STUDIES IN PHYSICAL CULTURE AND TOURISM

Vol. 12, No. 2, 2005

The aim of the paper is to design the body build type of bike trial competitors. The basis for the study consisted of measurements of 10 selected somatic features in 41 competitors belonging to the world bike trial top elite. The complex Sheldon method for typological assessment with Heath and Carter's modification was employed in the analysis. The study also used the UCI-approved classification into bicycle categories according to the size of wheels. In the light of the accepted distinction some differences between somatic features were noted, which, however, had no influence on the body build type obtained in both groups. This type may be defined as ectomorphic mesomorph (Mod category 2.0-5.3-2.6; Stock category 1.6-4.4-3.2)

Features of morphological build play a significant role in the selection of competitors for specific sports. Human properties like body height and proportions between longitudinal segments of the skeleton cannot be changed by training in view of significant genetic factors. This implies consideration of the aforementioned features, already at the stage of preliminary selection [10]. Genetic stability was also identified with reference to the somatotype, i.e. the global profile of the human body [15]. Many authors have made attempts to evaluate the types of body build of various sport groups [1, 3, 5, 8, 14, 20, 21] by creating somatic patterns characteristic of them. There are in fact somatotypes whose characteristics may determine sports success. Since the type of somatic build does not undergo any significant changes in the course of human growth, the assessment of the somatotype permits identification of competitors predisposed to specific sports disciplines [19]. The method for typological assessment of body build with Heath – Carter’s [8] modification can be accepted as useful in identification of desirable somatic properties.

Conclusions that can be drawn from previous research confirm the necessity to carry out further analysis, especially in the case of new sports.

One of such new sports is bike trial. The main goal of the bike trial competition is the faultless going through designated sections of the route within a precise time limit. These sections are 30-60-meter-long obstacle tracks, through which competitors are to go without support. A competitor gets penalty points for each contact with an obstacle or touching the ground with the foot as well as for falling off the bike. Leading competitors who achieve significant success usually undergo relatively long training.To describe the degree of difficulty of the obstacles on the velodromes, used in competitions such as world championships, it is possible to venture a statement that covering a velodrome in a natural way may turn out to be extremely difficult, if not altogether impossible, for an adult and healthy person. At present, the high sports standard of top world competitors often permits covering the arranged velodromes without any penalty points, i.e. with no support or falling off the bike.

Thus, the specificity of bike trial exceeds the commonly known cycling events. No scholarly study devoted to bike trial has been published so far, and yet differences both in the area of technique and the character of the undertaken effort are easily noticeable. The wide range of technical elements makes it possible for a bike trial competitor to overcome obstacles much taller than the bike itself and manoeuvre the latter on a relatively small area. When covering particular sections of the route, in time no longer than 2.5 minutes, competitors put forth a physical effort of very high intensity. In a competition, it is necessary to cover from 14 to 16 sections, depending on the age category and the rank of the competition. Competitors are allotted time, which should guarantee reaching all the sections without much hurry. Therefore, to a certain extent, competitors can manipulate the duration of rest breaks between the efforts by themselves.

Figure 1. A bicycle with 20-inch wheels. Mod category (Modified Trials Bike)

In bike trial events of a higher rank competition takes place in two bicycle categories which are distinguished mainly by the size of bicycle. The first category, called Mod (Modified Trials Bike), requires 20-inch wheels (Figure 1), whereas the second category, Stock (Stock Trials Bike), encompasses mountain bicycles with 26-inch wheels (Figure 2). There are also competitions with no specified bicycle categories. Besides, some top world competitors participate in both categories, which reflects their versatile preparation.

Figure 2. A bicycle with 26-inch wheels. Stock category (Stock Trials Bike)

Modern bicycle construction technologies used in bike trials have made it possible to reduce the weight of trial bike in comparison with ordinary bicycles. Consequently, high-performance bicycles with 20- and 26-inch wheels are typified by their relatively similar weight (the difference is 2-2.5 kg). A common feature of these bicycles is a lowered centre of gravity, which makes it easier for competitors to keep balance. Competitors vie only in the standing position, hence the absence of saddles in bicycles of this kind. The “lowered” frame that allows for more extensive body movement is another very important, distinctive element. The size of wheels determines the range of possible movements of a competitor. The scope of this movement is important for the basic technical elements in bike trial. Similar interrelations occur also in other sports.

Iskra [7] holds that specific parameters of somatic build may determine the sports success of competitors taking part in a hurdle race. The values of these parameters depend, in turn, on the statutory requirements of the discipline (the height of hurdles and the distance between them). The functions performed on the playing field in team sports may presuppose specific requirements pertaining to the type of competitors’ body build [13, 16]. In swimming, on the other hand, the distance to cover as well as the swimming style have been marked as elements which differentiate competitors in regard to somatic features [12].

Therefore, the parameters of bicycles may define some consistencies in the somatic build of competitors attaining a high sport level.

The aim of the work was to define the type of body build of competitors in bike trial and identify the differences between the types of body build and somatic features of competitors in different bicycle categories.

Forty one bike trial competitors representing Belgium, the Czech Republic, France, Germany, Poland, Slovakia, the United States and Switzerland were examined. Over 75% of the subjects are classified in the top UCI ranking (the Union Cycliste Internationale – International Cycling Union), which accounts for about one third of all the competitors practicing bike trial who are members of the UCI. The calendar age of the examined competitors ranged from 18 to 30 – the average age was 21 years (Table 1). The competitors were divided into two groups according to the bicycle category (Mod category n=20; Stock category n=21), in which they were most successful. The difference in the arithmetic mean of age and competitor training period between the groups was not statistically significant (Table 1). The research material was gathered in 2003 during national and international competitions.

Table 1. Age and training period of the competitors under study [in years]

Measurements were made of body height and weight, thickness of triceps, calf, subscapular and supraspinale skinfolds, arm and calf girth as well as biepicondylar breadth of the humerus and the femur. The somatotypes of the competitors were also determined with the use of W.H. Sheldon’s Somatotype Method modified by B.H. Heath and J.E.L. Carter [2]. The analysis of the material consisted of determining the significance of the differences between the average values of the measured body components and the somatic build features between the formed groups. These components make it possible to determine the degree of body adiposity (endomorphy), the level of the musculoskeletal component (mesomorphy) and body slenderness (ectomorphy).

The computed components and the somatic features were normalized to the mean value and standard deviation of the Mod category competitors (bicycles with 20-inch wheels).

The gathered research material was analyzed using simple statistical methods yielding arithmetic means and standard deviation, and the significance of the differences between the mean values was estimated by means of Student’s t-test.

The data analysis shows essential differences as far as somatic features are concerned (Table 2). The competitors riding the bicycles with smaller wheels (20-inch – Mod category) is on the average 3.4 cm shorter and are characterized by larger arm adiposity (1mm on the average). Furthermore, in this group, two leg features turn out to be considerably larger: shank fold thickness (1 mm) and biepicondylar breadth of the femur (2 mm).

The analysis of the normalized values of somatic features (Table 3) presents a slight diversity among the studied groups of competitors. The largest difference was noted in the case of the thickness of shank skin-fat folds and the biepicondylar breadth of the femur; however, none of these values exceeds the standard deviation.

Table 2. Arithmetic means and standard deviations of body build features of the Mod category competitors (bicycles with 20-inch wheels), the Stock category competitors (bicycles with 26-inch wheels) and the estimate of the significance of the differences between the mean values

Table 3. Values of features and body components normalized to arithmetic mean values and standard deviations of the competitors of the Mod category – bicycles with 20-inch wheels

While estimating the types of body build with the help of W.H. Sheldon’s Somatotype Method modified by B.H. Heath and J.E.L. Carter [2], it has been shown that mesomorphy is a dominant component among the competitors in both groups (Table 4). The majority of the obtained somatotypes fall within the mesomorphic group (Table 5). The mean value of the body components of all competitors makes it possible to describe their body build as ectomorphic mesomorph, where mesomorphy is the dominant component, and ectomorphy is at least half-unit larger [2]. The same type is characteristic of the competitors in the Mod category (20-inch wheels), and also of those riding the bicycles with 26-inch wheels (Stock category). Only the difference between the mean values of mesomorphy turned out to be statistically significant, where higher parameters were obtained for the competitors riding “smaller” bicycles (Table 4).

Table 4. Arithmetic means of typological components of the competitors assessed by means of Heath-Carter method [2] and the estimate of the significance of the differences between the mean values

Table 5. Somatic types of the competitors in Mod and Stock categories

While comparing the values of the normalized components in the juxtaposed groups, it was noted that competitors in the Mod category were characterized by a higher level of mesomorphy and edomorphy (Table 3), in comparison to those in the Stock category. Competitors using larger bicycles obtained, in turn, an upper hand as far as ectomorphy was concerned. The greatest difference was noted in the level of development of the musculo-skeletal component. The other constituents differ by about a half of standard deviation. Analyzing the individual distribution of somatotypes, one may notice their slight dispersion (Figure 3), and the competitors participating in both categories are placed in the same area in the somatogram. The mean values of the components calculated for both groups and all the competitors taken together delineated much related profiles.

Figure 3. Distribution of the somatotypes of the competitors and profiles of Mod and Stock categories. Triangles – somatotypes of the competitors in the Mod category; Circles – somatotypes of the competitors in the Stock category

The features of somatic build of the examined competitors approximate the somatic characteristics in other sports. The average level of endomorphy (1.8) typical of bike trial competitors was observed also among 400-meter track and field athletes, bodybuilders and free style wrestlers [19]. The average level of mesomorphy (4.8) obtained in the present study was also noted among top downhill race skiers and medium-distance runners [19]. The dominance of the mesomorphy component identified in the present analysis is also revealed in research pertaining to many other sports groups [1, 3, 9, 14, 20]. There are also studies [5] which indicate a higher level of this component in competitors who represent a higher sports level. This situation can be confirmed by research where the results of motor ability tests were positively correlated with the level of mesomorphy, whereas in the case of endomorphy, a negative correlation was identified [2]. This interrelation is confirmed by Gualdi-Russo et al. [5], who suggest that optimal values of the first two components (endo and mesomorphy) play the main role in sports activity. The level of the last component determined among bike trial competitors, i.e. ectomorphy (2.9), was identified also among competitors practicing team sports – mainly volleyball and basketball [5], karate [8] as well as 400 m runners [19].

Research results obtained by different authors for competitors practicing the same sports may, despite similar trends, differ when it comes to details. It is thus advisable to remain cautious when reaching conclusions from comparative analyses. Moreover, it seems that the picture of somatic build in its comprehensive, three-component interpretation analyzed with respect to the discipline practiced by competitors is more complete.

The somatotype of competitors practicing bike trial and described as ectomorphic mesomorph is characteristic also of road cyclists – 1.5-5.5-2.4 [18] and track cyclists – 1.6-5.4-2.5 [17]. Possible similarities in the type of body build with competitors practicing bike trial do not seem to result from the functional character of the aforementioned events. The latter is in fact significantly different. According to researchers, the ectomorphic mesomorph profile includes, among others, swimmers – 2.1-3.8-3.0 [14], volleyball players – 1.5-4.5-3.5 [16] and gymnasts – 1.5-5.6-2.1 [4]. It is not difficult, then, to realize that the forms of the sports competition or the conditions in which the competition is undertaken are completely different. Therefore, while searching for similarities in the area of somatic build, it is worthwhile to have a closer look at the form of the sports competition in the compared sports. The analysis of the technique of overcoming obstacles in bike trials points first of all to elements of jump. The similarity between the profile obtained in the present study and the somatic profile of high jumpers – 1.6-5.5-2.8, and long jumpers – 2.1-5.7-2.8 [19] can be attributed to the common feature of the sports competition. Both jumpers and trial cyclists try to lift the body center of gravity as high as possible. The large similarity between bike trial competitors and short- and medium-distance runners also seems interesting. A similar profile is characteristic of sprinters – 1.8-5.3-3.0 and 400 m-distance runners – 1.8-5.7-2.9 [19]. This likeness may stem from the character of the undertaken effort, which is highly intense over a short time. Nevertheless, without further research devoted specifically to the physiological basis for the effort, this statement remains not so much a conclusion as a conjecture.

In the past, having attained a specific sport level, competitors changed the category and started to compete on larger bicycles. At present, many competitors take part in both categories or specialize in one. Such a tendency is confirmed by the lack of a statistically significant age difference between the distinguished groups of competitors.

Furthermore, the values of somatic features characterizing the distinguished groups of competitors in the present research seem also interesting. It might appear that competitors riding bigger and heavier bicycles of larger length parameters are characterized by adequately larger values of the remaining somatic features. However, this is not so. Analysis of the normalized data implies that the above-mentioned competitors have the same body weight, while the values characterizing body adiposity are lower. The situation was reflected in the lower average level of the endomorphic component in the Stock category. Thus, it may be assumed that they are considerably slenderer than the competitors riding bicycles with 20-inch wheels. Considering the influence of adiposity on physical efficiency [2, 6, 11], it seems obvious that its excess is not a factor conducive to sport success for competitors riding smaller bicycles, but, it may actually be a factor restraining success in the competition involving bicycles with 26-inch wheels. Competition is more difficult when a bicycle has larger wheels, among other things due to the less extensive body movement of a cyclist. The basic elements, which include jumps, require the competitor to crouch down on the bike in the preparatory phase. The degree of the crouch determines the force of the take-off, and by the same token, the effectiveness of the jump, which can be compared to a long jump with no run-up. In the phase of landing on an obstacle, the competitor once again performs a deep crouch and at the same time pulls the bike maximally up, i.e. “closer to himself”. The degree of the crouch, that is the scope of the movement necessary to perform the jump, is limited by the size of the back wheel. As a consequence, the size of wheels may influence the height and the effectiveness of the jumps performed, and thus, the final sports result.

Accordingly, greater possibilities of a bicycle with smaller wheels may contribute to greater to-lerance for higher values of adiposity. More extensive body movement while riding a smaller bicycle may suggest another interesting conclusion concerning body musculature. A statistically significant and larger value of mesomorphy was obtained by the competitors riding bikes with 20-inch wheels, which are generally lighter. It may thus be concluded that the higher amplitude of possible movement enhances more intensive development of the musculo-skeletal system.

Despite the discussed differences, it can be stated that the examined competitors constitute a highly uniform group as far as the type of body build is concerned, in which mesomorphy is the principal component. In the light of the competitors’ classification into bicycle categories (based on the size of the bicycle), some differences between somatic features were noted, which, however, did not change the type of body build obtained for both groups.