The Effects of Caffeine on Strength & Power Performance in Athletes

Author: Melissa Shlotzhauer


There’s no better way to begin your day than by drinking a hot cup of coffee before enjoying a nice workout. Aside from being a delightful beverage that’s part of your morning routine, have you ever stopped and thought about all the benefits that the caffeine you’re consuming provides? Caffeine is found in many foods and beverages and over 90% of the US population consumes it on a regular basis (Mawer, 2016).

How Caffeine Works

Caffeine is rapidly absorbed into the bloodstream, which leads to blood levels of caffeine peaking by 90-100 minutes. Levels remain high for about 3-4 hours and then begin to drop. Caffeine affects many organ systems and processes throughout the body. Caffeine stimulates the central nervous system, allowing athletes to complete longer, harder workouts. New research suggests that athletes who usually avoid coffee and energy drinks will likely benefit the most from caffeine because they are less adapted to the effects it may have on their body (Mawer, 2016), (Kadey, 2018).

Caffeine as a Supplement

Caffeine is a very powerful substance that has been shown to improve physical and mental performance. It is commonly used as an ergogenic aid in team sports and endurance exercise. Supplementation with caffeine has been shown to decrease feelings of fatigue and promote mood and perceptual responses during exercise (Ali, O’Donnell, Foskett, & Rutherfurd-Markwick, 2016). However, if you regularly consume coffee, energy drinks, soda or dark chocolate, you may experience less benefits from supplements since your body has developed a tolerance to caffeine. Aside from coffee, caffeine anhydrous seems to have the most benefits for exercise performance. Dose is typically based on body weight, usually ranging between 200-400 mg of caffeine anhydrous. For optimal performance, it is advised to take the supplement about 60 minutes before exercise (Mawer, 2016).

Aside from all the benefits caffeine provides, there are also side effects of ingesting too much.  Caffeine may cause increased heart rate, anxiety, dizziness, insomnia, irritability, tremors or stomach discomfort. Doses of 600 mg have been shown to increase tremors and restlessness. It has also been advised for people who are prone to anxiety to avoid high doses. Timing is also important factor, which is why caffeine intake should be avoided after 4 or 5 pm as it can disrupt sleep patterns (Mawer, 2016).

Does Caffeine Enhance Strength Performance?

The eccentric capabilities of the knee flexors  (hamstrings) generate leg strength and power, which are essential components of performance in team sports. It has been shown that with ingestion of 6 mg/kg of body weight of caffeine, female team sport players have a significant increase in eccentric knee flexor strength and eccentric knee flexor and extensor (quandriceps) power. Females have higher risk at ACL tears to the knee, and knowing this could be beneficial to help prevent injuries from occurring as often (Ali, O’Donnell, Foskett, & Rutherfurd-Markwick 2016).

Another study examined the effects of a high caffeine pre-workout supplement on measures of muscle performance during an eight-week strength training exercise program. Subjects within the experimental group drank the supplement containing ergogenic aids including 450 mg of caffeine 15 minutes before each training session. There were significant improvements in strength and lean body mass in squats and bench press power after the resistance exercise training program (Kudrana., Moodie, McCartney, Bustamante, Fry, & Gallagher 2011).

Is There an Optimal Performance Enhancement Caffeine Dosage?

Caffeine is used in different ways throughout the body depending on the type of exercise that is being performed. Therefore, the dose of caffeine required to activate a mechanism of activity differs from endurance exercise to strength-power performance. The higher the work load, the higher dose of caffeine needed to achieve an ergogenic effect. On the other hand, the ergogenic effect of caffeine against the lighter work load was maximal with only a low dose of caffeine. Overall, the optimal dosage recommended depends on the resistance that athletes have to overcome (Pallares, Fernandez-Elias, Ortega, Munoz, Munoz-Guerra, & Mora-Rodriguez, 2013).

A study suggested that low dosages can enhance performance depending on the activity being completed. It was found that around 150-200 mg of caffeine ingested as coffee an hour before exercise improved 1,500 meter running performance in well-trained runners. The optimal dosage for male collegiate tennis players was found to be 3 mg/kg of body mass consumed 90 minutes before a match, which lead to an increase in their forehand shot performance. The same amount of caffeine was shown to improve ball velocity in a spike test, jump tests, the time to complete an agility test and the number of successful volleyball actions during the game in male and female volleyball players as well (Spriet, 2014).

In my opinion, I think that caffeine supplementation would overall be beneficial to athlete who engage in power and strength performances. Using the correct dosage depending on your specific body and the type of exercise you are engaging in is an important factor to keep in. The use of caffeine as a supplement, in my opinion is a better and possible a more natural option rather than others. Overall, I feel as though there’s not a problem with supplementing using caffeine if it’s being used to improve performance.


Mawer, R. (March 18, 2016). How caffeine improves exercise performance. Healthline. Retrieved from:

Ali, A., O’Donnell, J., Foskett, A., & Rutherfurd-Markwick, K. (2016). The influence of caffeine ingestion on strength and power performance in female team-sport players. Journal of International Society of Sports Nutrition, 13.

Kudrana, R., Moodie, N., McCartney, M., Bustamante, J., Fry, A., & Gallagher, P. (2011). The effect of a multi-ingredient high caffeine pre-exercise supplement on strength power and body composition in 8 weeks of resistance training. Journal of Strength and Conditioning Research, 25.

Kadey, M. (2018). Caffeine boosts performance in athletes who use it rarely. Health and Fitness Association. Retrieved from:

Pallares, J., Fernandez-Elias, V., Ortega, J., Munoz, G., Munoz-Guerra, J., & Mora-Rodriguez, R. (November 2013). Neuromuscular responses to incremental caffeine doses: performance and side effects. Medicine & Science in Sports & Exercise, 45(11).

Spriet, L. (2014). Exercise and Sport Performance with Low Doses of Caffeine. Sports Medicine, 44(2): 175-184.