Research background and hypothesis. According the methodological requirement testing procedures do not modify the main training objectives. It is well known that specificity of performance assessment tests is important if we want to compare performance of different groups tested.Research aim was to find out the peculiarities of muscular performance indices in sprint and endurance cohorts while performing a 30-s vertical jump test.Research methods. The participants of the study were two groups of athletes, i. e. sprint and endurance runners. The participants of the study performed a 30-s vertical jumps test with maximal efforts. The sum of height of all jumps was calculated by a special computerized program and the values in height of jumps, contact time and relative power at onset of workload and at each 5 seconds of the test were analyzed.Research results. The difference between the cohorts in jumps height was statistically significant (p < 0.05) during the whole series of jumps. Athletes’ adaptation to speed-power type of exercising produced higher anaerobic muscle performance indices while performing 30-s duration jumps test. Endurance runners usually demonstrate lower results in jumping than sprint- athletes and they compensate reduced muscular power with prolonged duration of take-off.Discussion and conclusions. Despite some methodological limitations the results of this study show that the assessment of muscular performance indices allows assessing the peculiarities of dynamics of relative muscle power and fatigue.

Research background and hypothesis. It is well established that regular physical activity (PA) has many short- and long-term benefi ts for children’s health. Physically active children are more physically fi t than their physically inactive counterparts. Insuffi cient physical fi tness of adolescents is one of the risk factors for chronic diseases and has a tendency to be carried over into adulthood. Research aim was to examine health-related physical fi tness in low, moderate and vigorous physical activity categories among 16-year-old schoolboys.Research methods. The participants were 155 healthy schoolboys of the 10 th  grade from secondary schools of Kaunas (Lithuania). Their physical activity was measured by a modifi ed short form of the International PA Questionnaire (IPAQ) (Craig et al., 2003). The respondents were divided in three PA categories: high (vigorous) (VPA) (n = 43), moderate (MPA) (n = 63), and low (LPA) (n = 49). Physical fi tness tests were performed to measure participants’ fl exibility (by sit-and-reach test) (Eurofi t, 1993), power (by vertical jump test), and muscular strength and endurance (by modifi ed push-up test) (Suni et al., 1994). Research results. There were no signifi cant differences between the boys in different PA groups in respect of anthropometrical and body composition parameters (p > 0.05). The results of health-related physical fi tness tests were signifi cantly better of the VPA group boys (p < 0.05). The total volume of PA correlated with all health-related physical fi tness components that were measured (r = 0.23–0.38, p < 0.01). Discusion and conclussions. We may conclude that health-related physical fi tness is positively related to the total amount of physical activity in 16-year-old schoolboys.

Nors fi zinis pajėgumas genetiškai determinuotas, jį lemia ir aplinkos veiksniai, iš kurių  vienas svarbiausių — fi zinis aktyvumas. Priklausomai nuo fi zinio aktyvumo intensyvumo poveikis gali būti skirtingas. Suaugusiųjų fi zinio aktyvumo (FA) teigiamas poveikis fi ziniam pajėgumui ir svarbiausiems sveikatos rodikliams plačiai tyrinėtas, tačiau duomenų apie vaikų ir paauglių fi zinį aktyvumą, fi zinį pajėgumą stokojama.  Tyrimo tikslas — nustatyti skirtingų fi zinio aktyvumo kategorijų 15 ir 16 metų berniukų su sveikata susijusio fi zinio pajėgumo pokyčius per vienus metus. Tyrimas buvo vykdomas  2008 m. (I tyrimas) ir 2009 m. (II tyrimas) kovo—ba-landžio mėnesiais atsitiktiniu būdu atrinktose keturiose Kauno miesto bendrojo lavinimo mokyklose. Tiriamąją imtį sudarė 118 devintų klasių berniukų, kurie pagal jų sveikatos būklę yra priskirti pagrindinei fi zinio ugdymo grupei. Mokinių fi zinis aktyvumas  nustatytas interviu metodu pagal modifi kuotą tarptautinio FA (IPAQ) klausimyno trumpąją formą (Ainsworth, Levy, 2004). Visi respondentai pagal FA apimtį buvo suskirstyti į 3 FA kategorijas (Guidelines for Data Processing and Analysis of the International Physical Activity Quostionnaire (IPAQ) Short and Long Forms, 2005): didelio FA (DFA) (≥ 3001 MET’os-min / sav.), vidutinio FA (VFA) (> 1387 < 3001 MET’os-min / sav.) ir mažo FA (MFA) (≤ 1387 MET’os-min / sav.). Visi tiriamieji atliko su sveikata susijusio fi zinio pajėgumo (SSFPj) testus, kuriais buvo nustatytas raumenų pajėgumas: kojų raumenų staigioji jėga — atliekant vertikalius šuolius į aukštį iš vietos su rankų mostu (naudotas matuoklis SBM–1, fi ksuojamas geriausias rezultatas iš 3), rankų ir liemens raumenų ištvermė — atliekant modifi kuotus atsispaudimus (Suni et al., 1994), lankstumas išmatuotas „Sėstis ir siekti“ testu (Eurofi t, 1993). Identiškas fi zinio pajėgumo tyrimas pakartotas 2009 m. kovo—balandžio mėnesiais, tačiau dėl objek-tyvių priežasčių buvo tiriami tik 56 tiriamieji iš 118 (I tyrimas). Tyrimo duomenims palyginti taikyta vienfaktorinė dispersinė analizė, Stjudento t (Student t) kriterijus taikytas priklausomoms imtims ir atlikta kovariacinė analizė.Gauti rezultatai parodė, kad didėjant fi zinio aktyvumo apimčiai tiesiškai gerėja paauglių raumenų pajėgumas — ran-kų ir liemens raumenų ištvermės bei kojų raumenų staigioji jėga (p < 0,05). Lankstumo rezultatų pokyčiai didėjant fi ziniam aktyvumui statistiškai nereikšmingi (p > 0,05).

Research background and hypothesis. The objective methods for measuring PA are used more and more widely in various research studies all over the world. To our best knowledge, this pilot study is the first attempt in Lithuania to objectively assess physical activity of adolescents with an ambition to develop a more accurate methodology in assessing physical activity. Research aim of this study was to analyze the objectively measured weekly physical activity results of adolescent boys.Research methods. The PA of schoolboys was measured using Tri-axis ActiTrainer Activity Monitors. Boys were asked to wear the monitors for the whole week. The level of the intensity of PA was determined by calculating energy consumption in METs. Based on the frequency of vigorous  and moderate PA per week, the participants of this study were devided into PA groups. Research results. All of the schoolboys experienced LPA on each of the assessed days. MPA on each day was experienced by 59.6 % of the boys. No participants achieved VPA on a daily basis. The frequency of MPA and VPA experienced most often was 5–7 and 1–3 days per week, respectively. The total PA measured during the week was largely comprised by LPA, i. e. 79.8%; MPA and VPA were 18.8 and 1.4%, respectively.Discussion and conclusion. Boys who achieve VPA, have a greater total PA during the week than those boys who do not experience VPA. If boys achieve VPA on more than 2 days during the week, even if it is just for 10 min, there is a significant increase in the total amount of weekly PA as well as a decrease in their body mass index (BMI). Boys’ who do not experience MPA at least for 6 days/week, the total amount of weekly PA decreases.

Research background and hypothesis. During the last five years Lithuanian long-term research related to the peculiarities of changes  in  physical fitness among 10-12 th -grade  schoolgirls has  not  been  found.  Other research in Lithuania showed negative tendencies of physical fitness changes of Lithuanian schoolchildren and prevailing sedentary lifestyle.Research aim was to determine peculiarities of change results in physical fitness among Kaunas schoolgirls (10–12 th  grades).Research methods. The present research included 10 th -grade schoolgirls (n = 244) of Kaunas city who were at school during the research and were able to perform the necessary Eurofit tests: 10  × 5 m Shuttle run, Standing Broad Jump, Sit ups in 30 seconds, 20 m endurance Shuttle run.Research  results.  Changes in results of Eurofit tests performed from 10 th  grade autumn to 12 th  grade spring were different. Results of girls (10–12 th -grade) in 10 × 5 m shuttle run test did not change (p > 0.05). Results of standing broad jump improved significantly in Grade 11 (p  < 0.05). Results in 20 m endurance shuttle run test improved in Grade 12 (p < 0.05). Results in Sit ups in 30 seconds test improved in spring. Significant differences were found between 10 and 12 th -grade schoolgirls spring Sit ups in 30 seconds test results, and 10 and 11 th -grade autumn results.Discussion and conclusions. Comparison of physical fitness of 10 and 12 th -grade girls showed that it improved only in 20 m endurance shuttle run, in the 11 th  grade explosive strength of schoolgirls significantly improved.