Oxidative stress is a state of disturbed balance between reactive oxygen species and reactive nitrogen species on the one hand and on the other antioxidant protection. Increased oxygen consumption during exercise could be the cause of oxidative stress. Th e aim of this study was to monitoring the parameters of oxidative stress and components of antioxidative defense during the training process, establish oxidative status basketball players in standby mode after the load caused by two types of aerobic training - continuous aerobic and interval (HIIT) training. As part of a longitudinal experimental study selected a sample of 12 basketball players during the training process. All respondents were female, age 14 to 27 years. Th e study was conducted in preparatory stage. Oxidative status was determined through the index of lipid peroxidation (measured as TBARS), nitric oxide (NO) in the form of nitrite (NO2) levels of superoxide anion radicals (O2) and hydrogen peroxide (H2O2), while the activity of the enzyme protection from oxidative damage was determined through superoxide dismutase (SOD), catalase (CAT) and reduction glutathione (GSH). Th e group analyzed in relation to the type of the training intervention was signifi cantly diff erent from the results in the test in the parameters of NO and TBARS. When the enzyme activity of protection against oxidative damage statistically signifi cant diff erences between groups arise for CAT and GSH. Th e emergence of oxidative stress is not necessary phenomenon of high aerobic training load, training leads to the maintenance of physiological balance in the body.

Previous research suggests that there is no single marker that would be su ciently reliable indicator of muscle damage and overtraining. Monitoring several physiological indicators can lead to the desired response. Among them is the creatine kinase serum as one of the best indicators of muscle damage accompanying physical activity. In addition to other properties, it is a direct indicator of muscle damage and overtraining. e aim of this paper is the organization of knowledge published in relevant scienti c journals that directly concern creatine kinase and its relation with other markers, as well as the limit of its use. By measuring the level of creatine kinase before and a er exercise, the existence of myopathy without muscle biopsy can be predetermined, which is one of the most important functions of this serum. In the future, research should include other factors that indicate muscle damage and overtraining, their synergistic activity, and new ndings in assessing transient muscle damage due to physical activity.

The World Health Organization recommends infants should be exclusively breastfed for the first six months of life. Various factors can affect the maintenance of lactation. Increased physical activity and stress are thought to negatively affect breastfeeding success. The aim of this case study was to examine the effect of high serum creatine-kinase (CK) values and the success of breastfeeding after sports competition. It is assumed that continuous aerobic exercise is a stress for the body that can have a negative impact on lactation and extended breastfeeding. Methods. The level of acute muscle damage (AC) was measured before and after the competition in order to confirm continuous exposure to aerobic exercise. Results. After the competition, elevated serum creatine-kinase levels were noted. Prolactin and TSH values remained within optimal values. Conclusion. Several months of preparation for the competition had an impact on increasing acute muscle damage (AC) after the competition. No negative effect of continuous aerobic exercise on breastfeeding success was observed in this case study.

Tokom intenzivnog vežbanja, naročito profesionalnih sportista, mišići se privremeno zamaraju i mogu da oslabe, te su nekad potrebni dani da bi se mišić oporavio. Cilj ove studije bio je da se praćenjem biohemijskih parametara oštećenja mišića u toku trenažnog procesa utvrdi zamor mišića košarkašica nakon opterećenja izazvanog dvema vrstama aerobnog trening. U sklopu longitudinalne, eksperimentalne studije izabran je uzorak od 12 košarkašica, životnog doba od 14 do 28 godina, sa sportskim stažom u trajanju od najkraće pet godina. Ispitivanje je sprovedeno u pretakmičarskoj fazi, gde su ispitanice imale dva treninga dnevno. Razmak između dva uzorkovanja bio je 14 dana, gde je prvo uzorkovanje rađeno pre i posle kontinuiranog aerobnog treninga, odnosno drugo uzorkovanje pre i posle intervalnog aerobnog (HIIT) treninga. Parametri koji su određivani su kreatin kinaza, mioglobin, troponin I i laktati. Analizirane grupe u odnosu na vrstu trenažne intervencije statistički se značajno razlikuju u odnosu na rezultate u testu u svim parametrima (p=0.05), osim u troponinu I, kako unutar treninga (pre i posle svake trenažne intervencije), tako i u odnosu na vrstu treninga. Primenom HIIT treninga ne narušava se homeostaza organizma više nego kod kontinuiranog aerobnog treninga, a benefiti takvog vežbanja su mnogostruki.