Factors affecting postural stability of healthy young adults.

The objective of this paper was to examine the relationship between body balancing functions and body characteristics, motor abilities and reaction time. Subjects were 33 university students and 11 professional basketball players sorted into four groups of athletic and non-athletic women and men. Each group consisted of eleven subjects. The body height, weight was measured and the body mass index (BMI) calculated. A bioelectrical device computed the body fat (%). Static and dynamic motor tests, as well as static and dynamic balance tests were used. The reaction time (RT) to sound and light stimuli was measured. The regression analysis of the data revealed significant linear relationship between the amplitude of body sways (BS) and BMI in all groups. Also high correlation was found between back muscle strength and BS in all groups except the non-athletic women. Negative correlation was found between endurance capacity and BS in basketball players, i.e. at higher endurance capacity smaller amplitude BS occurred (r = -0.620, p < 0.04). The RT values showed significant correlations with BS only in the basketball players (r = 0.620, p < 0.04). It is concluded that increase in BMI, back muscle strength and endurance capacity is associated with better postural stability. Some motor abilities (hip flexibility, vertical jumping) show no significant correlations with body balancing, while other motor performances (static hanging) and RT values correlate well with BS only in the well-trained elite basketball players.

Reproduction of reaching movements to memorized targets in the lack of visual control.

The objective of this study was to examine the precision of reaching movements to remembered target distances in the lack of visual information. Subjects were professional basketball players and nonathlete university students. The basketball players, having well-trained manual skills, performed better than the non-athlete students. Increase in the overestimation of the remembered target distances was found under the effect of fatigue. A weight load on the sliding handle caused some decrease in the errors of reaching the remembered targets. No significant gender differences were found.

Changes in the amplitude and direction of goal-directed hand movements in the lack of visual information.

The goal of the present investigation was to determine the precision of goal-directed hand movements in the lack of visual information. The movement amplitude and direction was examined under different experimental conditions. Subjects were ten female and ten male university students. The motor test was drawing 10 cm long straight line and 24 cm long zigzag line in four different experimental conditions. 1) The drawing with open eyes was followed immediately with drawing with closed eyes. 2) The drawing was executed from memory in the lack of visual information. 3) Drawing with restricted amplitude or direction. 4) Drawing with verbal feedback. The errors of the target distance and the lateral deviations from the target were different under the different experimental conditions. The largest errors and underestimation of the target distance occurred in drawing horizontal straight line with closed eyes. No statistically significant gender differences were found. It is concluded that the practice, adjustment of single movement parameter to the target, and the verbal feedback assist better the accuracy of unseen goal-directed hand movement than the recent visual memory.

Learning to produce predicted static handgrip forces.

The objective of this study was to prove the hypothesis that kinaesthetic sensations, without visual or verbal guidance, give sufficient information to produce predictive handgrip forces. The ability of 70 girls and 70 boys aged 11 to 17 years to produce predicted static handgrip force was examined. The subjects were requested to produce 50% of their individual maximum handgrip force and maintain it for 2 seconds without visual control. Ten trials were done first by the right-hand and then by the left-hand. The maximum grip strength increased parallel with age, but significant differences were found between both the right and the left-hand, and the genders. Close correlations were found between the desired and the exerted forces. The differences between the desired forces and the exerted forces produced by the fifth trials were significantly smaller than that of the first trials. The verbal information about each exerted force contributed to the learning with right-hand since it caused a further decrease in the difference between the desired force and the exerted force. In contrast, the learning with left-hand was not enhanced by verbal feedback. These results suggest that kinaesthetic feedback information from the hand plays an effective role in learning to produce predicted grip strengths without visual and verbal information.

Comparative analysis of the effects of physical exercise.

The purpose of this study was to assess anthropometrical, somatomotor, and cardio respiratory characteristics of athletes and non-athletes subjects to establish which effects of the organized physical training discriminate well between them. Subjects were 61 athlete and non-athlete medical students. Four groups were formed relying upon gender and physical activity. Body measures were computed. The motor abilities were tested by a set of static and dynamic motor tests, and cardio respiratory functions were recorded. No statistically significant differences were obtained from the comparisons of the body measures of basketball players and non-athlete medical students, except the body height. In contrast, significant differences were found both between the motor performances and between the cardio respiratory functions of the athlete and non-athlete groups. The body mass index (BMI) and the body fat (%) correlated negatively with static hanging, vertical jumping, and balance capability. On the contrary, BMI and body fat correlated positively with systolic blood pressure and vital capacity. The present results show that the effects of regular physical exercise on motor performances and cardio respiratory functions differentiate better between the athlete and non-athlete subjects than the changes in body measures.

Promoting physical activity in medical education. Mini-review.

The challenges in public health associated with sedentary lifestyle underline the need to prepare physicians to give appropriate medical counselling and exercise prescription. In addition, the medical students' lifestyle and physical fitness suggest changes in medical education. Physical education as a criterion subject in our medical school curriculum serves to direct students' attitude toward regular physical activity. The knowledge of exercise counselling is promoted by a credit course of human movement sciences.

Relationship of anthropometrical, physiological and motor attributes to sport-specific skills.

The purpose of this pilot study was to investigate the importance of the athlete's motor capabilities in success in sport. More precisely, the association of anthropometrical and physiological attributes, as well as motor abilities of elite basketball players with play elements of basketball. The subjects were seven elite basketball players. At the end of the competitive season, the anthropometrical and physiological features were measured to establish the physical fitness of the subjects. Both general and sport-specific motor tests were done. The coach estimated the performance of each player during the games of the competitive season. The coach's data sheet incorporated 14 parameters of the game. Regression analyses indicated significant correlation between certain variables of the laboratory tests and the data of the coach's estimation statistics. Knowing these relationships provides us with valuable predictive information about player's capabilities in sport.

Differential blood pressure and heart rate responses to supramedullary brain stimulation in cats.

The purpose of this study was to compare the cardiovascular responses to electrical stimulation of different supramedullary brain regions. Arterial blood pressure (BP) and heart rate (HR) effects were elicited by electrical stimulation of the lateral hypothalamus (LH), mamillary bodies (Mm), substantia nigra (SN), globus pallidus (GP), and the subthalamic nucleus (Sub) in conscious, freely moving cats. Pressor responses were obtained from all of these regions. The higher intensity of stimulation the higher increase in BP and HR was obtained. However, clear-cut differences occurred in the effects both during and after the termination of stimulations. Namely, a continuous increase in BP and HR was obtained from the LH and SN. In contrast, the initial increase in BP and HR was followed by a reduction compared to the peak value of the effects of stimulation in the GP and the Sub. However, the BP and HR never reduced to the pre-stimulaion level during the stimulation. Also the changes following the cessation of stimulation at the different brain loci were dissimilar. The BP and HR either returned gradually to the pre-stimulation level, or long-lasting oscillation occurred. The electrical activity of the nucleus of the solitary tract (NTS) and the vagus nerve co-varied with the changes in BP and HR. It is concluded that the supramedullary stimulations produce differential cardiovascular effects, and these effects are modified by the baroreflexes that are activated by the electrically elicited rise in blood pressure.

The role of kinaesthetic feedback in goal-directed movements.

The purpose of this study was to investigate the role of kinaesthetic feedback in the control of goal-directed movements. The subjects were qualified basketball and handball players compared to weightlifters as controls. The body measures and the general motor tests verified fit physical condition of the subjects, and detected no sign that would disturb the execution of special motor tests. The special motor tests were free-throw shootings with basketball to the basket, free shootings with handball to a rectangular frame, zigzag dribbling with basketball to 14 m among traffic cones 2 m apart, and stopping at a mark after running to 10 m. These tests were performed both with open eyes and closed eyes. The results of all special motor tests decreased significantly in the lack of visual information. Furthermore, in contrast to the significantly different results obtained from the three different groups with open eyes, these groups produced equally minor results with closed eyes. It is concluded that the practice of goal-directed movement, learned under visual guidance, does not make the kinaesthetic feedback able to compensate the lack of visual input.

Selected Physical Characteristics of Medical Students.

The purpose of this study was to measure selected anthropometrical characteristics, motor abilities and cardiorespiratory functions of medical students. Eighty-seven students were involved in this investigation. The students were categorized into five groups: (1) recrea-tional, doing sport activities irregularly, (2) basketball and (3) handball players, having training at least two times per week, as well as men (4) and women (5) students entering medical school. In all groups the mean body mass index and waist-to-hip ratio were at the upper level of the normal range, while body fat percentage was similar to standards for sedentary subjects. Better motor performances were obtained from the basketball and handball players than from the other groups. Static strength for the sample was somewhat above the normal sedentary level. The resting blood pressure and heart rate for most subjects were in the normal. Cardiovascular risk factors were found in six students. Their systolic blood pressure was above 140 mm Hg. There were no subjects identified with low blood pressure. The heart rate was elevated for three students from the recreational group, and in the women. Bradycardia did not occur. The vital capacity and the ability to hold one's breath was at the upper level of the normal range. The present results emphasis the need to improve the students prevention oriented life style through participation in exercising.

Respiratory responses to electrical stimulation of the basal ganglia in cats.

The aim of the present study was to investigate the involvement of basal ganglia in altering respiration. The experiments were carried out on cats using the electrical stimulation techniques. The electrical stimulation of the basal ganglia caused locus-dependent changes both in the tidal volume and the rate of respiration. The most frequent effect of stimulation was hyperpnea and decrease in the tidal volume in awake, freely moving cats. An increase in the tidal volume appeared only as rebound-like aftereffect. The stimulation that caused hyperpnea in awake cats elicited smaller changes under chloralose or ketamine-induced anaesthesia, and, in certain cases, the stimulation produced apnea. After locally applied neurotoxic damage, the electrical stimulation failed to induce significant respiratory changes. It is suggested that the fast, small amplitude ventilation is, probably, produced by high excitation that shifts the respiratory rhythm generator towards the upper limits of its regulatory range. The slowing of ventilation might be produced by an inhibitory mechanism, which is able to cause even apnea under anaesthesia.

Subthalamic influences on the cardiorespiratory functions in the cat.

The electrical stimulation of the subthalamic nucleus (STN) caused a conspicuous increase in arterial blood pressure (BP), heart rate (HR) and respiratory rate (RR) in freely moving cats. The pulse pressure (PP) increased significantly following an initial decrease at the beginning of the 10 s long stimulation. A rebound bradycardia occurred after switching off the stimulation. Cardiorespiratory responses might be elicited also during ketamine-induced anaesthesia. The BP responses reduced highly under the blockade of the alpha(1)-adrenergic receptors. The neurotoxic lesions of the ipsilateral globus pallidus caused no significant alterations in the cardiorespiratory responses to STN stimulation. It is concluded that, besides its role in the motor control, STN is also involved in adjusting the cardiorespiratory functions to the somatomotor activity.

Characterization of cardiorespiratory responses to electrical stimulation of the globus pallidus in cat.

The aim of the present study was to describe the characteristics of the electrically elicited cardiorespiratory responses from the globus pallidus (GP) in cat. GP stimulation caused an increase in the arterial blood pressure (BP), heart rate (HR), and respiratory rate (RR) in freely moving cats. Threshold, medium, and high intensity for stimulation at 100 Hz were determined by the somatomotor effects of stimulation. The higher stimulus intensity the higher increase in cardiorespiratory functions was obtained. The electrical stimulation within different segments of the GP caused changed effects. A continuous rise in BP, HR, and RR was induced by stimulating in the external segment (GPe). On the contrary, the stimulation in the internal segment (GPi) produced complex sequence of changes. At the beginning of the 10-s long stimulation the increase in diastolic pressure was more steep than that of the systolic pressure, so the pulse pressure decreased. However, 2-3 s after the onset of stimulation the diastolic pressure reduced; therefore, the pulse pressure increased. Simultaneously, the HR decreased below the prestimulation level. Occasionally, similar slowing in RR appeared as well. The blockade of the alpha 1-receptors by phentolamine, or neurotoxic lesion within the GP by kainic acid, reduced significantly the BP effects of GP stimulation of identical parameters. It is concluded that GP plays an intricate role in the adjustment of cardiorespiratory functions to the somatomotor activities.

Is it reasonable to involve kinesiology in medical education?

The purpose of this study is to argue for teaching kinesiology for medical students. To become familiar with the basics of the science of human motions is essential for the medical practice. There is substantial evidence that regular physical exercise is beneficial to improve health and prevent disease, and has a key place among the strategies in therapy and rehabilitation. However, before prescription of exercise programmes the physician must take into consideration all the benefits and risks of that exercise. The present curriculum offers insufficient information about the physiological effects and physiologically essential limits of physical exercise. Therefore, a regular study of human motions is required by the medical practice. The need for such education is also shown by the everlasting interest of medical students in credit courses of kinesiology and sports physiology.

Exercise-induced slow waves in the EEG of cats.

The aim of the present study was to investigate the early signs of fatigue. Cats were chronically implanted with electrodes in the frontal and occipital cortical areas, and a thermocouple was inserted into the nasal orifice to record respiratory rate. After a recovery of 10 days, the animals were trained for running on treadmill. On the day before recording, a catheter was tied into one of the common carotid arteries to record arterial blood pressure. The electroencephalogram (EEG), arterial blood pressure, and respiration were recorded continuously. At the time of deceleration of running high amplitude, slow waves appeared both in the sensorimotor and occipital cortical regions. The power spectra showed a significant increase in frequencies of 1-6 Hz in the sensorimotor cortex, and of 1-10 Hz in the occipital cortex, with a great increase in the total power. During rest the pre-running, brain activity reappeared gradually. The arterial blood pressure, the heart rate, and the respiratory rate were elevated during running, but no special changes occurred at the onset of the slow waves in the EEG. The blood glucose level was somewhat higher after the first 2-min running than the pre-running level. It is concluded that the appearance of slow waves in the EEG is an early manifestation of fatigue. The cardiorespiratory changes and the blood sugar concentrations play no role in the slowing of the electrocorticogram. The present results show the involvement of brain mechanisms in the onset of tiredness.

Cardiorespiratory effects of electrical stimulation of the globus pallidus in cats.

Increase in the arterial blood pressure (BP), heart rate (HR), and respiratory rate (RR) was regularly evoked by electrical stimulation of the globus pallidus (GP) in awake, freely moving cats. The somatomotor responses to GP stimulations consisted of either slow movements, localized mainly on the head, or contraversive circling. Both the peak and the shape of the BP curve were related to the stimulus intensity. Stimulations repeated under blockade of the adrenergic alpha-receptors failed to increase BP whereas the somatomotor responses occurred as in drug-free animals. Intra-arterious injection of procaine did not interfere with the electrically elicited elevation of BP. GP stimulations also caused arterial blood pressure changes under chloralose anesthesia. It is concluded that the globus pallidus has a role in connecting somatomotor activities with the appropriate cardiorespiratory changes.

[Evaluation of blood pressure changes]. / Vérnyomásváltozások értékelése.

Blood pressure measurements is one of the most frequently used and technically simple medical measurements, therefore, this study gives a brief survey of the evaluation of changes in blood pressure. After summarising the factors that determine the blood pressure, the meaning and the physiological mechanisms of blood pressure changes are defined. The causes and the consequences of hypotension and hypertension are summarised. The blood pressure is an excellent indicator for the general condition of circulation both in patients and in healthy people.

Somatomotor and cardiorespiratory responses to basal ganglia stimulation in cats.

The electrical stimulation of the neural elements within the basal ganglia circuitry caused characteristic somatomotor activities and changes in arterial blood pressure (BP), heart rate (HR), and respiratory rate (RR) in conscious, unrestrained cats. A highly constant pattern of responses was elicited by stimulating repeatedly at the same locus, but significant differences occurred among responses obtained from identified parts of the basal ganglia. Stimulation in the putamen evoked tachypnoe, but no remarkable change in BP and HR. Stimulation in the caudate nucleus produced either tachypnoe or respiratory arrest accompanied by a slight change in BP and HR. Stimulation within the medial dorsal nucleus of the thalamus and the substantia nigra caused increase in BP, HR, and RR of different magnitude. The increase in BP failed to appear under the effect of alpha-adrenergic blockade. The effects of procaine, injected through the arterial cannula, did not interfere with the electrically elicited responses. All the cardiorespiratory responses to basal ganglia stimulation diminished or did not appear in deeply anaesthetised animals. We conclude that besides its involvement in motor processing, the basal ganglia circuitry exerts an influence on the central cardiorespiratory mechanisms.

Medullary-induced alterations in intracranial self-stimulation from the substantia nigra.

The intracranial electrical self-stimulation (ICSS) from the substantia nigra (SN) was reduced by simultaneous stimulation of the nucleus of the solitary tract (NTS) in cats. This effect varied with the current intensity and the sequence of NTS stimulation paired with the rewarding SN stimulation. Namely, NTS stimulation preceding the SN stimulation was more effective in lessening ICSS than that following the SN stimulation. Both SN and NTS stimulations produced significant cardiorespiratory effects, when they were applied separately. However, the cardiorespiratory responses to NTS stimulation have no substantial role in altering ICSS, because vagotomy abolished the heart rate effects of NTS stimulation but caused no change in its reducing effect on ICSS. Moreover, no statistically significant correlation was found between the blood pressure changes and the decrease in response rate. These data are interpreted as suggesting that the NTS stimulation may reduce centrally the rewarding value ordinarily derived from ICSS at the SN.

[Mechanisms of cardiovascular adaptation]. / A kardiovaszkuláris adaptáció mechanizmusai.

This study gives a brief survey of the mechanisms initiating and executing cardiovascular adjustments to physical activity. The maximum physiological changes in cardiovascular functions are produced by endurance exercise. However, the advantageous effects of physical exercise might have a preventive role for cardiovascular diseases by following a healthy lifestyle.