Available via license: CC BY-SA
Content may be subject to copyright.
Inuence/effectiveness of carrot and orange mix juice on Ṽo2max in soccer players 23
Inuence/effectiveness of carrot and orange mix juice on Ṽo2max
in soccer players
Yeri Amranitalia Putri1*, Eni Yusniati1, Diana Nurrohima1, Herviana1, Desty Ervira Puspaningtyas1,Yuni Afriani1
1Nutrition Science Program, Faculty of Health Sciences, Universitas Respati Yogyakarta,
Jalan Raya Tajem KM 1,5., Depok, Maguwoharjo, Sleman, Yogyakarta
*Corresponding author: putriyeri81@gmail.com
ABSTRAK
Latar Belakang: Daya tahan kardiorespirasi merupakan salah satu unsur penting dalam melakukan
latihan sik. Daya tahan kardiorespiratori dapat diketahui dengan mengukur konsumsi atau volume
oksigen maksimal (ṼO2maks). Suplementasi buah dan sayur tertentu telah dibuktikan dapat berperan
terhadap daya tahan atlet. Buah dan sayur diduga mempengaruhi daya tahan dengan menunda kelelahan
disebabkan zat gizi yang terkandung seperti karbohidrat, vitamin, mineral, dan zat tokimia. Penelitian
sebelumnya menyatakan buah-buahan sumber karbohidrat diketahui dapat memperbaiki ṼO2maks. Beta
carotene dan vitamin C telah teruji dapat meningkatkan daya tahan. Buah wortel dan jeruk merupakan
buah-buahan dengan kandungan beta carotene dan vitamin C yang tinggi. Buah wortel dan jeruk juga
mengandung mineral yang tinggi yaitu kalium. Kalium merupakan mineral utama yang sangat dibutuhkan
pada latihan yang membutuhkan daya tahan (endurance) dan kalium diketahui juga berperan dalam
metabolisme karbohidrat untuk mengubah glukosa menjadi glikogen yang disimpan dalam hati untuk
energi. Efek dari kombinasi beta carotene, vitamin C dan kalium pada jus wortel dan jeruk terhadap daya
tahan kardiorespirasi pada atlit perlu analisis lebih lanjut.
Tujuan: Penelitian ini bertujuan mengetahui pengaruh pemberian jus wortel-jeruk terhadap nilai ṼO2maks
pada atlet sepak bola.
Metode: Penelitian ini merupakan penelitian quasi eksperimental dengan rancangan pre-post test without
control group. Jumlah subjek penelitian adalah sembilan atlet sepak bola yang memenuhi kriteria inklusi
di Unit Kegiatan Mahasiswa (UKM) Sepak Bola Universitas Ahmad Dahlan Yogyakarta. Subjek penelitian
menerima intervensi pemberian 250 ml jus wortel-jeruk selama 13 hari. Nilai ṼO2maks diukur menggunakan
yoyo intermittent recovery test I sebelum dan setelah intervensi. Perbedaan nilai ṼO2maks sebelum dan
setelah intervensi dianalisis menggunakan uji paired t-test.
Hasil: Hasil pengukuran nilai ṼO2maks sebelum pemberian jus wortel-jeruk (44,02 ± 2,66) ml /kg /menit
dan setelah pemberian jus wortel-jeruk (45,88 ± 3,11) ml /kg /menit. Terdapat perbedaan ṼO2maks yang
signikan setelah pemberian jus wortel-jeruk pada atlet sepak bola (p= 0.003).
Kesimpulan: Pemberian jus wortel-jeruk efektif meningkatkan nilai ṼO2maks atlet sepak bola.
KATA KUNCI: jeruk, sepak bola, ṼO2maks, wortel, yoyo intermittent recovery test I.
ABSTRACT
Background: Cardiorespiratory endurance is one of the main factors for exercising. Cardiorespiratory
endurance can be known by measuring ṼO2max. Fruits and vegetables intake can give benecial impact
for endurance athletes. Fruits and vegetables are thought to affect endurance by delaying fatigue caused
by nutrients contained such as carbohydrates, vitamins, minerals, and phytochemicals. Previous studies
stated that fruit sources of carbohydrates are known to improve ṼO2maks. Beta carotene and vitamin C
have been proven to increase endurance. Carrots and oranges are high in beta carotene and vitamin C.
Carrot and orange also contain a high level of potassium. Potassium is one of the main mineral which is
needed for endurance exercise and it also has the potential to help carbohydrates metabolism in converting
glucose to glycogen which later saved by the liver as an energy source. The effect of the combination
of beta carotene, vitamin C and potassium on carrot and orange juice on cardiorespiratory endurance in
athletes requires further analysis.
Indonesian Journal of Nutrition and Dietetics
Vol. 7, No. 1, 2019: 23-30
Available online at: http://ejournal.almaata.ac.id/index.php/IJND
DOI : http://dx.doi.org/10.21927/ijnd.2019.7(1).23-30
24 Yeri A. Putri, Eni Yusniati, Diana Nurrohima, Herviana, Desty Ervira Puspaningtyas,Yuni Afriani, Vol 7 No. 1, 2019: 23-30
Carrots and oranges are natural sources of
carbohydrates and electrolytes. Carrots are a type of
vegetable that is high in carbohydrates, potassium,
and antioxidants. The kind of simple carbohydrates
in citrus fruits are fructose, glucose, and sucrose
which can provide energy source quickly (9). The
high content of beta-carotene from carrots and high
vitamin C content in orange have the potential as
antioxidants to help oxidative inhibition that can
occur during endurance exercise thus preventing
fatigue and improving cardiorespiratory endurance.
Potassium in carrots and oranges works for
uid balance of the body and is responsible for
delivering nerve impulses and muscle contractions.
A study states thatincreased activity of Na +, K
+, and ATPase during exercise can stabilize the
concentration of sodium and potassium in the
membrane so that it can prevent fatigue (10).
Potassium also inuences the uptake and transport
of glucose in the small intestine for it to can be used
as an energy source (11).
UKM bola UAD (Universitas Ahmad Dahlan)
has a training schedule for four times a week with
90 minutes duration in each timeline. The endurance
training program carried out in the form of jogging,
zig-zag running, hurdles, and twisting which done
for 40 minutes every three times a week. On the
average, the Members of UKM have an excellent
nutritional status which is around 77.27% of the
population. According to the last ṼO2max records
which were measured by using bleep test, it shows
the mean of ṼO2max that had been accomplished
by the population only around 43.74 ml/kg/min which
Objectives: The purpose of this study was to assess the effect of carrot-orange juice on ṼO2max in
soccer players.
Methods: This study was a quasi-experimental with pre-post test without control group design. There
were nine soccer players from Universitas Ahmad Dahlan Yogyakarta that were taken by using purposive
sampling which is match with criteria. The subject had been given 250 ml of carrot-orange juice for 13 days.
ṼO2max was measured by using a yoyo intermittent recovery test I. All data were analyzed by paired T-test.
Results: The mean of ṼO2max in soccer players before consuming carrot-orange juice is 44.02 ± 2.66
ml /kg /min and after consuming carrot-orange juice is 45.88 ± 3.11 66 ml /kg /min. There was signicant
ṼO2max difference after carrot-orange (p= 0.003).
Conclusion: Consumption of carrot-orange juice for 13 days effectively increase ṼO2max level of soccer
players.
KEYWORDS: carrot, orange, soccer, ṼO2max, yoyo intermittent recovery test I.
INTRODUCTION
High-intensity training that is done continuously
can result in the increased of radical production
resulting in oxidative stress which then triggers the
gain of fatigue and causing the endurance to drop
(1). Fatigue can also be caused by the reduction
of muscle glycogen and blood glucose. Moreover,
during the game athletes also tend to sweat which
causes the risk of dehydration and electrolyte
imbalance (2).
Cardiorespiratory endurance and body
strength are essential in physical activity, workout,
and exercise (3). Cardiorespiratory endurance
can be known by measuring the maximum oxygen
volume. The maximum oxygen volume which
commonly called ṼO2max can be dened as the
maximum capacity in taking, transporting, and
using oxygen during exercise (4). The low value
of ṼO2max in athlete will affect the endurance
and performance while competing. Therefore, the
ideal value of ṼO2max will indirectly affect soccer
achievement (5).
The average score of athlete’s ṼO2max at
the Semarang State University Football Club was
41.7 ml/kg/ minute which depicted through with the
Multistage tness test (MFT) (6). The score of the
stamina of the Undip Tembalang Football School
athletes described by measuring ṼO2max with
Queen’s College Step Test is 49.67 ml/kg/ minute
(7). These results are still below the standard of
international soccer athletes in which the average
world soccer player has a high ṼO2max which is
around 60.5 ml/kg/ minute (8).
Inuence/effectiveness of carrot and orange mix juice on Ṽo2max in soccer players 25
mean the ṼO2max of the population stands at the low
to above average category. The aim of this research
was to assess the effect of carrot-orange juice on
ṼO2max in soccer players.
MATERIALS AND METHODS
Study design
This research was quasi-experimental with the
pre-post test without control group design. This study
had ethical clearance from Komite Etik Universitas
Respati Yogyakarta with the number 009.4/FIKES/
PL/I/2018. This research was conducted in two
places that are Laboratorium Dietetik dan Kuliner
Universitas Respati Yogyakarta (which where the
juice is made) and UKM sepak bola UAD (the
place where the test is conducted) on January
4th – January 21st , 2018. The population in this
research are soccer players from UKM sepak bola
UAD. There were 14 soccer players who had been
chosen by using purposive sampling.
Subjects
The subject size was calculated using the
formula for experimental research (12) with a
minimum sample size of eleven subjects. Subjects
must rst be informed through an agreement. All of
the subject’s information and data in this research
are kept condential and only used for scientic
purposes. The 14 soccer players had met the
inclusion criteria such as aged 18-25 years old active
member of UKM sepak bola UAD for at least three
months, in the research location during the research,
not smoker and also not an alcoholic. As for the
exclusion criteria were athlete ever with injury history
or in the medical treatment and having a heart or
lung defect. Meanwhile, only nine subjects nished
the study. During the study, one subject was lost to
follow-up because he could not be contacted while
four other subjects were unable to take the post-
intervention test due to sudden personal matters
and could not be abandoned. It is not possible to
replace the subject because at the recruitment stage
the subject was sampling from the entire subject
population in UKM UAD.
Experimental protocol
The subject was given carrot and orange
juice combination which was made from 75 g of
carrots, 25 g of sweet orange and addition of sugar
up to 8% diluted to 250 ml. The juice was given 1
x 250 ml every day for 13 days. The conditioning
procedures which were required during the test were
the subject had a minimum of 6-8 hours of sleep,
not consuming caffeine, energy drink, isotonic or
alcoholic beverages, not taking supplements and not
doing strenuous activities the day before ṼO2max
measurement.
ṼO2max measurement
The ṼO2max measurement used in this study
was the yoyo intermittent recovery test level I which
conducted before and after the intervention. The
yoyo intermittent recovery test level I was the kind
of test where the subject was asked to run based
on the rhythm of the tape recorder which increases
gradually. The equation used to calculate the
ṼO2max of athletes is (13):
ṼO2max (mL/min/kg) = distance (m) x 0.0084 + 36.4
Physical activity, dietary intake, and fluids
measurement
Forms of physical activity level, SQFFQ, and
uids food record were used as corrections to the
subject conditioning procedure. Other instruments
used in the study were informed consent forms,
prole data forms, weight scales, microtia, as well as
measuring tools and ṼO2max equipment. Calibration
of scales and microtones has been carried out before
the device was used for the study. Univariate analysis
was used to perform analysis of each variable studied
to know the frequency or distribution of the data.
Bivariate analysis was done to determine the effect
of carrot-orange mix juice on ṼO2max by using paired
T-test with a 95% condence level.
RESULTS
All subjects who participated in this study
were male student soccer players from UKM UAD.
26 Yeri A. Putri, Eni Yusniati, Diana Nurrohima, Herviana, Desty Ervira Puspaningtyas,Yuni Afriani, Vol 7 No. 1, 2019: 23-30
Subject characteristics conducted in this study
included age, weight, height, body mass index
(BMI), food consumption, uid intake and position
in the team (Table 1).
Table 1. Anthropometric characteristics and
macronutrient intake of participants
Subject
Characteristic N (%) Mean ± SD
Age (years) 9 (100) 20.78 ± 1.99
Body Weight (kg) 9 (100) 59.10 ± 5.98
Height (cm) 9 (100) 163.61 ± 4.63
BMI (kg/m2) 9 (100) 22.11 ± 2.27
Food Consumption
Energy (kcal)
Protein (g)
Fat (g)
Carbohydrate (g)
Vitamin A (µg)
Carotene (µg)
Vitamin C (mg)
Potassium (mg)
9 (100)
2504.23 ± 363.00
83.02 ± 13.34
109.58 ± 15.67
284.87 ± 45.26
3290.61 ± 370.20
400.00 (300.00 –
900.00)*
39.51 ± 9.61
1613.07 ± 305.13
Fluid Intake (mL) 9 (100) 2192.50 ± 911.93
Position in the Team
Defender
Midelder
Striker
5(55.56%)
1(11.11%)
3(33.33%)
*median (min-max)
According to interviews using physical activity
level forms, most subjects had a mild physical
activity. Beverage food record form was used as
a correction to subject beverage consumption one
day before the study. Based on the results of the
interview, it was known that one day before the study
one subject consumed caffeinated beverages that
were not recommended. Moreover, the subjects
had a different amount of sleeping duration with
most of them were following the recommendation
for adequate sleep although some subjects who
slept less than 6 six hours. Based on Table 2, it is
known that there is no ṼO2maks difference based on
physical activity, consumption of caffeinated drinks,
and sleep quality.
In this study, ṼO2max was indirectly measured
by using yoyo intermittent recovery test level I. There
is a different value of ṼO2max before orange-carrot
juice consumption and after getting carrot-orange
juice (p=0.003). The average of ṼO2max before
intervention of carrot-orange juice (44.02 ml / kg /
minute) was lower than the average of ṼO2max after
the intervention of carrot orange juice (45.88 ml / kg
/ minute) (Table 3).
Table 3. ṼO2max before and after treatment
Measurement N
ṼO2max (ml/kg/
min)
(Mean ± SD)
p
Before Intervention 9 44.02 ± 2.66 0.003*
After Intervention 9 45.88 ± 3.11
*signicant on p < 0,05
Table 2. Physical activity, caffeinated beverages consumption and sleeping quality before and after
intervention
Subject Conditioning
PRE POST
N (%) ṼO2max (mean ± SD
ml/kg/min) p N (%) ṼO2max (mean ± SD
ml/kg/min) p
Phisical Activity
Mild
Average
Heavy
6
2
1
43.62 ± 3.01
45.30 ± 2.60
43.79 ± 0.00
0.772 7
1
1
44.94 ± 2.63
47.15 ± 0.00
51.17 ± 0.00
0.463
Caffeinated beverages
consumption
Yes
No
0
9
-
-
- 1
8
43.12 ± 0.00
46.22 ± 3.13
0.381
Sleeping quality
Good
Bad
6
3
44.01 ± 2.01
44.01 ± 4.25
0. 111 4
5
46.48 ± 2.63
45.40 ± 3.67
0.672
*Mann-Whitney Correlation, α=0,05
Inuence/effectiveness of carrot and orange mix juice on Ṽo2max in soccer players 27
DISCUSSION
There is ṼO2max significant differences
before and after carrot-orange juice consumption
(p=0.003) with an average increase of 1.86 ml / kg
/ minute. This study showed that consuming 250
ml carrot-orange juice for 13 days affects ṼO2max
of soccer players. It is consistent with the previous
studies where the mean of ṼO2max in the group
that received 300 ml of orange juice (54.9 grams
of carbohydrate) 30 minutes before the test was
signicantly higher (p <0.05) compared to those
who did not receive it (14).
Carrot-orange juice which is produced in
this study has total carbohydrate content of 8%
or equal to 20 g carbohydrate of each serving.
Carbohydrates in carrot come in the form of ber
and sugar which the sugar has the highest amount
compared to any other vegetables. There are two
kinds of carbohydrates in orange, namely simple
carbohydrates in the form of fructose, sucrose and
glucose and complex carbohydrates in the form of
non-starch polysaccharides (ber). Carbohydrates
in carrot-orange juice act as a substrate for ATP
formation-energy source for muscle contraction
during exercise (15).
Reduction of carbohydrate reserves such as
muscle glycogen and liver glycogen is associated
with fatigue and decreased lung capacity. A beverage
contains of 6-8% carbohydrates do not interfere with
athletes so that carrot-orange juice can provide
enough energy to maintain muscle power, prevent
fatigue and slowing the decreased of glycogen
reserves (16). The factor which predicted to be the
cause for the signicant results of this study was
the higher glycogen reserves when subject received
carrot-orange juice given for 13 days compared to
glycogen reserves before getting carrot-orange
juice. Liver glycogen decreases during physical
exercise. It brings compensation in the form of liver
glycogen resynthesize by consuming carbohydrates
after exercise. Glycogen stores can be increased by
several diets and exercise procedures (17). During
the period of intervention, the subjects remained
on a regular diet with an average of 90% energy
fulllment each day. Subjects also keep running
routine training as usual according to the program
provided by the coach. The physical exercise
carried out continuously allows an increase in liver
glycogen deposits. Glycogen deposits are higher in
trained person and become 2.5 times higher after
exercise (18)height, percent body fat, lean body
mass, blood glucose levels and physical tness with
Asian Committee on the Standarization of Physical
Fitness Test (ACSPFT).
Same as glycogen reserve, blood glucose
levels may inuence the results of this study. During
the test before the intervention. Subjects were only
given plain water to prevent dehydration, while
subjects were given carrot-orange juice at the time
of the trial after the intervention. This condition
causes a difference in the intake of carbohydrate
which blood glucose is higher during the test after
the intervention compared to blood glucose during
the trial before the intervention. Good carbohydrate
intake and sufcient glycogen storage are the keys
in maximum aerobic endurance during exercise.
Low levels of muscle glyc ogen before exercise
can cause a decrease in performance (19).
soccer athletes receiving carbohydrate-electrolyte
supplementation experienced less weight loss and
had better sprint performance than athletes who did
not get any supplementation (20).
In the aerobic energy system, increased
oxygen consumption during exercise will be
followed by an increase of free radicals formation
in the muscle cells especially skeletal muscle cells
(21). Increased free radical formation in strenuous
exercise comes from an increase in the number
of leukocytes and xantindehydrogenase enzyme
activity (22). When free radicals attack the cell
membrane,lipid peroxidation (LPO) will occur which
causes changes in muscle conditions or muscle
cells damage (23).
Free radicals as a sign of the oxidative stress
occurrence can be neutralized by the body’s defense
system. The body’s defense system against oxidant
determined by the intake of vitamin and mineral
antioxidants and the formation of endogenous
antioxidants, such as glutathione (24). Carrot-
orange juice contains 12.585.75 IU of vitamin A
and 17.73 mg of vitamin C in every 250 ml which
28 Yeri A. Putri, Eni Yusniati, Diana Nurrohima, Herviana, Desty Ervira Puspaningtyas,Yuni Afriani, Vol 7 No. 1, 2019: 23-30
is suspected to improve muscle conditions during
endurance exercises. Vitamin C, vitamin E and beta
carotene (vitamin A) are secondary antioxidants that
are useful for capturing free radicals and preventing
chain-breaking antioxidants. This result is in line with
the previous studies which stated that vitamin C was
sufcient to reduce malondialdehyde levels when
subjects received a combination of maltodextrin
and vitamin C (25). Vitamin C contained in carrot-
orange juice acts as a cofactor of neurotransmitter
synthesis and as an antioxidant that can affect
energy metabolism. Consumption of vitamin C can
reduce muscle weakness after exercise, and the
recovery process becomes faster so that it affects
the endurance of athletes (26).
Carrots and oranges contain carotene, a
form of pro-vitamin A, where vitamin A is a type of
antioxidant that can reduce oxidative stress markers
during exercise (27). Vitamin A is lipophilic or a
‘lipoidal chain antioxidant’ which have a roll on the
cell membrane to prevent lipid / LPO peroxidation
or counteract peroxyl radicals (28).
Another nutrient needed to maintain exercise
with high endurance capacity is potassium.
Potassium can be lost along with sweat, so it
requires natural food intake as a source of potassium
to keep its balance in the body (29). Carrot-orange
juice contains 285.75 mg of potassium. There was
an average increase in potassium intake of 78.3
mg for 13 days of carrot-orange juice intervention.
Potassium plays a role in carbohydrate
metabolism, and it helps the storage of glucose
into glycogen stored in the liver. Glucose transport
from the intestine to the mucosa is affected by
the concentration of sodium and potassium in the
intestinal lumen. A high potassium ion concentration
increases the activity of K +, Na + and ATPase which
also makes it easier to enter sugar into the cells (30).
Membrane potential that occurs due to the diffusion
of Na + and K + ion molecules called primary active
transport supports the presence of secondary active
transport, and both co-occur. Secondary active
transport has the role to transport amino acids and
glucose to across the plasma membrane so that
the glucose can be used by the cell (11). Not only
that, potassium along with sodium can maintain
uid balance during the long duration of exercising
to prevent changes in nerve transmission and
disruption of muscle contraction (10).
In this study, there are several weaknesses
that are suspected to be another factor that causing
an increase in the ṼO2max including the inuence of
environmental temperature and athlete’s readiness.
The measurement test is scheduled to be carried
out at the same time of the morning in both before
and after the intervention but the temperature on
the measurement day after the intervention happen
to be lower than during the test before intervention
due to unfavorable weather. ṼO2max measurement
was done in outdoor so that there are things that
cannot be controlled by researchers including
weather conditions. Body temperature can rise
during the increased physical activity, environmental
temperature differences, and relatively high air
humidity (31). Increased body temperature can
be eliminated by the removal of heat through
the skin and a small portion through breathing
and urine (19). Hot ambient temperatures above
310C will reduce the effectiveness of body heat
extraction. This condition is due to the disruption
of the body’s balance between formation and heat
extraction which later affects physical endurance.
The decrease in endurance occurs due to an
increase in blood ow from the muscle to the skin
as thermoregulation efforts during exercise (32).
Another factor that contributes to ṼO2max is
the exercise carried out before the test, nutritional
intake, caffeine consumption, and sleep quality. In
this study, exercise had no effect on the athlete’s
ṼO2max because one day before the test the athlete
was conditioned not to engage in heavy activities
and training. Nutritional intake also does not effect
the athlete’s ṼO2max because one day before the
study the athlete is conditioned not to consume
certain foods and beverages. This condition is
strengthened based on the correction of subject
conditioning. Moreover, it was found that there was
no relationship between physical activity and all
nutrient intake with subject ṼO2max. In addition, it
is also known that there is no difference in subject
ṼO2max based on sleep quality and consumption
of caffeinated drinks.
Inuence/effectiveness of carrot and orange mix juice on Ṽo2max in soccer players 29
The athlete’s readiness factor is also
suspected to be another factor that increases the
ṼO2max. From the observations, some subjects felt
more prepared to take the test after the intervention
because they felt they had understood better the test
procedure. The readiness of athletes both physically
and mentally will cause athletes to be more relaxed
and focused during the game so that it has an impact
on increased performance (33).
CONCLUSION
There is a signicant effect of carrot-orange
juice on ṼO2max where the consumption of carrot-
orange juice for 13 days effectively increase ṼO2max
level of soccer players. Athletes should pay attention
to the pattern and consumption of food to maintain
cardiorespiratory endurance for better performance.
Further studies should pay more attention to other
variables that can inuence ṼO2max values such as
carbohydrate intake per day and also other foods
contain beta carotene, vitamin C, and potassium.
REFERENCES
1. Gao, Peng-Hua; Zhang Zh-M. Training Effects
of Different Approaching Steps on Overarm
Throwing Performance for Boys Aged 7-12
Years. Sport Exerc Res. 2010 Mar 31;12(1).
2. Lusamaki MF, Nyongombe UN, Batina AS,
Kayisu KA, J, Losimba L. Hydration in footballers
of Kisangani under the competition and training
seasons. J Exp Biol Agric Sci [Internet].
2015;3(2):151–6. Available from: http://www.
jebas.org/Abstract_jebas/003002/003002005.
htm
3. Fatimah R. Gizi kebugaran dan olahraga.
Bandung: Lubuk Agung; 2011.
4. Gomez-Cabrera MC, Domenech E, Romagnoli
M, Arduini A, Borras C, Pallardo F V., et al. Oral
administration of vitamin C decreases muscle
mitochondrial biogenesis and hampers training-
induced adaptations in endurance performance.
Am J Clin Nutr. 2008 Jan 1;87(1):142–9.
5. Nata DP. Pengaruh pemberian suplementasi
Fe dan Vitamin C terhadap nilai Estimasi
VO2max atlet sepakbola laki-laki Sekolah
Khusus Olahragawan Ragunan Jakarta Selatan
tahun 2012 = The effect of iron and vitamin C
supplementation to VO2max man football athletes
in a [Internet]. Universitas Indonesia ; 2012.
Available from: http://lib.ui.ac.id/opac/themes/
libri2/detail.jsp?id=20321353&lokasi=lokal
6. Satri, Iqlima; Dieny FF. Pengaruh Sari Umbi Bit
(Beta Vulgaris) Terhadap Vo2Max Atlet Sepak
Bola. Universitas Diponegoro; 2015.
7. Rachmawan B, Widodo S, Kumaidah E.
Perbedaan Pengaruh Interval Training dan
Circuit Training Terhadap Vo2max Siswa
Sekolah Sepak Bola UN [Internet]. Universitas
Diponegoro; 2016. Available from: http://eprints.
undip.ac.id/50373/
8. Murphy A, Reilly T, Spinks W, Reilly T,
Spinks W. Science and Football IV [Internet].
1st ed. Lomdon: Routledge; 2013. 456 p.
Available from: https://www.taylorfrancis.com/
books/9781315823775
9. Baghurst K. The Health Benets of Citrus Fruits.
2003.
10. McKenna MJ, Bangsbo J, Renaud J-M. Muscle
K + , Na + , and Cl − disturbances and Na + -K
+ pump inactivation: implications for fatigue. J
Appl Physiol [Internet]. 2008 Jan;104(1):288–95.
Available from: http://www.physiology.org/
doi/10.1152/japplphysiol.01037.2007
11. Thorsen K, Drengstig T, Ruoff P. Transepithelial
glucose transport and Na + /K + homeostasis in
enterocytes: an integrative model. Am J Physiol
Physiol [Internet]. 2014 Aug 15;307(4):C320–37.
Available from: http://www.physiology.org/
doi/10.1152/ajpcell.00068.2013
12. Lemeshow S, Hosmer DW, Klar J LS. Besar
sampel dalam penelitian kesehatan. Yogyakarta:
Gadjah Mada University Press; 1997.
13. Bangsbo J, Iaia FM, Krustrup P. The Yo-
Yo Intermittent Recovery Test. Sport Med.
2008;38(1):37–51.
14. Andani SA, Widyastuti N. Pengaruh pemberian
jus jeruk manis (citrus sinensis.) terhadap nilai
VO2 max atlet sepak bola di Gendut Dony
Training Camp (GDTC) Salatiga. J GIZI Indones.
2017 Nov 21;5(2):68.
30 Yeri A. Putri, Eni Yusniati, Diana Nurrohima, Herviana, Desty Ervira Puspaningtyas,Yuni Afriani, Vol 7 No. 1, 2019: 23-30
15. Irianto D. Panduan Gizi Lengkap Keluarga dan
Olahragawan. Yogyakarta: Andi Offset; 2007.
16. Rahmawati M. Menu Tepat Makanan Atlet 11
Olahraga Terpopuler | welcome to my channel
[Internet]. Yogyakarta: Pustaka Baru Press;
2015. Available from: http://hervinsarendi.blogs.
uny.ac.id/2017/09/16/menu-tepat-makanan-
atlet-11-olahraga-terpopuler/
17. Fox SI. Muscle: Mechanism of Contraction and
Neural Control. In: Human Physiology. 8th ed.
New York: McGraw-Hill; 2003.
18. Utoro BF, Dieny FF. Pengaruh penerapan
carbohydrate loading modifikasi terhadap
kesegaran jasmani atlet sepak bola. J GIZI
Indones [Internet]. 2017 Oct 19 [cited 2020
Mar 13];4(2):107. Available from: http://ejournal.
undip.ac.id/index.php/jgi/article/view/16306
19. Åstrand P-O. Textbook of work physiology :
physiological bases of exercise. 4nd ed.
Canada: Human Kinetics; 2003. 649 p.
20. McGregor SJ, Nicholas CW, Lakomy HKA,
Williams C. The inuence of intermittent high-
intensity shuttle running and fluid ingestion
on the performance of a soccer skill. J Sports
Sci [Internet]. 1999 Jan;17(11):895–903.
Available from: http://www.tandfonline.com/doi/
abs/10.1080/026404199365452
21. Alessio HM. Exercise-induced oxidative
stress. Med Sci Sports Exerc [Internet]. 1993
Feb;25(2):218–24. Available from: http://www.
ncbi.nlm.nih.gov/pubmed/8383786
22. Bagchi D, Garg A, Krohn RL, Bagchi M, Tran
MX, Stohs SJ. Oxygen free radical scavenging
abilities of vitamins C and E, and a grape seed
proanthocyanidin extract in vitro. Res Commun
Mol Pathol Pharmacol. 1997 Feb;95(2):179–89.
23. Das Sarma A, Mallick AR, Ghosh AK. Free
Radicals and Their Role in Different Clinical
Conditions: An Overview 2. Int J Pharma Sci Res
[Internet]. 2010;1(3):185–92. Available from:
http://www.ijpsr.info/docs/IJPSR10-01-03-04.
pdf
24. Bendich A. Exercise and Free Radicals:
Effects of Antioxidant Vitamins. Med Sport Sci.
1991;32:59–78.
25. Puspaningt DE, Sudargo T, Farmawati A.
Maltodextrin and Vitamin C Combination
Drink is Effective to Reduce Malondialdehyde.
Pakistan J Nutr [Internet]. 2015 Apr 1;14(4):214–
7. Available from: http://www.scialert.net/
abstract/?doi=pjn.2015.214.217
26. Carlson NR. Foundations of physiological
psychology. Pearson/A and B; 2008. 574 p.
27. Helwig B. ExRx.net : Antioxidants and Exercise
[Internet]. ExRx.net. 2014 [cited 2018 May
2]. Available from: https://exrx.net/Nutrition/
Antioxidants/Antioxidants
28. Kiyatno. Pengaruh Aktivitas Fisik Submaksimal,
Waktu Pemberian Antioksidan Vitamin dan
Tingkat Kebugaran Terhadap Kondisi Oto.
Universitas Negeri Semarang; 2009.
29. Whitney E, Rolfes S. Understanding Nutrition
by Whitney, Eleanor Noss; Rolfes, Sharon
Rady: Amazon.com: Books [Internet]. Eighth.
W. Rolfes, editor. USA: West/Wadsworth;
1999. Available from: https://www.amazon.
com/Understanding-Nutrition-Whitney-Eleanor-
Rolfes/dp/B001U001XK
30. Ganong W. Review of Medical Physiology 17th
Edition Middle East Edition by Ganong William
F - AbeBooks. In: Applentond & Large A Simon
& Schuster Company, editor. 17th ed. USA;
1995. p. 652–6. Available from: https://www.
abebooks.co.uk/book-search/title/review-of-
medical-physiology-17th-edition-middle-east-
edition/author/ganong-william-f/
31. Guyton AC, Hall JE. Textbook of Medical
Physiology. Eleventh e. Philadelphia, USA:
Philadelphia, PA : Saunders/Elsevier; 2008.
1120 p.
32. Guyton A, Hall J. Buku Ajar Fisiologi Kedokteran
- edisi 11 [Internet]. 11th ed. Jakarta: EGC;
2007. 81-85-880 p. Available from: https://www.
elsevier.com/books/guyton-dan-hall-buku-ajar-
siologi-kedokteran/hall/978-981-4371-18-6
33. Puspaningtyas DE, Sudargo T, Farmawati A.
Efek minuman kombinasi maltodekstrin dan
vitamin C terhadap VO2maks atlet sepak bola.
J Gizi Klin Indones. 2015 Jul 30;12(1):20.
