Supplementation of caffeine and sodium bicarbonate together could not improve performance and performance-related factors in CrossFit participants: a randomized, double-blind, placebo-controlled study

Amirhosein Ziyaiyan; Fatemeh Shabkhiz; Martin Hofmeister

doi:10.1080/15502783.2023.2206390

Supplementation of caffeine and sodium bicarbonate together could not improve performance and performance-related factors in CrossFit participants: a randomized, double-blind, placebo-controlled study

J Int Soc Sports Nutr. 2023 Dec;20(1):2206390. doi: 10.1080/15502783.2023.2206390.

Authors

Amirhosein Ziyaiyan¹, Fatemeh Shabkhiz², Martin Hofmeister³

Affiliations

¹ Department of Exercise Physiology, Faculty of Physical Education and Sports Science, University of Tehran, Tehran, Iran.
² Department of Exercise Physiology, Faculty of Physical Education and Sports Sciences, University of Tehran, Tehran, Iran.
³ Department Food and Nutrition, Consumer Centre of the German Federal State of Bavaria, Munich, Germany.

Abstract

Background: CrossFit includes weightlifting, powerlifting, and gymnastics in various combinations of overloads and repetitions with limited rest periods or no rest between training sets. Due to the novelty of CrossFit, there are few studies on the effect of nutritional strategies on the acute response to this type of sports activity. This study examined the effect of caffeine (CAF) and sodium bicarbonate (NaHCO₃) ingestion separately and in combination on the performance and rate of perceived exertion (RPE) during the Cindy CrossFit workout (Cindy) in CrossFit participants.

Method: In a double-blind, crossover, randomized, placebo-controlled trial, 20 CrossFit participants underwent five experimental conditions, including control (CON), placebo (PLA), CAF, NaHCO₃, and CAF + NaHCO₃ (7 days to wash-out between assessment sessions) before completing the Cindy protocol (age: 22.30 ± 2.88 years, body mass index: 25.22 ± 2.51 kg/m²). Capsules containing 6 mg/kg body weight (BW) CAF were consumed 50 min before the Cindy workout while 0.3 g/kg BW NaHCO₃ was consumed for 3 days, leading to 120, 90, and 60 min before the Cindy workout. Performance, RPE, muscular power (MP), handgrip strength (HGS), and maximum heart rate (MHR) were measured before and shortly after the Cindy.

Results: The performance of CrossFit participants during the Cindy protocol was not significantly improved following CAF, NaHCO₃, and CAF + NaHCO₃ (P > 0.05). In contrast, RPE during and at the end of the Cindy was significantly decreased following CAF + NaHCO₃ consumption compared to PLA and CON (P = 0.001, P = 0.02). However, MP (P = 0.82) and HGS (P = 0.52) were not significantly different between conditions. Also, MHR was significantly greater following CAF, NaHCO₃, and CAF + NaHCO₃ consumption than CON (P = 0.01).

Conclusion: CAF + NaHCO₃ supplementation decreased RPE despite significantly increased MHR, but with no significant effect on performance, HGS, or MP. Therefore, CrossFit participants may benefit from the ergogenic effects of CAF and NaHCO₃ when consumed separately or together.

Keywords: Sports performance; muscle strength; sports nutrition; supplementation.

Publication types

Randomized Controlled Trial

MeSH terms

Adult
Athletic Performance* / physiology
Caffeine* / pharmacology
Cross-Over Studies
Dietary Supplements
Double-Blind Method
Hand Strength
Humans
Polyesters
Sodium Bicarbonate / pharmacology
Young Adult

Substances

Caffeine
Sodium Bicarbonate
Polyesters

Grants and funding

The author(s) reported that there is no funding associated with the work featured in this article.