The purpose with this study was to investigate the effect of a carbohydrate (CHO) mouth rinse protocol on simulated cross country (XC) sprint. The primaryaim was to investigate ifa 10 secCHO solutionmouth rinsingprotocolimprovedthe finish timein a simulated cross country (XC) sprint(800 meters for female and 1000 meters for male) compared with control (CON).The second aim was to examif post-finish blood lactateconcentrationwouldbe lowercompared with CONwith mouth rinsing. Seven participants(four males and three females)completed four simulated sprints, two CON and two experimentalrinse protocols, CHO solution and placebo (PLA).Time to completion was not different with CHO compared with CON or PLA (203.0 ±16.5 sec, 202.3 ± 15.7 sec, 203.3 ± 14.6respectively.p >.05).Mean power output was CON 264 ± 73, PLA 258 ± 65, CHO 261± 70.Blood lactateat 15 minweresimilar between CHO, CON and and PLA(9.9 ± 3.9 mmol 7.6 ± 4.0 mmol, 10.1 ± 3.7 mmol respectively.p >.05).We concludethat mouth rinsing a CHO solutionfor 10 sechave no effect on high intensity exercise with duration lasting between 3 and 4 minutes.