Writing in the Journal of the International Society of Sports Nutrition, scientists from the University of Campinas and the University of Sao Paulo report that 0.5 grams of sodium citrate (SC) per kg of body mass led to greater shot consistency and a greater amount of games won in simulated matches.
“Importantly, no players reported any significant GI discomfort following SC supplementation,” they wrote.
“Practically, it appears that SC supplementation can be safely and effectively utilized in tennis players to enhanced skilled performance.
“Although, it cannot be known from these results if SC supplementation would be beneficial in long lasting matches, previous data has shown SC to be effective for up to 30 km of cycling, thus it is possible that SC could be beneficial in matches lasting for multiple hours. Importantly, if SC is utilized in training sessions, training volume could be increased to allow for greater duration of quality skill practice.”
"A mixed bag"
Commenting independently on the study’s findings, Dr Chad Kerksick, director of the Exercise and Performance Nutrition Laboratory at Lindenwood University in Missouri, told us that previous work on sodium citrate has been a “mixed bag of outcomes with many initial null outcomes may being due to inappropriate study designs”, before noting that the new study used a randomized, double-blind, placebo-controlled crossover design, which he described as “always a good start to developing a sense of trust for their outcomes”.
Dr Kerksick also said that the use of trained athletes was a positive, but the fact that tennis was investigated does hinder its external validity.
“Their measured outcomes were realistic and suitable for what they intended to investigate,” he added.
The researchers recruited 10 Brazilian nationally-ranked young male tennis players to participate in their study. The players were randomly given either placebo or 500 mg of SC per kg of body mass of sodium citrate two hours before skill tennis performance tests (STPT) and repeated-sprint ability shuttle tests. These tests were followed by a one hour simulated match.
Results showed that the sodium citrate group experienced increases in all metabolic parameters, including pH, from the start of the study to pre-match and then post-match. Pre- and post-match increases were greater compared to placebo, said the researchers.
“[T]he current study not only noted superior shot consistency (%) in STPT and a greater amount of games won in the simulated match in SC compared to [placebo], but also a positive correlation between pH level and games won,” wrote the researchers.
“Therefore, it seems that SC was able to prolong muscle contractile capabilities.
“Theoretically, prolonging muscle force production would enhance an athlete’s ability to perform training volume, which is the training variable most closely and positively associated with muscle performance adaptations.”
Source: Journal of the International Society of Sports Nutrition
Volume 16, Article number: 32, doi: 10.1186/s12970-019-0297-4
“Sodium citrate supplementation enhances tennis skill performance: a crossover, placebo-controlled, double blind study”
Authors: V.C.R. Cunha et al.