[Effect of exhaustive weightlifting exercise on EMG, biochemical markers of muscle damage and performance capacity in young male subjects].

The aim of this study was to examine the effect of exhaustive weightlifting exercise on electrical and biochemical variables and performance capacity in young male subjects. The onset of exercise (80-50% 1RM) was associated with a decrease in the amount of work performed, which was followed by a steady performance capacity at 40-10% 1RM. There were no significant changes of m. rectus femoris EMG maximal amplitude though it tended to be increased during the first half of exercise. A significant blood lactate concentration increase indicated that an anaerobic metabolism was a predominant mechanism of muscle contraction energy-supply. CK level in blood plasma did not change but plasma myoglobin concentration doubled immediately post-exercise. The data presented here suggest that decrease in performance capacity was likely due to progressive "refusal of work" of the fast motor units and work prolongation of weaker, intermediate and slow motor units. Unchangeable CK activity and relatively small increase in myoglobin concentration in plasma suggest that used weightlifting exercise did not induced substantial damage in myocytes' membranes in our subjects.

[Acute and remote biochemical and physiological effects of exhaustive weightlifting exercise].

The goal of the work was a study of exhaustive weightlifting exercise effect on prolonged changes in physiological and biochemical variables characterized functional status of skeletal muscles. An exercise gave rise to significant blood lactate concentration increase that was indicative of an anaerobic metabolism to be a predominant mechanism of muscle contraction energy supply. A reduction of m. rectus femoris EMG activity (amplitude and frequency), tonus of tension and an increase in tonus of relaxation were found immediately after exercise. Both EMG amplitude and frequency were increased 1 day post-exercise. However, after 3 days of recovery, EMG amplitude and frequency were decreased again and, in parallel, blood serum creatine kinase (CK) activity was significantly increased. After 9 recovery days, all measured variables with the exception of CK were normalized. A significant reverse correlation was found between blood serum lactate concentration and m. rectus femoris EMG activity at the same time points. Blood serum CK activity and m. rectus femoris EMG and tonus variables were observed to be significantly reversely correlated on the 3rd post-exercise day. Presented data demonstrate that exhaustive exercise-induced muscle injury resulted in phase alterations in electrical activity and tonus which correlated with lactate concentration and CK activity in blood serum.

[Morphological and biochemical aspects of skeletal muscle injury and regeneration subjected to physical load and hypodynamia].

This paper reviews the literature data on morphological and biochemical aspects of skeletal muscle injury by exercises, hypodynamia and microgravity. Muscle injury depends on the duration and intensity of action. In spite of differences of muscle injury mechanisms by exercises and hypodynamia, this injury restricts muscle function and capacity to continue muscle work. Possible approaches to minimization of the muscular tissue injury and accelerating its regeneration are discussed.

[The effect of 3',5'-AMP-dependent protein kinase on the release of cathepsin B from lysosomes of rat skeletal muscles and heart under exertion]. / Vliianie 3':5'-AMP-zavisimoi proteinkinazy na vykhod katepsina D iz lizosom skeletnykh myshts i serdtsa krys pri fizicheskoi nagruzke.

Single prolonged physical exercises are found to lower the total and bound activity of cathepsin D in the lysosome fraction and to enhance the nonsedimentary activity of the enzyme the dissolved fraction of the skeletal muscles and heart lysosomes. Systematic physical exercises make higher the ability of 3':5'-AMP-dependent protein kinases to regulate the yield of cathepsin D from lysosomes.

[Effect of isobutylmethylxanthine on the adenylate cyclase system of the myocardium and skeletal muscles of the rat during the recovery period following physical loading]. / Vliianie izobutilmetilksantina na adenilattsiklaznuiu sistemu miokarda i skeletnykh myshts krys v vosstanovitel'nyi period posle fizicheskoi nagruzki.

The in vivo experiments established that isobutyl methyl xanthine inhibits phosphodiesterase activity and activates adenylate cyclase in the skeletal muscles and myocardium. The preparation prevents phosphodiesterase activity from increasing due to physical exercises. Against a background of the latter it activates adenylate cyclase and prevents the cAMP level from declining in skeletal muscles. In the myocardium this effect of isobutyl methyl xanthine is less pronounced.

[Effect of training and physical load on 3':5'-AMP content and activity fo the enzymes of its metabolism in rat muscle]. / Vliianie trenirovki i fizicheskoí nagruzki na soderzhanie 3':5'-AMP i aktivnost fermentov ego ovmena v myshtsakh krys.

It is established tha in skeletal muscles of dormant animals under the influence of training the 3':5'-AMP content and the activity of adenylate cyclase increase; that of phosphodiesterase remains unchanged. A long physical load causes no changes in the 3':5"-AMP content in the skeletal muscles of the trained rats as compared to its content in the intact animals but evokes a decrease as compared to its level in the trained rats muscles. The activity of adenylate cyclase in the skeletal muscles of the trained rats under long physical load lowers, that of 3':5'-AMP phosphodiesterase also decreases but to a less extent. The found changes in the 3':5'-AMP metabolism in the trained animals skeletal muscles evidence for a possible participation of the 3':5'-AMP system in development of the organism adaptation to higher physical loads.

[ATP-dependent calcium transport in the sarcoplasmic reticulum of the myocardium during vitamin E deficiency in the rat diet]. / ATP-zavisimyi transport kal'tsiia v sarkoplazmaticheskom retikulume miokarda pri nedostatke vitamina E v ratsione krys.

The vitamin E deficiency in the rat diet was studied for its effect on the activity of Ca2+-pump and phosphorylation of sarcoplasmic reticulum membrane fragments of myocardium. It is shown that under such an antioxidant deficiency ATP-dependent accumulation of calcium is 2.5 times as low, from 490 down to 190 nmol/mg of protein for 5 min. The administration of ionol, a synthetic antioxidant, to animals reduces the level of calcium accumulation, it is 1.8 times as high as that with vitamin E deficiency; cAMP-dependent phosphorylation of the sarcoplasmic reticulum preparation membranes of the test animal myocardium produces a 1.6-2.1 times increase in them of the ATP-dependent accumulation of calcium, the kinetics of Ca2+ accumulation is unchanged.

[Iodine metabolism in rat tissues under physical loads]. / Obmen ioda v tkaniakh krys pri fizicheskikh nagruzkakh.

Single short-term physical loading as swimming and race in the treadmill evoke in rats changes in the total iodine amount, intensify the hormonogenic function of thyroid gland with hormonal iodine enrichment of tissues and metabolism of thyroid hormones. All these processes become more intensive when the duration of loads increases and they become weaker during 80 min swimming. The short-term swimming evokes more intensive mobilization and redistribution of iodine reserve in rats than race. The indices under study change to a greater extent with the long-term race in a treadmill.

[Effect of immobilized adrenaline on the state of the adenylate cyclase system in the cardiac and skeletal muscles of rats in the recuperative period after physical exertion]. / Deistvie immobilizovannogo adrenalina na sostoianie adenilattsiklaznoi sistemy v serdechnoi i skeletnykh myshtsakh krys v vosstanovitel'nyi period posle fizicheskoi nagruzki.

It is shown that in the rehabilitation period after a single long physical load the adenylate cyclase activity and cAMP content in the skeletal muscle are low and normalize by the 48th and 36th h, respectively. These indices in the myocardium in the nearest rehabilitation period increase considerably, gradually normalizing by 24th and 48th h, respectively. Immobilized epinephrine accelerates normalization of the adenylate cyclase activity and cAMP content in the skeletal muscle and in myocardium in the rehabilitation period after physical load, the phosphodiesterase activity being unchanged.

[Effect of carbostimulin on acid-base equilibrium of the blood of racing horses during exertion]. / Vliianie karbostimulina na kislotno-shchelochnoe sostoianie krovi sportivnykh loshadei pri fizicheskoi nagruzke.

The paper deals with possibility to regulate in a proper direction the acid-base state in race horse blood administering carbostimulin at rest and under physical exercises. The preparation is shown to favour an increase in alkaline blood reserves in race hours at rest and to prevent acidotic changes caused by physical exercises. The results obtained show a promising use of carbostimulin for the directed correction of the acid-base state of blood in race horses aimed at increasing the efficiency of the training process.

[Acid-base equilibrium in sportsmen during physical exercise]. / Kislotno-shchelochnoe ravnovesie krovi u sportsmenov pri fizicheskikh nagruzkakh.

Acid-base balance in venous blood of basketball players was studied under specific loadings of various intensity by means of the micro-Astrup device. It is established that under acyclic loadings (throwing the ball into the basket) the state of metabolic acidosis is developed in the sportsmen and the more intensive the work, the higher the degree of the state of metabolic acidosis. The efficiency of actions of the persons examined was in inverse dependence on the degree of metabolic disturbances, i.e. the least efficiency was marked under the most profound acidosis.

[ATP-dependent transport of calcium in the myocardial sarcoplasmic reticulum during adaptation to muscular activities]. / ATP-zavisimyi transport kal'tsiia v sarkoplazmaticheskom retikulume miokarda pri adaptatsii k myshechnoi deiatel'nosti.

Two-fold increase in Ca2+-transport properties of Ca2+-pump was detected in myocardial sarcoplasmic reticulum (SR) during adaptation of animals to muscular activity (training by means of running on treadmill within 6 weeks, with gradual increase in duration and intensity). Besides, the rate of SR membranes phosphorylation via cAMP-dependent protein kinase was increased 1.3-fold. At the same time, cAMP-dependent phosphorylation accelerated 1.4-1.5-fold the rate of ATP-dependent transport of Ca2+ in myocardial SR of both control and trained animals. The data obtained suggest that increase in the Ca2+-pump activity and in the rate of phosphorylation of SR membranes via cAMP-dependent protein kinase are of importance for adaptation of animal heart muscle to elevated activity.

[Change in some properties of soluble cAMP-dependent protein kinase from rat myocardium during physical exercise]. / Izmenenie nekotorykh svoistv rastvorimoi cAMP-zavisimoi proteinkinazy miokarda krys pri trenirovke fizicheskimi nagruzkami.

During 1.5- and 3-months physical exercise the activity of soluble 3':5'-AMP-dependent protein kinase of the rat increases 2.4- and 4.6-fold, respectively. The maximal activity of the enzymes from heart muscles of control and experimental animals is observed at the same concentration of 3':5'-AMP (10(-6) M) and pH (6.8-7.0). The degree of changes in V and apparent Km for ATP and histone H2b depend on the duration of physical exercise. The changes in the properties of soluble 3':5'-AMP-dependent protein kinase suggest the participation of the enzyme in adaptation to systematic muscular activity.

[cAMP-dependence of phosphorylation of the phosphorylase b kinase of the skeletal muscles of rats during physical exercise and training]. / O cAMP-zavisimom fosforilirovanii kinazy fosforilazy b skeletnykh myshts krys pri fizicheskoi nagruzke i trenirovke.

During relative rest of trained rats the phosphorylase b kinase activity is increased by 24% (pH 6.8). Physical load causes an increase of the phosphorylase b kinase activity of untrained and trained rats by 44 and 33%, respectively. The degree of phosphorylase b kinase phosphorylation by a homologous soluble cAMP-dependent protein kinase from the muscles of trained rats at rest is 1.9 times that of the control group. The cAMP-dependent phosphorylation of phosphorylase b kinase of untrained and trained rats under physical load is increased 2.5-fold. The data obtained are indicative of the regulatory role of cAMP-dependent phosphorylation in biochemical adaptation of skeletal muscles when their function is increased.

[Several properties of 3':5'-AMP-dependent skeletal muscle protein kinases in normal rats and following physical exertion to fatigue]. / Nekotorye svoistva 3':5'-AMP-zavisimykh proteinkinaz skeletnykh myshts krys v norme i pri fizicheskoi nagruzke do utomleniia.

Three fractions of rat adenosine-3',5'-monophosphate-dependent protein kinase were isolated, partially purified in buffer concentration gradient at normal state and after long-term physical loading and studied. It is found that first two fractions of protein kinases at normal state and after intensive muscular work have similar activities with and without cAMP, apparent Km values for ATP and total histone and half-maximal stimulation by cyclic AMP, but they differed from the third fraction. There are differences in some kinetic parameters and in the cyclic AMP stimulated activities between protein kinases after physical loading. The data obtained suggest the existence of at least two kinases in rat skeletal muscle. The isoenzymes differ in their activities during fatigue.

[Changes in some properties of 3':5'-AMP-dependent protein kinase from rat skeletal muscles during physical exercise]. / Izmenenie nekotorykh svoistv 3':5'-AMP-zavisimykh proteinkinaz skeletnykh myshts krys pri trenirovke fizicheskimi nagruzkami.

During 6-week training of rats the activity of isoenzymes I and II of soluble 3':5'-AMP-dependent protein kinase increases by 22 and 33%, respectively. A long-term physical load does not cause any significant changes in the activity of both isoenzymes. The maximal activity of the isoenzymes from skeletal muscles of the control and experimental rats is observed at the same concentrations of 3':5'-AMP and pH of 6,0-6,5. During training and under physical load the apparent Km values for ATP of both isoenzymes of 3':5'-AMP-dependent protein kinase do not change significantly, whereas that of V shows an increase. The apparent Km and V values for the histone increase for isoenzyme I obtained from skeletal muscles of trained rats both at rest and under physical load. In case of isoenzyme II the Km value for the histone decreases, while that of V remains unchanged. The changes in the properties of isoenzymes I and II of 3':5'-AMP-dependent protein kinase from skeletal muscles suggest the participation of the enzyme in adaptation to systematic muscular activity.