Sofia, Bulgaria

National Sports Academy
Sofia, Bulgaria
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Arakchiyski Z.,National Sports Academy
Series on Biomechanics | Year: 2015

Interest is the development of method, which is based on a known step tests for determination of the indirect VO2 max and allow the calculation of PWC170. The aim of this study was to develop a mathematical model to quantify the external mechanical work in step test, enabling calculation of PWC170 using the classical Margaria Step Test, considering the rhythmicity of the test performance. The proposed model is based on several assumptions. Our basic assumption is that external work satisfactorily estimates the total mechanical work performed on the body and that the downward movement time of the legs is equally for all steps of every single test-step and the center of mass motion is uniformly accelerated. The results from comparison of calculated PWC170 with developed version of the equation for the total mechanical work, using the aerobic step test of Margaria and standard bicycle ergometer test are within 3%. The proposed modified method by which is achieved using the classical aerobic step test of Margaria for indirect determining of VO2 max and simultaneous determination of PWC170 is original, easy to perform and capable of wider application in laboratory and field conditions, substituting cycling tests. © 2015, Bulgarian Academy of Sciences. All rights reserved.

Trenev L.,National Sports Academy
Series on Biomechanics | Year: 2016

The basic thing at training and improving the technical skills in the sport of cricket is the throwing of the ball (bowling), which has its specifics and crucial role for achieving success during matches. The bowling in the sport of cricket requires competitors technical skills, as well as good physical, tactical, and psychological training. © 2016, Bulgarian Academy of Sciences. All rights reserved.

Avramov .,National Sports Academy
Series on Biomechanics | Year: 2016

High achievements in contemporary sports are hard to imagine without a well organised, planned and systemic perennial, scientifically substantiated education and training. Not least, sports medicine and related prophylaxis and recovery have a growing role due to the fact that sports traumatism has serious consequences for athletes since they deprive them, temporarily or for good, of the opportunity to compete. On 15-17 June 2014, at the National Handball Championship for Adolescents of up to 16 years of age, a survey was held in the city of Varna among 95 handballers aged 15-16 years on the types of injuries they suffered so far. It was found that the largest number of injuries were in the area of the knee followed by injuries in the ankle. This is probably due to the physical and technical preparation of players, on the one hand, and, on the other, to the larger number of matches played. We recommend trainers, along with the rehabilitation of the injuries suffered, to consider the causes for their emergence. © 2016, Bulgarian Academy of Sciences. All rights reserved.

Arakchiyski Z.,National Sports Academy
Series on Biomechanics | Year: 2015

This report is an attempt to summarize some results of biomechanical research into the pole vault. Phases of the vault, functions of the phases and mechanical principles are combined in an effort to give the coach some background information about the event, but also to elicit comments and suggestions for future research from coaches and athletes. For the purpose of this report the pole vault is subdivided into five distinct phases: the approach, the take-off, the first phase on the pole, the second phase on the pole, the flight phase. For analysis of the kinematics and the energetic parameters of the vaulter’s movement was used video computer system. A good look at the energy budget of any vault yields the following helpful information: the total energy prior to take-off gives an indication of the vaulter’s potential; the difference between energy before and after take-off gives an indication of the take-off efficiency; the efficiency of the energy transformation from kinetic energy to potential energy of the vaulter can be deducted from remaining kinetic energy at the maximum height of the vaulter’s center of mass; the net work done by vaulter is a complex indicator for an individual vaulter’s technique. ©2015. Bulgarian Academy of Sciences. All rights reserved.

Temelkova-Kurktschiev T.,National Sports Academy | Temelkova-Kurktschiev T.,Robert Koch German Medical Center | Stefanov T.,National Sports Academy
Experimental and Clinical Endocrinology and Diabetes | Year: 2012

Obesity and type 2 diabetes mellitus are multifactorial health threats caused by a complex interplay between genetic predisposition and the environment with dramatically increasing worldwide prevalence. The role of heritability in their etiology is well recognized, however, the numerous attempts made in order certain genetic variants determining individual susceptibility to be identified have had limited success, until recently. At present the advancements in human genetics and the utilization of the genome-wide association approach have led to the identification of over 20 genetic loci associated with, respectively obesity and type 2 diabetes. Most of the genes identified to date, however, have modest effect on disease risk suggesting that both diseases are unlikely to develop without the individual being exposed to obesity- and/or type 2 diabetes-promoting environment. Indeed, unhealthy lifestyle, characterized by physical inactivity and food overconsumption is an unequivocally established risk factor for obesity and type 2 diabetes. Numerous epidemiological studies and randomized controlled trials, on the other hand, have demonstrated that lifestyle modification is effective in obesity and type 2 diabetes prevention. Furthermore, gene-lifestyle interaction studies suggest that genetic susceptibility to obesity and type 2 diabetes may be partially or totally kept under control by healthy lifestyle or lifestyle modification and that lifestyle determines whether an individual is likely to develop the disease. Inherited factors, however, seem to influence individual response to a lifestyle intervention program and even the motivation for lifestyle change. Personalized interventions according to genotype may be, therefore, considered in the future. By then lifestyle modification targeting dietary change and increased physical activity may be recommended for successful obesity and type 2 diabetes prevention irrespectively of genetic susceptibility. © Georg Thieme Verlag KG Stuttgart - New York.

Bell D.R.,University of Wisconsin - Madison | Guskiewicz K.M.,University of North Carolina at Chapel Hill | Clark M.A.,National Sports Academy | Padua D.A.,University of North Carolina at Chapel Hill
Sports Health | Year: 2011

Context: The Balance Error Scoring System (BESS) is commonly used by researchers and clinicians to evaluate balance. A growing number of studies are using the BESS as an outcome measure beyond the scope of its original purpose. Objective: To provide an objective systematic review of the reliability and validity of the BESS. Data Sources: PubMed and CINHAL were searched using Balance Error Scoring System from January 1999 through December 2010. Study Selection: Selection was based on establishment of the reliability and validity of the BESS. Research articles were selected if they established reliability or validity (criterion related or construct) of the BESS, were written in English, and used the BESS as an outcome measure. Abstracts were not considered. Results: Reliability of the total BESS score and individual stances ranged from poor to moderate to good, depending on the type of reliability assessed. The BESS has criterion-related validity with force plate measures; more difficult stances have higher agreement than do easier ones. The BESS is valid to detect balance deficits where large differences exist (concussion or fatigue). It may not be valid when differences are more subtle. Conclusions: Overall, the BESS has moderate to good reliability to assess static balance. Low levels of reliability have been reported by some authors. The BESS correlates with other measures of balance using testing devices. The BESS can detect balance deficits in participants with concussion and fatigue. BESS scores increase with age and with ankle instability and external ankle bracing. BESS scores improve after training. © 2011 The Author(s).

Stefanov T.S.,National Sports Academy
Folia medica | Year: 2011

The prevalence of the metabolic syndrome (MetS), a cluster of central obesity, hyper/dyslipiemia, hyperglycemia, and hypertension is constantly increasing worldwide. Although, the exact mechanisms underlying the development of the MetS are not completely understood, modern lifestyle of physical inactivity and unhealthy nutrition, obesity, and their interaction with genetic factors are considered largely responsible. It has been convincingly demonstrated that the metabolic syndrome is associated with substantially increased risk for the development of type 2 diabetes mellitus, as well as, with increased cardiovascular disease (CVD) morbidity and mortality. The prevalence of obesity and type 2 diabetes in Bulgaria has dramatically increased in the last decades. For the same period CVD mortality in the country have also gradually increased and Bulgaria is nowadays among the countries with the highest macrovascular disease death rates in Europe. A number of epidemiological studies have demonstrated that the prevalence of the MetS and of its individual components has also increased during the last decades and is nowadays relatively high among the general population in Bulgarian and extremely high among high-risk individuals. Surprisingly, the prevalence of the MetS is also high among the low risk population in the country and most of its components that are independent predictors of CVD mortality are largely undiagnosed. Furthermore, the presence of the MetS is associated with history of myocardial infarction in the country. Although objective data is somewhat scarce, several studies have reported association of the low physical activity level and the unhealthy nutritional habits with the prevalence of cardiometabolic diseases among the Bulgarian population. Taking into account these observations it may be suggested that indeed the high metabolic syndrome prevalence that results as a consequence of unhealthy lifestyle is responsible for the extremely high CVD mortality rates in Bulgaria. Therefore, large-scale screening programmes should be undertaken within this population in combination with health prevention strategies promoting regular physical activity and improvement of nutritional habits.

Padua D.A.,University of North Carolina at Chapel Hill | Bell D.R.,University of Wisconsin - Madison | Clark M.A.,National Sports Academy
Journal of Athletic Training | Year: 2012

Context: Knee-valgus motion is a potential risk factor for certain lower extremity injuries, including anterior cruciate ligament injury and patellofemoral pain. Identifying neuromuscular characteristics associated with knee-valgus motion, such as hip and lower leg muscle activation, may improve our ability to prevent lower extremity injuries. Objective: We hypothesized that hip and lower leg muscleactivation amplitude would differ among individuals displaying knee valgus (medial knee displacement) during a double-legged squat compared with those who did not display knee valgus. We further suggested that the use of a heel lift would alter lower leg muscle activation and frontal-plane knee motion in those demonstrating medial knee displacement. Design: Descriptive laboratory study. Setting: Research laboratory. Patients or Other Participants: A total of 37 healthy participants were assigned to the control (n = 19) or medialknee-displacement (n=18) group based on their double-legged squat performance. Main Outcome Measure(s): Muscle-activation amplitude for the gluteus maximus, gluteus medius, adductor magnus, medial and lateral gastrocnemius, and tibialis anterior was measured during 2 double-legged squat tasks. The first task consisted of performing a double-legged squat without a heel lift; the second consisted of performing a double-legged squat task with a 2-in (5.08-cm) lift under the heels. Results: Muscle-activation amplitude for the hip adductor, gastrocnemius, and tibialis anterior was greater in those who displayed knee valgus than in those who did not (P < .05). Also, use of heel lifts resulted in decreased activation of the gluteus maximus, hip adductor, gastrocnemius, and tibialis anterior muscles (P < .05). Use of heel lifts also eliminated medially directed frontal-plane knee motion in those displaying medial knee displacement. Conclusions: Medial knee displacement during squatting tasks appears to be associated with increased hip-adductor activation and increased coactivation of the gastrocnemius and tibialis anterior muscles. © by the National Athletic Trainers' Association, Inc.

TO investigate the association of physical activity with insulin resistance and biomarkers of inflammation, coagulation, and fibrinolysis in a population at high risk for type 2 diabetes. A total of 778 subjects from the Risk factors in Impaired Glucose Tolerance for Atherosclerosis and Diabetes (RIAD) study aged 40-70 years were included in the present cross-sectional analysis. Participants classified as having low physical activity (PA) were more insulin resistant in comparison to participants with medium (P = 0.042) and high PA (P = 0.015). Individuals with high physical activity had a significantly lower leucocytes count than individuals with low PA (P = 0.027) and significantly lower hs-CRP and fibrinogen concentrations than individuals with medium (P = 0.011 and P = 0.021) and low physical activity (P = 0.04 and P = 0.007). Although a trend towards a decrease in plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) levels with increasing physical activity was present, significant differences were observed only between subjects with high and medium physical activity (P = 0.045 and P = 0.033). In multivariate regression analyses physical activity was an independent determinant of insulin resistance, leucocytes count, hs-CRP, and fibrinogen concentrations. CONCLUSIONs: Physical activity was independently associated with insulin resistance and biomarkers of inflammation, whereas only a tendency towards decreased concentrations of coagulation and fibrinolytic biomarkers with increasing physical activity was observed.

Physical inactivity and excessive food consumption play a major role in the etiology of obesity and type 2 diabetes mellitus (T2DM). The aim of the present study was to investigate the relationship of physical activity (PA) and eating behaviour with obesity and T2DM in citizens of Sofia, Bulgaria. A total of 511 randomly chosen participants completed a validated questionnaire concerning age, body height and weight, medical history, and motivation for a lifestyle change. The Baecke PA questionnaire and the Three Factor Eating Questionnaire were also completed. Body mass index (BMI) was significantly higher among subjects in the lowest compared with the middle (P = 0.002) and with the highest tertile of leisure time PA (P < 0.001), also between the lowest and the highest tertile group of sport PA (P = 0.001). BMI differed significantly in the highest vs. the middle (P = 0.04), as well as vs. the lowest (P= 0.017) tertile of uncontrolled eating behaviour. The prevalence of T2DM was significantly greater in the lowest vs. the middle (P = 0.027) and the highest (P = 0.02) tertile of leisure time PA. In a multiple regression analysis both leisure time PA and uncontrolled eating were independently associated with BMI (beta = -0.13, 95% CI -1.83 to -0.11, P = 0.03 and beta = 0.32, 95% CI 0.23 to 0.44, P < 0.001). We found a strong inverse relationship between the level of PA during leisure time (including sport), BMI, and the prevalence of T2DM. Uncontrolled eating behaviour was also found to have a significant effect on BMI.

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