– 67 – SEXUAL DIMORPHISM IN MOTOR COORDINATION IN STUDENTS AT JAGIELLONIAN UNIVERSITY COLLEGIUM MEDICUM

****** Prof. Dr Habil., Department of Anthropomotorics, University School of Physical Education, Krakow, Poland ****** PhD, Department of Anthropomotorics, University School of Physical Education, Krakow, Poland ****** MSc, Department of Physical Fitness, Jagiellonian University Collegium Medicum, Krakow, Poland ****** PhD, Department of Gymnastics, University School of Physical Education, Krakow, Poland ****** PhD, Department of Theory and Methodology of Winter Sports, University School of Physical Education, Krakow, Poland ****** PhD, Department of Anthropology, University School of Physical Education, Krakow, Poland


Introduction
One aspect of motor action, in addition to intention and purpose, is its performance, which apart from strength, speed and endurance, also involves coordination [1].The latter term should be understood as processes for adjusting and organizing that are aimed at achieving goals.Even though coordination in everyday life does not manifest itself through individual stimuli (nor is this its purpose), but through "a systemic character of common actions and their effects," various tests are used to assess its selected aspects for diagnostic aims [2].Coordination displays an immensely complex structure of processes that are not always interconnected.This is the reason for its interpersonal and intrapersonal differences.Literature on the subject distinguishes between coordination understood as a set of processes responsible for preparing and controlling a motor action and as -----coordination motor abilities (CMA) that determine the relatively fixed and generalized forms of psychophysical processes of motor regulation [1,3].Apart from a natural need to determine the personal structure of coordination abilities, there exists the need to establish differences in the levels of coordination between genders.
Studies on sexual dimorphism in the area coordination are not rare; nonetheless, their results and conclusions drawn from them are highly ambiguous.Reasons for the ambiguity include the varied strength of genetic control over individual CMA, different research methods used to determine the level of CMA, different ages of research participants, and a significant influence of environmental factors (including socioeconomic factors) on the level of these abilities [4,5].Furthermore, one must note that the level of sexual dimorphism in terms of motor abilities is also affected by the volume, intensity, and type of physical activity [3,6].These factors will display different values in physically inactive persons compared to values in male and female athletes from various sports disciplines.
An analysis of literature on sexual dimorphism of CMA allows us to follow the development of observed strength and tendencies for each gender.
Many papers [7, 8, 9, 10, 11] on the level of spatial orientation often report contradictory findings.Some authors of studies with youth and persons engaging in sports have found that women performed considerably better.Yet other authors have observed that men were clearly dominant.
Results related to the level of adjustment ability are more uniform.Ljach's research [12] showed that boys performed better than girls in terms of movement adjustment already beginning at the age of 7 to 9 years.A similar tendency was found in sports groups, e.g., in male and female football players [9] or junior handball players [8].
Observations of the level of different aspects of balance have an exceptionally rich history of research.Findings on the subject of balance, as well as other CMA, are ambiguous.Some papers [5,13] have shown that in large cities, girls present a dominance over boys in terms of static balance.Furthermore, Raczek and Mynarski [14] found in a study with youth that girls displayed a higher level of static balance than boys, while a reverse relationship occurred for dynamic balance.On the other hand, Szopa [11] claimed that among all abilities, static balance shows the smallest sexual dimorphism.
Analyses of dimorphism in populations of university students are not as numerous and mainly involve students of schools of physical education [15, 16, 17, and others].For this reason, further research seems fully justified.
This study involves two main aims: 1. Determining the differences in selected CMA between first-year male and female students at Jagiellonian University Medical College (JUCM) in Krakow.2. Comparing the obtained results with available literature.

Studied group
Research participants comprised 96 female and 68 male first-year students enrolled in JUCM in Krakow.All were studying at the faculties of medicine, pharmacology, nursing, or obstetrics.The average age of participants was 21.3 years (ranging from 20.1 to 23.5 years).None of the participants reported disorders of the nervous system that could affect the results of the assessment of coordination abilities (as determined by interviews prior to the assessment).All participants volunteered to participate in the research.

Methods
Assessment of CMA aimed at establishing the levels of the following seven abilities: kinesthetic differentiation, balance, reaction time, motor adjustment and displacement, spatial orientation, and movement joining and rhythm.I. Kinesthetic differentiation 1. Laboratory test: a) Measurement with a kinematometer (a goniometer).This device is used to reproduce the angle of elbow flexion, that is, to assess the spatial aspect of movement differentiation.Two series of tests were conducted that involved reproducing the position of the arm and assessing (differentiating) the angle of flexion in degrees.b) Measurement with a dynamometer.Two series of tests were conducted that involved reproducing and differentiating the strength of one's hand in kilograms.IV.Motor adjustment 1. Laboratory test: a) An electronic device called "image in the mirror" allows for the assessment of spatial and dynamic aspects of motor adjustment.
During the assessment, the participant draws a circle using a special metal stylus by watching the drawing surface directly and by watching its reflection in a mirror placed perpendicularly to it.The assessment registers the time of performing the task and the number of mistakes made.

Population test [3]:
b) Forward and backward standing long jump (participants perform three standing long jumps forward as far as they can, followed by three standing long jumps backward, also as far as they can).
V. Spatial orientation 1. Laboratory test: a) Measurement using the Piórkowski meter.
Stimuli were emitted 107 times per minute.Each test lasted one minute.

Population test [3]:
b) Running to a ball (the participant faces a set of balls placed in a semicircle and, on cue, runs up to the indicated ball).
VI. Movement joining 1. Laboratory test [19]: a) "Path to the goal" computer test.The participant was asked to lead a pointer along a preset path as fast as possible, without touching the edges of the path.

Population test [3]:
a) Stepping over an exercise rod (participants hold an exercise rod low and steps over it, alternating between their right and left leg).
VII. Movement rhythm 1. Laboratory test [19]: a) "Repeat the rhythm" computer test.The participant was asked to repeat as closely as possible a rhythm emitted by a computer.

Methods of statistical analysis
Before conducting an assessment of basic parameters of the motor abilities using descriptive statistics, we evaluated the normality of obtained results with the Shapiro-Wilk test [20].Because the test found that most indicators displayed normal distribution, we calculated the arithmetic mean and standard deviation and determined the maximal and minimal values of the results. - To assess the level of sexual dimorphism, we calculated normalized indicators of dimorphism (ID) for all fractions of economic status, according to the method proposed by Szopa [11]: ( ) where: x ch -arithmetic mean of men in class n, x dz -arithmetic mean of women in class n, s ch -standard deviation of men in class n, s dz -standard deviation of women in class n.
The Student's t-test was used to assess statistical significance of the measured variables in men and women.

Results
Most conducted tests found significant sexual dimorphism, the direction of which depended to some extent on the type of the test.Below is a more detailed description of the obtained results based on data presented in Table 1.
Results of tests that involved the reproduction, differentiation, and assessment of spatial and strength aspects of movement indicate the significant dominance of women.This occurred only in the case of laboratory tests with a kinematometer and a hand dynamometer.It did not occur in population tests that measured the precision of ballistic movements.Greater dimorphism, amounting to ID = -0.45,was observed in tests performed with the left arm in terms of both reproduction and differentiation of spatial aspects of movement.A similar situation occurred in tests that measured strength parameters of movement (reproducing the indicated value of maximal strength), though in this case, the right hand showed greater dimorphism (ID = -0.48).The most significant disproportions were found in tests that assessed differentiation of strength aspects in the left hand: ID equaled -0.5.Women performed better than men in measurements that required reproducing low values of maximal strength.Women's precision in these tasks may stem from the fact that women achieve lower values of maximal strength.Subsequent repeated measurements indicated that dimorphism decreased to statistically insignificant levels.
The ability to maintain balance was measured in dynamic and unstable conditions (balancing).As a result, we registered relatively different values of indicators of dimorphism.In tests that assessed dynamic balance, male students remained on the exercise bench as long as female students; in the hexagon board test, which measured the number of steps taken, men performed significantly better than women (ID = 0.69).On the other hand, female students showed significant dominance over male students in tests that involved balancing on the Libra bench, as indicated by the registered indicators of line overlap (ID = -0.42).However, when the task required reproducing an elliptic path (meaning that, in addition to balance, a much greater area of coordination abilities was involved), both genders performed equally well, especially in the coronal plane.
High levels of dimorphism were registered in tests of reaction time.Application of a more precise device (an MRK reaction time meter) emphasized the dominance of men.This dominance occurred regardless of the type of emitted stimulus, although greater values of dimorphism were noted when participants reacted to a visual stimulus.Stronger dimorphism was observed in the laboratory test for tasks performed with the left arm, while the classical population test showed significant differences between genders only in tasks performed with the right arm (ID = 0.49).
The results of the assessment of motor adjustment indicated a very weak dimorphism.However, they suggest that women are more precise than men, as indicated by the only observed significant difference, i.e., the number of mistakes made.The applied test of reproducing a path as seen in a mirror was limited to aspects of manual precision and did not require the manifestation of energy components of motion.
Considerably different results were obtained in the running to a ball test, which assessed spatial orientation.Because the test required performing global, speed-based movements, its results show a very strong dominance of men (ID = 1.67).The test with the Piórkowski meter also indicated the statistically significant dominance of men; however, the indicator of dimorphism was lower by half compared to the previous test.
Both genders performed the computer test of rhythm, which involved repeating a rhythm indicated by the software, almost equally well (ID = 0.08).The last assessed ability was movement joining.The test, proposed by Jaworski, showed a much stronger sexual dimorphism (ID = 0.76) than the test with the exercise rod (ID = 0.36).Nonetheless, the differences between genders were statistically significant in both tests.

Discussion
Research on sexual dimorphism in university students has a rich tradition.However, because anthropologists rather than anthropomotorists have usually conducted such research, the research mainly investigated disproportions in somatic build.Therefore, discussing functional and motor differences has proven to be difficult, especially when such discussions involve the comparison of abilities in the area of motor coordination.Thus, bearing in mind that the assessed students were in their first year of studies and that coordination abilities reach the height of development relatively early [3,21], this discussion will also refer to the results of studies with youth.Authors observe [22,23] that in a population of university youth, especially significant sexual dimorphism occurs in constitution-based motor abilities.This phenomenon is a direct result of the differences that manifest themselves in this area during adolescence.Thus, many authors state that such sexual dimorphism in the area of coordination is relatively weak [12, 13,24].While Mleczko and Mirek [15] noted a weak dimorphism in terms of the above motor area, Mynarski and Żywicka [16], for example, claim that gender has a significant effect on the level of CMA of university students, with men demonstrating dominance.Szopa, Mleczko, and Cempla [25] conducted research on sexual dimorphism of psychosomatic traits.They state that apart from the proprioceptive area, which shows no sexual dimorphism, men perform better in tests that assess levels of psychomotor abilities.As can be seen in this short review, authors' opinions vary significantly.In general, the results obtained in our research confirm that sexual dimorphism in terms of CMA is strong in university students.It should also be noted that most studies referred to in this paper involved male and female students of schools of physical education, that is, persons with high physical activity.Therefore, it seems that the weak dimorphism, which has been reported numerous times in persons engaged in sports as a result of high physical activity, is mainly present in the area of energy.Keeping the above considerations in mind, the results obtained in this study that involve male and female students at JUCM -results which are discussed below -bring remarkable new data, as the study found that women performed better in most conducted tests.
Strong dimorphism, as caused by a more precise reproduction of strength and spatial aspects of movement by female students, was observed in tests of kinesthetic differentiation.Papers such as the publication by Górska and Gierat [4] support these results.They found significant differences in 11-year-old children, which confirmed the dominance of girls, and that such dimorphism decreases in children aged 12 and 13 years.Ljach and Witkowski [9] observed that through the age of 15-17 years, boys dominate in most aspects of kinesthetic differentiation, yet after this period, girls begin to perform better, especially in terms of reproducing, differentiating, and assessing strength parameters.Our research confirms observations provided by the quoted authors.Raczek and Mynarki registered a different, though equally significant, direction of dimorphism based on their sports and motor test [14], which indicated that boys perform better after the age of 15 years.Literature also frequently reports a statistically insignificant sexual dimorphism of this ability [24,26].
Our research assessed different aspects of the ability.The laboratory test of balance, especially in its first mode (controlling the position of the balance board to match the straight line), depended to a greater extent on the efficiency of proprioceptive mechanisms and, as such, was closer to measurements in static conditions on stabilographic boards [27].The second mode, which required participants to adapt to reproducing a sinusoid path, involved broader coordination mechanisms that engaged the whole human body, including the ability to adapt [18,28].This is why the dominance of women in the first task was consistent with results obtained by other authors who have indicated that women are more sensitive to the received kinesthetic and tactile stimuli.In the case of tests that assess dynamic balance, disproportions between genders were less pronounced, as confirmed by a lack of differences in the walking over an exercise bench test.The second test (walking over a hexagon board) found a statistically significant, strong dimorphism, as indicated by the number of steps taken, which suggests that the participants used different strategies to perform the task.We observed that with the increase in complexity of a balance task, the level of dimorphism increases in dynamic conditions and decreases in balancing tests.
With respect to the previously discussed ability, simple reaction time (which constitutes a latent component of quick reaction) unambiguously favored one gender.According to most authors, it reaches more beneficial values in boys rather than girls, both in groups engaged in sports [7,8,31] and not engaged in them [10,11,14].The strongest sexual dimorphism with the dominance of men was reported by Szopa et al. [25] in their study on reaction time to a visual stimulus [ID = 0.37].Women -----dominate men in the area of an aural stimulus, but the level of dimorphism is considerably lower.Data presented in Table 1 confirm the dominance of men and are consistent with findings of the first group of quoted authors.
The test that assessed the adjustment ability did not unambiguously indicate the direction of sexual dimorphism.Nevertheless, the obtained results show dimorphism on a smaller level.Literature reports different data.Omorczyk et al. [32], in their study on the adjustment ability with students of the University School of Physical Education in Krakow, observed that men performed significantly better than women.Authors who used laboratory methods to assess the same ability obtained similar results [33,34].
Demuth et al. [35], when assessing receptor and motor coordination using the Piórkowski meter, determined the level of dimorphism in youth who began attending the Military Academy of Land Forces in Wroclaw.The value of ID amounted to 17.4, indicating strong sexual dimorphism.In using the same method, Szopa, Mleczko, and Cempla found a weaker dimorphism, with men remaining dominant [25].
A very statistically significant difference between genders (as well as a high value of ID, which amounted to 0.7) was found in the laboratory test that assessed movement joining, as indicated by the time to perform the required task.Mynarski and Żywicka [16] also observed that male students performed better than female students in terms of quick coordination.
The above summary indicated that the level of sexual dimorphism in terms of coordination abilities is significant.In extreme cases, the values of ID were close to as much as 1.65.
Sekita [36] states that the reasons for a strong sexual dimorphism with the dominance of men are differences in interests of both genders, traditions of education, lifestyles, and social models and roles.Żak [37] shares this opinion and suggests that strong dimorphism is caused by the greater physical activity of men compared to women.Our observations are consistent with those done by other authors in terms of the existence of strong dimorphism However, they are not as consistent in regard to the direction of the phenomenon, as we found that women dominate in some coordination abilities.

Conclusions
1. Most CMA analyzed in this study show statistically significant differences between male and female students.2. Dominance of men was observed in tests that required global movements.In tests based on discrete, close movements, women often performed better than men.3. Dominance of women was the most pronounced in kinesthetic differentiation and static balance.

Table 1 .
Sexual dimorphism of students of the JUCM in terms of selected CMA (♂n=68; ♀n=96).