Dragan Radovanovic

Effects of 12-week medicine ball training on muscle strength and power in young female handball players.

Abstract Ignjatovic, AM, Markovic, ZM, and Radovanovic, DS. Effects of 12-week medicine ball training on muscle strength and power in young female handball players. J Strength Cond Res 26(8): 2166–2173, 2012—The purpose of this study was to examine the effects of medicine ball training on the strength and power in young female handball athletes. Twenty-one young female handball players (age, 16.9 ± 1.2 years) were randomly assigned to experimental and control groups. Experimental group (n = 11) participated in a 12-week medicine ball training program incorporated into the regular training session, whereas controls (n = 10) participated only in the regular training. Performance in the medicine ball throws in standing and sitting positions, 1 repetition maximum (1RM) bench and shoulder press, and power test at 2 different loads (30 and 50% of 1RM) on bench and shoulder press were assessed at pre- and posttraining testing. The athletes participating in the medicine ball training program made significantly greater gains in all medicine ball throw tests compared with the controls (p < 0.01). Also, the experimental group made significantly greater gains in bench and shoulder press power than control group (p < 0.05). Both training groups (E) and (C) significantly (p < 0.05) increased 1RM bench and shoulder strength, with no differences observed between the groups. Additionally, medicine ball throw tests showed stronger correlation with power tests, than with 1RM tests. These data suggest that 12-week medicine ball training, when incorporated into a regular training session, can provide greater sport-specific training improvements in the upper body for young female handball players.

The Effect of Aquatic Intervention on the Gross Motor Function and Aquatic Skills in Children with Cerebral Palsy

The Effect of Aquatic Intervention on the Gross Motor Function and Aquatic Skills in Children with Cerebral Palsy The objective of this study was to investigate the effect of an aquatic intervention on the gross motor function and aquatic skills of children with cerebral palsy (CP). Twenty-nine children with CP, aged 5 to 14, were recruited. Fourteen children completed an aquatic intervention (EG), and 13 children served as controls (CG). Two participants dropped out due to events (illness) unrelated to the intervention. The aquatic intervention lasted 6 weeks (2 sessions per week at 55 minutes per session) with a follow-up period of 3 weeks. The outcome measures were the Gross Motor Function Measure (GMFM) for motor function and the Water Orientation Test Alyn 2 (WOTA 2) for aquatic skills assessment. A significant improvement was observed in the secondary assessment of GMFM and WOTA 2. In contrast to the aquatic skills improvement, the GMFM change was not maintained at follow-up. Our results indicate that children with CP can improve gross motor function on dry land and aquatic skills with a 6-week water intervention. The intervention period was too short for sustainable improvement in dry-land motor skills after intervention (followup), but time was sufficient to achieve sustainable improvements in aquatic skills.

Bone Metabolism Markers in Sportswomen with Menstrual Cycle Dysfunctions

Bone Metabolism Markers in Sportswomen with Menstrual Cycle Dysfunctions It is a well known fact that sportswomen with irregular menstrual cycle are exposed to the risk of diminished bone mineral density, and consequentially osteoporosis may appear. Monitoring of the levels of biochemical markers of bone metabolism enables understanding of the dynamic changes during the bone remodeling process. The objectives of the conducted research were to determine the prevalence of menstrual dysfunctions in a sports-women sample and a control group, and also to determine the levels of bone metabolism markers in groups of women with menstrual dysfunctions. The women (n=117) were separated into two groups, the experimental group (S) (n=84) comprised of three subgroups of sports women (34 women who play ball game sports, 27 athletes and 23 sport dancers) and the control group (C) (n=34). To establish the menstrual profile and dysfunction of the menstrual cycle, we used a very detailed questionnaire. The level of mid-fragment osteocalcin (N-MID osteocalcin) as a marker of bone formation was deter mined, as well as β-Cross Laps (β-CTx-bone resorption marker) via the electro luminescent immunochemistry method on an Elecsys 1010 automated machine. Primary amenorrhea was found in 7 (8.33%) and oligomenorrhea in 11 (13.09%) sportswomen, which was statistically a much higher incidence (p<0.05) than in the control group (0/34). Values of bone metabolism markers showed a statistically significant difference in the level of the bone resorption marker β-CrossLaps between the groups of amenorrheic and oligomenorrheic sportswomen in comparison to the eumenorrheic women, both sportswomen and those in the control group. Accelerated resorption was accompanied with accelerated bone formation. Menstrual dysfunctions were statistically more present in the sports-women group than in the control group and were accompanied with accelerated bone metabolism from the point of view of the increase of bone metabolism markers level. Markeri Koštanog Metabolizma Kod Sportistkinja sa Poremećajima Menstrualnog Ciklusa Dobro je poznata činjenica da su sportistkinje sa neredovnim menstrualnim ciklusom izložene riziku od smanjenja koštane mineralne gustine i posledično osteoporozi. Praćenje nivoa biohemijskih markera koštanog metabolizma omogućava razumevanje dinamičkih promena tokom procesa remodeliranja kosti. Ciljevi sprovedenog istraživanja bili su: utvrditi prevalence menstrualnih poremećaja na uzorku sportistkinja i kontrolne grupe, kao i odrediti nivoe markera koštanog metabolizma u grupama ispitanica sa menstrualnim disfunkcijama. Ispitanice (n=117) bile su podeljene u dve grupe, eksperimentalnu (S) (n=84) podeljenu u tri podgrupe (34 sportistkinje igara sa loptom, 27 atletičarki i 23 takmičarke u sportskom plesu) i kontrolnu grupu (C) (n=34). Za određivanje menstrualnog profila i poremećaja menstrualnog ciklusa korišćen je upitnik. Određen je nivo srednjeg fragmenta osteokalcina (N-MID osteokalcin) kao markera formiranja kosti i β-CrossLaps (β-CTx - marker resorpcije kosti) elektro-luminiscentnom imunohemijskom metodom na automatskom aparatu Elecsys 1010. Primarna amenoreja nađena je kod 7 (8,33%) a oligomenoreja kod 11 (13,09%) sportistkinja, što je statistički značajno viša incidenca u odnosu na kontrolnu grupu. Vrednosti markera koštanog metabolizma su pokazale statistički značajnu razliku u nivou markera resorpcije kosti, β-CrossLaps, između grupa amenoreičnih i oligomenoreičnih sportistkinja u odnosu na eumenoreične ispitanice, kako sportistkinje tako i kontrolnu grupu. Ubrzanu resorpciju je pratilo i ubrzano formiranje kosti (povećane vrednosti osteokalcina). Menstrualne disfunkcije statistički su značajno više prisutne u grupi sportistkinja u odnosu na kontrolnu grupu i, gledajući nivoe markera metabolizma kosti, bile su praćene ubrzanim metabolizmom kosti.

Influence of resistance training on cardiorespiratory endurance and muscle power and strength in young athletes.

The purpose of this study was to investigate the influence of additional resistance training on cardiorespiratory endurance in young (15.8 ± 0.8 yrs) male basketball players. Experimental group subjects (n=23) trained twice per week for 12 weeks using a variety of general free-weight and machine exercises designed for strength acquisition, beside ongoing regular basketball training program. Control group subject (n=23) participated only in basketball training program. Oxygen uptake (VO(2max)) and related gas exchange measures were determined continuously during maximal exercise test using an automated cardiopulmonary exercise system. Muscle power of the extensors and flexors was measured by a specific computerized tensiometer. Results from the experimental group (VO(2max) 51.6 ± 5.7 ml.min(-1).kg(-1) pre vs. 50.9 ± 5.4 ml.min(-1).kg(-1) post resistance training) showed no change (p>0.05) in cardiorespiratory endurance, while muscle strength and power of main muscle groups increased significantly. These data demonstrate no negative cardiorespiratory performance effects on adding resistance training to ongoing regular training program in young athletes.

Oxidative stress in young judokas: Effects of four week pre-competition training period

Background The effects of long-term exercise on steady-state dynamics of antioxidant defence system are not clear yet fully, and there is an evident lack of studies focused on combat sports. This study aimed to evaluate the parameters of oxidative stress in young judokas during four weeks pre-competition training period. Material/Methods: Changes of oxidative stress parameters (malondialdehyde, catalase, carbonyl and sulphydryl groups, and total antioxidant status) were studied during four week pre-competition training period on a sample consisting of 10 male judokas (age 20±1.3 years, sport experience 11±3.4 years). Results: The changes in all examined oxidative stress parameters showed no statistical significance. Results also suggested that well-developed anti-oxidant defence, particularly because of the superoxide dismutase activity, kept the amount of oxidized proteins unmodified. The explanation for this finding can be found in the facts that the subjects, although of young age, had a long training and competitive experience with the similar training programs and that they did not undergo rapid weight reduction. Conclusions: The obtained results suggest that four week pre-competition training period pattern had no effects on oxidative stress parameters in well-trained young judokas, and that natural antioxidant defences of the body responded adequately to complex training program.

Changes in the muscular outputs of young judoists during resistance exercises performed on unstable equipment: A case study

BackgroundResistanceexercisesunderunstableconditionshavegainedpopularityamongathletes.�Theaimofthestudywas� toinvestigatethechangesinmuscularoutputs�(peakpowerandvelocityofmovement)�duringbenchpressesand� squatsunderunstableconditionsincomparisontotheoutputsunderstableconditions. �:� Atotalof�20�participants,�dividedintotwogroups,�tookpartinthestudy.�Thefirstgroupconsistedof�9�top-lev- elyoungmalejudoists,�whilethesecondgroupconsistedof�11�students.�Alloftheexerciseswereperformedonce� 70%�ofone-repetitionmaximum�(1RM)�wasdetermined. � Results:� Theanalysisshowedasignificantreductioninmuscularoutputsduringsquatsunderunstableconditions�(the� BOSUball)�incomparisontostableconditionsforthegroupofjudoists.�However,�therewasnosignificantreduc- tioninmuscularoutputsduringthebenchpressesunderunstableconditions�(theSwissball)�comparedtothesta- bleflatbench.�Forthegroupofstudents,�theanalysisshowedasignificantreductioninmuscularoutputsduring� thebenchpressunderunstableconditionswhencomparedtothestableflatbench.�Inaddition,�forthisgroupthe� muscularoutputsweresignificantlylowerduringsquatsunderunstableincomparisontostableconditions. � Conclusions:� ThebenchpressasaresistanceexerciseperformedonaSwissballwithreducedtrainingloadcannotberecom- mendedasaneffectivetrainingmodelforjudoists.�Nevertheless,�thesquatwithreducedtrainingloadunderun- stableconditionsprovidedsufficientchallengestotheneuromuscularsystemandcouldbeincorporatedintotrain- ingprograms.

Heart rate recovery time in metabolically healthy and metabolically unhealthy obese children

ABSTRACT Background: Autonomic dysfunction is an emerging non-traditional cardiovascular risk factor that correlates with obesity, components of metabolic syndrome, as well as cardiorespiratory fitness. As a simple and validated index of autonomic balance, heart rate recovery (HRR) has been reported as a useful biomarker for predicting cardiovascular morbidity and mortality. Objectives: The aim of this study was to compare HRR in metabolically healthy vs. metabolically unhealthy obese children. Methods: A total of 56 obese children of whom 31 had metabolic syndrome were examined. All the participants underwent the multistage submaximal cycle ergometer test and HRR was determined one minute after the test. Results: The HRR was significantly lower (18.9 ± 3.7) in a group of metabolically unhealthy obese children compared to metabolically healthy obese children (24 ± 4.1) p < 0.001. Logistic regression analysis showed that reduction in HRR was also influenced by higher BMI. Conclusion: Our findings implicate the presence of the autonomic dysfunction as reflected by impaired heart rate recovery (HRR) in obese children with metabolic syndrome.

ANTIOXIDANTS AND THEIR IMPORTANCE DURING MUSCULAR EXERCISE: A REVIEW

Physiological levels of reactive oxygen species, as an essential part of the homeostatic milieu, are required for normal functioning of skeletal muscle. High levels of reactive oxygen species promote contractile dysfunction resulting in muscle weakness and fatigue, oxidative stress, apoptosis and necrosis of muscle cells. It is known that both resting and contracting skeletal muscles produce reactive oxygen species and reactive nitrogen species. The first suggestion that physical exercise results in free radical-mediated damage to tissues appeared in 1978. The newest researches investigate the mechanisms by which oxidants influence skeletal muscle contractile properties and explore how to protect muscle from oxidant-mediated dysfunction. Principal antioxidant enzymes include superoxide dismutase, glutathione peroxidase, and catalase. Numerous non-enzymatic antioxidants exist in cells within skeletal muscle fibers, the most abundant of which include glutathione, bilirubin, α-Lipoic acid , uric acid, and ubiquinones, or coenzyme Q (CoQ) andflavonoids. Dietary antioxidants are vitamins C- L ascorbic acid , vitamin A, retinol and their provitamins, carotenoids (especially β-carotene), vitamins E, tocopherol (especially a-tocoferol ), folic acid or folates. The usage of endogenous enzymatic and non-enzymatic antioxidants protects muscle from strong damaging effects caused by free radicals during acute exercise or longer term physical exercise. Scientific researches now confirm that the long-term use of antioxidants is safe and effective. The actual recommendation for physically active individuals is to ingest a diet rich in antioxidants.

Physical Activity in Adolescent with Mental Retardation: Is Adapted Basketball Training Adequate Stimulus to Improve Cardiorespiratory Fitness and Sport Skills Performance?

Summary The purpose of the study was to examine the effects of an adapted basketball training program on the cardiorespiratory fitness and sport skills performance of adolescents with mental retardation (MR). Fifty adolescents with mild MR who participated in this study were divided in two groups. Experimental group (n = 25; mean ± SD age: 15.7 ± 0.9 years) performed the adapted training program, four times per week during eight weeks. A control group (n = 25; mean ± SD age: 15.9 ± 0.8 years) followed ordinary physical education classes and continued with their normal lifestyle. Exercise testing included the six-minute walk test (6MWT), monitoring of heart rate frequency and sport skills performance test battery. Results showed a significant difference between groups pre- and post-treatment in 6MWT distance. The experimental group experienced a 10% increase in covered distance pre- to post-testing (p < 0.05), whereas controls had no significant changes in the same period. Conducted adapted training also resulted in significant improvement in examined sport skills performance. However, this kind and duration of experimental procedure did not result in significant differences in anthropometric variables and heart rate frequency. This study demonstrated that adapted basketball training is an adequate stimulus for improvement in cardiorespiratory fitness and sport skills performance of adolescents with mild MR. The advantage of this type of adaptive training program is that it does not require a large financial input, but only the engagement of a qualified and dedicated physical education professor.