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To determine the effect of a caffeine-containing supplement on golf specific performance and fatigue during a 36-hole competitive golf tournament METHODS: Twelve male golfers (34.8 ± 13.9 yrs, 175.9 ± 9.3 cm, 81.23 ± 13.14 kg) with a United States Golf Association (USGA) handicap of 3-10 participated in a double-blind, placebo-controlled, crossover design in which they played an 18-hole round of golf on two consecutive days (36-hole tournament) and were randomly assigned to consume a caffeine-containing supplement (CAF) or placebo (PLA). CAF/PLA was consumed before and after 9 holes during each 18-hole round. Total score, drive distance, fairways and greens in regulation, first putt distance, heart rate, breathing rate, peak trunk acceleration and trunk posture while putting were recorded. Self-perceived ratings of energy, fatigue, alertness and concentration were also recorded. Total score (76.9 ± 8.1 vs 79.4 ± 9.1, p=0.039), greens in regulation (8.6 ± 3.3 vs 6.9 ± 4.6, p=0.035) and drive distance (239.9 ± 33.8 vs 233.2 ± 32.4, p=0.047) were statistically better during the CAF condition compared to PLA. Statistically significant main effects for condition (p<0.05) and time (p<0.001) occurred for perceived feelings of energy and fatigue. Compared to PLA, CAF reported more energy (p=0.025) and less fatigue (p=0.05) over the competitive round of golf. There were no substantial differences in heart or breathing rates, peak trunk acceleration or putting posture between conditions or over the round (p>0.05). A moderate dose (1.9 ± 0.3 mg[BULLET OPERATOR]kg) of caffeine consumed before and during a round of golf improves golf-specific measures of performance and reduces fatigue in skilled golfers.
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Effect of Caffeine on Golf Performance and
Fatigue during a Competitive Tournament
Molecular and Applied Sciences Laboratory, School of Kinesiology, Auburn University, Auburn, AL;
Department of Human
Performance Studies, Wichita State University, Wichita, KS;
Department of Applied Physiology and Wellness, Southern
Methodist University, Dallas, TX;
School of Medical and Applied Sciences, Central Queensland University, Rockhampton,
Queensland, AUSTRALIA;
MusclePharm Sport Science Institute, Denver, CO; and
Department of Cell Biology and
Physiology, Edward Via College of Osteopathic Medicine, Auburn Campus, Auburn, AL
Effect of Caffeine on Golf Performance and Fatigue during a Competitive Tournament. Med. Sci. Sports Exerc., Vol. 48, No. 1, pp. 132–138,
2016. Purpose: This study aimed to determine the effect of a caffeine-containing supplement on golf-specific performance and fatigue
during a 36-hole competitive golf tournament. Methods: Twelve male golfers (34.8 T13.9 yr, 175.9 T9.3 cm, 81.23 T13.14 kg) with a
United States Golf Association handicap of 3–10 participated in a double-blind, placebo-controlled, crossover design in which they
played an 18-hole round of golf on two consecutive days (36-hole tournament) and were randomly assigned to consume a caffeine-
containing supplement (CAF) or placebo (PLA). CAF/PLA was consumed before and after nine holes during each 18-hole round.
Total score, drive distance, fairways and greens in regulation, first putt distance, HR, breathing rate, peak trunk acceleration, and trunk
posture while putting were recorded. Self-perceived ratings of energy, fatigue, alertness and concentration were also recorded.
Results: Total score (76.9 T8.1 vs 79.4 T9.1, P= 0.039), greens in regulation (8.6 T3.3 vs 6.9 T4.6, P= 0.035), and drive distance
(239.9 T33.8 vs 233.2 T32.4, P= 0.047) were statistically better during the CAF condition compared with those during PLA.
Statistically significant main effects for condition (PG0.05) and time (PG0.001) occurred for perceived feelings of energy and
fatigue. Compared with PLA, CAF reported more energy (P= 0.025) and less fatigue (P= 0.05) over the competitive round of golf.
There were no substantial differences in HR or breathing rates, peak trunk acceleration, or putting posture between conditions or over
the round (P90.05). Conclusions: A moderate dose (1.9 T0.3 mgIkg
) of caffeine consumed before and during a round of golf
improves golf-specific measures of performance and reduces fatigue in skilled golfers. Key Words: NUTRITION, GOLFERS,
Golf is a popular sport around the world with in-
dividuals playing competitively and recreationally.
When played competitively, golf involves high
cognitive loads, critical shot-making decisions, hand–eye
coordination, high-level motor and biomechanical skill, and
an extended duration of play that exceeds most other sports
(28). From an intensity perspective, the physiological de-
mands of golf are considered low, with one round of 18
holes taking approximately 4 h to complete and having an
energy expenditure of 4.3–4.5 METs (1,11). However, one
round of golf can result in walking well over 10,000 steps
covering distances over 8000 m (13). Furthermore, com-
petitive golf settings include preround warm-ups, practice
swings, and execution of in-round swings. During an 18-hole
round, swinging a golf club will be repeated, on average,
50 times and over 300 times during a practice session (30).
This combination of critical shot-making decisions, multiple
maximum effort swings, putting, and long distances of walk-
ing during the round can result in physical and mental fatigue,
which can potentially have a negative effect on golf perfor-
mance (9,29). Specifically, mental fatigue may affect the
ability to select the correct club, shot type, and execution of
the golf shot (28), whereas physical fatigue may affect the
mechanics of the golf swing (14). Therefore, competitive
golfers may benefit from preround and in-round nutritional
and supplementation strategies aimed at offsetting fatigue
experienced during a competitive round of golf (13).
Because caffeine has psychological and physiological
effects, it has become one of the most consumed ergogenic
aids to date (3). Indeed, Del Coso et al. (8) reported that
74% of the 20,686 elite athletes sampled between years
2004 and 2008 were found to consume caffeine either be-
fore or during competition. Furthermore, consuming mod-
erate doses of caffeine either 1 h before or throughout the
cycling exercise has been shown to enhance performance
and improve time to fatigue (7,20). The ergogenic benefits
Address for correspondence: Kaelin C. Young, Ph.D., Edward Via College
of Osteopathic Medicine, Auburn Campus, 910 S. Donahue Dr., Auburn,
AL 36832; E-mail:
Submitted for publication April 2015.
Accepted for publication July 2015.
Copyright Ó2015 by the American College of Sports Medicine
DOI: 10.1249/MSS.0000000000000753
Copyright © 2015 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
of caffeine are not restricted solely to physical performance
outcomes because several studies support its effectiveness
of enhancing cognitive ability during mentally (19) and
physically fatiguing tasks (19,27). For instance, in situa-
tions where fatigue is forced such as in sleep deprivation
studies, moderate doses of caffeine have been shown to
reduce fatigue during short-term vigilance tasks (32). There-
fore, caffeine may play an important role in performance
outcomes during periods of increased cognitive demand, re-
action time, and when technical/tactical skills have a major
influence on physical and mental performance (15,33). To
our knowledge, only one study has previously attempted to
determine the effects of caffeine supplementation on golf
performance. Stevenson et al. (29) determined the acute
effects of a caffeine and glucose drink on golf performance
in a laboratory setting to simulate competitive golf course
play (29). Their findings suggested that consuming a combi-
nation of glucose and caffeine was beneficial for minimizing
fatigue and improving golf performance. However, there is
a lack of research on overall golf performance in a true
competitive tournament setting. Therefore, the purpose of
this study was to investigate the acute effects of a caffeine-
containing nutritional supplement on golf performance and
fatigue during a competitive 36-hole tournament.
Subjects. A convenience sample of 12 male golfers
(Table 1) were recruited from local golf courses, newspaper
advertisements, and the local university campus. Participants
were included if they were habitual caffeine consumers (35–
300 mgId
), had a United State Golf Association (USGA)
handicap between 3 and 10, were between 20 and 55 yr of
age, free of known cardiovascular, respiratory, metabolic, or
musculoskeletal ailments, and were not taking any other pur-
ported performance-enhancing supplements/ergogenic aids.
After ethical approval from the institutional review board,
participants were informed of all experimental procedures, read
and signed informed consent forms, and filled out medical
history forms detailing caffeine use and golf playing history.
Experimental protocol. In a double-blind, placebo-
controlled, crossover design, participants played an 18-hole
round of golf on two consecutive days (36-hole tournament).
A simple randomization procedure was used to assign par-
ticipants to consume a caffeine-containing supplement
(CAF) or placebo (PLA) during each 18-hole round. Par-
ticipants reported to the human performance laboratory 1 wk
before their first round of golf for anthropometric and
physiological assessments. During this visit, participants
were familiarized with tournament procedures and USGA
rules. The tournament was conducted at the local university
golf course where tee box markers and hole locations were
held constant. To ensure a competitive setting, a $1000
purse provided by the researchers was awarded to partici-
pants on the basis of the place finished in the 36-hole tour-
nament. Participants were allowed to use their own golf
equipment (clubs/golf balls) but were restricted to remain
consistent between 18-hole rounds. The brands/models of
golf equipment were documented before the start of the
tournament, and adherence was ensured by researchers be-
fore the start of each round. Importantly, each participant
had previously played a round of golf on the golf course.
On the day of each round, participants were informed to
abstain from consuming any foods, drinks, or nutritional
products containing caffeine, to arrive hydrated, and to have
consumed a meal 2 h before. Participants were asked to
follow the same procedures for the second day including
consumption of the same meal. Upon arriving, participants
produced a urine sample, were fit with a mobile physiolog-
ical monitoring device, and rested in a seated position for
10 min for collection of resting data. Afterwards, partici-
pants assigned to the CAF or PLA group consumed their
first dose and were driven to the driving range where they
were allowed 10 min to hit 20 golf balls and were not re-
stricted to swinging specific clubs. Once completed, partic-
ipants were taken to a practice hole for an iron club accuracy
assessment. The time that elapsed between the first CAF or
PLA oral dose and the accuracy assessment was approxi-
mately 25–35 min. This time course was maintained to al-
low caffeine levels to reach peak plasma concentration (4).
After the assessment, participants were driven to the first tee
box by a research assistant who collected in-round golf data
and transported golf clubs via a golf cart. Participants then
completed an energy/mood status questionnaire and began
their round of golf thereafter. Participants walked the entire
tournament and had access to chilled water bottles ad libitum.
After completion of the first nine holes, participants con-
sumed a second dose of CAF/PLA, were provided a stan-
dardized meal aimed at offsetting the decline in blood
glucose levels (13), and completed a second questionnaire.
Upon completion of the round, participants completed the
final questionnaire, physiological monitors were turned off
and collected, and participants were debriefed and reminded
of the procedures for the following day/round. See Figure 1
for an overview of the protocol.
Anthropometric and physiological assessment.
Standing height was measured to the nearest 0.5 cm using a
calibrated stadiometer. Body mass was measured with a
calibrated clinical scale to the nearest 0.01 kg with partici-
pants wearing minimal clothing (Table 1). After resting
quietly, systolic and diastolic brachial blood pressure and
HR were measured using an automatic blood pressure cuff
(model HEM-773; Omron, Vernon Hills, IL) in a seated
position. Urine samples were collected for determination of
TABLE 1. Baseline male subject characteristics (mean TSD).
Height (m) 1.76 T0.09
Weight (kg) 81.2 T13.1
Age (yr) 34.8 T13.9
BMI (kgIm
) 26.3 T3.6
USGA handicap 5.5 T2.7
Caffeine intake (mgId
) 101.7 T59.8
BMI, body mass index.
CAFFEINE AND GOLF PERFORMANCE Medicine & Science in Sports & Exercise
Copyright © 2015 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
hydration status via urine specific gravity (USG) with a
handheld refractometer (model CLX-1, precision = 0.001 T
0.001; VEE GEE Scientific, Inc.). A USG reading between
1.000 and 1.029 was considered adequately hydrated (5). If
participants had a USG reading at or above 1.030, they were
instructed to drink water and rest comfortably until a second
urine sample could be provided. Hydration was assessed as a
precautionary measure to ensure participants_safety and to
minimize the effects of dehydration on performance.
Environmental conditions. Ambient temperature (-C),
relative humidity (%), wind speed (kmIh
), and direction
during each round were documented in 30-min intervals.
Data was provided by the Wichita division of the National
Oceanic and Atmospheric Administration from weather sen-
sors located near the golf course.
Five-ball iron club accuracy assessment. On a
100.5-m practice hole, participants were allowed eight at-
tempts to land the golf ball as close to the hole as possible.
The first three attempts were for practice, and the last five were
measured. Once the golf ball came to rest, distance (m) from the
front of the ball to the middle of the hole and whether the ball
rested on the green (# balls) were measured and documented.
Distances were measured using a 92-m industrial tape measure.
Participants chose a club of their choice but maintained the use
of this club on both days. Furthermore, the same golf balls were
used each day, which were provided by researchers.
Drive and putt distance. Drive distance (m) (when
a driver club was used) was measured using a SkyCaddie
LINX GPS device (SkyHawke Technologies, LLC,
Ridgeland, MS). Once participants placed the tee and ball
into the ground of the tee box, the location was marked with
the GPS by standing directly over the ball, waiting 3 s, and
then marked using the device_s ‘‘mark ball’’ function. After
the tee shot, the resting location of the ball was identified;
the device was then held over the top of the ball for three
seconds and ‘‘marked’’ again. The distance between the two
locations was displayed on the device and documented
by researchers. Intra- and interdevice test–retest reliability was
previously determined on the same golf course from 15 dis-
tances measured twice and computed using intraclass corre-
lation coefficients (ICC), SEM, and minimal difference (MD)
to be considered real. Intradevice measurements resulted in an
ICC of 0.999, SEM of 0.73 m, and MD of 2.02 m, whereas
interdevice measurements resulted in an ICC of 0.997, SEM
of 1.92 m, and MD of 5.32 m. On the basis of this analysis,
each participant was assigned their own GPS, which was used
for both rounds. All first putt attempts were measured for
distance (m) from the front of the ball to the middle of the
hole with a 92-m industrial tape measure. Care was taken to
ensure that the tape was straight, taut, and laid flat against
the putting surface.
Physiological and accelerometry measures. HR
(bpm), breathing rate (BR, breaths per minute), trunk posture
(POS (-)), and peak trunk acceleration (ACC
(g)) were
determined using the Zephyr Bioharness
3 (Zephyr
Technology, Annapolis, MD). The device was worn just
beneath the chest across the sternum and secured with an
elastic nylon strap with extra support provided by a shoulder
strap. The monitoring device is secured to the chest strap and
acts as a transmitter and data logger. The device uses a pie-
zoelectric triaxial accelerometer, electrode, and pressure
sensors within the strap. The validity and reliability of this
device have been described previously (HR: r=0.61,PG
0.01; BR: r=0.67,PG0.01; ACC: r=0.90,PG0.01) (17).
Specifically, trunk POS immediately before putting was
assessed during the first and last three holes of each round.
Trunk ACC
was assessed on all holes only when the
FIGURE 1—Overview of experimental protocol on the day of each
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driver club was used. Data were logged, time-stamped, and
exported to Microsoft Excel (Microsoft, Redmond, WA)
immediately after each round for subsequent analysis. To
minimize interdevice error (17), all participants were
assigned their own Bioharness device, which was used for
both rounds (Table 1).
Golf-specific performance. Total score (number of
strokes to complete 18 holes), putts per round, fairways hit
in regulation (FIR, defined as the ball lying in the fairway
after a tee shot on a par 4 or 5 hole), greens hit in regulation
(GIR, defined as the ball lying on the surface of the green
after the tee shot on a par 3, after the second shot on a par 4,
or after the third shot on a par 5 hole), sand shots (defined as
a ball being hit into a sand bunker), sand save percentage
(SS%, defined as the percentage of time a golfer success-
fully hits the ball onto the green from a bunker and makes
the following putt to save par), and shots hit out of bounds
(OB, defined as a ball being hit out of the field of play
resulting in a penalty stroke) were documented by research
staff following participants throughout both rounds.
Energy/mood questionnaire. A five-item visual an-
alog scale questionnaire previously used in caffeine research
and partly adapted from Rogers et al. (26) was used to assess
self-perceived feelings of concentration, energy, fatigue,
alertness, and overall confidence. Each mood state/feeling
was followed by a 100-mm horizontal line with vertical
lines anchored at each end. The left-end anchor was labeled
‘Very Low,’ and the right anchor was labeled ‘‘Very High.’
Participants were instructed to make a vertical mark through
the line on the basis of how they felt at that moment. Re-
sponses were measured in millimeters (0–100) starting at
the left anchor of the scale. The questionnaire was admin-
istered at the beginning of each round (pre), after the ninth
hole (mid), and after the 18th hole (post).
Supplementation/in-round nutrition. Caffeine (CAF,
155 mg) was provided in two forms: raw caffeine and
(caffeine and pterostilbene; ChromaDex,
Inc., Irvine, CA) in a multi-ingredient proprietary blend sup-
plement in a purified water-based medium containing vitamin B
complex, citric acid, elevATP
(VDF FutureCeuticals Inc.,
Momence, IL) and sucralose. PLA was provided in a similar
purified water-based medium matched for color and consis-
tency but containing only sucralose to match flavor profile. To
maintain blinding, both CAF and PLA were delivered directly
from the third-party manufacturer (BioZone Laboratories, Inc.,
Pittsburg, CA) in unmarked black and white plastic vials
containing a single 2-mL serving. Vials were administered
to participants before each round of golf and after the ninth
hole. A second dose was given because of the half-life of
caffeine and the lengthy play of golf (2). After consuming
the second vial of CAF or PLA, a standardized meal pro-
protein was provided in the form of two off-the-shelf meal
replacement bars. After data analysis and drafting of the
final report, researchers were notified by the manufacturer
which color vials were the CAF and PLA.
Statistical analysis. Data are reported as mean TSD
for all dependent variables. Statistical analyses were per-
formed using SPSS for Windows version 21.0 (IBM,
Seattle, WA). Before analysis, the distributional proper-
ties of each dependent variable were tested for normality
using the Kolmogorov–Smirnov procedure, with an alpha
level of 0.05. Mean differences between conditions for
all dependent golf-specific performance variables were ex-
amined using paired-samples t-tests. Dependent variables
from the self-perceived mood and energy questionnaire
were assessed using a 2 3 (condition time) factorial
ANOVA. Physiological and accelerometry data were ana-
lyzed using a 2 2 (condition time) factorial ANOVA.
If a significant interaction effect was found, follow-up analysis
included one-way ANOVA with repeated measures and
paired-samples t-tests with Bonferroni corrections. Statis-
tical significance for all null hypothesis testing was set at
Pe0.05. Furthermore, magnitude of the effect was calcu-
lated using the formula for the Cohen d effect size: (CAF
mean jPLA mean)/pooled SD) for all performance vari-
ables with observed effects as well as 95% confidence in-
tervals (CI) for the mean difference between conditions.
Effect sizes of 0.2, 0.5, and Q0.8 were considered small,
moderate, and large, respectively.
Baseline subject characteristics are presented in Table 1.
Mean ambient temperature (36.6-CT0.8-C vs 36.7-CT
0.5-C), wind direction and speed (south 32.1 T5.6 kmIh
south 30.9 T4.6 kmIh
), and humidity (24.3% vs 28.7%)
were similar (P90.05) between rounds 1 and 2, respectively.
Under the CAF condition, mean relative CAF intake was
3.8 T0.6 mgIkg
of body mass over the entire round.
Furthermore, there was no substantial difference (P90.05)
between conditions for total water intake (CAF vs PLA,
2.21 T0.44 L vs 2.12 T0.45 L) or preround USG (1.016 T
0.006 vs 1.018 T0.006).
Iron club accuracy assessment. The mean number
of balls on the green and distance to the hole for each con-
dition is presented in Table 2. Both the number of balls on
the green (mean difference (95% CI), 1.08 (0.34–1.82); P=
0.008; ES, 0.86) and distance left to the hole (j2.42 m
(j3.95 to j0.88); P= 0.005; ES, 1.00) were statistically
better under the CAF condition compared with those in
the PLA, with the mean differences between conditions
resulting in large and meaningful effects.
Golf-specific performance. There were no substan-
tial differences in the number of FIR, putts/round, shots hit
OB, sand shots, SS%, or first putt distance between con-
ditions (Table 2). However, total score (j2.50 (j4.85 to
j0.15) strokes; P= 0.039; ES, 0.3), GIR (1.75 (0.14
3.36); P= 0.035; ES, 0.4), and drive distance (6.70 m
(0.10–13.31); P= 0.047; ES, 0.2) were statistically better
under the CAF condition compared with those under the
PLA condition.
CAFFEINE AND GOLF PERFORMANCE Medicine & Science in Sports & Exercise
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Physiological and accelerometry data. Average
HR and BR over the entire round under the CAF condition
was 120.0 T21 bpm and 19.0 T2.7 breaths per minute,
respectively, and 117.0 T14.0 bpm and 20.0 T2.0 breaths
per minute for the PLA condition, with no substantial dif-
ference between conditions (P90.05). Neither trunk posture
while putting nor peak trunk acceleration while hitting a
driver changed substantially over the round (front nine holes
vs back nine holes) or between conditions (Table 3).
Mood and energy state questionnaire. There were
no statistically significant condition–time interactions for
self-perceived ratings of alertness (P= 0.77), overall confi-
dence (P= 0.06), or concentration (P= 0.64). However, a
significant main effect for condition (P= 0.047) and time
(PG0.001) was detected for self-perceived ratings of ‘‘en-
ergy’’ (Table 4). Follow-up analyses revealed that energy
declined after 18 holes of golf compared with baseline for
both conditions, but the CAF condition maintained greater
feelings of energy after nine holes (mid) compared with PLA
(9.58 (1.44–17.73) mm; P= 0.025; ES, 0.5). Furthermore,
a statistically significant (P= 0.045) condition–time in-
teractions effect occurred for self-perceived ratings of fa-
tigue. Post hoc analysis revealed that fatigue increased over
the PLA round but did not substantially change from base-
line during the CAF round (Table 4). Lastly, golfers expe-
rienced less fatigue under the CAF condition compared with
during the PLA condition after nine holes (j13.42 mm
(j26.82 to j0.14); P= 0.05; ES, 0.6).
The objective of this study was to determine the effect of
a caffeine-containing supplement on golf performance and
fatigue in a competitive tournament setting. Our findings
suggest that acute consumption of a caffeine-containing sup-
plement taken before and during a round of golf 1) attenuates
self-perceived ratings of fatigue and sustains ratings of energy
compared with a placebo and 2) improves measures of golf-
specific performance.
Typically, golf is perceived as a nonfatiguing sport
because of the low physiological intensity at which it is
played. However, laboratory-based (29) and on-course
investigations (9) have found evidence of golf-specific fa-
tigue. Specifically, Doan et al. (9) reported an increase in
mental and physical fatigue in the latter half of a competi-
tive golf tournament in collegiate male golfers. Similarly,
Stevenson et al. (29) reported a significant decrease in mea-
sures of energy as well as a significant increase in mental
fatigue from a laboratory-based simulated round of golf. Our
findings support these results, as we found a decline in mea-
sures of energy and an increase in the perception of fatigue
throughout a competitive round of golf. However, caffeine
supplementation was able to significantly attenuate fatigue
during the round, which may have contributed to our findings
of improved measures of golf performance. Fatigue has been
shown to affect both physical and cognitive performance,
especially when cognitive tests are performed during or after
physically fatiguing exercise (21). Because competitive golf
demands a high level of cognitive and motor performance to
be successful, fatigue may negatively affect golf performance
through both central and peripheral mechanisms. The fatigue-
delaying effects of caffeine are well-known. Caffeine acts as
a CNS stimulant mainly by its interactions with adenosine
receptors functioning as a receptor antagonist, leading to
increased excitability of neuronal tissue, level of arousal,
and cognition (10,22). Along these lines, consumption of
moderate doses (100–300 mg) of caffeine has been shown
to positively affect cognitive and motor performance dur-
ing physically fatiguing tasks (15,31). Our data suggest that
a moderate dose of caffeine reduces golf-specific fatigue,
which seems to translate to improved accuracy and overall
golf performance.
TABLE 2. Golf-specific measures of performance for each condition (mean TSD).
Iron accuracy assessment
Balls on green (n) 1.75 2.83 0.008
Distance to hole (m) 7.84 5.42 0.005
FIR (n)4.7T2.0 5.3 T2.0 0.31
Putts per round (n) 33.4 T3.2 32.6 T4.7 0.49
Putt distance (m) 5.81 T0.86 5.58 T1.21 0.59
OB (n)0.7T1.2 0.2 T0.4 0.11
Sand shots (n)1.0T0.9 1.2 T1.0 0.50
SS% 25.0 T45.2 26.4 T41.1 0.67
GIR (n)6.9T4.6 8.7 T3.4 0.035
Drive distance (m) 233.3 T32.5 239.9 T33.8 0.047
Total score (strokes) 79.4 T9.1 76.9 T8.1 0.039
TABLE 3. Trunk posture while putting and peak trunk acceleration while swinging
(mean TSD).
Condition Front Nine Back Nine P
Posture (-) PLA 36.5 T7.0 36.9 T7.7 Condition, 0.20
CAF 34.9 T7.5 33.3 T5.3 Time, 0.43
Condition time, 0.54
(g) PLA 3.6 T1.0 3.7 T1.0 Condition, 0.22
CAF 3.6 T1.0 3.5 T1.0 Time, 0.88
Condition time, 0.15
TABLE 4. Self-perceived ratings of energyand mood questionnaire for each condition
(mean TSD).
Pre 63.8 T20.6 66.4 T19.1
Mid 53.2 T20.4 62.8 T20.9*
Post 42.2 T23.1** 49.8 T17.7**
Pre 24.8 T14.5 30.5 T20.6
Mid 47.7 T22.6 34.3 T22.3
Post 46.4 T21.9 43.3 T21.9
Pre 67.8 T22.1 64.1 T24.1
Mid 57.8 T20.1** 59.9 T22.6*
Post 49.2 T20.5** 52.8 T18.9
Pre 70.2 T20.0 67.8 T19.7
Mid 59.9 T20.0 61.6 T22.1
Post 56.7 T20.5 54.2 T16.7
Overall confidence
Pre 70.4 T14.5 67.9 T18.3
Mid 63.1 T17.5 59.8 T15.2
Post 52.6 T21.3 62.4 T14.5
*Significantly different from PLA, Pe0.05.
**Significantly different from pre, Pe0.05.
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There are limited original nutritional investigations aimed
at improving golf performance. To our knowledge, this is
the first study to attempt such a task in a competitive tour-
nament setting using skilled golfers. Stevenson et al. (29)
sought to determine the effects of a CHO and caffeine sport
drink on golf performance. Similar to our findings, they
reported improvements of accuracy under the condition and
a time effect for increases in measures of fatigue. However,
unlike our findings, the sports drink failed to attenuate the
fatigue response. These conflicting results may be from
methodological differences, as caffeine doses in our study
were almost twofold higher (29). Because of the metabolic
clearance rate of caffeine in humans, we chose to have par-
ticipants consume a second dose of the caffeine-containing
supplement after the first nine holes with an aim to maintain
blood caffeine levels over the entire round (4+ h). Moreover,
we observed improvements in iron club accuracy from
supplementation, whereas Stevenson et al. (29) reported
improvements in putting accuracy. We did not see im-
provements in putting, and the methodological differences
between studies render it incapable of adequate comparison.
Specifically, Stevenson et al. (29) used the same synthetic
surface at fixed distances (2 and 5 m) for putting assess-
ments for all 18 holes, whereas we used true grass multi-
farious putting greens on the golf course. Nevertheless, our
because of the importance of iron club play. Recently,
Robertson et al. (25) reported that iron shot accuracy, on
approach shots to the green, was a significant predictor of
overall golf performance in a competitive tournament
setting. Therefore, caffeine, at doses used in this study,
has the ability to minimize golf-specific fatigue, which
may contribute to overall golf performance by improving
accuracy and drive distance, leading to a better golf score.
A second noteworthy finding in our study was the in-
crease in drive distance under the CAF condition. Longer-
drive distances result in less distance to the green, allowing
the use of a more accurate iron club on the approach shot.
Not considering environmental factors, maximum golf ball
displacement during a drive is a function of the linear ve-
locity and angle of the club head at the point of impact be-
tween the club face and ball (16). Importantly, Fletcher and
Hartwell (12) reported a strong relation between club head
speed and peak drive distance in skilled (mean handicap,
5.5) male golfers. In a laboratory-based golf-specific fatigue
study, Higdon et al. (14) reported that fatigue resulted in
a 2.0%–2.5% reduction in club head velocity when swinging
a driver, which, statistically, was not related to trunk or
pelvic rotation velocity (14). We did not observe differences
in peak trunk acceleration between conditions, but average
drive distance was significantly increased in the CAF con-
dition. It is possible that the improved drive distance was
due to the attenuation of fatigue via caffeine, which led to a
maintenance and/or increase in club head velocity. How-
ever, because we did not directly measure club head veloc-
ity, this hypothesis is only speculative, and therefore, other
factors that may have contributed to the increase in drive
distance cannot be ruled out.
There are some limitations to our investigation. First, it
is possible that some of the positive effects reported from
caffeine supplementation were due to a withdrawal effect.
Under the PLA condition, participants were asked to abstain
from consuming caffeine, which may have impaired per-
formance. Caffeine withdrawal symptoms typically appear
12 h after abstinence, and severity of symptoms is related to
the chronically consumed dose of the user (18). Further-
more, most of our participants were low-dose caffeine users
ranging between 35 and 180 mgId
. Second, there are other
active secondary ingredients in the caffeine supplement that
may have contributed to our findings. Vitamin B supple-
mentation is considered beneficial when in a deficient or
malnourished state. Our subjects were apparently healthy
and did not report a history of malnourishment or hypovi-
taminosis. Furthermore, previous work reported that vitamin
B supplementation failed to show an acute effect on en-
hancing cognitive ability (23). Therefore, we do not believe
that B vitamins contributed to our findings. ElevATP
a proprietary blend of plant bio-inorganic trace minerals
and polyphenols, which is purported to improve mitochon-
drial ATP production when consumed. To our knowledge,
only one study has been published on the acute effects of
elevATP ingestion on blood ATP concentration in humans
(24). Their results suggested that whole blood ATP levels
increased by 45% after ingestion of 150 mg of elevATP.
However, bioavailability studies of adenosine and its prod-
ucts suggest that whole blood ATP is rapidly metabolized,
on the order of minutes, by the blood components (6).
Therefore, future research should test these ingredients in-
dividually to determine their specific effects on overall golf
performance and fatigue.
Our findings suggest that skilled golfers experience
fatigue and reduced energy levels during a competitive
round of golf, which may negatively affect their playing
ability. Importantly, caffeine supplementation offset this
response, which seems to have contributed to improved iron
club accuracy, drive distance, and overall golf score. With
the lengthy duration of game play, walking long distances,
and potential environmental challenges, it is important for
competitive golfers to have evidence-based, practical rec-
ommendations to offset the physical and mental demands of
competitive golf play. Pre- and in-round nutrition and sup-
plementation strategies have thus far been lacking. For the
first time, we show that a caffeine-containing supplement,
consumed before and during a round of golf, can reduce
fatigue and improve measures of golf performance in a true
competitive tournament setting.
The funding and product support for the study were provided by
MusclePharm, Inc.
Petey W. Mumford and Aaron C. Tribby contributed equally to the
writing of the manuscript.
J. R. M. works for the funding company, whereas the remaining
authors proclaim no conflict of interest from the outcomes of this
CAFFEINE AND GOLF PERFORMANCE Medicine & Science in Sports & Exercise
Copyright © 2015 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
study. J. R. M. had no influence on data collection or analysis but
contributed to the drafting and editing of the manuscript.
The results of the present study do not constitute endorsement by
the American College of Sports Medicine.
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http://www.acsm-msse.org138 Official Journal of the American College of Sports Medicine
Copyright © 2015 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
... Depending on the length of the golf course the energy expenditure covers 20 to more than 50% of the normal recommended daily energy need (2400 kcal) of an active 75 kg young male (USDA and USDHHS, 2020). The long durations of golf rounds and the required intense focus may negatively impact golfers' performance, but only a few studies have assessed alertness, fatigue, and stress during a golf round (Jäger et al., 2007;Mumford et al., 2016;Stevenson et al., 2009). Mental fatigue (Stevenson et al., 2009) and golf specific fatigue (Grealy and Mathers, 2014;Higdon et al., 2012) lead to performance decline. ...
... No study has compared the effect of three macronutrient feedings on outdoor golf performance (Mumford et al., 2016;Smith et al., 2012;Stevenson et al., 2009). Therefore, the objective of this study was to assess in a small group of golf players the potential performance effects of a feeding of carbohydrates, carbohydrates and protein, or a zero-calorie control during a 9-hole simulated competitive golf game. ...
... Fatigue and alertness. A two-item visual analog scale questionnaire adapted from Mumford et al. (2016) was used to measure self-perceived levels of alertness and fatigue. A horizontal scale from 0-10 was used before the first shot on each hole; 0 was labeled "very low" with 10 labeled "very high." ...
Background: No study has evaluated the effect of macronutrient feedings on golf performance. Aim: Determine the effect of feedings during simulated golf game using a randomized cross-over study design. Methods: Male participants (n = 6, USGA handicap index 8.5 ± 6.72) played three standardized nine-hole rounds, consuming 30 g of carbohydrate, 15 g + 15 g protein and carbohydrate, or a zero-calorie control. Measurements of driving, chipping, and putting distance and accuracy were taken, as well as perceived levels of fatigue and alertness. Results: No relevant differences (P > 0.05) were seen in golf performance or alertness, but self-reported fatigue differed between conditions (P = 0.02), with scores of 2.5 (0.8 to 3.6) for the combination of carbohydrate and protein, 3.0 (1.5 to 4.3) for carbohydrate, and 4.0 (2.9 to 6.5) for the control, with higher levels indicating more fatigue. Conclusion: Macronutrient feedings led to a significantly lower level of self-reported fatigue without affecting golf performance and alertness compared to a control.
... Scores awarded to the 13 reviewed studies are provided in Table 4. According to these scores, the methodological quality of one study (8%) was classified as excellent [38], of nine studies (69%) as very good [33,37,39,[46][47][48][49][50][51], and of three studies (23%) as good [52][53][54]. ...
... Hogervorst et al. [37] used a protocol that included the ingestion of caffeine 1 h before the test and every 20 min during the protocol. Mumford et al. [48] administered caffeine 120 min after starting a game of golf. Finally, Russell et al. [52] employed caffeine 15 min during exercise through the use of caffeinated gums. ...
... Of the 13 studies reviewed, eight could not be included in the meta-analysis because: only one trial was reported in [47,49,51,53]; no cognitive tasks were performed and only mood was tested in [48,50,54]; and means and standard deviations were not provided in [38]. This left five studies that fulfilled the criteria for meta-analysis. ...
Full-text available
Cognitive functions are essential in any form of exercise. Recently, interest has mounted in addressing the relationship between caffeine intake and cognitive performance during sports practice. This review examines this relationship through a structured search of the databases Med-line/PubMed and Web of Science for relevant articles published in English from August 1999 to March 2020. The study followed PRISMA guidelines. Inclusion criteria were defined according to the PICOS model. The identified records reported on randomized cross-over studies in which caffeine intake (as drinks, capsules, energy bars, or gum) was compared to an identical placebo situation. There were no filters on participants' training level, gender, or age. For the systematic review, 13 studies examining the impacts of caffeine on objective measures of cognitive performance or self-reported cognitive performance were selected. Five of these studies were also subjected to meta-analysis. After pooling data in the meta-analysis, the significant impacts of caffeine only emerged on attention, accuracy, and speed. The results of the 13 studies, nevertheless, suggest that the intake of a low/moderate dose of caffeine before and/or during exercise can improve self-reported energy, mood, and cognitive functions, such as attention; it may also improve simple reaction time, choice reaction time, memory, or fatigue, however, this may depend on the research protocols.
... Mumford and Tribby recruited 12 male golfers with handicaps between 3 and 10 and gave them solely 155 mg of caffeine at the start of the round and after 9 holes. In this study, no benefit was obtained with putts per round, but there was a significant improvement in iron club accuracy, driving distance and overall score [45]. ...
Full-text available
Nutritional guidance for competitive golfers to improve performance is limited. Recommendations and study conclusions from older research used smaller golf courses compared to today and require a reevaluation of energy expenditure. This review identifies aerobic fitness, in addition to strength, as a key determinant of success. A novel nutritional approach that incorporates carbohydrate supplementation to support aerobic fitness without sacrificing the ability to build strength is presented since longer courses require more stamina. Strategies for training, competition, and recovery are outlined based on different skill levels. American College of Sports Medicine (ACSM) guidelines for carbohydrates, protein, and hydration intake are tailored specifically for competitive golf based on this approach. Putting requires precise movement and can be affected by fatigue. Nutritional studies in golf and similar sports that require focused movements are presented, exhibiting an improvement with adequate hydration and carbohydrate status and caffeine use. Competitive golf poses unique challenges to an athlete and commonly used ergogenic supplements that can improve performance in a variety of circumstances during training, competition, and while traveling are reviewed.
... Although a past report explored inadequate sleep habits in collegiate golfers and studied the relationship between sleep restriction (SR) and golf performance, that study was limited to golfers' self-reported perception of their performance, thereby lacking objective measurements of sleep (Zrinikova& Harmon, 2021). To our knowledge, no other studies have explored the detrimental effects of SR on golf performance (Mumford et al., 2016;Smith, 2010). Moreover, it is beneficial for studies to include golfers of all levels to best understand factors that impact putting performance. ...
In the present study, we aimed to explore the effects of sleep restriction (SR) on self-reported golf putting skills. Eleven collegiate golfers participated in a self-reported, counterbalanced experimental study under two conditions: (a) a SR condition in which sleep on the night prior to putting was restricted to 4–5 hours, and (b) a habitual normal sleep (NS) condition on the night before the putting test. Following each sleep condition, participants engaged in ten consecutive putting tests at 7 am, 11 am, and 3 pm. Participants reported their subjective sleepiness before each time frame, and their chronotype, defined as their individual circadian preference, was scored based on a morningness–eveningness questionnaire (MEQ). Participants restricted sleep to an average period of 267.6 minutes/night ( SD = 51.2 ) in the SR condition and 426.2 ( SD =38.0) minutes/night in the NS condition. A two-way analysis of variance revealed a significant main effect of the sleep condition on the lateral displacement of putts from the target (lateral misalignment) ( p = 0.002). In addition, there was a significant main effect of time on distance from the target (distance misalignment) ( p = 0.017), indicating less accuracy of putting in the SR condition. In the SR condition, the MEQ score was positively correlated with distance misalignment at 3 pm ( ρ = 0.650, p = 0.030), suggesting that morningness types are susceptible to the effects of SR on putting performance. Our findings suggest that golfers should obtain sufficient sleep to optimize putting performance.
... r Grgic et al. (2019). s Mumford et al. (2016). t Bottoms et al. (2013). ...
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New findings: What is the topic of this review? The nutritional strategies that athletes use during competition events to optimize performance and the reasons they use them. What advances does it highlight? A range of nutritional strategies can be used by competitive athletes, alone or in combination, to address various event-specific factors that constrain event performance. Evidence for such practices is constantly evolving but must be combined with understanding of the complexities of real-life sport for optimal implementation. Abstract: High-performance athletes share a common goal despite the unique nature of their sport: to pace or manage their performance to achieve the highest sustainable outputs over the duration of the event. Periodic or sustained decline in the optimal performance of event tasks, involves an interplay between central and peripheral phenomena that can often be reduced or delayed in onset by nutritional strategies. Contemporary nutrition practices undertaken before, during or between events include strategies to ensure the availability of limited muscle fuel stores. This includes creatine supplementation to increase muscle phosphocreatine content and consideration of the type, amount and timing of dietary carbohydrate intake to optimize muscle and liver glycogen stores or to provide additional exogenous substrate. Although there is interest in ketogenic low-carbohydrate high-fat diets and exogenous ketone supplements to provide alternative fuels to spare muscle carbohydrate use, present evidence suggests a limited utility of these strategies. Mouth sensing of a range of food tastants (e.g., carbohydrate, quinine, menthol, caffeine, fluid, acetic acid) may provide a central nervous system derived boost to sports performance. Finally, despite decades of research on hypohydration and exercise capacity, there is still contention around their effect on sports performance and the best guidance around hydration for sporting events. A unifying model proposes that some scenarios require personalized fluid plans while others might be managed by an ad hoc approach (ad libitum or thirst-driven drinking) to fluid intake.
... Two of these studies used golf players, and one used fencing athletes as their study sample. Mumford et al. [52] reported a significant improvement in total score, greens in regulation, and drive distance with the ingestion of an energy drink before and after 9 holes during each 18-hole round. Stevenson et al. [61] reported improved golf performance during putting and increased feelings of alertness in golfers when they had ingested a caffeinated sports drink before and during simulated competition. ...
Full-text available
Caffeine (1,3,7-trimethylxanthine) is one of the most common substances used by athletes to enhance their performance during competition. Evidence suggests that the performance-enhancing properties of caffeine can be obtained by employing several forms of administration, namely, capsules/ tablets, caffeinated drinks (energy drinks and sports drinks), beverages (coffee), and chewing gum. However, caffeinated drinks have become the main form of caffeine administration in sport due to the wide presence of these products in the market. The objective of this systematic review is to evaluate the different effects of caffeinated drinks on physical performance in various sports categories such as endurance, power-based sports, team sports, and skill-based sports. A systematic review of published studies was performed on scientific databases for studies published from 2000 to 2020. All studies included had blinded and cross-over experimental designs, in which the ingestion of a caffeinated drink was compared to a placebo/control trial. The total number of studies included in this review was 37. The analysis of the included studies revealed that both sports drinks with caffeine and energy drinks were effective in increasing several aspects of sports performance when the amount of drink provides at least 3 mg of caffeine per kg of body mass. Due to their composition, caffeinated sports drinks seem to be more beneficial to consume during long-duration exercise, when the drinks are used for both rehydration and caffeine supplementation. Energy drinks may be more appropriate for providing caffeine before exercise. Lastly, the magnitude of the ergogenic benefits obtained with caffeinated drinks seems similar in women and men athletes. Overall, the current systematic review provides evidence of the efficacy of caffeinated drinks as a valid form for caffeine supplementation in sport.
... It has been established that caffeine improves cognitive and physical performance and specifically diminishes feeling of physical fatigue following physically fatiguing conditions. [87][88][89] Perhaps our participants consumed more caffeine to account for their states of increased fatigue. It should also be noted that in our study, increased caffeine consumption was also positively associated with worse sleep quality, which suggests that our subjects may have consumed increased caffeine to attenuate the effects of poor sleep. ...
Objective: The objective of this study was to identify factors associated with the occurrence and severity of depressive mood states among graduate-level allied health students. Participants: Students (N = 77) completed this study. Methods: Participants completed a series of self-reported surveys measuring moods, lifestyle behaviors, trait mental and physical energy and fatigue, and objective assessments of Trail-Making Test Part-B, and muscle oxygen consumption. Multiple backwards linear regression models were fitted to identify factors associated with depressive mood states. Results: When accounting for all subjects, increased severity of depressive mood states was associated with worse sleep quality (SQ), increased sitting time (ST), and trait physical fatigue (TPF). When examining subjects reporting depressive mood states, increased severity of depressive mood states was associated with worse SQ, increased ST, decreased mental workload on non-school days, and trait physical energy (TPE). Conclusion: Adjustments in lifestyle factors such as sleep, mental workload, and ST, may ameliorate depressive mood states.
... The results advised that a moderate dose (1.9 ± 0.3 mg/kg (−1)) of caffeine consumed before and during a round of golf improves golf-specific measures of performance and reduces fatigue in skilled golfers. [9] The effect of cocrystalizing pterostilbene and caffeine on their respective bioavailability was evaluated in various studies. Cocrystalizing pterostilbene and caffeine modulates the bioavailability of the two components and provides a choice for a reduction in the amount of caffeine in different products without noticeably impacting the consumer experience. ...
... We also found that caffeine consumption was higher among individuals with high trait fatigue. A possible explanation for caffeine being a predictor of physical fatigue may be that people who are characteristically physically fatigued may consume caffeine to help attenuate those feelings [55,56]. Also, these individuals may consume caffeine to help improve their cognitive and physical performance. ...
Background: Mental and physical energy and fatigue can be assessed as either stable long-term traits or as a temporary state. Although researchers recognize the need to separate the two, most research has focused on state, leaving trait understudied. Therefore, the objective of this study was to apply demographic, lifestyle and psychosocial variables known to be associated with state fatigue and energy to examine predictors of trait mental and physical energy and fatigue. Methods: A convenience sample (N = 671) completed an online survey measuring mood, physical activity, mental workload, polyphenol (plant-based healthy micronutrients) consumption in the diet, and sleep quality. A multivariate multiple regression model was fit to simultaneously test associations between covariates for each four trait fatigue indicators. Results: Poor sleep quality was the only consistent predictor of both energy and fatigue (mental and physical), with confusion correlating with all but physical energy. Age and depression were predictors of mental and physical fatigue, but caffeine consumption was predicted by higher physical fatigue only. Mental workload and physical activity on off-days predicted physical energy only, while polyphenol consumption and BMI predicted mental energy only. Conclusions: Findings suggest that mental/ physical energy and fatigue may be separate constructs that can be treated as empirically distinct. The distinctions between physical and mental fatigue are less pronounced, needing further exploration. Subsequent research should explore other potentially important biopsychosocial sources of variation in trait mental and physical energy and fatigue.
Full-text available
Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature regarding the effects of energy drink (ED) or energy shot (ES) consumption on acute exercise performance, metabolism, and cognition, along with synergistic exercise-related performance outcomes and training adaptations. The following 13 points constitute the consensus of the Society and have been approved by the Research Committee of the Society: Energy drinks (ED) commonly contain caffeine, taurine, ginseng, guarana, carnitine, choline, B vitamins (vitamins B1, B2, B3, B5, B6, B9, and B12), vitamin C, vitamin A (beta carotene), vitamin D, electrolytes (sodium, potassium, magnesium, and calcium), sugars (nutritive and non-nutritive sweeteners), tyrosine, and L-theanine, with prevalence for each ingredient ranging from 1.3 to 100%. Energy drinks can enhance acute aerobic exercise performance, largely influenced by the amount of caffeine (> 200 mg or >3 mg∙kg bodyweight [BW⁻¹]) in the beverage. Although ED and ES contain several nutrients that are purported to affect mental and/or physical performance, the primary ergogenic nutrients in most ED and ES based on scientific evidence appear to be caffeine and/or the carbohydrate provision. The ergogenic value of caffeine on mental and physical performance has been well-established, but the potential additive benefits of other nutrients contained in ED and ES remains to be determined. Consuming ED and ES 10-60 minutes before exercise can improve mental focus, alertness, anaerobic performance, and/or endurance performance with doses >3 mg∙kg BW⁻¹. Consuming ED and ES containing at least 3 mg∙kg BW⁻¹ caffeine is most likely to benefit maximal lower-body power production. Consuming ED and ES can improve endurance, repeat sprint performance, and sport-specific tasks in the context of team sports. Many ED and ES contain numerous ingredients that either have not been studied or evaluated in combination with other nutrients contained in the ED or ES. For this reason, these products need to be studied to demonstrate efficacy of single- and multi-nutrient formulations for physical and cognitive performance as well as for safety. Limited evidence is available to suggest that consumption of low-calorie ED and ES during training and/or weight loss trials may provide ergogenic benefit and/or promote additional weight control, potentially through enhanced training capacity. However, ingestion of higher calorie ED may promote weight gain if the energy intake from consumption of ED is not carefully considered as part of the total daily energy intake. Individuals should consider the impact of regular coingestion of high glycemic index carbohydrates from ED and ES on metabolic health, blood glucose, and insulin levels. Adolescents (aged 12 through 18) should exercise caution and seek parental guidance when considering the consumption of ED and ES, particularly in excessive amounts (e.g. > 400 mg), as limited evidence is available regarding the safety of these products among this population. Additionally, ED and ES are not recommended for children (aged 2-12), those who are pregnant, trying to become pregnant, or breastfeeding and those who are sensitive to caffeine. Diabetics and individuals with preexisting cardiovascular, metabolic, hepatorenal, and/or neurologic disease who are taking medications that may be affected by high glycemic load foods, caffeine, and/or other stimulants should exercise caution and consult with their physician prior to consuming ED. The decision to consume ED or ES should be based upon the beverage’s content of carbohydrate, caffeine, and other nutrients and a thorough understanding of the potential side effects. Indiscriminate use of ED or ES, especially if multiple servings per day are consumed or when consumed with other caffeinated beverages and/or foods, may lead to adverse effects. The purpose of this review is to provide an update to the position stand of the International Society of Sports Nutrition (ISSN) integrating current literature on ED and ES in exercise, sport, and medicine. The effects of consuming these beverages on acute exercise performance, metabolism, markers of clinical health, and cognition are addressed, as well as more chronic effects when evaluating ED/ES use with exercise-related training adaptions.
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Abstract The aim of this study was to investigate the convergent and predictive validity of two skill tests that examine the ability of golfers to hit accurate approach-iron shots. Twenty-four high-level golfers (handicap = 2.6 ± 1.7) performed the Nine-Ball Skills Test (assesses the ability to shape/control ball trajectory with high accuracy) and the Approach-Iron Skill Test (assesses the ability to hit straight shots from varying distances with high accuracy). Participants then completed at least eight rounds of tournament golf over the following 90 days and reported an indicator of approach-iron accuracy (per cent error index). A moderate correlation (r = 0.50, P < 0.05) was noted between scores for both tests. Generalised estimating equations, using two covariates (lie of the ball and distance to hole), were used to determine model fit and the amount of variance explained for tournament per cent error index. Results showed that the Approach-Iron Skill Test was the slightly stronger predictor of on-course per cent error index. With both test scores considered together, a minimal amount of additional variance was explained. These findings suggest that either of the tests used individually or combined may be used to predict tournament approach iron performance in high-level golfers.
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The Bioharness™ device is designed for monitoring physiological variables in free-living situations but has only been proven to be reliable and valid in a laboratory environment. Therefore, this study aimed to determine the reliability and validity of the Bioharness™ using a field based protocol. Twenty healthy males participated. Heart rate (HR), breathing frequency (BF) and accelerometry (ACC) were assessed by simultaneous measurement of two Bioharness™ devices and a test-retest of a discontinuous incremental walk-jog-run protocol (4 - 11 km·h(-1)) completed in a sports hall. Adopted precision of measurement devices were; HR: Polar T31 (Polar Electro), BF: Spirometer (Cortex Metalyser), ACC: Oxygen expenditure (Cortex Metalyser). For all data, precision of measurement reported good relationships (r = 0.61 to 0.67, p < 0.01) and large Limits of Agreement for HR (>79.2 b·min(-1)) and BF (>54.7 br·min(-1)). ACC presented excellent precision (r = 0.94, p < 0.01). Results for HR (r= ~0.91, p < 0.01: CV <7.6) and ACC (r > 0.97, p < 0.01; CV <14.7) suggested these variables are reliable. BF presented more variable data (r = 0.46-0.61, p < 0.01; CV < 23.7). As velocity of movement increased (>8 km·h(-1)) data became more erroneous. A data cleaning protocol removed gross errors in the data analysis and subsequent reliability and validity statistics improved across all variables. In conclusion, the Bioharness™ HR and ACC variables have demonstrated reliability and validity in a field setting, though data collected at higher velocities should be treated with caution. Measuring human physiological responses in a field based environment allows for more ecologically valid data to be collected and devices such as the Bioharness™ could be used by exercise professionals to begin to further investigate this area.
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The purpose of this investigation was to study the effects of 36 continuous holes of competitive golf on salivary testosterone, cortisol, and testosterone-to-cortisol ratio and their relation to performance in eight elite male collegiate golfers (age 20.3 [+/- 1.5] years). Thirty-six holes of a 54-hole NCAA golf tournament were played on the first day of the competition. A saliva sample was taken 45 minutes prior to the round and immediately following each hole for a total of 37 samples per subject. Time matched baseline samples were collected on a different day to account for circadian variation. Six-hole areas under the curve (AUC) values were calculated for endocrine measures. Significant (p < 0.05) increases were noted for cortisol during competition, however, testosterone did not change during competition compared to baseline. Testosterone-to-cortisol (T/C) ratio was significantly lower throughout the competition compared to baseline measures. Thirty-six-hole AUC testosterone-to-cortisol ratio response was correlated (r = 0.82) to 36-hole score. There was a high correlation between pre-round testosterone (r = 0.71), T/C ratio response (r = 0.82), and 36-hole score. CSAI-2 somatic anxiety was correlated to pre-round cortisol (r = 0.81) and testosterone (r = - 0.80) response. These results indicate a significant hormonal response during 10 hours of competitive golf. Good golf performance (low golf scores) in this competition was related to low T/C ratio (r = .82). Additionally, results from this investigation validated CSAI-2 somatic anxiety with physiological measures of anxiety.
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The aim of this investigation was to determine the use of caffeine by athletes after its removal from the World Anti-Doping Agency list. For this purpose, we measured the caffeine concentration in 20 686 urine samples obtained for doping control from 2004 to 2008. We utilized only urine samples obtained after official national and international competitions. Urine caffeine concentration was determined using alkaline extraction followed by gas chromatography-mass spectrometry. The limit of detection (LOD) was set at 0.1 µg·mL(-1). The percentage of urine samples below the LOD was 26.2%; the remaining 73.8% of the urine samples contained caffeine. Most urine samples (67.3%) had urinary caffeine concentrations below 5 µg·mL(-1). Only 0.6% of urine samples exceeded the former threshold for caffeine doping (12 µg·mL(-1)). Triathlon (3.3 ± 2.2 µg·mL(-1)), cycling (2.6 ± 2.0 µg·mL(-1)), and rowing (1.9 ± 1.4 µg·mL(-1)) were the sports with the highest levels of urine caffeine concentration; gymnastics was the sport with the lowest urine caffeine concentration (0.5 ± 0.4 µg·mL(-1)). Older competitors (>30 y) had higher levels of caffeine in their urine than younger competitors (<20 y; p < 0.05); there were no differences between males and females. In conclusion, 3 out of 4 athletes had consumed caffeine before or during sports competition. Nevertheless, only a small proportion of these competitors (0.6%) had a urine caffeine concentration higher than 12 µg·mL(-1). Endurance sports were the disciplines showing the highest urine caffeine excretion after competition.
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A well designed diet is the foundation upon which optimal training and performance can be developed. However, as long as competitive sports have existed, athletes have attempted to improve their performance by ingesting a variety of substances. This practice has given rise to a multi-billion-dollar industry that aggressively markets its products as performance enhancing, often without objective, scientific evidence to support such claims. While a number of excellent reviews have evaluated the performance-enhancing effects of most dietary supplements, less attention has been paid to the performance-enhancing claims of dietary supplements in the context of team-sport performance. Dietary supplements that enhance some types of athletic performance may not necessarily enhance team-sport performance (and vice versa). Thus, the first aim of this review is to critically evaluate the ergogenic value of the most common dietary supplements used by team-sport athletes. The term dietary supplements will be used in this review and is defined as any product taken by the mouth, in addition to common foods, that has been proposed to have a performance-enhancing effect; this review will only discuss substances that are not currently banned by the World Anti-Doping Agency. Evidence is emerging to support the performance-enhancing claims of some, but not all, dietary supplements that have been proposed to improve team-sport-related performance. For example, there is good evidence that caffeine can improve single-sprint performance, while caffeine, creatine and sodium bicarbonate ingestion have all been demonstrated to improve multiple-sprint performance. The evidence is not so strong for the performance-enhancing benefits of β-alanine or colostrum. Current evidence does not support the ingestion of ribose, branched-chain amino acids or β-hydroxy-β-methylbutyrate, especially in well trained athletes. More research on the performance-enhancing effects of the dietary supplements highlighted in this review needs to be conducted using team-sport athletes and using team-sport-relevant testing (e.g. single- and multiple-sprint performance). It should also be considered that there is no guarantee that dietary supplements that improve isolated performance (i.e. single-sprint or jump performance) will remain effective in the context of a team-sport match. Thus, more research is also required to investigate the effects of dietary supplements on simulated or actual team-sport performance. A second aim of this review was to investigate any health issues associated with the ingestion of the more commonly promoted dietary supplements. While most of the supplements described in the review appear safe when using the recommended dose, the effects of higher doses (as often taken by athletes) on indices of health remain unknown, and further research is warranted. Finally, anecdotal reports suggest that team-sport athletes often ingest more than one dietary supplement and very little is known about the potential adverse effects of ingesting multiple supplements. Supplements that have been demonstrated to be safe and efficacious when ingested on their own may have adverse effects when combined with other supplements. More research is required to investigate the effects of ingesting multiple supplements (both on performance and health).
Over the years, golf has become an increasingly popular sport, attracting new players of almost all ages and socioeconomic groups. Golf is practised by up to 10 to 20% of the overall adult population in many countries. Beyond the enjoyment of the sport itself, the health-related benefits of the exercise involved in walking up to 10km and of relaxing in a pleasant natural environment are often reported to be the main motives for adhering to this activity by recreational golfers. Golf is considered to be a moderate risk activity for sports injury; however, excessive time spent golfing and technical deficiencies lead to overuse injuries. These are the 2 main causes of injuries among golfers, and each has specific differences in the pattern in which they occur in professional and amateur golfers. Golf injuries originate either from overuse or from a traumatic origin and primarily affect the elbow, wrist, shoulder and the dorsolumbar sites. Professional and weekend golfers, although showing a similar overall anatomical distribution of injuries by body segment, tend to present differences in the ranking of injury occurrence by anatomical site; these differences can be explained by their playing habits and the biomechanical characteristics of their golf swing. Many of these injuries can be prevented by a preseason, and year-round, sportspecific conditioning programme including: (i) muscular strengthening, flexibility and aerobic exercise components; (ii) a short, practical, pre-game warm-up routine; and (iii) the adjustment of an individual’s golf swing to meet their physical capacities and limitations through properly supervised golf lessons. Finally, the correct selection of golf equipment and an awareness of the environmental conditions and etiquette of golf can also contribute to making golf a safe and enjoyable lifetime activity.
The purpose of this study was to determine if body position, weight transfer, and/or pelvis/trunk rotations changed as a result of a golf specific fatiguing protocol and whether these changes affected resultant club head velocity at impact and shot consistency. Six male golfers and one female golfer participated in the study, who had a mean age, height, and body mass of 23.9 +/- 3.9 years, 177.4 +/- 4.9 cm, and 75.3 +/- 9.9 kg, respectively. Path analysis was used to determine the relationships between fatigue, biomechanical variables, and resultant club head velocity at impact and shot consistency. In the statistical models representing the effects of biomechanical variables calculated at the top of the swing and ball contact, golf specific fatigue was associated with a 2.0% and 2.5% reduction in the club head velocity and a 7.1% and 9.4% improvement in the shot consistency, respectively. These data suggest that golf specific fatigue was not related to the initial lower body sagittal plane angles at address nor was simulated golf specific fatigue related to peak transverse plane pelvis and trunk rotational velocities (or their timings) in a manner that indicates a relationship to resultant club head velocity and shot consistency.