International Peer-Reviewed Journal  
Patil Rita and Cheulkar Kashyapi*  
The certainty of success depends on consistency and intensity of practice by an athlete.  
Carbohydrate plays an important role as a fuel for performance in practice and during competitions.  
Indian studies on athletes are few and therefore this study was undertaken. The aim was to  
understand the effect of carbohydrate intake of endurance athletes on their performance. One  
hundred and four athletes of 400 meters sprinting events were selected from various schools and  
clubs in Mumbai. General information and other questions were used to collect data. Anthropometric  
measurements were taken. A 24-hour dietary recall was also obtained. Coopers 12-minute walk  
run test was conducted. Results indicated a significant association between carbohydrate intake  
of athletes and their performance (Coopers test). Aerobic capacity was significantly associated  
with carbohydrate intake. Total energy, protein intake and duration of practice were significantly  
correlated with performance and aerobic capacity of athlete.  
Keywords : Endurance athletes, sprinters, 24-hour dietary recall, Coopers test.  
Importance of carbohydrate intake in exercise and performance has been established since early  
930s in the classic respiratory exchange studies and biopsy studies (Christensen and Hansen.,  
939; Bergstrom and Hurtman, 1967). Immense attention has been given to carbohydrate stores,  
how to minimize the effect of carbohydrate depletion and also to enhance performance of athletes  
Coyle, et. al., 1985).  
Carbohydrate provides energy for high- intensity endurance exercise at 85% to 100% VO max,  
which is more than any other nutrient (Antonio et al., 2008). When exercise intensity increases, the  
dependency on carbohydrate as a fuel also increases. Dietary sources and endogenous stores of  
carbohydrate contribute for fuel in high intensity event. Thus, the effect of both acute and chronic  
dietary intake of carbohydrate is important in an athlete’s diet (Koopman et al., 2006). Along with  
exercise, consistent training plays a role in improving performance. Also process of appropriate  
recovery, overcoming gaps of nutrient intake and repairing damage helps an athlete to improve  
performance (Campbell and Spano, 2011). It is most important for an athlete to fuel the body for  
maximum recovery and to enhance performance who undergo multiple workouts daily (Costill, 1988).  
In addition to high energy requirements, athletes undergoing moderate to high intensity exercise  
have an immense need of carbohydrate. The high intensity workout stimulates glycogenolysis.  
Therefore, with the inadequate supply of carbohydrate, a decline in the performance of an athlete  
may be seen. Carbohydrates play an important role to provide fuel during training sessions, to  
promote muscle glycogen re-synthesis post exercise and also for good performance (Fink et al.,  
009).This study was undertaken to understand carbohydrate intake of athletes in Mumbai and to  
observe their performance in Coopers test.  
A cross-sectional study on one hundred male and female sprinter athletes participating in 400 meters  
events between the age group of 12 to 20 years were selected by the purposive sampling approach.  
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The questionnaire included general information (name, age, sex, school, designation, etc).  
Anthropometric measurements height and weight was measured and the BMI was calculated.Height  
was measured to nearest 1 cm and weight was measured to nearest 100 gms. Their performance in  
athletic activity was assessed using questions related to practice such as practicing ground, best  
timings for 400 meters, level in which athletes participated in past, were asked. Questions related to  
practice schedule, diet behavior and its influence on athletic performance were also included in the  
questionnaire (average duration of training in a day/ week, supplements intake during exercise, diet  
regimes during competition, carbohydrate consumed during practice, complications suffered during  
practice, etc).  
A 24-hour dietary recall and other dietary information were collected from the participants.Subjects  
were asked to report all foods and beverages consumed in the past 24 hours. Portion size of the food  
was asked using measuring cups and spoons. Carbohydrate content of their diet was calculated.  
Cooper test (1968): Coopers 12 minutes run walk test was conducted to test physical endurance.  
The test is to run or walk as far as possible within 12 minutes. Coopers test was explained to subjects  
in detail. The distance covered by athletes was measured in meters after the time of 12 minutes was  
The study was approved by Inter System Biomedical Ethics Committee (ISBEC). Informed consent  
was taken from subjects as well as from parents (for subjects below 18 years).Statistical analysis was  
done using SPSS version 20 was used to analyse data.  
The participants in the study were between 12-20 years of age group. The mean height of subjects  
was 156.9 cms and mean weight was 48.3 kg. Twenty-nine boys and 7 girls were underweight, 48  
boys and 16 girls belonged to normal weight category. Although there were 4 boys in the overweight  
category, there were no girls and boys in obese category. The mean anthropometric measurements  
are given in Table 1.  
Table 1 Mean Anthropometric Measurements of Subjects in Different Age Groups  
Mean ±SD  
Age- (12-15 years)  
Age-(15-18 years)  
Age- (18-20 years)  
Height (cms)  
149.72 ±15.31  
144.41 ±15.97  
168.86 ± 9.28  
172.82 ± 6.01  
156.71 ± 5.70  
BMI (kg/m2)  
42.86 ± 9.53  
19.14 ± 3.28  
39.00 ± 11.02  
18.55 ± 2.85  
54.45 ± 8.38  
19.06 ± 2.52  
46.25 ±12.5  
18.60 ±2.19  
63.00 ± 4.88  
21.08 ± 1.16  
52.14 ± 7.64  
21.15 ± 2.48  
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Athletic performance is affected by several other factors and the diet of an athlete is one of them.  
Intake of proper diet during exercise helps to improve the performance. A diet prescribed by a sports  
nutritionist may enhance levels of performance. Only 9 athletes were found in this study to be consulting  
a sports nutritionist. Some athletes did consult a sports nutritionist; however, they did not follow the  
prescribed diet. Out of 104 subjects, 91 did not have a planned diet.  
Dietary intake was analysed. There were 6% athletes who were following a specific diet before and  
during their competitive days. Two percent of the athletes avoided non-vegetarian diet and increased  
their carbohydrate intake. Out of all the subjects, 3% increased intake of water before main competition  
days. One percent of the athletes restricted food intake during competition, and reported to consume  
fruits and vegetables to increase their vitamin and minerals intake. Rest of the 87% athletes continued  
a regular diet during competition.  
The macronutrient intake of subjects was compared with recommended dietary guidelines for athletes  
(Table 2). The mean calorie intake of athletes was 1877 Kcal/day, which is towards the low- borderline  
range of recommendation. Mean carbohydrate intake was 264g/day which is adequate for general  
physical activity of 30-60 minutes for 3-4 days/week, but it is low for moderate to high intensity  
workouts. The mean intake of protein was 65g/day which was in adequate range of recommendation  
for general physical activity and was low for moderate to high intensity exercise. Table 2 shows  
dietary guidelines for athletes  
Table 2 Dietary Guidelines for Athletes  
Physical activity levels  
Kcal/kg/day Kcal/day  
(g/kg BW/day)  
g/kg BW/day)  
General physical activity  
0-40 min/day(3 times/week)  
Moderate physical activity  
-3 hours/day(5-6 times/week)  
High physical activity  
-6 hours/day(5-6 times/week)  
Source: Potgieter, S. (2013)  
Coopers 12-minute run and walk test is an indicator of cardiovascular fitness. This test also helps to  
estimate aerobic power of athletes. Figure 1 shows the Coopers test performance of athletes.  
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Figure 1 Coopers Test Performance by athletes  
Eighteen athletes showed excellent performance in Coopers test. Seventeen athletes had an above  
average performance and fifteen athletes showed an average performance. Ten athletes had a  
below average performance and more than 40% athletes showed a poor performance.  
Athletic performance in Coopers test was correlated with other parameters such as body mass index  
BMI), carbohydrate intake duration of training, total energy consumed and protein intake.The  
performance of athletes in Coopers test was not significantly correlated with BMI (r=0.143,p=0.147).  
Total carbohydrate intake was significantly correlated with performance in Coopers test (r=0.501,  
p=0.000). The duration of training hours per day was significantly correlated with the performance of  
Coopers test (r=0.401, p=0.000). Comparison of Coopers test remarks between boys and girls  
showed 49.4% of boys and 17.4% of girls had poor score. Eleven percent boys and 4.3% of girls had  
below average performance. Average score was observed in more girls (21.7%) and less boys  
12.3%). Between both the sexes, boys (18%) and girls (8.7%) had above average performance. A  
very high percentage of girls (47.8%) secured an excellent score compared to boys (8.6%). Also,  
most of the boys had a poor score in Coopers test performance compared to that of girls. The total  
calorie intake had a significant positive relationship with performance of athletes (r=0.560, p=0.000).  
Protein intake too indicated a significant positive relationship with performance in Coopers test  
r=0.552, p=0.000).  
Athletes differ in their performance at inter school, district and national level. Most of the athletes in  
this study were participating in district level. Thirty-one athletes participating in state level during  
competition and 29 athletes participating in inter school events. Only 10% of the athletes participated  
in national level competition. The best timing to cover 400 meters also differ. The best timing for  
completing 400 meters for boys was 50 seconds and for girls was 58 seconds. Also, the timings of  
completing 400 meters were seen to be as high as 118 seconds in boys and 120 second in girls.  
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The macronutrient intake of study subjects was compared with recommended amount of  
macronutrients given by ACSM.The mean calorie intake of athletes was towards the low- borderline  
range of recommendation. Thus, the performance in Coopers test may be poor. Results of study by  
Weiss et al., 2007 had reported that a low-calorie intake and energy restriction resulted in muscle  
loss and thereby reduced muscle strength and effected physical performance of athletes.  
Mean carbohydrate intake in athletes of this study was 264g/day which is adequate for general  
physical activity of 30-60 min for 3-4 days/week, but is low for moderate to high intensity workouts.  
Study by Rico-Sanz et al., 1998 done on soccer players reported that carbohydrate intake of subjects  
was the minimum which was recommended to maximize glycogen storage. This intake helped the  
subjects show good endurance capacity. Similarly, a study conducted on eight cyclists involved in  
endurance training showed improvement in completion of exercise regime with carbohydrate intake  
Chambers et al., 2009). Another study done on trained and untrained athletes also showed a  
significant improvement in performance of untrained athletes with carbohydrate intake (Sullo, et. al.,  
In this study, total carbohydrate intake was significantly positively correlated with performance of  
Coopers test. Hargreaves et al., (1984) showed feeding carbohydrates to athletes maintained their  
blood glucose level and reduced their muscle glycogen utilization. Also, enhancement in the sprinting  
performance was observed. In another study carbohydrate was given for 3 days. They reported an  
increased level of workout. Carbohydrate intake increased muscle glycogen stores and thus had a  
positive effect on performance (Hawley et al., 1999).  
Athletes having adequate amount of carbohydrate and optimal glycogen stores run faster (Sullo, et.  
al., 1998). In the present study, the athletes who scored poor remark in Coopers test were found  
consuming low carbohydrates compared to those athletes in the excellent performance group. Higher  
energy is required for moderate to high intensity training. Thus, chronic fatigue is experienced when  
athletes have inadequate carbohydrate intake.  
The mean intake of protein was found to be adequate for general physical activity and was low for  
moderate to high intensity exercise. Comparison of total protein intake within groups showed a  
significant difference between poor and excellent score groups (F=5.918, p=0.000) and no other  
groups. This may be due to inputs given by their coaches to increase protein intake. Also, athletes  
deliberately pay attention to protein intake as it is known to help good performance. Contradictory to  
the present study no relation of aerobic capacity with protein intake was found by Kerksick in 2006.  
They also suggested that protein can be used to increase fat-free mass and body composition of  
athletes during training (Kerksick, et. al., 2006).  
Food intake of athletes suggested that they may be underweight because of an inadequate intake. A  
low macronutrient intake may limit athlete’s growth and performance to a certain level. Intake of  
proper diet during exercise helps to improve the performance. A diet prescribed by a sports nutritionist  
may enhance levels of performance. Even if a qualified sports nutritionist was consulted, they did not  
follow the prescribed diet.  
Protein intake is looked upon as a performance enhancer and hence intake was adequate.  
Carbohydrate intake and other supplements were ignored, possibly due to lack of knowledge.  
Carbohydrate loading method during competitive days was not reported to be used by any subject.  
During Coopers test 42.3% of the athletes were found under poor remark. This could be due the low  
energy and macronutrient intake and no supply of carbohydrates during practice. Their duration of  
training was also low. Also, most of the boys had a poor score in Coopers test performance compared  
to that of girls. This could be because girls were concerned about their diet, they consulted a sports  
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nutritionist and followed a balanced diet. None of the boys consulted any professional sports nutritionist  
for their diet.  
In our study the duration of training hours in a day was significantly correlated with the performance  
of Coopers test. Houmard (1991), observed decrease in performance if practice is reduced for  
several days. He suggested muscle power is reduced by 20% when there is a reduction in training.  
Also, reduction in 70-80% of VO max was observed. Thus, athletes were suggested not to reduce  
training duration and intensity prior to competition (Houmard, 1991).  
Gelibter, et. al., (1997) studied relation between peak oxygen consumption and duration practice.  
He observed peak oxygen consumption increases with the duration of training. Correlations of different  
parameters like carbohydrate intake, protein intake, total energy intake and duration of training was  
found to be positively correlated with the distance covered in Coopers test and also with aerobic  
capacity of an athlete. Factors like total energy intake, total carbohydrate and protein intake and the  
duration of training has an influence on the performance and aerobic capacity of an athlete.  
Our study observed that the difference in performance in Coopers test was highly significant between  
the poor performers and excellent performers. Similar results were seen for duration of training, total  
energy intake and carbohydrate intake.  
The results of this study show a significant positive correlation with total energy, carbohydrate, protein  
intake and duration of training. Athletes consuming adequate diets were seen to have better  
performance than athletes who ignored their diet or lacked proper knowledge about it. Duration of  
training also had a positive impact on performance. Athletes in the present study were found to  
consume inadequate diet when compared to the dietary guidelines for athletes. This study also  
found majority of athletes to be underweight or at the borderline of normal range.  
Results of Coopers test clearly suggest that adequate energy and carbohydrates are required for  
good performance. It is challenging for athletes to meet dietary requirements, be fit without injury  
and concentrate on a good performance. Not only athletes but coaches should also have adequate  
knowledge of all factors affecting athletic performance.  
Sports nutrition is important for all sports and also at every stage of sports. Whatever athletes eat or  
drink affects exercise and performance. Therefore, a well-balanced diet is necessary to maintain fuel  
sufficiency during exercise. Meeting energy and macronutrient requirements is a challenge for athletes.  
They need to consume adequate calories and carbohydrates daily in their diet. They also need to  
practice regularly to excel in their performance. The type and amount of carbohydrates and time of  
consumption of carbohydrate are factors that will affect athletic performance. Glycemic index of  
foods and loading of carbohydrates should be kept in mind too. Overtraining of athletes and burn  
out are issues which impact performance. It is also important to remember that athletes who practice  
regularly but may have an inadequate calorie and carbohydrate intake may perform poorly.  
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PhD Associate Professor, Dept of Food and Nutrition, Maniben Nanavati Women’s College, Mumbai  
Masters in Clinical Nutrition and Dietetics, SNDT Women’s University, Mumbai