Impact of liquid carbs on power levels

Author: Frédéric Delavier and Michel Gundill: Chapter from the book "Sports Supplements for Athletes".
2011-10-13

As with endurance tests, a lot of energy is expended during strength-building workouts. During such physical exertion, carbohydrates are the best source of energy for the muscles. Muscle glycogen plays a special role during prolonged intense training: it prevents a sequential and significant decline in performance. Nutrients supplied to the body during physical exertion not only provide energy support but also protect muscles from catabolism. After all, catabolism is directly linked to significant muscle strain, which leads to fiber injuries, and indirectly associated with increased production of catabolic factors that destroy muscle cells.

Can energy drinks fulfill this dual task? We are talking about the same drinks consumed by athletes engaged in endurance sports. The results obtained from various studies are quite contradictory regarding the capabilities of energy drinks to enhance strength performance when taken during workouts. When exercise lasts less than 60 minutes, the impact of such drinks on performance is likely to be limited. However, after this period, the effectiveness of drinks containing carbohydrates may show its potential. Thus, the duration of physical activity serves as an important factor determining the necessity of using such drinks. The longer the workout lasts, the more energy the muscles have to draw from their own stores. Eventually, these reserves become completely depleted.

Although research has not shown an increase in strength, it has indicated that carbohydrate intake during physical activity preserves muscle glycogen stores. For instance, the intake of liquid carbohydrates before and during a 39-minute workout halved the depletion of muscle glycogen in men performing muscle-building exercises (G. Haff, 2000).

When taking a placebo, the level of depletion was 26%, while with the carbohydrate-containing drink, it was 13%, even though no performance improvements were observed during this workout. Nevertheless, due to the greater preservation of energy reserves, the recovery process after physical exertion was easier and faster. This is crucial for athletes who train every day and sometimes multiple times a day. In this case, the energy effects of the drinks will have a prolonged nature.