mass/ fat mass loss ratio and strength and power gains.

The results were eye-opening. While all three groups demonstrated a significant decrease in bodyweight, the diet-only group experienced significant lean mass loss along with the fat loss. In fact, they lost over 30% of their total weight from lean mass. They also showed a decrease in power as determined by 30-second Wingate test. The diet and aerobics group also had less than desirable fat/ muscle loss with almost 25% of total weight loss coming from lean mass. The diet, aerobic and exercise group, however, had outstanding results. They not only lost most of their weight from fat (97%) they also significantly increased their strength in a 1RM test of the bench press and squat, the only group to do so, and showed an increase in peak oxygen consumption. This led researchers to conclude what we already suspected- a weight loss program combining diet, aerobics and strength- training is head and shoulders above any other method currently available.

Putting Vanadyl Sulfate to the Test

The role of insulin and insulin sensitivity in muscle building and fat loss has led to a whole sub- industry within the fitness industry. From diets like the Zone and Atkins’ diet designed to manipulate insulin levels to supplements that "mimic" insulin’s effects in the body, companies have introduced several innovations into the fitness world in an attempt to capitalize on insulin’s effects. One of the first supplements to do this was vanadyl sulfate. While very little hard, scientific data exists for weight- trainers, users report increased vascularity and pumps from working out, along with enhancing the effects of their creatine. Researcher in New Zealand conducted a study in order to shed some more light as to vanadyl’s possible performance enhancing effects.

The researchers split 31 subjects into two groups, with one group receiving .5 grams of vanadyl sulfate per kilogram of body weight per day and one group receiving a placebo using a double- blind, placebo controlled format. Body composition and performance on a 1RM and 10RM test on the bench press and leg extension were measured both before and after the study as a means of measuring vanadyl’s effects. 2 vanadyl sulfate users did have to withdraw during the study for apparent side effects from the supplement. At the conclusion of the test there were no significant changes in body composition in either group. Both groups did show significant strength improvements but no edge was seen in the vanadyl group. This led researchers to conclude that vanadyl sulfate is ineffective at either altering body composition or enhancing performance in strength- training activities.

The Zone Diet and Athletic Performance

One of the most popular diets to hit the nutrition scene recently has been the "Zone" diet, or one that has a macronutrient ratio of 40% carbs, 30% protein and 30% fat. The proposed benefits of this type of diet range from enhanced fat burning to increased performance in endurance based events. However, not all of those in the scientific community are in agreement as to the efficacy of such a diet, especially for performance enhancement. The Department of Nutrition, Food and Exercise at Florida State University recently completed a critique of the Zone diet and it’s claims of enhancing athletic performance.

Among their challenges were several key and often overlooked facts. The Zone diet, when followed as outlined by it’s proponents, is both low in carbs and deficient in total calories. They point out that there is an abundance of reliable peer reviewed literature that is in direct opposition to the idea that a low carb, low calorie diet can support athletic performance, much less improve it. In addition, several of the supposed metabolic benefits of the Zone diet are also unfounded. While the insulin response is reduced when comparing a 40% and 60% carbohydrate diet, the insulin response is still enough to offset the fat burning effects of glucagon. In addition, the key eicosanoid reportedly produced by the use of a Zone diet and responsible for the increased muscle oxygenation is not even found in skeletal muscle tissue according to the most recent reports on eicosanoid biology. It seems that several pieces of contradictory information have been left out of the Zone diet proponents arguments in favor of their approach. While the Zone diet does show some promise in the weight loss arena, mainly from it’s low total calorie content, it’s effectiveness for performance enhancment is still highly debatable.