Effects of Caffeinated Chewing Gum on 400-meter Performance and Fatigue Index of Sprinters: a Crossover Trial
Phase: NA
Conditions: Caffeine, Placebo
Sponsor: Chih-Hui Chiu

Effects of caffeinated chewing gum on 400-meter performance and 
fatigue index of sprinters: a crossover trial 
 
Document Date: May 23, 2024 
 
Project summary 
The purpose of this study was to investigate the effect of caffeinated chewing gum on 
400-meter sprint performance. Methods: Eight trained sprinter were divided into 
caffeine Gum trial (CAF) and Placebo trial (PL) with a randomized, double-blind study 
design. The participants chewing either caffeine Gum (CAF trial, containing 3 mg/kg 
of caffeine) or Placebo Gum (PL) for 10 minutes. After rested for 15 minutes, the 
participants underwent a Running-Based Anaerobic Sprint Test. After a 30-minute 
break, a 400-meter sprint test was performed. The blood lactate concentration were 
collected before and after 400-meter sprint from finger. Saliva samples were predicted 
to be collected before chewing gum, before the RAST, and after a 400-meter sprint. 
Saliva samples will be analyzed for caffeine and α–amylase concentrations in saliva. 
 
Introduction  
Many athletes use caffeine (1, 3, 7-trimethylxanthine) as a nutritional supplement, 
which is widely available in everyday foods such as coffee, chocolate, tea, cola and 
energy drinks. Caffeine intake can reduce fatigue by inhibiting adenosine receptors, 
increase the ability of the sarcoplasmic reticulum to release calcium ions, maintain 
sodium-potassium ATPase activity, and increase glycolysis before exercise(1, 2), all of 
which are mechanisms that can significantly increase sprinting speed (3), repetitive 
sprinting ability, and maximal muscular strength and explosive power (4). These 
increases in physical performance may be effective in improving athletic performance. 
Previous studies have shown that a pre-exercise caffeine intake of 3-6 mg per kilogram 

of body weight can achieve the highest concentration in the bloodstream one hour after 
intake (5, 6), resulting in performance enhancement. However, caffeine is slowly 
absorbed in the gastrointestinal tract and may cause gastrointestinal discomfort or 
excessive fluid intake (8). Finding alternative forms of caffeine supplementation may 
reduce gastrointestinal discomfort. 
 
Caffeine supplementation using caffeinated gum before exercise has been found 
to be absorbed through the oral mucosa at a faster rate than caffeine capsules (7). In a 
study by Morris et al. in 2019, test subjects chewed gum containing 100 mg of caffeine 
for 2, 5, and 10 minutes to observe their caffeine absorption rate and blood levels. The 
results showed that 85% of the caffeine was effectively absorbed after 5 minutes of 
chewing caffeinated gum, and after 10 minutes, the caffeine in the gum was almost 
completely absorbed. In terms of blood concentration, the highest concentration of 
caffeine (8) was observed after 15 minutes of chewing caffeine gum. In terms of 
exercise performance, chewing gum containing 100-300 mg of caffeine 5-15 minutes 
before exercise can effectively improve aerobic capacity, slow down the decline of 
sprinting speed, increase vertical jump height, and enhance the effect of explosive 
power (9, 10). 
 
Caffeine supplementation has been shown to be effective in enhancing exercise 
performance; however, it remains unclear whether chewing caffeine has the same 
significant effect on 400-meter spirting. Therefore, the purpose of this study was to 
investigate the effect of caffeine chewing gum on 400-meter spirting exercise 
performance and fatigue index.  
 
 

Methods 
Design 
This study used a randomization crossover design with double-blind experimental 
design.  Participants will be divided into a caffeinated chewing gum trial (CAF) and a 
placebo trail (PL). The placebo trail (PL). After the first trial, the participants rested and 
recovered for 7-10 days before the next trial, which was expected to be completed 
within one month. During the trial period, all participants maintained their normal 
training status, with no changes in training or retraining menus, and no over-training or 
extra competitions. 
 
Participants 
   In this study, 15-20 healthy adult male sprinters were recruited as participants. 
Inclusion criteria were: 1. 6 years of professional short sprinting training, 2. 6 months 
of ongoing training, and 3. 3 months of recovery from sports injuries such as strains 
and sprains. Exclusions: 1. Non-specialized sprinters. 2. has not trained regularly for 
the past 6 months. 3. has recovered from an athletic injury. 4. less than 3 months of 
recovery from a sports injury, or participants with epilepsy, hypertension, 
hyperlipidemia, heart disease, arthritis, osteoporosis, brain injury, or a history of 
caffeine allergy. According to the results of last year's National Academy of Sciences 
program, caffeinated gum was found to have an effect on the fatigue index of basketball 
players with Cohen's d = 1.00. The effect was measured using the G*POWER statistical 
software, with the POWER value set to 0.8, it was found that eight participants were 
sufficient to explain the validity of the study data. In order to achieve a more precise 
POWER value, the number of participants in this study was set at 15-20. All participants 
were fully explained the experimental procedure and informed of the possible risks 
before the experiment. This study received approval from the Institutional Review 

Board of Jen-Ai Hospital - Dali Branch (202300071B0). This study was conducted 
following the Declaration of Helsinki.  
 
Protocol 
Experimental procedure 
All experiments were scheduled to start at 3:00 pm. Upon arrival at the stadium, 
participants were fitted with a heart rate monitor (RS800; Polar Electro Oy, Kempele, 
Finland) to record their quiet heart rate and heart rate variability. This heart rate meter 
has been found to have very good reliability in measuring heart rate variability during 
exercise (11). After the heart rate meter is attached, the saliva of the participant is 
collected and analyzed for biochemical parameters. At the same time, a fingertip blood 
sample was taken to analyze the blood lactate concentration in the quiet state. After a 
10-minute rest period, the participant will start a dynamic warm-up and record the 
content of the warm-up, and use the same warm-up content in the next experiment. 
After the warm-up, participants chewed caffeine gum (4 mg/kg for 10 minutes each 
time) or placebo (regular gum for 10 minutes each time) and rested for 15 minutes after 
the chewing. Before and after the 400-meter test, saliva samples and fingertip blood 
were taken again for subsequent biochemical and blood lactate analyses. After 
completing the first experiment, we rested for 7 days and then proceeded to the second 
formal experiment. Both experiments were completed within one month. 
 
Outcome measure 
The countermovement jump test was performed using a jumping mat (Fusion 
Sport, Coopers Plains, QLD, Australia). The participant stands on the jumping mat and 
stays as still as possible, jumping with his hands on his hips without swinging. After 
hearing the tester's instruction, the participant quickly squatted down until the knees 

were bent at a ninety-degree angle, and then jumped vertically as quickly as possible, 
allowing the feet to return to the jumping mat at the same time as a cushion. A total of 
3 jumps were performed and the average height was analyzed. 
The anaerobic sprint test, which consists of six 35-m maximal effort sprints with 
a 10-second rest between sets, measures peak power, mean power, minimum power, 
and fatigue index. It has been shown to have adequate reliability (12). The first time 
gate was placed at the starting position and the second time gate was placed at the 35m 
end point, with a sufficient distance for a 10 second buffer. After the participants were 
familiarized with the test procedure, they could start to prepare for the test. When the 
participants is ready, he stays still and completes six 35-meter sprints at maximum effort, 
with a 10-second break between each sprint. The time of completion of each sprint was 
recorded for subsequent analysis. 
The 400-meter segmented sprint test is conducted using a timing grating (Witty, 
Microgate, Bolzano, Italy), which is placed at the starting point, 100 meters, 200 meters, 
300 meters and 400 meters.  
 
Caffeine and placebo gum 
The caffeinated chewing gum used in this study (Military Energy Gum, Arctic 
Mint flavor; Stay Alert, Chicago, USA) has been used in previous studies (13). Each 
piece of gum contains 100 mg of caffeine in approximately 5 g of gum. The placebo 
gum used was a commercially available blue mint gum. In order to provide 4 mg of 
caffeine per kilogram of body weight and to achieve a double-blind effect, all chewing 
gums will be mashed, ground, homogenized, and reshaped with 0.3 g of peppermint 
flavoring powder, and will be similar in color, appearance, taste, weight, and size. All 
chewing gums were prepared by specialized personnel and given to the on-site testers 
after numbering. After chewing the gum, a questionnaire was given to the subjects to 

confirm whether they could tell the difference between the two chewing gums. 
 
Statistical analysis 
All data are presented as averages ± standard deviations. The Shapiro–Wilk test 
was used to examine the normality of the data. The result of were analyzed through a 
paired sample t test. All data were calculated using SPSS (version 20, Chicago, IL, 
USA), and the significance level was α < 0.05. 
 
 
 
 

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