Effects of Caffeinated Chewing Gum on Shot Put Performance
Phase: NA
Conditions: Performance Enhancing Product Use
Sponsor: National Taiwan Sport University

Effects of Caffeinated Chewing Gum on Shot Put Performance 
 
Document Date: Jan 05 2026 
IRB approved date: August 1, 2025 
 
Project summary 
15-20 active throwers who have received professional shot put training are expected to 
be recruited for the study. In a randomisation crossover design, the study was divided 
into caffeinated chewing gum trial (CCG) and placebo trail (PL). Participants wore a 
heart rate monitor to record their heart rate and heart rate variability during the 
experiment, and were given either a caffeinated chewing gum containing 3 mg/kg of 
body weight (CAP trial) or a placebo chewing gum, and rested for 15 minutes. After 
the warm-up, the athletic ability test and shot put performance were conducted in order. 
Saliva samples were collected for analysis of caffeine and α-amylase before and at the 
end of the experiment. 
 
Introduction 
The shot put is a discipline emphasizing explosive power, requiring athletes to propel 
the shot to a standard height and angle within a brief timeframe to achieve optimal 
distance. Previous studies have shown that increased sympathetic nervous system 
activation can effectively enhance energy output during maximal exercise intensity and 
improve torque during isometric contraction of the quadriceps femoris. Research on 
caffeine and shot put performance remains limited. In a 2012published in 2012, 
morning caffeine supplementation significantly improved alertness and throwing 
distance in shot put athletes. Another study found that 3 mg of caffeine per kilogram of 
body weight effectively enhanced several physiological indicators related to explosive 
power, but only marginally affected shot put distance. Considering the combined 
findings of these two studies, current research has not specifically examined the effects 
of caffeine supplementation on autonomic nervous system changes or blood and saliva 
biochemical indicators. Therefore, future studies that strengthen the investigation of 
these two areas would still hold potential for publication.  
 
Methods 
Study design 
This study employed a randomized crossover, double-blind experimental design, 
divided into two trials: the caffeinated chewing gum trial (CCG) and a placebo trial 
(PL). All trials were scheduled for completion during the off-season. Off-season 
training featured similar schedules Monday through Friday, with weekends reserved for 

rest and recovery. Consequently, trials commenced on Mondays following athletes' 
return from rest periods to ensure consistent pre-trial recovery states. Following the first 
trial, after 5 days of rest and 2 days of recovery, the second and third trials will be 
conducted immediately. The trial sequence will be randomized by computer. 
 
Participants 
This study plans to recruit 15-20 active throwing athletes with professional shot put 
training as subjects. Inclusion criteria are: 1. At least 6 years of training in shot put or 
related track and field throwing events. 2. No cardiovascular or joint diseases. 3. 
Recovered from sports injuries such as strains or sprains for at least 3 months. Exclusion 
criteria are: 1. Non-specialized track and field throwers. 2. Presence of cardiovascular 
or joint diseases, or any conditions that may be exacerbated by exercise. 3. Female and 
underage subjects. 4. Individuals with caffeine sensitivity. The consent form is 
completed after the participant has given consent. This study was conducted following 
the Declaration of Helsinki. 
 
Protocol 
All experiments are scheduled to commence at 3:00 PM. Upon arrival at the assembly 
area, participants must rest in a seated position for at least 10 minutes. Subsequently, 
saliva samples will be collected for subsequent biochemical analysis. Concurrently, 
participants will wear heart rate monitors to record heart rate and heart rate variability 
changes throughout the experiment. Immediately after, participants chewed caffeine 
gum (3 mg/kg body weight) for 10 minutes (CCG trial) or caffeine-free placebo gum 
(3 mg/kg body weight) for 10 minutes (PL trial) before discarding it. They then began 
a dynamic warm-up lasting approximately 15 minutes. For caffeine gum, chewing for 
10 minutes followed by a 15-minute rest period allowed for peak salivary caffeine 
concentration. Following the warm-up, a second saliva sample was collected. After 
sample collection, participants sequentially performed maximum grip strength, vertical 
jump, and squat tests. After testing, subjects rested for 5 minutes before performing the 
shot put-specific test. Following this test, participants provided another saliva sample, 
concluding the entire testing protocol. 
 
Caffeine and placebo gum 
The caffeinated chewing gum employed in the present study (Military Energy Gum, 
Arctic Mint flavour; Stay Alert, Chicago, USA) has been utilised in previous studies(1, 
2). It is estimated that a single piece of gum contains approximately 5 grams and 100 
milligrams of caffeine. The placebo gum was a commercially available blue mint gum 

(Lotte Gum Mint., Ltd., Tokyo,Japan). In order to administer a dose of 3 mg/kg of 
caffeine per unit of body weight, it was necessary to crush, grind, blend, reshape and 
flavor all chewing gums with 0.3 g of peppermint-flavored powder. The process was 
designed to ensure that the new chewing gums were comparable to the original in terms 
of appearance, color, flavor, weight and size. Previous studies have demonstrated that 
this method renders it impossible for the participant to distinguish the type of gum (1, 
3). 
 
Saliva sample collection and analysis 
Saliva samples were stored in a refrigerator at -80 degrees immediately after collection. 
For analysis, samples were thawed and centrifuged at 4000 rpm for 5 min. 500 μL of 
saliva samples were transferred to glass tubes for mass spectrometry analysis and 
Enzyme-linked immunosorbent assay (ELISA) analysis respectivelyThe analysis of 
saliva α-amylase concentration was conducted utilising an enzyme-linked 
immunosorbent assay (ELISA) with commercially available reagents (Neogen 
Corporation, Kentucky, USA; Salimetrics LLC, State College, PA, USA).  
 
Statistical analysis 
All data are presented as means ± standard deviations. The Shapiro–Wilk test was 
utilised to evaluate the normality of the data. The grip strength and number of fall on 
each rounds between the two trials were analyzed using paired t-tests. The saliva 
caffeine and α-amylase concentration and RPE were analyzed using two-way ANOVA 
with repeated measures. If the interaction effect (trial × time) were significant, the 
Bonferroni method was used to perform post hoc comparisons. Effect sizes were 
calculated using Cohen's d to quantify the magnitude of observed ef-fects and defined 
as trivial (<0.20), small (0.20–0.40), moderate (0.40–0.80), and large (>0.8), 
respectively. The power value of each data was conducted using G*Power 3.1.9.6 
software (4) 
 
 
 

Reference 
 
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