Vitamin D and Cortisol as Moderators of the Relationship Between Testosterone and Exercise Performance in Adolescent Male Athletes.

PURPOSE: Reported associations between vitamin 25(OH)D and exercise performance are equivocal, perhaps due to complex interplay with cortisol and testosterone. In this study, the authors investigated serum 25(OH)D and cortisol as moderators of the testosterone relationship with exercise performance in adolescent male athletes. METHODS: A total of 88 ice hockey players were assessed for serum 25(OH)D, cortisol, testosterone, body composition, and exercise performance, based on countermovement jump power and muscle torque. The authors tested independent relationships, before examining complex interactions via moderated regression analyses. RESULTS: Most athletes (62.5%) exhibited a suboptimal (20-30 ng·mL-1) serum 25(OH)D concentration, whereas 9.1% of athletes were deficient (<20 ng·mL-1). Serum 25(OH)D was not related to performance when controlling for testing year, age, and fat mass. Further modeling revealed a significant hormonal interaction. Specifically, in low-25(OH)D subjects, testosterone predicted countermovement jump power at a high (ß = 7.10, effect size = .43, P < .01), but not low (ß = -3.32, effect size = -.20, P = .09), cortisol concentration. CONCLUSIONS: Serum 25(OH)D was a poor predictor of exercise performance, but it did moderate (with cortisol) the testosterone link to muscle power. Notably, this relationship emerged among individuals with a 25(OH)D concentration (∼22 ng·mL-1) approaching the deficiency cutoff. Viewing 25(OH)D as a moderating, rather than dose responsive, variable could help explain equivocal cross-sectional associations.

[Eating disorders - diagnosis and characteristics]. / Zaburzenia odzywiania ­ rozpoznanie i charakterystyka.

Eating disorders are characterized by eating and appetite disorders, which develop on a mental basis. Currently, there is a rapid increase in the frequency of these disorders, especially among children and adolescents. Eating disorders include anorexia nervosa, bulimia nervosa and EDNOS, which include a dozen or so disorders, but this group is still expanding. Eating disorders are characterized by the highest mortality rate among all mental illnesses. They mainly affect adolescents and young adults as well as the female sex, however, there are more and more cases among men and people from other age groups. Anorexia nervosa is the conscious reduction of food intake in order to reduce body weight. In this disorder there is abnormal body image, underweight and fear of weight gain. According to the American Psychiatric Association, there are two types of anorexia nervosa - restrictive (limiting) and bulimic (laxative). Bulimia nervosa is characterized by abnormal food intake (overeating) and co-occurrence of compensatory methods aimed at limiting the absorption of consumed food. These methods include: provoking vomiting, excessive physical effort, taking diuretics and laxatives. Among the eating disorders we also distinguish eating disorders not defined otherwise (EDNOS). This is a group of diseases in which pathological eating behaviour occurs, but they do not meet the diagnostic criteria of anorexia or bulimia. The diagnosis of eating disorders is difficult not only because of the lack of specialists dealing with this subject, but also because of the lack of public awareness of these diseases. That is why it is so important to educate both medical staff and the general public about eating disorders.

Nutrition knowledge of people with eating disorders

Background: Eating disorders are an increasingly common health problem that is a major therapeutic challenge. For many years, the basic form of therapy used to be psychiatric and psychotherapeutic treatment, but now it is postulated that the dietetician should also be part of the therapeutic teams. Objective: The main purpose of the study is to assess nutrition knowledge of people with eating disorders with consideration to their age, place of living, education, BMI, type of disease, participation in dietary consultations and in therapy. Material and methods: Nutrition knowledge of the respondents was assessed by means of an author's survey questionnaire. The questionnaire was published in one of the social portals in the "Eating disorders ­ tackling" group gathering people with different types of eating disorders. The survey questionnaire consisted in 33 questions. Arithmetic mean and standard deviation for the number of correct answers provided by the respondents by the selected criteria. Results: In terms of age, the least nutrition knowledge was attributable to the persons below 20 years of age (25.24 points in average). When considering the place of living, the least nutrition knowledge was revealed among the subjects living in medium cities (between 20 and 100 thousand of population) i.e. 25.31 points. In terms of education, the least nutrition knowledge was recorded in people with vocational education (24.83 points). When classifying the respondents by BMI, the highest average score was gained by the respondents with normal body mass index (BMI) (26.42 points). Conclusions: The study on the level of nutrition knowledge among the people with eating disorders demonstrated that this knowledge was selective and insufficient to provide rational nutrition. It aimed at teaching the rules of healthy lifestyle and nutrition and thorough discussing of all nutrients, their functions and effect on the body.

The Factors Influencing the Concentration of Histamine in Jarred Baby Foods Containing Fish, Considering Evaluation of Daily Histamine Intake.

Histamine is one of the biogenic amines produced naturally in the human body, but also in foods, especially those rich in protein. Exogenous and endogenous histamine is subject to degradation in vivo, but in the case of sensitive groups, including children, these degradation processes may be less intense, resulting in adverse health effects from histamine excess. The aim of the study was to determine the histamine content in jarred baby foods containing fish, taking into account the selected product characteristics and storage conditions. The study included 140 meals with added fish, intended for infants and young children, from 5 leading manufacturers available in Poland. The infant meals were analyzed on the day of opening, after 24 h and 48 h of storage in the refrigerator and at room temperature. Histamine concentration was determined by ELISA. The THQ was calculated from the EDI values for histamine. Histamine was present in all analyzed baby foods. On the day of opening, the products had a lower content of this monoamine (Me = 2.59 mg/kg), which increased systematically during storage. Samples taken at 2 °C after 48 h showed an average histamine content of 4.4 mg/kg, while products stored at 22 °C at the same time showed a 1.8-fold higher concentration of this monoamine (Me = 7.9 mg/kg). Dishes containing tuna and sea fish had higher histamine levels on average than those containing pollock. The storage conditions of the children's food had a significant effect on histamine concentration. The level of histamine in baby foods was related to the amount and type of fish in certain products. The results indicate the need for increased awareness of the risks associated with histamine, especially in a group of people with increased sensitivity to this amine, which may include infants and young children.

The Impact of Health Education on the Quality of Life of Patients Hospitalized in Forensic Psychiatry Wards.

PURPOSE: An original health education program, developed for a group of patients of forensic psychiatry wards, was the basis for conducting a study on the impact of educational influences on the quality of life of patients long-term isolated from their natural environment. The main aim of the study was to answer the question: Does health education affect the quality of life of patients in forensic psychiatry wards and is educational activity effective? METHODS: The study was conducted at the State Hospital for Mental and Nervous Diseases in Rybnik, Poland, in the forensic psychiatry wards, and lasted from December 2019 to May 2020. During the study, patients gained knowledge in the field of broadly understood health education. The study group consisted of 67 men, aged 22-73, diagnosed with schizophrenia. The method of double measurements (before and after the health education cycle) was applied, using the WHOQOL-BREF scale of quality of life and the first author's questionnaire of patients' knowledge, from the educational program used. RESULTS: Health education does not significantly affect the overall quality of life of patients staying in forensic psychiatry wards, but it does affect their somatic condition. The proprietary health education program is effective because the patients' knowledge has significantly improved. CONCLUSIONS: The quality of life of interned patients with schizophrenia is not significantly related to educational activities, however, psychiatric rehabilitation through educational activities effectively increases the level of patients' knowledge.

Reference Values of the Forearm Tremor Power Spectra for Youth Athletes.

The aim of the study was to determine reference graphs of power spectral density functions of forearm physiological tremor and to compare their parameters in the male and female population of young athletes from various sports. One hundred fifty-nine (159) female (15.7 ± 2.1 years, 59.8 ± 8.1 kg, 169.1 ± 7.5 cm) and 276 male (16.4 ± 1.9 years 72.7 ± 10.3 kg and 180.9 ± 8.7 cm) youth athletes participated in the study. Forearm tremor was measured accelerometrically in a sitting position. Power spectrum density (PSD) function was calculated for each individual tremor waveform. Because of right skewness of power distribution, the PSD functions were subjected to logarithmic transformation. Average log-powers in low (2-4 Hz) and high (8-14 Hz) frequency ranges and mean frequencies in those ranges were analyzed. Tremor log-powers for male were greater than for female athletes (p < 0.001), while frequencies of spectrum maxima did not differ from each other. Frequencies of spectrum maxima correlated (p < 0.001) with age (r = 0.277 and 0.326 for males and females, respectively). The obtained reference functions may be utilized in order to quantify and assess tremor size and its changes evoked by stress and fatigue, which can be applied for selection and training monitoring in sports, but also in medicine for detection and diagnosis of pathologic tremor in young individuals.

Type D Personality and Health Behaviors in People Living with Obesity.

BACKGROUND: Considering that health behaviors and personality traits play an important role in the formation of health attitudes, the main objective of this study was to evaluate the relations that occur between type D personality and health behaviors in a group of obese patients. METHODS: 443 adult patients with BMI ≥ 30 kg/m2, who had been hospitalized in selected hospital facilities in the Silesian Voivodeship (Poland), participated in the study. Respondents completed three standardized questionnaires-the Multidimensional Health Locus of Control Scale, version A (MHLC-A), the Inventory of Health Behaviors (IZZ), and the Type D Scale (DS-14). RESULTS: Patients with type D personality were characterized by the least effective mental attitudes and preventive behaviors, and differed significantly from the other personality types (intermediate and non-type D). Type D personality increased the risk of initiating improper health behaviors by more than five times. Regarding the sense of health control, patients with type D personality had significantly lower scores for the Internal Dimension subscale (21.3 ± 3.1) and higher for the Powerful Others Dimension subscale (24.0 ± 2.6), compared to patients with intermediate and non-type D personality. Proper health behaviors correlated with an internal sense of health control; the strongest correlation, defined as a medium, was with Preventive Behaviors (R = 0.42; p < 0.0001). CONCLUSIONS: Type D personality was associated with poorer attitudes towards health. Among obese respondents with a type D personality, there was a significantly higher prevalence of those who believed that their health status was a consequence of chance events.

Drunkorexia - knowledge review. / Alkoreksja ­ przeglad wiedzy.

Eating disorders are often accompanied by a lack of ability to manage emotions. Drunkorexia is a phenomenon that occurs mainly among a group of students. This disorder is characterized by significant dietary restrictions and excessive physical activity in order to be able to consume more alcohol without fear of weight gain. It is attributed to peers pressure, the popularisation of a slim figure and the desire to increase the state of intoxication. Women are more likely to report experiencing drunkorexia along with other eating disorders. Like any eating disorder, drunkorexia can lead to serious health consequences, but also increases the risk of violence, sexual assault and car accidents. Drunkorexia requires treatment for alcohol dependence and correction of inappropriate eating habits. Drunkorexia is a relatively new term and requires the development of diagnostic criteria and strategies to help people struggling with this disorder. Drunkorexia should be distinguished from alcohol use disorder and other eating disorders. It is necessary to spread knowledge about this type of behaviour, its consequences and education about coping with stress.

Public Vaccination Reluctance: What Makes Us Change Our Minds? Results of A Longitudinal Cohort Survey.

The paper presents a longitudinal cohort survey on the public acceptability of COVID-19 vaccination and real vaccination levels. A survey on a representative sample of adult Polish citizens (n = 1066) was conducted in June 2020 and, one year later, the same group was approached to compare the hypothetical declarations with the real vaccination decisions (n = 438). A significant part of the group that declared reluctance and hesitation toward COVID-19 vaccination before that vaccination was available actually got vaccinated or plans to get vaccinated. Those respondents were asked about the reasons for changing their attitudes. Among the previously vaccine-reluctant individuals, the main reasons included concern about their health and safety (50%) and their desire to travel (26.6%). Vaccine-hesitant individuals also indicated health and safety as their primary concern (69%), as well as the pursuit of herd immunity and a notion of common social safety (12.6%). The main factors helping to increase vaccination acceptance are based on a self-centered pursuit of safety and freedom from restrictions. The survey results may help to prepare a more effective vaccination campaign.

The Level of COVID-19 Anxiety among Oncology Patients in Poland.

Cancer patients tend to have a high psychological burden. Half of cancer patients suffer from severe affective disorders and anxiety disorders, while one-third struggle with mild forms of these. The COVID-19 pandemic is damaging the mental health of the population due to social restrictions. A growing number of studies note the role of COVID-19 anxiety in the health and quality of life of cancer patients. The purpose of this study is to estimate the level of COVID-19 anxiety among oncology patients and to test the utility of the FCV-19S scale in a population study of cancer patients. The study included 600 respondents (300 oncology patients and 300 control subjects not undergoing oncological treatment). The FCV-19S scale and the GAD-7 scale were used in the study. The results were interpreted according to the following verbal scale: 76-100%, high anxiety; 56-75%, moderate anxiety; 26-55%, low COVID-19 anxiety; <25%, no COVID-19 anxiety. In the analysis of the GAD-7 questionnaire results, the mean score obtained was 8.21 (min. 0; max. 21; SD 5.32). For 81% of respondents in the group of oncology patients, the total score indicated the presence of anxiety symptoms with varying degrees of severity; in the control group, this proportion was 55% of respondents. The FCV-19S scale score as a percentage was 57.4% for oncology patients, indicating a moderate level of fear of the SARS-CoV-2 virus, and 30.3% for the control group, indicating a low level of fear of the SARS-CoV-2 virus. One-fifth of oncology patients were afraid of losing their lives due to the SARS-CoV-2 virus; in the control group, this proportion was 13% of respondents. Oncology patients were characterized by a higher prevalence of sleep disturbance than control group respondents, which was associated with greater anxiety. The study, therefore, shows that oncology patients have moderate levels of anxiety associated with the COVID-19 pandemic, and non-oncology patients show lower levels of anxiety.

The attitude of Polish consumers toward food irradiation as one of the methods of food preservation.

Background: Food irradiation is one of the methods of food preservation. Unfortunately, despite many opinions from national and international organizations that confirm the safety of the irradiation technique, the irradiated food market is slowly developing, which is particularly noticeable in European countries, including Poland. Objectives: The main objective of this study was to determine the attitude of Polish consumers toward irradiated food and to find out whether familiarizing the respondents with educational materials on the irradiation technique would change their attitudes. Material and methods: In response to the objective of the study, an online survey (with the presentation of educational materials) was conducted with 609 respondents living in the Silesian Voivodeship, Poland. A specially prepared author's questionnaire was used, containing questions relating to: sociodemographic data, food preservation, food irradiation. An integral part of the survey was a multimedia presentation containing information about the food irradiation process. Results: A low level of knowledge about food irradiation was found--90.31% (n = 550) of the respondents had never heard of this method of preservation before. The percentage of respondents with a positive attitude toward radiation-preserved products increased significantly after providing informative material, from 6.20 (n = 38) to 67.16% (n = 409). The final attitude of the respondents toward irradiated food varied and depended on age, education and place of residence-positive attitudes toward irradiation predominated among those who were young (<30 years old), had a higher education and lived in cities >100,000 inhabitants. Educational materials also had a significant impact on consumers' interest in purchasing irradiated food-the percentage of people declaring a willingness to purchase this type of product increased from 19.20 (n = 117) to 59.30% (n = 361). Almost 60% of the respondents were willing to purchase irradiated foods. Women, on average, were more likely to be interested in purchasing irradiated food compared to men. Conclusions: The survey indicates that irradiated food could be commercially introduced in Poland, but on the condition that an effective educational program is planned.

The digit ratio (2D:4D) and testosterone co-predict vertical jump performance in athletic boys: Evidence of organizational and activational effects of testosterone on physical fitness.

The digit ratio (2D:4D) is a negative correlate of boy's physical fitness, and thought to arise from organizational effects of prenatal testosterone on different bodily systems. During human ontogeny, activational effects of testosterone on body size and strength offers another pathway to physical fitness. We tested these hypotheses by examining the organizational and activational effects of testosterone on vertical jump performance in athletic boys. Using a cross-sectional design, 173 boys (aged 9 to 18 years) were tested for standing height, body mass, body fat, fat-free mass, weekly training activity, training history, salivary testosterone and cortisol, R2D:4D, L2D:4D, and right-left 2D:4D (Dr-1), and vertical height in 3 different countermovement jump (CMJ) tests. A generalized additive model was employed to delineate age-related trajectories and predict CMJ performance. Our models yielded significant non-linear increases (or changes) in body size, current hormone concentration, training outcomes, and CMJ performance with chronological age. All 2D:4D measures were age invariant. The R2D:4D and testosterone were significant non-linear predictors of CMJ height with (R2 = 66.2%) or without (R2 = 54.3%) covariates, whereby a higher current testosterone concentration (up to a certain level) and a lower or higher R2D:4D were linked to better performance. The L2D:4D and Dr-1 had no predictive value. In conclusion, the R2D:4D and testosterone were co-predictors of CMJ height among athletic boys, with non-linear performance effects that differed in timing, tempo, and direction. Our findings confirm that testosterone can regulate a simple measure of boy's physical fitness through both an activational and organizational pathway.

Depressive disorders among long-term care residents in the face of isolation due to COVID-19 pandemic. / Zaburzenia depresyjne wsród pensjonariuszy osrodka opieki dlugoterminowej w obliczu izolacji spowodowanej pandemia COVID-19.

OBJECTIVES: The main aim of this study was to assess the effects of social and familial isolation due to COVID-19 on the mental well-being of patients staying in a residential medical care facility and evaluation of the effectiveness of therapeutic measures. METHODS: The study was conducted among the patients of a residential medical care facility (58 patients). A short form of the Geriatric Depression Scale (GDS) was used to assess the severity of depressive disorders. The number of medical and psychological interventions during the individual months of isolation was also compared. RESULTS: In February 2020, when there was no isolation, 87.9% of the study group did not suffer from depression compared to 72.4% during the period of full isolation. After introducing controlled methods for contacting loved ones, the number of individuals with no depressive symptoms increased again. A mean of 1.76 medical and 0.23 psychological interventions per one patient were conducted during the period of full isolation. CONCLUSIONS: The number of medical and psychological interventions was higher during the period of full isolation compared to months without compulsory isolation due to COVID-19. After the introduction of full isolation, the scores in the GDS were significantly higher, which means that the residents were at a higher risk of depressive disorders than in the months without isolation.

Ambulophobia as a Specific Phobia-Defining the Problem Among Patients of Long-Term Care Facilities in Poland.

Background: Ambulophobia is a type of specific phobia that involves a fear of walking. This phobia mainly affects older people, who prefer not to leave their bed or home to avoid walking on uneven surfaces and reduce the risk of falling. The problem seems to be very important in terms of public health and the organization of long-term care, as Poland has one of the highest rates of elderly population growth. Objectives: The aim of the study was to determine the prevalence of ambulophobia among patients of long-term care facilities in Poland and to identify factors increasing the risk of this specific phobia in the study group. Material and Methods: The study was conducted between January and July 2021. Data collected from 379 patients of 16 long-term care facilities located in Poland were analyzed. The study used the diagnostic criteria for specific phobias according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, and standardized questionnaires such as MMSE, GDS-16, DOS and ADL. The χ2 test was used to test the significance of differences (p = 0.05). Results: The prevalence of ambulophobia in the study group was 30.1%. Ambulophobia significantly more often concerned the female sex (37.7%) and people over 70 years of age (42,1%). Factors such as depression, Parkinson's disease, orthostatic hypotonia, a history of falling or being a witness to another person falling, and disability of at least a moderate degree increased the likelihood of ambulophobia. Conclusions: Based on the obtained results, it was found that the protective factors in the development of ambulophobia are male sex, younger age, high independence, fewer drugs used per day and no previous falls or seeing another person fall.

Feelings Related to the COVID-19 Pandemic Among Patients Treated in the Oncology Clinics (Poland).

Background: The number of cancer patients is constantly growing. Both WHO and IARC report that this number may reach up to 24 million new diagnosed cases in the next two decades. The proposed treatment and especially the diagnosis can have a significant impact on an individual's approach to the disease, as well as on the patient's quality of life. Objectives: The study aimed to assess the quality of life, feelings, and fear of cancer-treating oncological patients, before and during the COVID-19 pandemic. Material and Methods: The study used the standardized WHOQOL quality of life questionnaire in a shortened version, the COVID-19 fear scale (FCV-19S), and the AIS disease acceptance scale (in terms of cancer-related sensations). The questionnaire survey was conducted among patients of cancer clinics (Poland). The study was conducted in two stages-before the COVID-19 pandemic (May 2019) and during the COVID-19 pandemic (May 2020). Data from 450 correctly completed questionnaires were analyzed statistically. The obtained data were statistically processed using the Kruskal-Wallis and Mann-Whitney U test (p = 0.05). Results: Among the surveyed patients of the cancer clinic, the quality of life during the COVID-19 pandemic decreased by 2%, compared to the period before the pandemic. The frequency of negative feelings associated with cancer increased during the COVID-19 pandemic-by 11% more men, and 4.4% of women determined the frequency of negative feelings to be 2-3 times a week. The level of fear associated with COVID-19 was moderate (57.1%), with women having a higher level of fear (12.5% higher than men). Conclusion: The development of the epidemic is very important in terms of public health. COVID-19 should be considered as one of the factors that bring about sudden changes in the mental health of the population, which may result from the dynamic development of this disease, dramatic media coverage, and own experiences. It has been shown that the sudden appearance of such a large stressor causes a decrease in patients' quality of life and an increase in negative feelings associated with chronic disease.

Nutritional Therapy in Persons Suffering from Psoriasis.

Psoriasis is a chronic inflammatory skin disease. Immunological, genetic, and environmental factors, including diet, play a part in the pathogenesis of psoriasis. Metabolic syndrome or its components are frequent co-morbidities in persons with psoriasis. A change of eating habits can improve the quality of life of patients by relieving skin lesions and by reducing the risk of other diseases. A low-energy diet is recommended for patients with excess body weight. Persons suffering from psoriasis should limit the intake of saturated fatty acids and replace them with polyunsaturated fatty acids from the omega-3 family, which have an anti-inflammatory effect. In diet therapy for persons with psoriasis, the introduction of antioxidants such as vitamin A, vitamin C, vitamin E, carotenoids, flavonoids, and selenium is extremely important. Vitamin D supplementation is also recommended. Some authors suggest that alternative diets have a positive effect on the course of psoriasis. These diets include: a gluten-free diet, a vegetarian diet, and a Mediterranean diet. Diet therapy for patients with psoriasis should also be tailored to pharmacological treatment. For instance, folic acid supplementation is introduced in persons taking methotrexate. The purpose of this paper is to discuss in detail the nutritional recommendations for persons with psoriasis.

Assessment of the Risk of Depression in Residents Staying at Long-Term Care Institutions in Poland During the COVID-19 Pandemic Depending on the Quality of Cognitive Functioning.

Background: The development of the COVID-19 pandemic has prompted the implementation of many procedures to safeguard against further increases in illness. Unfortunately, this has drastically reduced residents' contact with their families, which has increased feelings of loneliness and isolation. This is particularly difficult in long-term care facilities, where the risk of developing depression is higher than in the general population. Objectives: The aim of the study was to assess the risk of depression among the residents of long-term care institutions in Poland during the COVID-19 pandemic and to determine the relationship between the risk of depression and the occurrence of cognitive impairment in the study group. Methods: The study included 273 residents from long-term care institutions in Poland. The risk of depression was determined based on an originally designed questionnaire. The cognitive state of the subjects was assessed using the screening test Mini-Mental State Examination (MMSE). Both the depression risk assessment and the MMSE test were conducted twice: in March and December 2020. Results: In March, severe dementia was present in 28.2% of the residents and normal MMSE scores were observed in 16.1% of the subjects; in December, the prevalence of severe dementia increased to 31.1% and that of normal scores decreased to 10.3%. In March, no participant was found to be at high risk of depression and moderate risk was observed in 14.3% of the subjects; in December, 2.6% of the residents had a high risk score and 45.4% had a moderate risk score. Statistical analysis revealed that higher MMSE scores correspond with a higher risk of depression. Conclusion: A higher risk of depression was observed with the development of the pandemic. Residents with cognitive impairment were characterised by a lower risk of depression compared to individuals with normal MMSE scores. During the study, progression of cognitive impairment was observed in the residents.

Gender differences and relationships between upper extremity muscle strength, lower limb power and shuttle velocity in forehand smash and jump smash in badminton.

PURPOSE: The aim of the study was to investigate the relationships between shuttlecock velocity during a badminton forehand smash with and without jump (VmaxWJ and VmaxNJ), strength of upper limb muscles, vertical jump height and to analyze differences in these parameters for each gender. METHODS: The study examined members of the Polish National Badminton Team seven women and seven men. A special torque meter was used to assess the strength of the upper limb muscles. Vertical jumps were performed on an AMTI force plate. Shuttlecock velocity was measured using Vicon motion capture system. RESULTS: Differences between the right and left limbs were observed in all muscle groups except shoulder flexion for both genders. The results of all measured parameters: torques, height of countermovement and spike jump (HACMJ, HCMJ, HSPJ), VmaxWJ and VmaxNJ, were greater for men than for women. No statistically significant differences were found between VmaxWJ (men: 83.27 ± 4.83 m/s; women: 67.57 ± 4.21 m/s) and VmaxNJ (men: 84.19 ± 6.05 m/s; women: 69.70 ± 6.53 m/s) within the same gender. Positive correlations were found between both HCMJ and HSPJ regarding VmaxWJ in men; the height of shuttlecock impact in jump smash (HWJ) and HSPJ in women; proving the importance of jumping ability in badminton. Negative correlations were found between HWJ and VmaxWJ for both genders. CONCLUSIONS: The jump before smash is not used in order to hit the shuttle from the highest point, but to gain time to correctly prepare the phase of stroke while being in the air.

Accelerometer profile of motion of the pelvic girdle in butterfly swimming.

PURPOSE: The aim of the study was to develop a method to measure and analyse kinematics of movement of the pelvic girdle in butterfly swimming in order to support training of technical skills. METHODS: A device for recording triaxial accelerations and triaxial rotational angular velocities was mounted on the dorsal part of the pelvic girdle of athlete. The measurements were performed in ten elite butterfly swimmers (age: 23.1 ± 3.7 years, body height: 187.6 ± 4.3 cm, body mass 83.4 ± 6.33 kg). The task of the athlete was to swim one length of short course pool at maximal intensity. Individual mean graphical and numerical profiles of the kinematics of the movement of the pelvic girdle was computed, within the average cycle based on five consecutive cycles. RESULTS: Statistical analysis of numerical individual parameters of profiles of the athletes studied revealed statistically significant differences between the swimmers. Statistically significant correlations were also found between personal best times in 50 m swimming (r = -0.76, p < 0.05) and 100 m swimming (r = -0.76, p < 0.05) and duration of the part of the cycle connected with the decline in velocity from maximum translational motion velocity obtained during propulsion with the upper and lower limbs to minimum value of the velocity obtained before the beginning of propulsion only with the lower limbs. CONCLUSION: The proposed measurement method, presentation and analysis of the profile of the pelvic girdle motion in butterfly swimming represents a good tool for fast and effective qualitative and quantitative biomechanical evaluation of movement technique components.

Changes of Strength and Maximum Power of Lower Extremities in Adolescent Handball Players During a Two-year Training Cycle.

The aim of the study was to investigate changes of strength and power of the lower extremities in adolescent handball players during a two-year training cycle. Thirty-one male handball players (age 16.0 ± 0.2 years, body mass 81.4 ± 9.7 kg, body height 188.2 ± 6.4 cm) took part in this study. All tests were conducted three times at the beginning of a one-year training programme. The maximum joint torque (JT) of flexors and extensors of the elbow, shoulder, hip, knee and trunk was measured under static conditions. Power of lower extremities was assessed with a repeated sprint ability (RSA) test on a cycloergometer and jump tests: akimbo counter-movement jump (ACMJ), counter-movement jump (CMJ) and spike jump tests on a force plate. Peak power (PP) increased from 914.8 ± 93.9 to 970.0 ± 89.2 and 1037.8 ± 114.4 W (p < 0.05) following the RSA test results. Maximum power increased significantly (p < 0.05) in ACMJ (1951.9 ± 359.7 to 2141.9 ± 378.5 and 2268.5 ± 395.9 W) and CMJ tests (2646.3 ± 415.6 to 2831.2 ± 510.8 and 3064.6 ± 444.5 W). Although significant differences in JT (p < 0.05) were observed during the two year period, their values related to body mass for the lower right extremity, sum of the trunk and sum of all muscle groups increased significantly between the first and the second measurement (from 13.7 ± 1.8 to 14.58 ± 1.99 N·m·kg-1, from 9.3 ± 1.5 to 10.39 ± 2.16 N·m·kg-1, from 43.4 ± 5.2 to 46.31 ± 6.83 N·m·kg-1, respectively). The main finding of the study is that PP in the RSA test and maximal power in the ACMJ and CMJ increase in relation to training experience and age in the group of youth handball players.