• Because of sweating he will lose about 6 litters of water and an important quantity of electrolytes.

The energy spent solely by the physical exercise would be about 3.000 kcal. All the previous energy expenses are on top of the Resting metabolic energy at rest.

The correct diet is the one that provides the sufficient energy and the suitable nutrients (carbon hydrates, proteins, fats, vitamins, minerals and water) for the sportsman according to its age, gender, weight, and sport activity⁶.

The group of sportsmen is one of the most motivated to follow a correct diet; but for a long time it has been one of the groups that commit the greater errors, and believe in myths with respect to which it is a correct feeding⁷.

The deficits in nutrition jeopardise the sportive performances, but what about the diets with excessive intake of macronutrients? The recommended meals before/during/after the competition must be followed, to avoid the insufficient recharges of glycogen and to obtain the correct hydration^8,9.

The drinks should contain Carbohydrates, because they are very useful to maintain the blood glucose levels by the sportsmen. Due to the limited rate of the recovery of the muscular glycogen in competitions of several daily stages, it is convenient to drink isotonic drinks with carbohydrates during the long lasting competitions^10,11.

The stress of the sportsman delays the gastric emptiness and the digestions, reason why it is fundamental to control it, and to take meals with small quantities of fats⁴.

In addition to the healthful physiological effects, the exercise produces health benefits, such as preventing the appearance of chronic diseases, and also facilitating the treatment of already existing diseases¹².

Psychological aspects of cycling

Cycling puts stringent physical and psychological requirements on the sportsmen. The level of demands is quite often near to exhaustion.

Every evening cyclists have to fully recover physically and psychologically for next day competition stage. If you do not sleep well, next day will be worse than present day, and your state of mind enters in a cycle of negative thoughts.

The physiological and psychological stress associated to the competition is directly associated to nutritional practice, because it over-stimulates the sympathetic autonomous nervous system which makes difficult the digestion of the foods, and modifies the feeling of thirst and hungry. At the end of a strong competition you are neither hungry nor thirsty and you have to relax, to be able to eat and drink to re-hydrate and to start reloading your glycogen stores within the first two hours after the end of competition when the glycogen sintetasa enzyme is at its higher level. A good digestion is promoted by activation of the parasympathetic autonomous nervous system (antagonist of the sympathetic).

There have been several studies showing what are the important psychological factors determining the sport performances. By working on those psychological factors, the cyclist may improve his sport performances and his quality of life.

Methods

Thirty four young cyclists pertaining to the junior team (of 15 to 17 years) and to the Sub23 team (of 18 to 23 years). (http://www.echozas.com/), have participated in the nutritional study.

The cyclists have a regular program of training with technical Directors and trainers; the cyclist were training about six days a week. Along the year they participate in about 12 competitions in the community of Madrid (Spain) and other six Spanish national competitions.

They run more than 25,000 km per year.

The nutritional and psychological evaluations are mandatory for the Juniors team; and optional for the Sub-23 team.

All are healthy, without disease.

They have signed an informed voluntary consent, together with their parents or tutors, if they are under 18 years of age.

They have information on the good and safe sport practices¹³.

The psychological evaluation performed used the CPRD test¹⁴ to determine the psychological profile of the cyclists.

Antropometric data and energy requirement

The information required for the evaluation, is provided by cyclists in the "Questionnaire of nutritional habits and physical activity" such as anthropometric data, as well as the amount and intensity of the physical activity that every individual cyclist make.

The Body fat mass (FM) was assessed by bio-impedance measurements, INBODY520 body fat analyzer. Other methods, like skin folds thickness have been used but only with some of the cyclists, and the errors are of similar level¹⁵.

The anthropometric results show the average and the standard deviation of several parameters like age, weight, height, and Body Mass Index (BMI) is in table I.

BMI: body mass index, FM: body fat mass; SD: standard deviation.

Note: The quantities showed in the all Tables have been rounded to the units value, no comma and decimals were used (ie: if the means of age the cyclist teams were 20,1 years, in the table it is put 20 y).

To calculate the activity factor the DIAL program is used¹⁶; DIAL uses an equation with the weighted daily activity duration of table II; on the basis of values of WHO¹⁷.

In the example of the table II, the following Activity factor would result = (1 * 8 h + 1,5 * 7 h + 2.5 * 5 h + 5 * 2 h + 7 * 2 h)/24 h = 2.3.

To calculate resting metabolic rate (RMR) for sportsmen, the Cunninghan formula has been used because it is more appropriate than others¹⁸:

RMR = 500 + 22 * FFM (Body Fat free mass in kg)¹⁹.

The Energy required is calculated, based on the Resting Metabolic Rate (RMR) multiplied by the activity factor. The example of the cyclist X, whose data are given in table III is used to illustrate the method.

Total energy required = 2.3 * 1,761 = 4,050 Kcal²⁰.

The average results of the Resting metabolic energy at rest (RMR), and the daily activity factor for the cyclists of the present work, is shown in table IV.

The average results of the energy required and the calories consumed by the cyclist of the study; it appears that the Average of intake of Calories by the cyclist team are, slightly lower to the energy required by them. Certainly the body fat (MEANS ± SD) of the cyclists goes from 15% ± 2 down to about 7% along the sport season.

Statistical method

The results are expressed in MEANS ± SD. To determine the statistical significance, independent sample t - tests were used to evaluate differences between groups of the same team. Values of p < 0.05 are considered statistically significant.

Linear correlation method has been used to analyse possible associations between nutritional variables and sport achievement variables (using Microsoft Excel).

PC informatics tools of the Department of Nutricion and Bromatologia I of the Faculty of Pharmacy UCM. Madrid (Spain), have been used.

The DIAL program, using a Table with the composition of foods¹⁶, calculates the energy consumed and the Nutrients (macro nutrients, minerals and vitamins) contained in the daily food ingestion, using the foods composition Table of the Faculty of Pharmacy in Madrid²¹. The information of the ingested food is extracted from the "Questionnaires of Record of food consumption of 7 consecutive days".

In addition the DIAL program uses equations to calculate the energy required (total energy spent is equal to basal energy spent multiplied by the activity factor), based on the anthropometric data and the hours of physical activity. The serving sizes are based on information provided by the University of Leon, Spain^13,22.

Nevertheless for the cyclists we have used the Cunninghan equation in the calculation of energy spent, because it is more appropriated for sportsmen^18,19.

The Microsoft Excel and SIGMA 2.0 programs have been used for the statistical analysis, statistical significance and linear correlation²³.

Dietetic evaluation

Every cyclist participating in the study fill up several questionnaires:

• Questionnaire of nutritional habits and physical activity: where it is recorded the frequency of intake of different groups of foods, some anthropometric data, as well as the amount and intensity of the physical activity that the cyclists make.

The Questionnaires data are input into the DIAL Report detailing the Energy intake, nutrient and the Quality of the Diet, the later based on the recommendations applicable to the studied population group²⁴. The results of the cyclist nutritional evaluation are used to determine the diet unbalances; which are compared with those of the Spanish young population of the enKid study²⁵.

The recommended macronutrients intake for the cyclists have been calculated as follows:

• Proteins: 1.5 g/ kg of body weight per day^26,27.

• Carbohydrates: to complete the amount of energy required²⁸.

The resulting recommended average values for the cyclist teams are shown in the table V.

Phychological evaluation

The CPRD model contains 55 items related to 5 psychological factors involved in sport performances, which explains the 63% of the total variance. The alpha coefficient measuring the reliability of the five CPRD factors is 0.85¹⁵.

The test takes into account the following five factors of the personality, which are considered important in the achievement of the success in sports, namely:

• Stress control.

• Team cohesion and degree of commitment with peers.

Weak points of the juniors cyclist team are Self Control of the stress, followed by the Influence of the evaluation (by oneself, coaches and peers) of his own performances.

Strong points are Team cohesion, correct use of mental skills, and motivation.

Sport performance index (SPI)

Sport performance index (SPI) is a relative evaluation (from 0 till 100) of the sport achievements of each cyclist.

It is done by coaches and trainers of the team, at the beginning and at the end of each sport season.

The following achievement criteria are taken into account (for each evaluated cyclist):

• Number of triumphs in National Spanish cyclist competitions (within first three winners of the competition; within the first group attaining the goal).

• Achievements during the Training (climbing, speed, order of arrival)

The first evaluation is done by the couches at the beginning of the sportive campaign (the one presented in this paper has been done in the beginning of 2006).

Next evaluation will be done by the couches at the ending of the sportive campaign (the next one will be done in the end of 2006) to show the team performance evolution.

Results of the nutritional evaluation

The energy balance show that the Average of intake of Calories by the cyclist team (n = 34) is as average, slightly inferior to the energy required by them. The table VII presents the average data of the studied group.

Since the factor of activity is greater in the time of competitions from february to october, a reduction of the weight of the cyclists takes place, but it returns to normal weight because there is a diminished the factor of activity from november to january.

In the Spanish young people community (as average, more sedentary than the studied cyclists), the mean daily energy consumption is 2,189 kcal among males, and 1,781 kcal among females²⁵. The rate between the cyclist caloric intake and the male young people caloric intake, is 1.55 times.

Regarding the average consumption of macronutrients the results, of cycling young people, shows important unbalances in the caloric profile.

The macronutrients and energy intake of cyclists participating in the present study; as well as the ones of the homologous Spanish young people of the enKID study²⁵, are shown in table VIII.

We found the same eating patter in both groups of Spanish young people participating, namely excessive intake of proteins and fats. By contrary the intake of carbohydrates is noticeable not sufficient.

Cyclists consume an excessive amount of Proteins (= 16.36% of the energy) and Fats (= 38.71% of the energy); while the recommended profile would be less than 10% of the energy form proteins and less than 30% of the energy from fats.

The same tendency is found in the Spanish young people, where the mean daily energy consumption shows that the percentage of energy from fat and saturated fat was 38.65% and 13.4%, respectively, without any differences by gender. If we consider only the intake of males, the fat and saturated fat was 40.1% and 12.7%, respectively²⁵.

Instead the Carbohydrates ingestion (= 44.94% of the energy) is inferior to the recommended value (more than 60% of the energy). The consumption of cereals seems to be adequate, but the intake of fruits and vegetables is insufficient. The means of carbohydrates intake was less than the recommended 7-10 g/kg BM per day⁹.

In this food group of Carbohydrates, the intake of the sugar is 16,59%; this consumption is higher than the recommended quantity (less than 10%) for the Spanish population, but in general that does not give us any concern, if it is consumed during and after the exercise; to maintain glycaemia and to make faster the reload of the glycogen reserves, by taking foods with high glycaemic index.

It is advisable to perform series of snacks during the early recovery phase, but during longer recovery periods (24 h) the athlete should organize the pattern and timing of carbohydrate-rich meals and snacks according to what is practical and comfortable for their individual situation⁹.

Evaluation of the index of quality of the diet (ICD)

The index of quality of the Diet (12), allows to classify the Diets as, poor diet (< 50 points), diet which needs to be improved (51-80 points), and excellent diet (80-100 points)²⁹.

The ICD is calculated analysing the variety and quantity of groups of food consumed by comparison with the recommendations (CRD). The CRD are determined taking into account the anthropometric data and the energy requirements of the cyclist²⁴.

Ten criteria are evaluated corresponding to groups of food in the food pyramid. Each criteria may have from 0 till 10 points. The ICD evaluation therefore has a range from 0 till 100 points.

The intake of different groups of foods by the cyclist team is shown in the table IX.

The resulting index of quality of the diet of the cyclists teams (as calculated by the DIAL program), expressed as MEANS ± SD; is ICD = 67 ± 11 points, which means as average it is a good diet, but has to be improved.

The cyclist of the present study consumes excessive quantities of meat, eggs, cholesterol and sodium. At the same time they consume less quantities of vegetables and fruits than the recommended ones, The intake of cereals and legumes is slightly under the recommended quantities.

As part of the nutritional intervention, individual diets have recommended to the cyclist to correct those unbalances. Those fat and sodium unbalances may jeopardise their health as they are considered risk factors for obesity, heart and kidneys in the long term³⁰ and excess of proteins with excretion of calcium in the urine may be a risk of osteoporosis³¹.

Comparison of carbohydratesintake by he Junior and by the Sub-23 teams

The carbohydrates intake of the Juniors and Sub-23 teams in shown in table X.

The mean intake of carbohydrates was significantly greater in Sub-23 than in Juniors team. One reason is, may be, because sub-23 cyclists (18-23 years old) have learned the importance of eating sufficient amounts of carbohydrates, while Junior cyclists (15-17 years old) are still in the process of learning good nutritional habits.

Association between nutritional intake and the achiements of the cyclists

In the present study we have analysed the possible correlation between the nutritional intakes defined as the quality of the diet (ICD) and the sport achievements index (SPI) obtained by the cyclists:

• SPI average of both teams (n = 34), means ± sd = 49 ± 16.

• ICD average of both teams (n = 34), means ± sd = 67 ± 11.

Possible reasons are that for those young cyclist, the physiological capabilities are the main determinants of their sportive achievements; given that all are in rather good nutritional state, and given that the cyclist competitions for young people have a relative short duration: they last one, two or maximum three consecutive days. That relatively short duration makes not significant differences in the management of their glycogen stores.

The unbalances encountered in their evaluation are excessive intake of proteins and fats, that may present a health risk in the long term, but they do not jeopardise their sport performances in the short term.

Comparison of quality of diet among the cyclists

When we classify the cyclists into two groups W and L, according to their score index of quality of their Diet (ICD), we have the results shown in table XI.

There is statistically significant difference between both groups in the quality of their diets (group W have better diet than group L); but there is not statistical difference in sport achievements between group W and L.

The correlation factor between SPI and ICD for group L is = 0.07; there is a no association between achievements in sport and the quality of the diet. Figure 2 shows the ICD and SPI scores of the 16 cyclists with poorer diet quality (bellow the average of the team).

Comparison of sports achievements among the cyclists

When we classify the cyclists into two groups G and B, according to their index of quality of sports achievements (SPI) , we have the results shown in table XII.

There is statistically significant difference between both groups in sport achievements (group G have better achievements than group B); but there is not statistical difference between group G and B, in the quality of their diets.

The correlation factor between SPI and ICD for group G is = 0.46; there an association was found between achievements in sport and the quality of their diet (for the better performing group G). Figure 4 shows the SPI and ICD scores of the 20 cyclists better performing (above the average of the team).

The correlation factor between SPI and ICD for group B is = -0.42; there is an inverse association (within the poorer performing GROUP) between sport achievements and the quality of their diets. Figure 5 shows the SPI and ICD scores of the 14 cyclists less performing (bellow the average of the team).

• The group that has poor achievements, the better are the achievements, the worse is quality of their diet.

• The group that performs better, the better are the achievements, the better is quality of their diet.

Therefore the cause of sport achievements cannot be associated, for those young cyclists with the "quality of their diets" as it have been measured here; mainly because"bad diet" in this study means unbalanced diet with excessive proteins and fats and may be because the index of quality of the diet used has been indicated for normal people and not specifically for sportsmen²⁹.

It is important to practice healthy nutritional habits which are useful along all the time; because while the sportsmen make much physical activity they maintain under control their corporal fat, but they will become over-weighted, if they do not make a correct de-training program³².

Discusion and conclusions

Several cyclists present unbalances in their diets (this situation is worse within the junior team than sub23 team), namely:

• The cyclists, as average, take insufficient amount of carbohydrates, reason why they do not probably recharge its reserves of glycogen to the maximum.

NO association between nutritional state and the achieved sport performances, has been found in the present study, because the results are contradictory. Excessive intake of proteins and fats do not jeopardise their sportive performances. The commonly studied psychological variables are not determinant of sportive achievements of young cyclists; additional work is needed to determine the psychological profile playing a determinant role in cyclists success. The linear correlation found is weak.

• Possible reasons are that all young cyclist are in good nutritional state for the practice of the sport, in fact the unbalances are excessive intake of proteins and fats, which may present a health risk in the long term, but they do not jeopardise their sport performances in the short term. In addition it seems that the duration of the competitions (up to three days) is not long enough to affect significantly the recovery of their glycogen reserves. The index of quality of the diet used is applicable to general people, it is not specific for sportsmen, therefore it may be not a suitable predictor of sport performances.

• The evaluation was done at the beginning of the sport season, therefore without enough data on their sport achievements.

We have designed individual diets to correct their nutritional unbalances found during the evaluation (reducing the proteins, fats and cholesterol in their diets; while increasing the starch and carbohydrates); and we are performing nutritional campaigns to inform the cyclists, their parents and their sport couches of the suitable nutrition habits.

The weak emotional skills of the studied young cyclist are, the control of their stress and their dependency on critics and comments (received by peer's, couches, and be themselves) related to their performance.

Strong emotional points are, their motivation and their consciousness of belonging to the same team.

We are providing psychological advice and support, to develop emotional shelf-control skills of the cyclist team.

The results of the mentioned interventions will be the subject of a future work to be published at the end of the year, when the present cyclist season has ended.

Acknowledgements

We wish to thank the advice of Ascensión Marcos Sánchez, Julia Wärnberg, Instituto del Frío del CSIC; Rosa M. Ortega Anta, Cátedra de Nutrición I de la facultad de Farmacia (UCM), Eva Montero psychologyst; Eduardo Chozas (http://www.echozas.com/).

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]]> Correspondence:
José Luis Sánchez-Benito
E-mail: jl.sbenito@ya.com

Recibido: 30-XI-2006.
Aceptado: 12-II-2007.