Physiological comparison between non-athletes, endurance, power and team athletes.

We hypothesized that endurance athletes have lower muscle power than power athletes due to a combination of weaker and slower muscles, while their higher endurance is attributable to better oxygen extraction, reflecting a higher muscle oxidative capacity and larger stroke volume. Endurance (n = 87; distance runners, road cyclists, paddlers, skiers), power (n = 77; sprinters, throwers, combat sport athletes, body builders), team (n = 64; basketball, soccer, volleyball) and non-athletes (n = 223) performed a countermovement jump and an incremental running test to estimate their maximal anaerobic and aerobic power (VO2max), respectively. Dynamometry and M-mode echocardiography were used to measure muscle strength and stroke volume. The VO2max (L min-1) was larger in endurance and team athletes than in power athletes and non-athletes (p < 0.05). Athletes had a larger stroke volume, left ventricular mass and left ventricular wall thickness than non-athletes (p < 0.02), but there were no significant differences between athlete groups. The higher anaerobic power in power and team athletes than in endurance athletes and non-athletes (p < 0.001) was associated with a larger force (p < 0.001), but not faster contractile properties. Endurance athletes (20.6%) had a higher (p < 0.05) aerobic:anaerobic power ratio than controls and power and team athletes (14.0-15.3%). The larger oxygen pulse, without significant differences in stroke volume, in endurance than power athletes indicates a larger oxygen extraction during exercise. Power athletes had stronger, but not faster, muscles than endurance athletes. The similar VO2max in endurance and team athletes and similar jump power in team and power athletes suggest that concurrent training does not necessarily impair power or endurance performance

Prefrontal Cortex Activity Predicts Mental Fatigue in Young and Elderly Men During a 2 h “Go/NoGo” Task

Background: Although the effects of mental fatigue on cognitive–motor function and psychological state in young adults are well-documented, its effects in the elderly are not completely understood. The aim of this study was to estimate the effect of prolonged cognitive load on the indicators of psychological, cognitive, and motor functions.Methods: Fifteen young and 15 elderly men were asked to perform a 2 h “Go/NoGo” task. Psychological state (mood and motivation), cognitive (prefrontal cortex activity and cognitive performance), and motor (motor cortex excitability and grip strength) functions were measured before and after the task. During the 2 h task, both groups had a significantly similar increase in the number of “Incorrect NoGo” errors. Only in young men reaction time (RT) of “Incorrect NoGo” and intraindividual variability of RT of “Incorrect NoGo” significantly increased during task. After the task, handgrip strength decreased for the young men, whereas latency of motor evoked potentials prolonged both groups. Nevertheless, both groups indicated that they felt fatigue after the 2 h task; we observed that mental demand increased, whereas intrinsic motivation and mood decreased only in young men. Prolonged task decreased the switching/rest ratio of oxygenated hemoglobin for the young and the elderly men; however, greater for elderly than young men. Interestingly, the more the prefrontal cortex was activated before the 2 h task during the switching task, the fewer of “Incorrect NoGo” errors made by the young men and the greater the number of errors made by the elderly men.Conclusion: Because of the greater mental load and (possibly) greater activation of prefrontal cortex during the 2 h “Go/NoGo” task, there was greater mental and neuromuscular performance fatigue in young men than in elderly men

High-velocity elastic-band training improves hamstring muscle activation and strength in basketball players.

BACKGROUND:The aim of this study was use surface EMG activity to assess changes in co- activation of knee flexors and extensors muscle groups during elastic-band exercise after 5 weeks of high-velocity elastic-band training in basketball players. METHODS:College male basketball players (n = 18) were randomly divided into one of two groups: (1) The elastic-band training group performed low-load and high-velocity - lying prone - hamstring curls training three times per week; (2) The control group did not do any training. Pre- and post- training assessment included concentric knee extension and flexion at 60°/s and 240°/s, and the frequency of knee flexion and extension with elastic bands in the prone position. The EMG of the rectus femoris, semitendinosus muscles and the long head of the biceps femoris were assessed during these activities, and 30-m sprint running speed was measured from a stationary start and a running start. RESULTS:It was shown that high-velocity elastic-band training was 1) feasible, 2) increased movement velocity and 3) muscle strength, 4) altered neural control such that excessive lengthening of the hamstring muscle, and hence strain-injuries, may be prevented and 5) improved sprint performance in basketball players. CONCLUSIONS:In addition, these results suggest that high-velocity elastic-band training may be a tool to prevent hamstring strain-injuries in basketball players

Human alpha-actinin-3 genotype association with exercise-induced muscle damage and the repeated-bout effect

Alpha-actinin-3 (ACTN3) is an integral part of the Z line of the sarcomere. The ACTN3 R577X (rs1815739) polymorphism determines the presence or absence of functional ACTN3, which may influence the extent of exercise-induced muscle damage. This study aimed to compare the impact of, and recovery from, muscle-damaging eccentric exercise on subjects with or without functional ACTN3. Seventeen young men (20-33 years old), homozygous for the R (n = 9) or X (n = 8) alleles, performed two bouts of stretch-shortening exercise (50 drop jumps) two weeks apart. Muscle soreness, plasma creatine kinase (CK) activity, jump height, maximal voluntary isometric torque (MVC), peak concentric isokinetic torque (IT), and electrically stimulated knee extension torques at 20 and 100 Hz were measured at baseline and at a number of time points up to 14 days after each bout. There were no significant baseline differences between the groups. However, significant time point &times; genotype interactions were observed for MVC (p = 0.021) and IT (p = 0.011) for the immediate effect of eccentric exercise in bout 1. The RR group showed greater voluntary force decrements (RR vs. XX: MVC, -33.3% vs. -24.5%; IT, -35.9% vs. -23.2%) and slower recovery. A repeated-bout effect was clearly observed, but there were no differences by genotype group. The ACTN3 genotype modulates the response of muscle function to plyometric jumping exercise, although the differences are modest. The ACTN3 genotype does not influence the clearly observed repeated-bout effect; however, XX homozygotes recover baseline voluntary torque values faster and thus may be able to undertake more frequent training sessions

Physical Activity and Healthy Habits Influence Mood Profile Clusters in a Lithuanian Population

Moods have been investigated previously in a range of cultural contexts. In our study, we investigated if six mood profiles previously identified, termed the iceberg, inverse Everest, inverse iceberg, shark fin, submerged, and surface profiles, were also evident among a Lithuanian sample. A Lithuanian translation of the Brunel Mood Scale (BRUMS-LTU) was completed by a sample of 746 participants (male = 199, female = 547) aged from 17–78 years (M = 41.8 years, SD = 11.4 year). Seeded k-means cluster analysis clearly identified the six hypothesized mood profiles, the prevalence of which reflected previous findings. Cluster prevalence varied significantly by sex, age, exercise and smoking status, frequency of overeating, and self-rated health of participants. Male participants and older adults were under-represented for the inverse Everest profile and over-represented for the iceberg profile. Those who reported more healthy habits (i.e., exerciser, non-smoker, rarely overeat) and those reporting better self-rated health were over-represented for the iceberg profile and under-represented for negative mood profiles; namely, the inverse Everest, inverse iceberg, and shark fin profiles. Findings supported the cross-cultural invariance of the mood profile clusters and confirmed the link between unhealthy habits and negative mood profile

Paradigm errors in the old biomedical science

The aim of this article was to review the basic drawbacks of the deterministic and reductionistic thinking in biomedical science and to provide ways for dealing with them. The present paradigm of research in biomedical science has not got rid of the errors of the old science yet, i.e. the errors of absolute determinism and reductionism. These errors restrict the view and thinking of scholars engaged in the studies of complex and dynamic phenomena and mechanisms. Recently, discussions on science paradigm aimed at spreading the new science paradigm that of complex dynamic systems as well as chaos theory are in progress all over the world. It is for the nearest future to show which of the two, the old or the new science, will be the winner. We have come to the main conclusion that deterministic and reductionistic thinking applied in improper way can cause substantial damage rather than prove benefits for biomedicine science

Bi-modal recovery of quadriceps femoris muscle function after sustained maximum voluntary contraction at different muscle length

The aim of this study was to test the hypothesis that contractility of quadriceps femoris muscle during a 15-min period after a sustained maximum voluntary contraction for 1 min is determined by the interaction of posttetanic potentiation, metabolic fatigue, and nonmetabolic fatigue. Eleven healthy untrained men (age, 22.9±1.8 years; body weight, 77.5±5.2 kg) performed isometric 1-min maximum voluntary contraction at long (90° in knee joint) and short (135° in knee joint) muscle length at two different occasions. Contractility of quadriceps femoris muscle was monitored via the evoked contractions at 1, 10, 20, and 50 Hz and maximum voluntary contraction at short and long muscle length on both occasions. Force generating capacity was reduced immediately after 1-min maximum voluntary contraction at short and long muscle length, and then a bi-modal time-course of recovery was observed which consisted of (1) rapid recovery of all measured indexes at 3 min and (2) divergence in the changes of forces at low and high stimulation frequencies, as well as maximal voluntary contraction force at 7 and 15 min after exercising. The decline in force immediately after 1-min isometric load was caused by metabolic and nonmetabolic fatigue; however, factors related to the metabolic fatigue were prevalent. As the effect of metabolic fatigue was diminishing and posttetanic potentiation was still present, force generation capacity recovered at 3 minutes after exercising. Further dynamics of contractility can be explained by the fading influence of posttetanic potentiation and dominant effect of nonmetabolic fatigue

Sport science - the science of complex dynamic systems

Sporto mokslo pagrindinė funkcija - pažinimas. Sporto mokslas nagrinėja įvairias sporto formas ir vertybes, stengiasi paaiškinti ir atskleisti sporto fenomeną. Sportas - tai žmogaus galių ir kūno grožio išraiškos, žmogaus sveikatos stiprinimo, jo kūrimo ir žmonių bendravimo reiškinys. Jis šiuo metu tik ieško savo vietos ir pripažinimo tarp kitų mokslų. Šis naujas mokslas turi kovoti, kaip ir kiekvienas kitas, už savo egzistenciją. [...] Iš jauno sporto mokslo reikalaujama naujų technologijų ir gilių mokslinių tyrimų. Jau šiandien sporto mokslas turi savo teoriją, kuri nagrinėja ir sieja į vientisą sistemą esamas žinias apie sportą, tiriamojo objekto efekto esminiai, dėsningi ryšiai atskleidžiami remiantis kitomis mokslinio pažinimo formomis. Jei neatliekami išsamūs sporto tikrovės tyrimai, o remiamasi tik metodinėmis rekomendacijomis, kylančiomis iš praktinių stebėjimų, pakertamas sporto mokslo kamienas. O didžiausias naujojo mokslo - sudėtingiau dinaminių sistemų mokslo - laimėjimas - tai realus supratimas, ką gali ir ko negali mokslas. Galima teigti, kad šių dienų mokslo laimėjimai skęsta mūsų meto deterministinėje paradigmoje, subjekto silpnybėse ir klaidose bei objekto neapibrėžtume. Tačiau paradigma keičiasi lėčiausiai, nes jos galia mokslo plėtrai didžiausia. Naujosios mokslo paradigmos pokyčių pagrindinė jėga - noras aiškiau suprasti sudėtingą dinamišką spontanišką realybę ir jos tyrimo įrankius. Apibendrinant galima teigti, kad mąstymo kultūra turi milžinišką galią mokslo ir viso pažinimo vyksmo plėtrai. Sporto mokslas privalo keisti tyrimo metodologiją, kuri turėtų būti orientuota į sistemų ir evoliucinę paradigmą.The main function of sport science is cognition. Sport science analyses different sport forms and values, tries to explain and reveal the phenomenon of sport itself. Sport is the phenomenon of human's powers and body's beauty expression, human's health development, its creation and people's communication. The sport science currently only looks for its place and recognition among the other sciences. This new science must fight for its existence just as every another ones. The buildings of science fundamentals and their constant maintaining, disquisition of the deepest, essential problems of existence are the very first steps in consolidating its positions at the world level. Young sport science is being challenged for new technologies and significant scientific researches too. Today sport science has its theory that analyses and relates existing sport knowledge into integral system. The essential and regular links of searching object effect are revealed in reference with other scientific recognition forms. The very basis of sport science is destroyed if methodical recommendations that arise from practical observations are being followed instead of carrying out comprehensive researches of sport reality. The practical understanding what science is able or enable to achieve is the ultimate accomplishment of the newly born science - science of complex dynamic systems. It can be stated that the achievements of nowadays science are being destroyed by necessitarian paradigm, subject vulnerabilities, inaccuracies, and object indetermination. But the paradigm changes are the hardest because of its strongest influence on science development. The main power of the new science paradigm is in the intention to understand the very difficult dynamic spontaneous reality and the means of its analysis in much clearer way. In summary it may be stated that the culture of cogitation has enormous impact on the development of science and the whole cognition. Sport science must change its researching methodology that should be polarized towards the paradigm of systems and evolution

The paradigm of sport psychology and educational science research in the world and in Lithuania

The new science paradigm is built on new scientific literacy and new science culture. Critical thinking, doubt, ongoing search for the truth, endless dialogue with nature, person and society are the main elements of it...[Visą santraukos tekstą skaitykite spustelėję interneto prieigos nuorodą]

New science - complex dynamic systems - research paradigm : from biology to law

Straipsnio tikslas – apžvelgti naujojo mokslo – sudėtingųjų dinaminių sistemų – tyrimo paradigmos privalumus ir trūkumus biologijos ir socialinių mokslų srityje (akcentuojant teisę). Šių dienų pasaulyje vyksta mokslo paradigmos kaita. Vyksta pasaulėžiūrų sankirtis. Dabar naujasis mokslas verčia senąjį mokslą. Viena iš didžiausių senojo mokslo klaidų yra ta, kad išskyrė griežtas ribas tarp mokslų. Todėl atsirado labai daug atskirų mokslo „specialistų“ ir mažai besuprantančių, kas yra mokslas iš tikrųjų. Kovoja, nors tai dažnai sunkiai įžvelgiama, senasis deterministinis ir mechanistinis mąstymas, pagrįstas visiško aiškumo ir objektyvumo siekiu, su naujuoju – sudėtingųjų (kompleksinių) dinaminių sistemų paradigma, kuri nesuabsoliutina pažinimo galimybių ir vis labiau supranta, kad kiekvienas pažinimas priklauso ne tik nuo subjekto silpnybių, bet ir nuo objekto sudėtingumo, kaitos, t. y. negalimumo iš principo jį tiksliai pažinti, ištirti, suprasti. Kas laimi šiuo metu? Nėra abejonės, kad senasis, labiau patyręs ir daugiau „užtarėjų“ turintis mokslas. Tačiau pergalė yra gana trapi, nes įvairių mokslų lyderiai vis drąsiau kelia senojo mokslo trūkumus ir rodo naujojo privalumus. Reikšminiai žodžiai: Chaosas; Mokslo paradigma; Sudėtingosios dinaminės sistemos; Chaos; Complex dynamic systems; Science paradigmMain purpose of the article is to review the advantages and disadvantages of the new science paradigm – complex dynamic systems. In the present-day world changes in the science paradigm are in progress. Presently, the new science is rejecting the old science. One of the greatest errors made by the old science was determining strict limits between separate sciences. This delimitation resulted in a multitude of separate science “specialists” and, as a consequence, very few nowadays realize the true nature of science. Thus, there is a struggle between the old – deterministic thinking based on search for complete clearness and objectivity, on the one hand, and the new – the paradigm of complex dynamic systems, on the other hand. The new science paradigm does not regard the possibilities of cognition as the absolute ones coming to realize ever more fully that each act of cognition depends not only on the weaknesses of the subject alone but also on the complexity and dynamics of the object, i. e. on the impossibility to precisely cognize and understand it in principle. Who is the winner at present? There is a doubt that the old science, possessing greater experience and more "patrons", turns out to be the winner. This victory, however, is a frail and questionable one, since the leaders of various sciences are bravely revealing the faults of the old, deterministic and reductionistic science and pointing out the advantages of the new science