Muscular and neuromuscular control following soccer-specific exercise in male youth: Changes in injury risk mechanisms.

Poor neuromuscular control has been proposed as a risk factor for non-contact injuries, thus this study aimed to explore the effects of soccer-specific fatigue on leg muscle activation, reactive strength, leg stiffness, and functional hamstring/quadriceps ratio (H/QFUNC ) in elite male youth soccer players. Outcome measures were determined in 18 youth players (age 14.4 ± 0.5 years; stature 169.4 ± 9.9 cm; mass 59.3 ± 8.9 kg; maturity offset 0.86 ± 0.88 years) pre and post simulated soccer match play (SAFT90 ). There was no fatigue-related change in the H/QFUNC ; however, reactive strength and leg stiffness were both compromised (P < 0.001) after soccer-specific fatigue. Muscle activation was also locally compromised (P < 0.001) in the medial hamstring and quadriceps but not in the lateral muscles. Where statistically significant changes were observed, the effect sizes ranged from small to large (0.33-0.97). Compromised stiffness when fatigue is present suggests an increased yielding action, greater ground contact times, greater center of mass displacement, and less efficient movement when the limb comes into contact with the ground. This combined with a reduction in medial quadriceps muscle activation may reflect poor kinetic chain control at the hip and an increase in knee injury risk.

Training-induced changes in physical performance can be achieved without body mass reduction after eight week of strength and injury prevention oriented programme in volleyball female players.

The purpose of the study was to analyse the changes in muscle strength, power, and somatic parameters in elite volleyball players after a specific pre-season training programme aimed at improving jumping and strength performance and injury prevention. Twelve junior female volleyball players participated in an 8-week training programme. Anthropometric characteristics, isokinetic peak torque (PT) single-joint knee flexion (H) and extension (Q) at 60º/s and 180º/s, counter movement jump (CMJ), squat jump (SJ), and reactive strength index (RSI) were measured before and after intervention. Significant moderate effects were found in flexor concentric PT at 60º/s and at 180 º/s in the dominant leg (DL) (18.3±15.1%, likely; 17.8±11.2%, very likely) and in extensor concentric PT at 180º/s (7.4%±7.8%, very likely) in the DL. In the non-dominant leg (NL) significant moderate effects were found in flexor concentric PT at 60º/s and at 180º/s (13.7±11.3%, likely; 13.4±8.0%, very likely) and in extensor concentric PT at 180º/s (10.7±11.5%, very likely). Small to moderate changes were observed for H/QCONV in the DL at 60º/s and 180º/s (15.9±14.1%; 9.6±10.4%, both likely) and in the NL at 60º/s (moderate change, 9.6±11.8%, likely), and small to moderate decreases were detected for H/QFUNC at 180º/s, in both the DL and NL (-7.0±8.3%, likely; -9.5±10.0%, likely). Training-induced changes in jumping performance were trivial (for RSI) to small (for CMJ and SJ). The applied pre-season training programme induced a number of positive changes in physical performance and risk of injury, despite a lack of changes in body mass and composition.

[Continuous passive motion in joint rehabilitation after injury and surgery]. / Kontinuální pasivní pohyb v rehabilitaci kloubu po úrazech a operacích.

Devices for continuous passive motion, also known as motor-driven splints, are widely used in rehabilitation therapy following injuries and surgery. They present an adjunct method substituting the physical work of a physiotherapist. The method is indicated in early post-injury or post-operative periods. It is expected to increase blood drainage and remove haemarthrosis and synovial fluid exudate which precede an undesired development of granulation and fibrous tissues. However, continuing such an intensive therapy after 3 to 4 post-operative weeks lacks its raison d'être. The only exceptions include conditions after autologous chondrocyte transplantation and a supplementary therapy to active rehabilitation programmes for releasing muscle hypertonia which restricts movement. Values for the range of motion set up on the device cannot be considered the real values pertinent to the exercised joint; these are usually considerably lower. Key words: continuous passive motion, motor-driven splint.

Angiopoietin-like protein 4: development, analytical characterization, and clinical testing of a new ELISA.

The aim of our work was to develop an assay for the determination of angiopoietin-like protein 4 (Angplt4) in human blood, and to investigate its levels in healthy volunteers and donors suffer from metabolic syndrome. We developed and evaluated the sandwich ELISA method for the quantitative determination of human Angplt4 in serum samples. We conducted also the pilot study on individuals with metabolic syndrome or familiar hypercholesterolemia and healthy probands and measured blood pressure, waist circumference, Angplt4 serum levels, serum cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, insulin, glucose, A-FABP and calculate BMI and QUICKI insulin sensitivity index. In the study on 30 healthy volunteers we demonstrated that sex or age is not the determinant for Angplt4 serum values. Furthermore, we tested 115 individuals with metabolic syndrome and found that probands with metabolic syndrome did not differ in Angplt4 values than healthy individuals from the first study (medians 8.7 vs. 8.1 ng/ml, p = 0.6). Individuals with metabolic syndrome did not differ in sex or age from healthy. Angplt4 values correlated with the HDL-cholesterol (r = -0.25; p < 0.01), FGF-21 (r = 0.23, p < 0.01), glucose (r = 0.17; p = 0.03), uric acid (r = 0.17; p = 0.49), lipocalin-2 (r = 0.23, p < 0.01), triacylglycerols (r = 0.25; p < 0.01) and number or characters of metabolic syndrome (r = 0.21; p < 0.01). No significant correlation was found between serum Angplt4 and BMI, WC or QUICKI. However, we performed stepwise regression and we found that Angplt4 was not an independent marker for metabolic syndrome. The patients from the metabolic syndrome group suffering diabetes mellitus (n = 83) did not differ in serum Angplt4 from the group of healthy patients, too. The pilot study supports the hypothesis about the role of Angplt4 as a new class of lipid metabolism modulator. Their values could be a new key predictors of metabolic syndrome. Further research is necessary to confirm our findings in individuals with dyslipidemia, obesity, coronary artery diseases and different medication in order to assess Angplt4 value as a risk predictor of accelerated atherosclerosis.

How to estimate overweight in pubescent asthmatics?

PURPOSE: The purpose of our research was to compare the body mass index (BMI) and selected anthropometric parameters in asthmatic and non-asthmatic pubescents. MATERIAL AND METHODS: The study group consisted of 64 asthmatic boys and 45 girls; the control group consisted of 68 nonasthmatic boys and 48 non-asthmatic girls. All the children were 12-14 years old. We measured anthropometric parameters by a standardized method and the percentage of fat using the simple 2-site skinfold method. Additionally, we calculated the percentage of body composition (Matiegka) and the components of somatotype (Heath-Carter). Statistical significance was estimated at the level of p<0.05 by ANOVA test. RESULTS: The asthmatic boys were significantly shorter than the non-asthmatic (p=0.015), however, we did not find any significant differences in weight and/or BMI in boys nor girls. The asthmatic boys had significantly higher fat mass % than the non-asthmatic ones (p<0.001). Moreover, they had significantly lower muscle mass % (p<0.001) as well as the bone mass % (p<0.001). The asthmatic girls had higher fat mass % than the non-asthmatic ones (p=0.028) and lower muscle mass % (p<0.001). The simple 2-site skinfold method also showed higher fat % in the asthmatic boys (p<0.001) but not in the girls. Examining the Heath-Carter somatotype components, the higher endomorphy was the only significant difference in asthmatic boys (p<0.001) and near significant in asthmatic girls (p=0.053). CONCLUSION: Examination of the BMI alone is not sufficient in asthmatic children because of their high percentage of fat. That is why additionally testing fat % is recommended.

Optimized and parallelized implementation of the electronegativity equalization method and the atom-bond electronegativity equalization method.

The most common way to calculate charge distribution in a molecule is ab initio quantum mechanics (QM). Some faster alternatives to QM have also been developed, the so-called "equalization methods" EEM and ABEEM, which are based on DFT. We have implemented and optimized the EEM and ABEEM methods and created the EEM SOLVER and ABEEM SOLVER programs. It has been found that the most time-consuming part of equalization methods is the reduction of the matrix belonging to the equation system generated by the method. Therefore, for both methods this part was replaced by the parallel algorithm WIRS and implemented within the PVM environment. The parallelized versions of the programs EEM SOLVER and ABEEM SOLVER showed promising results, especially on a single computer with several processors (compact PVM). The implemented programs are available through the Web page http://ncbr.chemi.muni.cz/~n19n/eem_abeem.