The aim of the present study was to establish the influence of muscle heating and cooling on knee flexors and extensors during fatiguing exercise. The participants of the study were 10 healthy males aged 19–23 years. The participants of the study were tested with the isokinetic dynamometer. Control measurements were done before the load as well as 10 min, 30 min, 60 min, and 24 h after the load. The participants performed concentric exercise bouts: 50 knee extensions and flexions at the fixed speed of 180°/s, when femoral muscles before concentric load were of normal temperature, were heated or cooled. Creatine kinase activity in blood serum was estimated 1 h before the load and 24 h after it. Internal temperature of the muscle quadriceps femoris after muscle heating for 45 min increased to 39.5±0.2°C (P<0.001) and after muscle cooling for 30 min decreased to 32.5±0.3°C (P<0.05) as compared to baseline temperature (before heating – 36.9±0.1°C, before cooling – 36.8±0.2°C). Creatine kinase activity in blood serum 24 h after concentric load was significantly increased as compared to control values. Passive muscle warming increased muscle contraction force of knee extensors, but did not cause any changes either in the rate of muscle fatigue or in the rate of muscle recovery. Muscle cooling did not decrease muscle contraction force and did not increase muscle fatigue resistance. The findings of this study showed that both, muscle warming and muscle cooling, brought about a decrease in an indirect parameter of muscle damage – the amount of creatine kinase 24 h after concentric load.

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ĮvadasPažangios ekonomikos šalyse daugiausia žmonių miršta nuo širdies ir kraujagyslių sistemą pažeidžian-čių ligų bei sindromų. Šios ligos sudaro apie pusę visų mirties ir vieną trečdalį invalidumo priežasčių. Svarbiausi jų yra aterosklerozės, ypač vainikinių širdies arterijų, sukelti miokardo išemijos sindromai, kurie dėl didelio paplitimo ir blogos baigties (invalidumas, miokardo infarktas ir staigi mirtis) dabar sudaro vieną svarbiausių medicininių ir socialinių problemų. Todėl šie sindromai dažnai apibūdinami vienu nozologiniu vienetu -vadinamąja išemine širdies liga (IŠL). PSO vykdomi platūs tarptautiniai IŠL patogenezės, klinikos, diagnostikos, gydymo bei profilaktikos tyrimai (1, 2). Sergamumas miokardo infarktu ir mirtingumas nuo IŠL yra susijęs su rizikos veiksniais. Daugelio šalių patirtis rodo, kad laiku pradėta rizikos veiksnių korekcija padeda sumažinti sergamumą MI (3-6). Vienas svarbiausių veiksnių, nulemiančių širdies fiziologiją ir patologiją, yra vainikinė kraujotaka. Vainikinių širdies kraujagyslių būklei įtaką daro jų inervacija, kuri užtikrina kraujagyslių sienelės tonuso refleksinę reguliaciją. Dabar mokslininkai skiria daug dėmesio prieširdžių miokardo autonominių nervinių rezginių tyrimams, nes prieširdžiuose yra svarbiausios širdies ritmo dažnio valdymo bei elektrinio signalo perdavimo struktūros. Daugeliu neuroanatominių tyrimų nustatyta, kad prieširdžių miokarde yra žymiai tankesni nei

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Research background and hypothesis. Lack of physical activity is influenced by a number of chronic non-infectious, mental (Corbin et al. 2001; Golden et al., 2004) and other diseases (Katzmarzyk et al., 2003). Students’ physical activity and nutrition research remains relevant, especially for those students the future profession of which is not related to physical activity and health. Research aim. The aim of the study was to estimate the relation between physical activity and health among highly and moderately active students.Research methods. All the subjects (n = 327) were grouped according to their physical activity levels. The group highly physically active students – female athletes (n = 32) and male athletes (n = 79) who were physically active more than 3000 minutes per week. The group of moderate physical activity included females (n = 47) and males (n = 169) who were physically active 600–3000 minutes per week (Ainsworth, Levy, 2004). The respondents filled in anonymous questionnaires: the International Physical Activity Questionnaire (IPAQ). The questions dealt with the time being physically active in the last seven days. The survey took place in February–April, 2012. Research results. The subjects in high physical activity group gave a subjective evaluation of their physical activity as high (53%) and moderate (32%). The subjects in the moderate physical activity group evaluated their physical activity as moderate (60%) and high (26%). All subjects in both groups indicated that their health was good. The headache symptoms, stomach, abdominal or back pains, sadness, depression, insomnia and dizziness were rare or not common at all to subjects in high (63%) physical activity group. Sadness, depression, nervous tension and irritability, and bad mood were common to subjects in moderate (59%) physical activity group. The subjects in high physical activity group had their meals three – four times per day (76%), but subjects in moderate group ate only two - three times per day (61%). Irregular lunch and dinner were common to subjects in moderate physical activity group (63%). Discussion  and  conclusions.  Research  results  showed  that  subjects  in  high  and  moderate  physical  activity groups gave correct subjective evaluations of their physical activity forms. Also subjects in high physical activity group had breakfast, dinner and supper on regular basis and they had balanced diets more often (p < 0.05).