Should Endurance Athletes Use Creatine?
There are relatively few supplements on the market that live up to their marketing hype and provide a meaningful performance improvement for athletes. Those that do often only work under certain circumstances (i.e. beta-alanine will only work when doing exercise of sufficient intensity and after an adequate loading period of the supplement itself) or in specific individuals.
Creatine Monohydrate is one of only five supplements recognised by an expert panel from the International Olympic Committee as having a sufficient body of scientific evidence showing that it is effective in enhancing athletic performance to be worthy of consideration for use. It is one of the most effective ergogenic aids for enhancing high-intensity exercise capacity and lean body mass (i.e. muscle) during training.
How Does It Work?
Creatine's main role is within the muscle, where it facilitates the rapid regeneration of ATP (the energy currency of the muscle) during periods of high-intensity exercise through the phosphocreatine energy system. Around 95% of the creatine that we consume in our diets (predominantly through meat) is stored within muscle. On a typical omnivorous diet, only 60-80% of muscle creatine and phosphocreatine stores are saturated. By supplementing creatine, we can increase this by a further 20-40%.
We typically get creatine in our diets through meat and manufacture around 1 gram daily within the body. Due to the low creatine content in many vegetarian-based foods, athletes following a vegetarian or vegan diet often have very low muscle creatine stores and, therefore, see the most significant effects of creatine supplementation on performance.
What Does It Do?
As nicely summarised by Kreider et al. (2022), Supplementing with creatine can result in…
• Increased single and repetitive sprint performance
• Increased work performed during sets of maximal effort muscle contractions
• Increased muscle mass & strength adaptations during training
• Enhanced glycogen synthesis
• Increased anaerobic threshold
• Possible enhancement of aerobic capacity via greater shuttling of ATP from mitochondria
• Increased work capacity
• Enhanced recovery
• Greater training tolerance
Can It Enhance Endurance Performance?
Creatine supplementation has been shown to negatively impact an athlete's VO2 max and provide relatively limited benefits at the intensity at which most endurance activities are predominant (i.e., moderate intensities). A recent meta-analysis on the effects of creatine supplementation on endurance performance in trained athletes evaluating our limited current research on this area concluded that supplementation with creatine was ineffective, regardless of the supplementation protocol, at improving endurance performance (i.e. VO2 Max, lactate threshold, time trail performance or time to exhaustion) in a trained population. However, let’s not write it off entirely just yet.
Whilst it may not come as a surprise that a supplement that predominantly improves high-intensity efforts doesn’t improve endurance performance, there are often occasions in endurance events where high-intensity efforts are required or can easily be the difference between winning or losing a race. From breaking away and sprinting for the line to overcoming short, sharp climbs, sprint performance is still highly relevant to many endurance competitions, and this is where creatine can be effective.
A few studies have evaluated the impact of creatine supplementation on high-intensity performance when it’s included in an endurance-based task. One study, particularly from Tomcik et al., (2018) took a group of well-trained cyclists and supplemented them with creatine (20 grams a day for 5 days + 3 grams a day for 9 days) before subjecting them to a 120-km cycling TT interspersed with alternating 1- and 4-km sprints (six sprints each) performed every 10 km followed by an inclined ride to fatigue (at around 90% of their VO2 Max), design to replicate the demands of a typical multistage tour. Whilst creatine did not affect the 120km time trial performance, it did increase power output during the sprint efforts. Whilst participants did gain weight in the creatine trial, it didn’t appear to negatively impact performance on a simulated uphill time trial at the end of the 120km TT. So, in effect, this study suggests that it can still be beneficial if the exercise task involves sprints, and the impact of increased body weight may be negligible.
The Body Weight Issue?
One of the significant issues with creatine supplementation is that an athlete's power-to-weight ratio, particularly on hilly courses, is a critical factor in race performance in endurance sports. Short-term, aggressive creatine loading protocols, i.e. 5-7 days of 20 grams a day of creatine, which are often used in research studies, are commonly associated with increased body weight, often in the range of 1-2kg. This is typically the result of fluid retention in the muscle. As such, there is usually a reduction in power-to-weight ratio from creatine supplementation and for a long time, this has deterred many endurance athletes from using creatine.
However, the effect of creatine on body weight doesn’t seem to be uniform, with some individuals seeing no weight gain from creatine supplementation. A meta-analysis of studies evaluating the impact on body composition found of 67 studies included, 43 observed increases in body mass, with 24 reporting no change. Similarly, a recent review alludes to weight gain predominantly being seen when athletes adopt aggressive loading strategies, and in the long term, this effect may become negligible. As such, for any athlete looking to use creatine with a concern about fluid gain, a gradual loading approach may help ensure you achieve the benefits of creatine without the negative impact on weight.
Periodised Intake
An intelligent approach to creatine supplementation for most endurance would be to use the supplement at strategic times throughout the year. For example, experimenting with creatine during a non-competitive training phase where performance is less of a focus to allow the rider to evaluate their response to it and monitor its impacts on body weight. Similarly, this could involve strategically using the supplement around key races during the season where explosive power may be a key performance determinant and power-to-weight ratio may be less of an issue (i.e. flatter race). The use of creatine may also help maximise specific training adaptations, which we’ll cover in the next section, and therefore may warrant use during specific phases of training.
It’s worth bearing in mind that once loaded, it can take around four weeks from the point of stopping taking creatine for the supplement to wash out of the system and therefore, care must be taken when using the supplement if there is concern around weight gain, as this cannot be reversed quickly.
Training Adaptations
Any dietary supplement that can enhance training volume and/or intensity has the potential to increase the training adaptations that an athlete can achieve from their training, as such helping an athlete to maximise the benefit of the work they complete or at least enhance the amount of work that they can do. Whilst there is limited evidence of benefit from creatine for endurance training adaptations, during strength and power-based training phases (i.e. winter-based gym work), there are likely significant benefits to creatine supplementation, and the strategic use of the supplement around these training blocks may be beneficial.
Glycogen Storage
One further benefit to creatine supplementation, which may benefit many endurance athletes, is its ability to augment glycogen storage. Research has shown that combining creatine with a high carbohydrate diet can enhance glycogen storage compared to placebo. The figure below is from a study that showed a 82% increase in muscle glycogen storage in a creatine compared to a placebo group after only a single day of creatine supplementation.
Is It Safe & Are There Any Health Concerns WIth Creatine Use?
Generally, the impact of creatine is seen as a positive to health and is considered safe, despite tabloid headlines.
As an athlete using any supplement, there is a always a need to ensure that you only consume a creatine supplement that has been batch-tested for banned substances by choosing a product that has informed sports testing, for example.
How much to take?
There are two main supplementation strategies that are commonly utilised in order to saturate creatine levels within the muscle, before reveting to a maintainance dose in order to maintain this saturation. Ultimately this will be a little dependent on the base levels of creatine within the muscle which will be dicatated by the creatine content of your diet.
Acute Loading Phase - 20grams of creatine monohydrate/0.3grams per kilogram body weight, divided into 3-4 doses consumed evenly throughout the day. This dose is consumed over 5 days before reverting to a maintenance dose. It’s worth noting, this approach is typically associated with the greatest increase in fluid retetion and therefore body weight, although this affect maybe relatively short term.
Chronic Loading Phase - 3-4grams of creatine monohydrate a day over 3-4 weeks.
Maintainance Phase - A typical maintenance dose of 0.03g/ kg body mass (e.g. 2.25grams a day for a 75kg athlete) continued for as long as required.
Thanks for reading, please feel free to drop a question below if you have one.
Ben
References
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