Fluid and carbohydrate consumption is crucial in order to maintain performance during a marathon run. A decrease of more than 2% of hydration in body mass can start to impair physical and cognitive function.
The study looked at improving marathon times by implementing an in-race nutritional strategy intervention.
The study: 28 non elite marathon pairs were matched
The pairs had to be of same gender and their 10km time run cannot have more than 1% difference.
On marathon day between the pair they were split into a either 1) freely chosen strategy (FRE), where the runners would choose when and how much they would drink and consume the gel packs, while 2) nutritional strategy group (SCI) consumed 0.750L water, 3 x gels packs every hour.
(each gel contains 20g of glucose & maltodextrin, 0.02g sodium & 0.03g caffeine)
Results: The SCI group was overall 11 minutes faster (5%) compared to the FRE group.
Water consumption was the same between the 2 groups
SCI group consumed considerably more carbohydrates (64.7g/hr) than FRE group (38.0g/hr)
Between 30-35km FRE group dropped significantly in running speed
Conclusion: The study attributed a faster marathon time in the SCI group due to higher carbohydrate consumption. It highlights the importance of adequate nutrition during race day for a better performance.
Hansen et al. (2014). Improved Marathon Performance by In-Race Nutritional Strategy Intervention