The effect of the acute and chronic administration of dalargin to mongrel rats on cardiac chronotropism at rest and under physical loading]

In chronic experiments on untrained awakening males of white rats it has been shown that the prolonged intraperitoneal injection of the opiate receptor agonist delargin (during 4, 5 days; 10 mkg/kg; twice a day) leads the chronotropic heart response to the maximum level of exercises and simultaneous decrease of heart rate variability. All this is accompanied by animals' undue fatiguability. It has been concluded that the chronic injection of opioid agonist receptors causes the decrease of sensitivity of these receptors to the action of endogenic opioids and as a consequence--the increase of sympathetic regulatory action on the heart rate at physical exercises and growth of fatiguability.     

The steroid hormone levels and receptors of steroid hormone receptors in rat muscles during physical exertion

It is shown that the testosterone content in skeletal muscles of female albino rats is 2-fold decreased, while the estradiol content-1.5-fold increased and progesteron content showed no changes after systematic physical exercises. The pharmacokinetic investigations showed that androgen half-life in the organism decreased from 8 to 5 h under physical exercises. The amount of androgen receptors in cytosol of skeletal muscles increases from 1.34 +/- 0.08 to 1.71 +/- 0.10 fmol/mg per 1 mg of protein. Kd is 0.40 +/- 0.03 and 0.48 +/- 0.08 nM, respectively. Sensitivity of the organism to hormonal signal play an important role in the metabolism regulation in skeletal muscles along with the hormonal content change during the organism adaptation to physical exercises.     

Endometriosis and physical exercises: a systematic review

Regular physical exercise seems to have protective effects against diseases that involve inflammatory processes since it induces an increase in the systemic levels of cytokines with anti-inflammatory and antioxidant properties and also acts by reducing estrogen levels. Evidence has suggested that the symptoms associated with endometriosis result from a local inflammatory peritoneal reaction caused by ectopic endometrial implants. Thus, the objective of the present review was to assess the relationship between physical exercise and the prevalence and/or improvement of the symptoms associated with endometriosis. To this end, data available in PubMed (1985–2012) were surveyed using the terms “endometriosis and physical exercises”, “endometriosis and life style and physical exercises” in the English language literature. Only 6 of the 935 articles detected were included in the study. These studies tried establish a possible relationship between the practice of physical exercise and the prevalence of endometriosis. The data available are inconclusive regarding the benefits of physical exercise as a risk factor for the disease and no data exist about the potential impact of exercise on the course of the endometriosis. In addition, randomized studies are necessary.     

Cerebral hemodynamic reaction to physical exercise of moderate intensity

The aim of this research was to study the cerebral hemodynamic reaction to stepped increase of physical exercises during the bicycle ergometer test in 12 young healthy male patients. The starting value of exercise was 0.25 W/kg of the body weight, with the 0.25 W/kg increase at every subsequent step up to the value of 1.75 W/kg of the body weight. Hemodynamic parameters were registered with the Doppler ultrasonography of middle cerebral artery before the study, during the last 10 seconds of every step, and during the 3 minutes of restorative period with a 1-minute interval. The peak systolic blood flow increase in the middle cerebral artery was observed only as the result of low intensity exercises (0.25 W/kg of the body weight). The blood pressure (BP) restoration occurred by the end of the third minute of the rest, while the cerebral hemodynamic indices became normal during the first minute. The research revealed a correlation between increases of vascular resistance caused by physical exercises and the BP, and no correlation between increases of peak systolic blood flow and BP, which displays the phenomenon of cerebral circulation autoregulation.     

Efficiency of use of physical exercises for management of the functional state of 6-8 year-old anxious children

In the research directed on optimisation of a functional state (FS) of disturbing children of 6-8 years, complex application of physical activities of mainly aerobic character, relaxation training is shown, that, respiratory exercises and functional music in long-term aspect selective use of considered means possesses more efficiency. At selective influence the expressed influence on FS disturbing children of 6-8 years in the conditions of intense information loading is rendered only by physical exercises. Application of other ways of optimisation FS is less effective. High effectiveness of use of physical exercises is caused by adaptable changes of mechanisms of regulation FS of disturbing children. Apparently, long-term adaptation to adequate muscular activity provides improvement of functioning and perfection of interaction activating and nonactivating structures of modulating system of the brain, localised on different levels the central nervous system (CNS) and, in particular, frontal departments of a bark. It is underlined, that features of influence of various receptions of regulation FS on an organism of disturbing children of younger school age are substantially caused by immaturity frontocortical-thalamic regulating system and specificity of the functional organisation limbic brain structures.     

Effectiveness of physical exercises for regulation of the functional state of six- to eight-year-old anxious children

The study aimed at optimizing the functional state (FS) of anxious six- to eight-year-old children showed that integrated use of physical exercises of a mainly aerobic character, relaxation training, respiratory exercises, and functional music is more effective in the long-term aspect than selective use of these means. Only physical exercises exert a marked influence in the FS of six- to eight-year-old anxious children under a stressful informational load. The use of other means of optimizing the FS appears to be less effective. The high effectiveness of physical exercises is determined by adaptive changes in the mechanisms of FS regulation in anxious children. Apparently, long-term adaptation to an adequate muscular activity ensures improved functioning of, and a better interaction between, the activating and inactivating structures of the modulating brain system located at different levels of the CNS, in particular, in the frontal cortical areas. It is emphasized that the peculiarities of the influence of different means of regulation of the FS on the body of anxious elementary school children are, largely determined by the immaturity of the frontothalamic regulatory system and the specifics of the functional organization of the limbic brain structures.     

Effect of Adaptation to Graduated Physical Exercises on the Function of the Rat Myocardium

On isolated hearts obtained from control rats and rats subjected to regular physical exercises (forced swimming) during 6 weeks, we studied the contractile activity of the heart, resistance of the myocardium to ischemia/reperfusion-induced injuries, as well as the dependence of the developed and end-diastolic pressures in the aortic ventricle (AV) on the strain of the myocardium (by means of a dosed increase in the volume of a polyethylene reservoir inserted into the ventricle). It was demonstrated that adaptation to regular graduated physical exercises exerts a positive effect on the functional state of the AV myocardium and its contractile function. This was manifested in intensification of the contractile activity of the myocardium, a decrease in its oxygen “job cost,” and an increase in the resistance to injuries induced by ischemia-reperfusion. In addition, regular physical trainings led to an increase in the resistance of the AV myocardium to the strain. In trained rats, the plateau of the Frank–Starling plot was significantly greater than that in control animals, while the rigidity of the AV myocardium was significantly lower. Neirofiziologiya/Neurophysiology, Vol. 41, No. 1, pp. 41–47, January–February, 2009.     

"Effects of baicalin on protease-activated receptor-1 expression and brain injury in a rat model of intracerebral hemorrhage"

"Regular physical exercise plays an important role in reducing obesity, preventing hyperglycemia, lowering blood lipids and reducing systemic blood pressure. But the question about the nature of the relationship between homocysteine, nitric oxide and physical activity remains unanswered. The aim of this study was to investigate the effects of callisthenic exercises on plasma lipids, homocysteine (Hcy), total nitric oxide (NOx) and body composition in middle-aged healthy sedentary women. Forty-two middle-aged women (ages: 28-49; mean: 41.40 ± 7.3 years) were asked to perform a callisthenic exercise 50 min per session, 3 times per week for 12 weeks in a sports hall. Before and after the exercise, plasma lipids (total cholesterol, high density lipoprotein, low density lipoprotein and triglyceride), Hcy and NO were determined. Body composition, including body mass index, fat percentage, fat free mass, resting systolic and diastolic blood pressures and heart rates were measured. After a 12-week callisthenic exercise program, plasma NOx and Hcy levels were found to be significantly increased (P < 0.05). Body composition parameters, lipid profile, resting systolic and diastolic blood pressures and heart rate significantly decreased (P < 0.05). Aerobic callisthenic exercises characterized by 50 min/day and 3 days/week resulted in positive changes in important health parameters like reducing obesity, lowering blood lipids and increasing plasma NOx. Cardiovascular improvements might be dependent on the increase of NOx values. But callisthenic exercise in such intensity did not lower the plasma Hcy level. Moreover, Hcy level increased significantly. The result shows that if the Hcy is in the normal levels in healthy subjects, long-term callisthenic exercise do not decrease the Hcy levels despite some beneficial effects on health. On the contrary, the Hcy levels are increased by long-term callisthenic exercises."     

Electromyography activation of shoulder and trunk muscles is greater during closed chain compared to open chain exercises

BackgroundTo compare the activation of shoulder and trunk muscles between six pairs of closed (CC) and open chain (OC) exercises for the upper extremity, matched for performance characteristics. The secondary aims were to compare shoulder and trunk muscle activation and shoulder activation ratios during each pair of CC and OC exercise.MethodsTwenty-two healthy young adults were recruited. During visit 1, the 5-repetition maximum resistance was established for each CC and OC exercise. During visit 2, electromyography activation from the infraspinatus (INF), deltoid (DEL), serratus anterior (SA), upper, middle and lower trapezius (UT, MT, LT), erector spinae (ES) and external oblique (EO) muscles was collected during 5-repetition max of each exercise. Average activation was calculated during the concentric and eccentric phases of each exercises. Activation ratios (DEL/INF, UT/LT, UT/MT, UT/SA) were also calculated. Linear mixed models compared the activation by muscle collapsed across CC and OC exercises. A paired t-test compared the activation of each muscle and the activation ratios (DEL/INF, UT/LT, UT/MT, UT/SA) between each pair of CC and OC exercises.ResultsThe INF, LT, ES, and EO had greater activation during both concentric (p = 0.03) and eccentric (p < 0.01) phases of CC versus OC exercises. Activation ratios were lower in CC exercises compared to OC exercises (DEL/INF, 3 pairs; UT/LT, 2 pairs; UT/MT, 1 pair; UT/SA, 3 pairs).ConclusionUpper extremity CC exercises generated greater activation of shoulder and trunk muscles compared to OC exercises. Some of the CC exercises produced lower activation ratios compared to OC exercises.     

Comparative analysis of the psychophysiological parameters of the system quanta of performance in physically trained and untrained subjects

Physiological mechanisms of muscle activity have been studied in 14 athletes and 15 untrained students during cyclic physical exercises of various intensities, including the individual maximum. The principle of system quantization of behavior has been used to find opposite changes in the spectra of the tachograms of athletes and physically untrained students after the completion of the same physical exercises. It has been shown that, after cyclic physical load in trained and untrained subjects, opposite changes in the effectiveness of their testing activity occur.     

Lipid peroxidation in skeletal muscles of rats during maximum physical exertion and its correction by ionol

The maximum physical exercises lead to the activation of lipid peroxidation in rats. It is accompanied by an increase in the concentration of diene conjugates and malonic dialdehyde in skeletal muscles. Preliminary administration of ionol antioxidant, prevents these changes. The possibilities of using the antioxidant in the prevention of skeletal muscle lesion during physical exercises are discussed.     

Ultrastructural characteristics of rat neuromuscular junctions after physical load

It is interesting to ascertain the adaptive reaction of rat neuromuscular junctions (NMJ) of muscle fibers of different types to a chronic physical load. We examined ultrastructural changes in NMJ following both static load (pre- and postnatal ontogenesis of Wistar rats till a 2 month age took place under a constant rotation on the centrifuge at hypergravity conditions 2G), and after three kinds of dynamic loads (1/run on treadmill with a speed 35 m/min for 6 wks, 10-60 min/day; 2/swimmings, each 10 hrs/day for 10 days; 3/strength exercises on a vertical treadmill with load for 6 wks). Differences in NMJ reaction of muscle fibers of the same type to various loads were established. A low secretory activity of axonal terminals of type I muscle fibers of m. soleus was shown after the static load. The dynamic load (run) is accompanied with a high secretory activity of axonal terminals in m. soleus type I muscle fibers and of some axonal terminals of m. quadriceps femoris IIB type muscle fibers after strength exercises; the secretory activity of axonal terminals of m. quadriceps femoris IIA and IIB types muscle fibers is expressed in a lesser degree after swimming. The NMJ ultrastructure remodelling (terminal renewal) of type I muscle fibers of the 2 month old control rats increases after static and dynamic (run) loads. Some correlations between different kinds of physical load, muscle fiber type and the degree of NMJ ultrastructure transformation have been shown.     

Plasmatic markers of muscular stress in isokinetic exercise

In this paper we examined the variations of plasmatic concentrations of hypoxanthine and xanthine, and their relation with other important indicators of muscular stress creatine-kinase (CK), myoglobin, uric acid, leucocytes, in prolonged, isokynetic physical exercise, performed in a concentric mode at different joint excursion. Twenty healthy male subjects performed isokinetic exercises in concentric-concentric mode, with joint excursion of 30, 60, 90 deg/sec. Blood samples were drawn at rest, immediately after exercise and after 45 min of recovery. The plasmatic concentration of hypoxanthine increased at the end of physical exercise, compared to the rest value of about 1,5 micromol/L, up to a level of greater than 19 micromol/L; the values were higher after a period of recovery of 45 min and the increase varies considerably according to the type of exercise that was performed. Myoglobin has a slight but sensible increment too, with the same trend as hypoxanthine, while CK increase without correlation to the type of exercises. The relation with other indicators of muscular activity demonstrates that in none of the different isokinetic exercises, performed at concentric mode, was there ultrastructural damage, while it is possible to come across a considerable metabolic stress, which is dissimilar in the different kinds of exercises. The results suggest that hypoxanthine can be useful in monitoring the effectiveness of a work load and the metabolic stress consequences on the muscle tissue in training or rehabilitation programs. The results also suggest that even myoglobin, at small concentrations, can have the same function.     

Strength and conditioning practices of National Basketball Association strength and conditioning coaches

This study describes the results of a survey of the practices of National Basketball Association strength and conditioning (NBA S&C) coaches. The response rate was 68.9% (20 of 29). This survey examines (a) background information, (b) physical testing, (c) flexibility development, (d) speed development, (e) plyometrics, (f) strength/power development, (g) unique aspects, and (h) comments from coaches providing additional information. Results indicate, in part, that coaches assess an average of 7.3 parameters of fitness, with body composition testing being the most common. All coaches used a variety of flexibility development strategies. Results reveal that 17 of 20 (85.0%) of NBA S&C coaches follow a periodization model. Nineteen of 20 coaches (95.0%) indicated that their athletes used Olympic-style lifts. All coaches employed plyometric exercises with their athletes. The squat and its variations, as well as the Olympic-style lifts and their variations, were the most frequently used exercises. The survey serves as a review and a source of applied information and new ideas.     

Evaluation of fatigue of respiratory and lower limb muscles during prolonged aerobic exercise

The respiratory muscles may fatigue during prolonged exercises and thereby become a factor that limits extreme physical activity. The aim of the current study was to determine whether respiratory muscle fatigue imposes a limitation on extreme physical activity of well-trained young men. Electromyography (EMG) signals of respiratory (external intercostal and sternomastoid) and calf muscles (gastrocnemius) were measured (N = 8) during 1 hr of treadmill marching at a speed of 8 km/hr with and without a 15 kg backpack. The root mean square (RMS) and the mean power frequency of the EMG signals were evaluated for calculating fatigue indices. The EMG RMS revealed that the respiratory and calf muscles did not fatigue during the marching without a backpack load. The study did show, however, a significant rise in the EMG values when a backpack was carried with respect to the no-load condition (p < .05), which suggests that respiratory muscles should be trained in military recruits who are required to carry loaded backpacks while marching.     

Application of determined NT-proBNP in physical standardized exercise

Natriuretic peptides can be used as markers of heart failure, its severity and also in the differential diagnosis of dyspnea. Moreover, the dynamics of natriuretic peptides in physical standardized exercise may be used in the assessment of latent heart failure. AIM OF THE STUDY: Can determination of NT-proBNP be used in the diagnosis of exercise-induced ischemia or latent heart failure? 18 probands (10 men, 8 women) under study were risk persons with unspecified ECG, without signs of manifest heart failure. They were subjected to ergometric bike exercises up to the subjective maximum, SPECT myocardium with estimated ejection fraction of the left ventricle at peak ergometric exercise. The following parameters were followed-up: a) before ergometric exercise: NT-proBNP, CRP, TNF-alpha, Hb, Htc, lactate b) at subjective maximum: NT-proBNP, Hb, Htc, lactate c) 30 min after stopping the exercise: NT-proBNP d) 60 min after stopping the exercise: NT-proBNP. The volume blood changes were taken into account (estimation from the dynamics of Htc, Hb with calculation of metabolic changes of NT-proBNP). To evaluate the dynamics of NT-proBNP, the group was divided into subgroups according to the results obtained in ergometric exercises. RESULTS: initial values of NT-proBNP within normal limits (< 59 pmol/l, 500 ng/l) in 94%, the submaximal pulse rate was reached in 94%, ischemic changes in ECG were observed in 59%, typical clinical signs of heart ischemia were recorded in 35%. Signs of heart dysfunction according to SPECT were found in 47% and ischemic symptoms were observed in 43%. In general, the plasmatic volume decreased by 24% at maximal exercise. Lactate concentration in the plasma increased in all cases. Conversion of NT-proBNP into volume blood changes revealed that increased NT-proBNP occurred only in 22%. Differences between NT-proBNP before exercises and at maximal exercise prior and after correction into volume blood changes were statistically insignificant. 30 and 60 min after the exercise, no significant differences were found in NT-proBNP concentrations. Dividing into subgroups according to the results of ergometric exercises, showed no significant differences in NT-proBNP concentrations. Dynamics of NT-proBNP changes during and after ergometric exercises cannot be used for the diagnosis of exercise-induced heart failure. The high stability of NT-proBNP related to physical activity was confirmed.     

Cerebral hemodynamics response to low intensity physical exercise

The aim of this research was to study the cerebral hemodynamics reaction to step increase of physical exercises intensity during bicycle ergometer test in young healthy male subjects. Hemodynamics parameters were registered with the transcranial Doppler ultrasonography of middle cerebral artery (MCA) prior to the study and during the last seconds of every step of physical exercise. Cerebral hemodynamics response to physical exercise was characterized by a significant increase of peak systolic blood velocity in the MCA up to 0.25 W/kg of the body weight (90 rpm with regard to 0 W/kg) without further increase of blood velocity in the same physical exercise becoming more intensive up to 0.5 W/kg of the body weight. The stabilization mechanism of blood velocity in cerebral arteries in case of physical exercise increase and, hence, the autoregulation mechanism of cerebral circulation means that the increase of regional cerebral vascular resistance depends on the value of arterial pressure. The autoregulation mechanism of cerebral circulation starts working with he exercise intensity of 0.25 W/kg and the value of systolic blood pressure about 140-145 mm Hg.     

Hemodynamic indices of the cardiovascular system in children as related to their constitutional characteristics

In children five to seven years of age, the adaptation of their cardiovascular system to a high physical activity as related to their individual somatic characteristics was studied. The methods of rheography and bicycle ergometry were used under physical loads with the power increasing from 1 and 1.5 W/kg body weight. During exercises, load grading according to the body’s somatic characteristics led to a significant increase in the degree of the children’s functional training. In children of different somatotypes, the indices of absolute physical efficiency and of both cardiac output (Q) and stroke volume (SV) increased significantly. The increase in hemodynamic indices in girls was higher than in boys of the same age.     

Effect of phenamine and gutimine and gutimine on adaptive changes in arterial pressure occurring during skeletal muscle contraction]

Effects of amphetamine (0,1--11 mg/kg) and gutimin (5--50 mg/kg) on the pressor reflex originating in the exercising muscle were studied on nonanesthetized decerebrate cats. Isometric exercise of the hind limb muscles was elicited by stimulating the spinal ventral roots L6--S1. Amphetamine (0.1 mg/kg) increased the level of arterial pressure and the amplitude of the pressor reflex. Higher doses of amphetamine decreased the pressor reflex to exercises and there was a fall of arterial pressure. Gutimin elevated the arterial pressure and failed to alter the pressor reflex to exercises.