One of the most researched supplements on the market is creatine. Creatine combined with strength training has been shown to consistently help individuals gain more muscle mass, strength, power, and muscle function across the lifespan (from adolescents to older adults). The effects on endurance performance are much less studied, but there is a growing body of evidence that creatine can benefit endurance athletes in critical race situations such as finishing kicks or breakaways (1).
What is creatine?
As discussed in a previous blog creatine is made from three amino acids, arginine, glycine, and methionine. Your body can make its own creatine within your liver and pancreas, albeit at a limited rate. Therefore, to keep up with the normal daily loss of creatine, we must either ingest creatine containing foods and or supplement with creatine. Red meat, seafood, and chicken are all great sources of dietary creatine; however, these are all animal foods. If you are a vegetarian or vegan, you will have lower amounts of creatine within your muscles. The good news is that you will also be more responsive to taking a creatine supplement (2).
Importantly, even if you ingest these creatine containing foods, most people who supplement with creatine will get ~20% increase in creatine into their muscles (3). In theory, creatine supplementation provides the muscle with more phosphocreatine. Phosphocreatine can be broken down very rapidly to resynthesize adenosine triphosphate (ATP), as required to support intense muscular contractions, such as sprinting or performing a breakaway in a cycling race. Basically, it gives your muscles a greater capacity to generate energy quickly.
Creatine gives your muscles a greater capacity to generate energy quickly.
How can creatine help or hinder endurance performance?
Creatine gets converted into phosphocreatine which is stored energy and supports high intensity exercise. Creatine can also impact endurance performance in a variety of other ways, including by buffering hydrogen ions and by facilitating glycogen resynthesis. We know that glycogen stores need to be normal to high at the start of a marathon or a cycling race, that is because carbohydrates get stored as glycogen and glycogen is the predominate fuel used during endurance events (See this blog about the role of muscle glycogen).
Glycogen can make ATP at a faster rate than fat and uses less oxygen to do so, making it a more economical fuel. Interestingly, combining creatine with carbohydrates can facilitate glycogen resynthesis and may be an important mechanism whereby creatine can further benefit endurance athletes. There is also evidence that creatine can reduce oxidative stress and inflammation following endurance activities, which may enhance acute recovery.
One interesting study (4), performed in rats, examined muscle adaptations using chronic low frequency stimulation with and without creatine. Low frequency electrical signals were sent to the muscles of the rats to evoke a muscle contraction over and over, for 12 hours a day. This type of experimental model causes a robust increase in mitochondria and oxidative capacity but tends to impair the fast twitch fibers. Interestingly, the rats that supplemented with creatine had the same increase in oxidative capacity but preserved their fast twitch characteristics. These findings need to be replicated in humans but suggest that endurance athletes engaged in a high-volume training camp or high volume training phase should consider creatine to help maintain their fast twitch fibers, which are important for sprinting or running fast.
Endurance races vs. laboratory testing
It is critical to use evidence collected from high quality scientific investigations to support our sport nutrition decisions, however, it is important to note that laboratory-based assessments may not perfectly represent what occurs in “real” races. For example, race dynamics including changes in elevation, course design, and competitors pacing strategies all might influence how an athlete paces themselves. There are a few unique studies that have attempted to close the gap between traditional steady state laboratory testing and what occurs in the field. For example, Engelhardt and colleagues (5) had competitive triathletes perform 30 minutes of exercise at an intensity just below lactate threshold followed by 10 fifteen second sprints before another bout of sub threshold exercise. This type of model allowed the researchers to see if creatine could impact short sprints immersed in endurance exercise. They found that creatine improved their sprinting power output by 18%.
Another study (6) conducted in well-trained cyclists (~65 mL·kg-1·min-1) examined the effects of a 120 km time trial interspersed with alternating 1 and 4-km sprints every 10-kms. The authors reported that creatine improved the final 1 and 4-km sprints despite not statistically improving the total time trial performance. The authors suggested that creatine may help with final breakaway attempts in a cycling race. They also examined the impact of body mass gain using a time to exhaustion protocol on an 8% incline at 90% of VO2max. The creatine mediated increase in body mass had no detrimental effect on hill climbing performance. In contrast, using weight bearing (running) steady state exercise, creatine had a detrimental impact on endurance performance. There is also evidence that creatine can help with the finishing kick in a race. For example, in a group of swimmers receiving creatine (10 g/day) for 7 days their final 50-m sprint times were faster in a 400-m race (7).
Summary
Overall, creatine does appear to play a small beneficial role in endurance performance, particularly, if the events involve changes in pace, breakaways, or finishing kicks. The creatine mediated gain in body mass may be a consideration for weight bearing sports but does not appear to have any detrimental effect in non-weight bearing activities including cycling and swimming. Runners may consider creatine supplements when performing high volume training or to enhance strength training adaptations.
Interested in creatine and athletic performance? Watch our webinar recording on The latest on creatine with Scott Forbes, Darren Candow, and Abbie Smith-Ryan.
Reference
Forbes, S. C., Candow, D. G., Neto, J. H. F., Kennedy, M. D., Forbes, J. L., Machado, M., … Antonio, J. (2023). Creatine supplementation and endurance performance: surges and sprints to win the race. Journal of the International Society of Sports Nutrition, 20(1).
Burke DG, Chilibeck PD, Parise G, Candow DG, Mahoney D, Tarnopolsky M. Effect of creatine and weight training on muscle creatine and performance in vegetarians. Med Sci Sports Exerc. 2003 Nov;35(11):1946-55.
Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, Candow DG, Kleiner SM, Almada AL, Lopez HL. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017 Jun 13;14:18.
Putman CT, Gallo M, Martins KJ, MacLean IM, Jendral MJ, Gordon T, Syrotuik DG, Dixon WT. Creatine loading elevates the intracellular phosphorylation potential and alters adaptive responses of rat fast-twitch muscle to chronic low-frequency stimulation. Appl Physiol Nutr Metab. 2015 Jul;40(7):671-82.
Engelhardt M, Neumann G, Berbalk A, Reuter I. Creatine supplementation in endurance sports. Med Sci Sports Exerc. 1998 Jul;30(7):1123-9.
Tomcik KA, Camera DM, Bone JL, Ross ML, Jeacocke NA, Tachtsis B, Senden J, van Loon LJC, Hawley JA, Burke LM. Effects of Creatine and Carbohydrate Loading on Cycling Time Trial Performance. Med Sci Sports Exerc. 2018 Jan;50(1):141-150.
Anomasiri W, Sanguanrungsirikul S, Saichandee P. Low dose creatine supplementation enhances sprint phase of 400 meters swimming performance. J Med Assoc Thai. 2004 Sep;87 Suppl 2:S228-32.
