You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Mouth Rinsing with Maltodextrin Solutions Fails to Improve Time Trial Endurance Cycling Performance in Recreational Athletes
Abstract 1:
The carbohydrate ( CHO ) concentration of a mouth rinsing solution might influence the CHO sensing receptors in the mouth , with consequent activation of brain regions involved in reward , motivation and regulation of motor activity . The purpose of the present study was to examine the effects of maltodextrin mouth rinsing with different concentrations ( 3 % , 6 % and 12 % ) after an overnight fast on a 20 km cycling time trial performance . Nine recreationally active , healthy males ( age : 24 ± 2 years ; V˙O2max : 47 ± 5 mL·kg−1·min−1 ) participated in this study . A double-blind , placebo-controlled r and omized study was conducted . Participants mouth-rinsed every 2.5 km for 5 s. Maltodextrin mouth rinse with concentrations of 3 % , 6 % or 12 % did not change time to complete the time trial and power output  compared to placebo (  p > 0.05 ) . Time trial completion times were 40.2 ± 4.0 , 40.1 ± 3.9 , 40.1 ± 4.4 , and 39.3 ± 4.2 min and power output 205 ± 22 , 206 ± 25 , 210 ± 24 , and 205 ± 23 W for placebo , 3 % , 6 % , and 12 % maltodextrin conditions , respectively . Heart rate , lactate , glucose , and rating of perceived exertion did not differ between trials ( p > 0.05 ) . In conclusion , mouth rinsing with different maltodextrin concentrations after an overnight fast did not affect the physiological responses and performance during a 20 km cycling time trial in recreationally active males


Title 2:
Effect of a carbohydrate mouth rinse on simulated cycling time-trial performance commenced in a fed or fasted state.
Abstract 2:
It is presently unclear whether the reported ergogenic effect of a carbohydrate ( CHO ) mouth rinse on cycling time-trial performance is affected by the acute nutritional status of an individual . Hence , the aim of this study was to investigate the effect of a CHO mouth rinse on a 60-min simulated cycling time-trial performance commenced in a fed or fasted state . Twelve competitive male cyclists each completed 4 experimental trials using a double-blinded Latin square design . Two trials were commenced 2 h after a meal that contained 2.5 g·kg(-1 ) body mass of CHO ( FED ) and 2 after an overnight fast ( FST ) . Prior to and after every 12.5 % of total time during a performance ride , either a 10 % maltodextrin ( CHO ) or a taste-matched placebo ( PLB ) solution was mouth rinsed for 10 s then immediately expectorated . There were significant main effects for both pre-ride nutritional status ( FED vs. FST ; p < 0.01 ) and CHO mouth rinse ( CHO vs. PLB ; p < 0.01 ) on power output with an interaction evident between the interventions ( p < 0.05 ) . The CHO mouth rinse improved mean power to a greater extent after an overnight fast ( 282 vs. 273 W , 3.4 % ; p < 0.01 ) compared with a fed state ( 286 vs. 281 W , 1.8 % ; p < 0.05 ) . We concluded that a CHO mouth rinse  improved performance to a greater extent in a fasted compared with a fed state ; however , optimal performance was achieved in a fed state with the addition of a CHO mouth rinse


Title 3:
Mouth Rinsing With Carbohydrate Solutions at the Postprandial State Fail to Improve Performance During Simulated Cycling Time Trials
Abstract 3:
Abstract Ispoglou , T , O'Kelly , D , Angelopoulou , A , Bargh , M , O'Hara , JP , and Duckworth , LC . Mouth rinsing with carbohydrate solutions at the postpr and ial state fail to improve performance during simulated cycling time trials . J Strength Cond Res 29(8 ) : 2316–2325 , 2015—Mouth rinsing with carbohydrate ( CHO ) solutions during cycling time trials results in performance enhancements ; however , most studies have used approximately 6 % CHO solutions . Therefore , the purpose of this study was to compare the effectiveness of mouth rinsing with 4 , 6 , and 8 % CHO solutions on 1-hour simulated cycling time trial performance . On 4 occasions , 7 trained male cyclists completed at the postpr and ial period , a set amount of work as fast as possible in a r and omized counterbalanced order . The subjects rinsed their mouth for 5 seconds , on completion of each 12.5 % of the trial , with 25 ml of a non-CHO placebo and 4 , 6 , and 8 % CHO solutions . No additional fluids were consumed during the time trial . Heart rate ( HR ) , ratings of perceived exertion ( RPE ) , thirst ( TH ) , and subjective feelings ( SF ) were recorded after each rinse . Furthermore , blood sample s were drawn every 25 % of the trial to measure blood glucose and blood lactate concentrations , whereas whole-body CHO oxidation was monitored continuously . Time to completion was not significant between conditions with the placebo , 4 , 6 , and 8 % conditions completing the trials in 62.0 ± 3.0 , 62.8 ± 4.0 , 63.4 ± 3.4 , and 63 ± 4.0 minutes , respectively . There were no significant differences between conditions in any of the variables mentioned above ; however , significant time effects were observed for HR , RPE , TH , and SF . Post hoc analysis showed that TH and SF of subjects in the CHO conditions but not in the placebo were significantly increased by completion of the time trial . In conclusion , mouth rinsing with CHO solutions did not impact 1-hour cycling performance in the postpr and ial period and in the absence of fluid intake . Our findings suggest that there is scope for further research to explore the activation regions of the brain and whether they are receptive to CHO dose , before specific recommendations for athletic population s are established . Consequently , mouth rinsing as a practical strategy for coaches and athletes is question able under specific conditions and should be carefully considered before its inclusion . Emphasis should be focused on appropriate dietary and fluid strategies during training and competition


Title 4:
The effect of carbohydrate mouth rinse on 1-h cycle time trial performance.
Abstract 4:
PURPOSE AND METHOD To investigate the possible role of carbohydrate ( CHO ) receptors in the mouth in influencing exercise performance , seven male and two female endurance cyclists ( VO(2max ) 63.2 + /- 2.7 ( mean + /- SE ) mL.kg*(-1).min(-1 ) ) completed two performance trials in which they had to accomplish a set amount of work as quickly as possible ( 914 + /- 40 kJ ) . On one occasion a 6.4 % maltodextrin solution ( CHO ) was rinsed around the mouth for every 12.5 % of the trial completed . On the other occasion , water ( PLA ) was rinsed . Subjects were not allowed to swallow either the CHO solution or water , and each mouthful was spat out after a 5-s rinse . RESULTS Performance time was significantly improved with CHO compared with PLA ( 59.57 + /- 1.50 min vs 61.37 + /- 1.56 min , respectively , P = 0.011 ) . This improvement result ed in a significantly higher average power output during the CHO compared with the PLA trial ( 259 + /- 16 W and 252 + /- 16 W , respectively , P = 0.003 ) . There were no differences in heart rate or rating of perceived exertion ( RPE ) between the two trials ( P > 0.05 ) . CONCLUSION The results demonstrate that carbohydrate mouth rinse has a positive effect on 1-h time trial performance . The mechanism responsible for the improvement in high-intensity exercise performance with exogenous carbohydrate appears to involve an increase in central drive or motivation rather than having any metabolic cause . The nature and role of putative CHO receptors in the mouth warrants further investigation


Title 5:
Design and analysis of research on sport performance enhancement.
Abstract 5:
PURPOSE The purpose of this study was to assess research aim ed at measuring performance enhancements that affect success of individual elite athletes in competitive events . ANALYSIS Simulations show that the smallest worthwhile enhancement of performance for an athlete in an international event is 0.7 - 0.4 of the typical within-athlete r and om variation in performance between events . Using change in performance in events as the outcome measure in a crossover study , research ers could delimit such enhancements with a sample of 16 - 65 athletes , or with 65 - 260 in a fully controlled study . Sample size for a study using a valid laboratory or field test is proportional to the square of the within-athlete variation in performance in the test relative to the event ; estimates of these variations are therefore crucial and should be determined by repeated- measures analysis of data from reliability studies for the test and event . Enhancements in test and event may differ when factors that affect performance differ between test and event ; overall effects of these factors can be determined with a validity study that combines reliability data for test and event . A test should be used only if it is valid , more reliable than the event , allows estimation of performance enhancement in the event , and if the subjects replicate their usual training and dietary practice s for the study ; otherwise the event itself provides the only dependable estimate of performance enhancement . Publication of enhancement as a percent change with confidence limits along with an analysis for individual differences will make the study more applicable to athletes . Outcomes can be generalized only to athletes with abilities and practice s represented in the study . CONCLUSION estimates of enhancement of performance in laboratory or field tests in most previous studies may not apply to elite athletes in competitive events
The key to time-trial performance is the completion of a set distance or work in the shortest time possible , so the cyclist should produce the highest average power .
This relationship can be expressed as power = k(speed)x , where k and x are constant for a particular mode of exercise and for a specific ergometer in cycling [ 5 , 6 ] .