Caffeine vs. Carbohydrate Mouth Rinsing in Soccer

Participants' solutions were prepared in separate Falcon Sterile Tubes: LSPTCAFF (1.2% w/v caffeine solution, Nature's Supreme). An MRI was performed before the LSPT. The solution was sweetened with non-caloric artificial sweeteners consisting of sucralose. The caffeine solution was prepared in an equivalent saccharin base and shaken for 30 seconds in a vortex mixer to ensure distinguishability. Participants swished the solution in their mouth for 10 seconds before LSPT and then emptied it back into the container to be weighed again. To ensure that the solutions were not swallowed, the containers were measured before and after all MRs using a full precision balance (Etekcity, USA) accurate to 1 g/0.04 oz.

Participants' solutions were prepared in separate Falcon Sterile Tubes: LSPTCHO (6% w/ v glucose solution, Protein Ocean, Turkey) An MRI was performed prior to LSPT. The solution was sweetened with non-caloric artificial sweeteners consisting of sucralose. The CHO solution was prepared in an equivalent saccharin base and shaken for 30 seconds in a vortex mixer to ensure distinguishability. Participants swished the solution in their mouth for 10 seconds before LSPT and then emptied it back into the container to be weighed again. To ensure that the solutions were not swallowed, the containers were measured before and after all MRs using a full precision balance (Etekcity, USA) accurate to 1 g/0.04 oz.

For the control condition, no supplements were taken and only exercise was performed.