Introduction. Timely detection of insulin resistance is of great importance and a number of indices have been developed for its evaluation, among which the homeostasis model assessment of insulin resistance index is the most commonly used in clinical practice. However, it can be calculated via two different models - homeostasis model assessment 1 and homeostasis model assessment 2. Most studies determine the cut-off values of the study population using the homeostasis model assessment 1, while recently most physicians use homeostasis model assessment 2 in everyday clinical practice. The aim of our study was to examine whether there was a difference in the values of homeostasis model assessment of insulin resistance and homeostasis model assessment of panceratic beta cells function calculated using these two models. Material and Methods. Laboratory findings of 42 patients who were diagnosed with glycemia and insulinemia were used in this study. Fasting and postprandial glycemia and insulinemia were used to calculate homeostasis model assessment indices using homeostasis model assessment 1 and homeostasis model assessment 2. Results. When comparing the values of the homeostasis model assessment of insulin resistance and homeostasis model assessment B indices, calculated via homeostasis model assessment 1 and homeostasis model assessment 2, we found a statistically significant difference (p < 0.001) which was also obtained when comparing the values of the homeostasis model assessment B index. Linear correlation analysis showed a significant positive correlation between the measured values of the homeostasis model assessment of insulin resistance (calculated via both models) and postprandial insulinemia at 120 minutes (p < 0.005). Conclusion. The results indicate that homeostasis model assessment 2 yields significantly lower homeostasis model assessment of insulin resistance and homeostasis model assessment B index values than when calculated by the homeostasis model assessment, which may be a stumbling block in the use of homeostasis model assessment index. It is necessary to pay attention which homeostasis model assessment model was used to define the cut-off values of these indices, and to use the same model in the diagnosis of insulin resistance in each patient in everyday clinical practice.
Introduction. Annual and periodized training protocols significantly affect the muscle adaptation in rowers. Considering that the main goal of the training period is increasing specific muscle strength and of detraining period increasing general strength and active rest, the aim of this study was to compare the strength of different muscle groups between training and detraining periods. Material and Methods. The study was conducted at the Department of Physiology, Faculty of Medicine Novi Sad, and it included 34 male and female rowers, 15 to 18 years of age. The muscle strength was measured using a Concept 2 DYNO dynamometer. The strength of the arm extensors and flexors, as well as the leg extensors was measured twice, at the end of the competition season (peak of performance) and before the beginning of the preparation season (after detraining). Results. A statistically significant decrease was found in absolute and relative muscle strength, flexor and arm extensor contraction rate, as well as relative leg extensor strength and contraction rate during the training and detraining periods (p < 0.05). No difference was found in the absolute leg extensor power between the two measurements (p > 0.05). Conclusion. Periodization of the annual training program in rowers has a higher impact on differences in the upper limb muscle adaptation, compared to lower limb muscles in terms of absolute strength.
ABSTRACT Introduction: A sedentary lifestyle is one of the biggest health problems of the 21st century. The role of the trainer in motivating the sedentary individual is crucial. Also, there is a growing accessibility to gyms today, especially outdoor gyms, as a novel way to motivate people to train. Objective: The aim of the study was to evaluate the impact of regular combined indoor and outdoor physical activity on anthropometric and functional parameters and the adoption of a more active lifestyle. Methods: The study included 45 participants between 18 and 56 years of age. They underwent 12 weeks of resistance training, focusing on chest presses and leg presses. Height, weight, bioelectrical impedance, chest and leg press one-repetition maximums, push-up and curl-up counts, and sit and reach were measured both before and after the 12-week training program. Results: After 12 weeks of training, male participants showed a significant increase in the percentage of skeletal muscle mass (p<0.05) and a significant decrease in the fat mass percentage (p<0.05). Female participants experienced a significant reduction in the fat mass percentage (p<0.05). Both groups were able to significantly increase their one-repetition maximums for the chest press (p<0.05) and leg press (p<0.05). Push-up and curl-up counts increased significantly after 12 weeks of training in both sexes, as did flexibility in both sexes. A year after the study, 80% of all participants were still training with a combination of indoor and outdoor physical activities. Conclusions: After 12 weeks of training, the body composition of both female and male participants had changed significantly. Twelve weeks of resistance training significantly increased strength and flexibility in both male and female participants. A well-thought-out training plan seems to be the key factor in motivating a beginner trainee to adopt a more active lifestyle. Level of Evidence IV; Case series.
Introduction. The difference between 24-hour daily energy intake and total daily energy expenditure determines whether we lose or gain weight. The resting metabolic rate is the major component of daily energy expenditure, which depends on many different factors, but also on the level of physical activity. The aim of the study was to determine anthropometric and metabolic parameters of athletes engaged in different types of training, to compare obtained results and to examine whether there are statistically significant differences among them. Material and Methods. The study included a total of 42 young male athletes divided into two groups. The first group included 21 athletes who were predominantly engaged in aerobic type of training, and the other group of 21 athletes in anaerobic type of training. Anthropometric measurements were taken and resting metabolic rate was assessed using the indirect calorimetry method. The results were statistically analyzed and the differences in parameters between the two groups were compared. Results. Statistically significant differences were established in total body mass, amount of fat-free mass and muscle mass, body mass index, as well as in the relative metabolic indices between two groups of subjects. Conclusion. The percentage of fat-free body mass has the greatest impact on the resting metabolic rate. The rate of metabolic activity of this body compartment is higher in athletes engaged in aerobic than in athletes engaged in anaerobic type of training.
In combat sports, competitors are separated into weight divisions, to create equality between the athletes. Consequently, rapid weight loss (RWL) is a common practice in combat sports. Although the methods used to induce RWL are similar among athletes, currently, there are limited data concerning the RWL methodologies used by sambo athletes. Therefore, this study aimed at determining RWL procedures among female sambo athletes. Participants in the study were top-level athletes competing at the World Sambo Championship held in Novi Sad. A total sample of 47 female sambo athletes, of whom 24 were seniors (27.3 ± 4 year/age, 1.61 ± 0.09 m/height, 61.8 ± 8.87 kg/weight) and 23 juniors (18.7 ± 0.8 year/age, 1.66 ± 0.07 m/height, 63.7 ± 12.1 kg/weight), were examined in the study. To determine RWL methods, data were collected through a standardized questionnaire. As a result, 88.7% of the female sambo athletes declared that they intentionally cut their weight before the competition. The most commonly used methods were gradual dieting, followed by sauna, fluid restriction, and skipping meals. The most considerable influence on the RWL strategies of athletes came from coaches and personal trainers, while physicians and dietitians were far less influential. The results obtained from this representative sample highlight the most common practices concerning weight cutting prior to competition among females. Therefore, there is a need to inform and educate both athletes and coaches about the potentially harmful effects of RWL in combat sports.
Abstract Vitamin D is known to affect the functions of pancreatic beta cells, but the effects of vitamin D deficiency on glucoregulatory mechanisms are still inconclusive. The aim of this study was to link vitamin D levels with parameters of insulin resistance and insulin secretion. The study included 70 male and female participants, 40 newly diagnosed patients with type 2 diabetes mellitus (T2DM) and 30 healthy controls. All participants were tested for fasting glucose, hemoglobin A1c, fasting insulin, vitamin D levels, and the HOMA indexes were calculated using HOMA2 calculator. Fasting glucose levels, insulinemia, hemoglobin A1c levels and HOMA IR were all significantly higher in the diabetic group (p<0.001), while vitamin D levels and HOMA S index were significantly lower (p<0.001). HOMA-B values did not differ between the two groups (p=0.31). Vitamin D levels moderately correlated with HOMA S and HOMA B indexes (r=0.466, p<0.001; r=0.394, p<0.001, respectively), whereas a negative correlation was found between vitamin D levels and HOMA IR (r=−0.285; p<0.001). Multiple regression analysis showed that vitamin D levels significantly predicted the values of HOMA B index (p=0.001), but they had no predictive value on HOMA IR (p=0.26). In conclusion, the group of newly diagnosed patients with T2DM showed significantly lower vitamin D values compared to the healthy control group. The connection between vitamin D, glucose levels, hemoglobin A1c and insulin secretion index underlines the role of this vitamin in glucoregulation.