[Comparative analysis of body fat measurement using two bioelectric impedance devices and three household scales (with the function of determining body composition) with dual-energy X-ray absorptiometry].

Body composition assessment is often used in clinical practice to assess and monitor nutritional status. For example, body fat mass is a predictor of metabolic diseases, and for an athlete it is a criterion of performance. "Gold standard" - the method of dual-energy X-ray absorptiometry - in contrast to bioelectrical impedance analysis, is difficult to apply in everyday clinical practice. Therefore, it becomes relevant to compare the consistency of measured body fat mass using densitometry and bioimpedanceometry. The aim of the study was to perform a comparative analysis of body fat mass estimated by bioimpedanceometry (two bioelectric impedance devices and three household scales with a function of determining body composition) and dual-energy X-ray absorptiometry. Material and methods. Sixteen healthy, physically active adults aged 25 [23; 26] years, male (n=7) and female (n=9), participated in the cross-sectional study. Body composition was assessed under standard conditions in the morning, after a 12-hour fast, using densitometry (Stratos Dr X-ray densitometer) and bioimpedanceometry [bioelectric impedance devices: Medass ABC-01, Diamant AIST (with manufacturer's predictive equations); household scales with a function of determining body composition: Tanita BC-718, Picooc Mini, Scarlett SC-216]. Statistical analysis was performed using Statistica 10 package (StatSoft, USA), and included Friedman's chi-criterion, Lin's correlation concordance coefficient, Bland-Altman method, Spearman's correlation coefficient, and Wilcoxon's criterion with Bonferroni correction for multiple studies. Results. None of the bioimpedanceometry devices studied showed a relationship (Bland- Altman coefficient >0.2) or consistency (Lin's correlation concordance coefficient <0.9) when compared to densitometry, although Spearman correlation was moderate for Tanita BC-718 (r=0.603, p<0.05), Diamant AIST (r=0.641, p<0.01) and Scarlett SC-216 (r=0.609, p<0.05), and notable for Medass ABC-01 (r=0.841, p<0.01) and Picooc Mini (r=0.718, p<0.01). Conclusion. This study found that no bioelectrical impedance device has consistency with dual-energy X-ray absorptiometry in assessing body fat mass. Since the accuracy of body fat mass measurement is critical in body composition diagnosis, the assessment results obtained by bioimpedanceometry should be interpreted with caution.

[Impact of isometric training on blood pressure: an umbrella study of systematic reviews and meta-analyses]. / Vliyanie izometricheskoi trenirovki na arterial'noe davlenie: zontichnyi obzor sistematicheskikh obzorov i metaanalizov.

High blood pressure causes 45% of deaths from heart diseases and 51% of deaths from stroke. OBJECTIVE: To conduct systematic search and summarize the systematic reviews and/or meta-analyses about impact of isometric training on blood pressure. MATERIAL AND METHODS: Systematic search for publications in PubMed, Cochrane Library and Epistemonikos databases for the period from January of 2017 yr. to 19 of January 2023 yr. was carried out. The search was done by keywords: isometric exercises, isometric training, blood pressure, arterial hypertension, static resistance training, handgrip test. Methodological quality of included articles was assessed using the «Assessment of methodological quality of systematic reviews¼ (AMSTAR-2) tool. The number of systematic reviews equal 15 was analyzed. RESULTS: The overall methodological quality of 15 included reviews, obtained by AMSTAR-2, revealed a very low confidence rate (critically low confidence, 10 publications) for results of systematic review and meta-analyses. In total, analysis and generalization of all results of included systematic reviews about blood pressure decrease by isometric training showed, that systolic blood pressure against the background of this method decreases on average by 6.1±2.0 mm Hg, and diastolic blood pressure - by 3.0±1.0 mm Hg. CONCLUSION: Authors of 15 systemic reviews, included in an umbrella study, reached a common conclusion about isometric training efficacy in secondary prevention of arterial hypertension.

[Effect of dietary supplements and whey protein on muscle mass and strength of the operated limb after anterior cruciate ligament reconstruction: a systematic review].

Muscle weakness and atrophy of the quadriceps muscle after anterior cruciate ligament reconstruction may persist for up to 6 months after surgery and cause re-injury to the ipsilateral or contralateral limbs. Many authors state that adequate nutritional status during the rehabilitation period can contribute to faster postoperative recovery of muscle mass and strength of the lower limb, be an adjunct to exercise, or serve an alternative treatment strategy. The purpose of the research was to conduct a systematic review of the literature and evaluate the degree of influence of dietary supplements on muscle mass and strength of the operated limb after reconstruction of the anterior cruciate ligament (ACL). Material and methods. The search for articles was carried out in international databases PubMed, Google Scholar, Cochrane Library. The time frame of the search was 22 years. To be included in the review, studies had to meet the PICOS criteria: participants were men and women over 18 years of age after ACL reconstruction; intervention - supplementation after and/or before and after ACL reconstruction; comparison - placebo group or no supplementary interventions; results - assessment of the dynamics of changes in muscle mass (cross-sectional area, muscle thickness or size of skeletal muscle fibers) and / or maximum strength (dynamic or isometric) of the operated limb; research design - randomized controlled trials (RCT). The quality of selected RCTs was assessed using the Cochrane Collaboration Risk of Bias (RoB 2) tool. Results. A total of 1397 articles were found after searching in the databases. This systematic review included 6 RCTs with a total number of patients 186. The following dietary supplements were used: leucine - 1 article, glucosam ine - 1 article, creatine - 1 article, vitamins E and C - 2 articles. One study evaluated the effect of whey protein supplementation in combination with neuromuscular electrical stimulation on isometric strength of the operated limb. When comparing the data of 3 groups in the pre- and postoperative periods, there were no statistically significant differences between the groups. When considering the protocols for taking dietary supplements based on creatine, glucosamine, vitamins E and C, none of the studies demonstrated statistically significant improvements in the parameters of maximum strength or muscle hypertrophy of the operated limb in the main groups compared with the control groups. Also, no results have been obtained indicating that these dietary supplements can slow down muscl e atrophy after surgery. In another study that evaluated the effect of leucine supplementation, by the end of the rehabilitation program, the muscle strength of the operated limb tended to increase more in the leucine group than in the placebo group, but without a statistically significant difference. At 10 cm from the patella, the femoral circumference of the operated limb in the leucine group increased more than in the placebo group, and the differences were statistically significant (р=0.009). Two studies were rated as high risk of bias, three as moderate risk, and one as low risk. Conclusion. None of the supplements used had a statistically significant effect on the muscle strength of the operated limb after ACL reconstru ction. In terms of thigh muscle hypertrophy, the only significant improvement was associated with leucine supplementation and an increase in thigh circumference at a distance of 10 cm from the patella.

[The role of interval training in the physical rehabilitation of strength sports athletes with hypertension: a randomized controlled study]. / Rol' interval'noi trenirovki v fizicheskoi reabilitatsii sportsmenov silovykh vidov sporta s arterial'noi gipertenziei: randomizirovannoe kontroliruemoe issledovanie.

OBJECTIVE: To evaluate the effect of high-intensity interval aerobic work on blood pressure and body composition in strength sports athletes of heavy weight categories. MATERIAL AND METHODS: The examination and physical rehabilitation of 55 strength sports athletes of heavy weight categories with arterial hypertension were performed. Athletes were randomized into two groups: the main group (n=35) and the control group (n=20). The main group athletes trained 120 days (3 times a week) on a bicycle ergometer according to the high-intensity interval protocol, and the control group participants trained 120 days (3 times a week) according to their traditional strenght protocol. All athletes underwent a complex examination, including: a survey, examination, three-time measurement of blood pressure, bioelectrical impedance analysis and calculations of body composition indices, Before and after the physical rehabilitation. RESULTS: After 120 days of physical rehabilitation, there was an improvement in body composition and a significant decrease in blood pressure: systolic blood pressure by 4.7%, diastolic blood pressure by 5.6%. CONCLUSIONS: High-intensity aerobic interval work, regardless of the athlete's body composition, has a therapeutic and prophylactic effect on the cardiovascular system. The aerobic workout training protocol taking into account metabolic variables, that we developed, will allow athletes to effectively and safely influence the prevention and treatment of hypertension.

Filament lattice changes in smooth muscle assessed using birefringence.

The long functional range of some types of smooth muscle has been the subject of recent study. It has been proposed that the muscle filament lattice adapts to longer lengths by placing more filaments in series and that lattice plasticity is facilitated by myosin filament evanescence, with filaments dissociating during relaxation and reforming upon activation. Support for these dynamic changes in the filament lattice has been provided partly by changes in contractile parameters at different times in the contraction-relaxation cycle at different lengths. If the changes in contractile parameters result from filament formation and dissociation, these structural changes must occur on the time scale of tension development and relaxation. To assess whether thick-filament formation could account for the contractile changes, we measured birefringence continuously during activation and relaxation and compared these optical changes with the time course of force development and relaxation. Birefringence is a well-known property of muscle; striations in skeletal and cardiac muscle result from the A-bands being anisotropic, i.e., birefringent, and it is now known that this optical property is due to the presence of myosin thick filaments in the A-bands. Thus, the strength of birefringence is expected to represent the density of thick filaments. Here, we describe the principle of the method, the techniques for recording the optical signals, some initial results, and discuss the interpretation of results and some limitations of the method.