CLINICAL REVIEWS

Caffeine-containing beverages, such as the Hardcore Energize Bullet, have been shown to be beneficial for increasing the total weight lifted as well as increasing high-intensity power output!

By Bill Campbell, Ph.D.
Exercise and Performance Nutrition Laboratory
University of South Florida

Caffeine Ingestion Improves Weight Lifting and Power Performance

Woolf K, Bidwell W.K, Carlson A.G. The Effect of Caffeine as an Ergogenic Aid in Anaerobic Exercise. Int J Sport Nutr Exerc Metab. 2008 Aug;18(4):412-29.

It has been well established that caffeine improves endurance performance, such as long distance running and cycling. The evidence for caffeine as a performance aid for resistance exercise and explosive power, on the other hand, has been mixed.

In an effort to find a more conclusive answer, highly trained, competitive male athletes ingested one of two beverages—one with caffeine (5 mg/kg of bodyweight) and one without caffeine, separated by one week. This amount of caffeine would be equivalent to roughly three to four cups of coffee for a 200-pound individual.

After ingesting the caffeinated beverage, the subjects ingested a normal breakfast (cereal, banana, orange juice, etc.). This is a great aspect of this study, as this scenario is similar to how an athlete would use caffeine in competition or practice.

One hour after ingesting the caffeinated (or placebo) beverage, each athlete performed three exercise tests with 60 seconds of rest between tests—leg press, chest press, and a 30-second all-out sprint test on a cycle ergometer (i.e., Wingate test).

During the caffeine trial, more total weight was lifted with the chest press, and a greater peak power was obtained during the Wingate test. No differences, however, were observed between treatments for the leg press.

So it appears from this study that ingesting a caffeine-containing beverage is beneficial in lifting more total weight during resistance exercise for the upper body as well as in its ability to increase high-intensity power output.

Loss of Muscle Mass in Outer Space

Trappe S, Costill D, Gallagher PM, et al. Exercise In Space: Human Skeletal Muscle After 6 Months Aboard The International Space Station. J Appl Physiol. 2009 Jan 15.

Crewmembers aboard the International Space Station for six months were analyzed before and after their departure into space for calf muscle volume and calf muscle performance. Calf muscle volume was assessed via magnetic resonance imaging, and calf muscle performance was measured both statically and dynamically.

While on the International Space Station, crewmembers had access to a running treadmill, cycle ergometer, and resistance exercise device. The exercise regimen varied among the crewmembers with aerobic exercise performed about five hours per week at a moderate intensity and resistance exercise performed three to six days per week, incorporating multiple lower leg exercises.

Even with this exercise program, calf muscle volume decreased approximately 13% and peak power was 32% lower after six months of spaceflight. In addition, force-velocity characteristics were reduced 20 to 29% across the velocity spectrum.

The authors of this study recommended that future long duration space missions should modify the current International Space Station exercise prescription and/or equipment to better preserve human skeletal muscle mass and function, thereby reducing the risk imposed to crewmembers.

The bottom line? If you want to increase/maintain skeletal muscle mass, then traveling to outer space is probably not the best place to reach your goals!

Yet again, there is powerful evidence that creatine supplementation combined with resistance training has beneficial results on muscle, for both vegetarians and non-vegetarians.

Resistance Training, Creatine, and IGF-1

Burke DG, Candow DG, Chilibeck PD, et al. Effect of creatine supplementation and resistance-exercise training on muscle insulin-like growth factor in young adults. Int J Sport Nutr Exerc Metab. 2008 Aug;18(4):389-98.

Insulin-like Growth Factor-1 (IGF-1) has been shown to influence all three cellular processes related to muscle hypertrophy—satellite cell activity, gene transcription, and protein translation. Therefore, research into this powerful growth factor could produce new information that is highly relevant for those seeking to enhance body composition through increasing lean muscle mass.

Recently, a study was conducted to compare changes in muscle IGF-I content resulting from resistance-exercise training and creatine supplementation. Forty-two recreationally active male and female participants volunteered for the study. Participants were randomly assigned in blocks (gender) to supplement with creatine (0.25 g/kg lean-tissue mass for 7 days; 0.06 g/kg lean-tissue mass for 49 days) or isocaloric placebo and engage in a whole-body resistance exercise program for eight weeks.

Eighteen of the forty-two participants were classified as vegetarian. Muscle biopsies (vastus lateralis, in the front of the thigh) were taken before and after the intervention and analyzed for IGF-I using standard procedures.

Results showed that resistance training increased intramuscular IGF-I content by 67%, with greater accumulation from creatine (+78%) than placebo (+54%). There were no differences in IGF-I between vegetarians and non-vegetarians.

These findings indicate that creatine supplementation during resistance-exercise training increases intramuscular IGF-I concentration in healthy men and women, independent of habitual dietary routine. This is yet another clinical investigation that can be added to the long list of studies reporting beneficial effects of creatine supplementation combined with resistance training.

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