Caffeine has been described as an effective ergogenic aid for increasing performance in several sports, from events with greater involvement of muscle strength and power, to sports that depend mainly on aerobic endurance. Caffeine is a stimulant of the central nervous system and its pre-workout intake is related to a lower perceived exertion/fatigue.
Caffeine seems to work especially well for improving performance in the gym. For example, 13 resistance-trained men ingested a caffeinated (179 mg) energy drink or placebo solution 60 minutes before completing about of the following exercises: bench press, deadlift, prone row, and back squat exercise to failure at an intensity of 60% 1-repetition maximum. Subjects who consumed the caffeinated beverage performed more repetitions to failure in all exercises. Another study had 15 women consume caffeine (6 mg/kg) or placebo (PL) seven days apart. Sixty min following supplementation, participants performed a one-repetition maximum (1RM) barbell bench press test and repetitions to failure at 60% of 1RM. They discovered that 1-RM strength was greater during the caffeine condition in these resistance-trained women.
Several studies revealed an effect of caffeine on maximal strength. For instance, studies that have tested percent muscle activation and maximal muscle strength of the knee extensors under isometric conditions have shown that caffeine is capable of increasing voluntary activation and strength. A 2014 study reported that caffeine can increase not only concentric (i.e. lifting the weight) and eccentric (i.e. lowering the weight) maximal strength, indicating that caffeine increased maximal strength regardless of the contraction mode.
There are many studies have documented that the placebo effect is a powerful stimulator of performance. Researchers examined the placebo effect of caffeine and the combined effect of caffeine and caffeine expectancy on maximal voluntary strength. Fourteen men completed four randomized, single-blind experimental trials:
1) Told caffeine, given caffeine (5mg.kg);
2) Told caffeine, given placebo;
3) Told placebo, given placebo;
4) Told placebo, given caffeine.
Maximal voluntary concentric force and fatigue resistance of the knee flexors and extensors was measured using isokinetic dynamometry. So we have an interesting study which compared the direct effects of caffeine vs. the placebo effect. At the end of the study, a significant and equal improvement in peak concentric force was found in the told caffeine, given caffeine subjects and told placebo, given caffeine trials. Despite participants believing caffeine would evoke a performance benefit, there was no effect of told caffeine, given placebo. Caffeine caused an improvement in some aspects of muscle strength; however there was no additional effect of expectancy. The performance was poorer in participants who believed caffeine would have the largest benefit, which highlights a link between expected ergogenicity, motivation, and personality characteristics.
So for all you caffeine addicts, keeps on drinking your coffee and pre-workout drinks, it ain’t just all in your head like some supplements.
Does Caffeine Cause Muscle Damage?
Caffeine ingestion has been shown to be an effective ergogenic aid in several sports. Caffeine administration may increase exercise capacity, which could lead to a greater degree of muscle damage after exercise. Researchers examined the effect of caffeine on muscle damage. In a randomized, double-blind, placebo-controlled crossover study. Six male athletes ingested placebo or caffeine (6 mg.kg body mass) capsules on two different occasions. 60 min after the ingestion the capsules was to evaluate serum caffeine levels. After that, all participants performed a protocol of vertical jumps to examine explosive power. The protocol consisted of four sets of 30 sec of continuous vertical jumps with 60 sec of recovery between sets. Blood lactate (LAC) and creatine kinase (CK), a marker of muscle damage, was measured before and after the protocol.
At the end of the study, caffeine elicited a 5.23% improvement in the leg power compared to placebo. There was no elevation of muscle damage found after caffeine administration. These results indicate that acute ingestion of caffeine (6 mg.kg body weight) can reduce the level of muscle fatigue and preserved leg power during the test, with no increase in muscle damage, leading to believe that acute administration of (6 mg.kg body weight) caffeine is safe. Thus, caffeine can help athletes in supporting a greater physiological overload during high-intensity training sessions.
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