Search

Copyright of International Journal of Engineering & Management Sciences (2498-700X) / Műszaki és Menedzsment Tudományi Közlemények is the property of University of Debrecen and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The randomized trials showed that the addition of training resistance program to androgen-deprivation therapy (ADT) had many beneficial effects for prostate cancer (PC) patients (significant protective effect on the volume of muscle mass) and the studies have revealed a panel of miRNAs, which are deregulate in PC and may serve as promising biomarkers of PC risk. The primary aim of our present study was to investigate the effect of exercise training to changes in body composition (muscle strength) and the secondary endpoint was to investigate the impact of an exercise training program on plasma levels of selected myogenic microRNAs (miRNAs) (miRNA-1, miRNA-29b, and miRNA-133) in PC patients undergoing the ADT. Effect of ADT and exercise intervention showed significant increase (experimental group vs. control group) the changes in body composition, free testosterone levels, IL-6 and plasma levels of myogenic miRNAs and significant reduced insulin serum levels. In conclusion, resistance training with ADT in the treatment of PC significantly changed the physical and metabolic function and the plasma levels of specific myogenic miRNAs. Our data support with the other publicized results. [ABSTRACT FROM AUTHOR]

Slovak children spent almost all afternoon with sedentary activities. Such manner negatively influences physical fitness compared to previous generations. Reduction in regular physical activity is linked with daily routine changes of children due to compulsory full-time schooling. Regular physical activity performed from an early children age does not influence only physical fitness, rather favor heathy child growth and reduces risk of overweight and obesity in advanced age. Regular physical activity helps with developing skills, promotes social behaviour, family life and psychosocial health. Daily recommended physical activity for children is 90 min of moderate intensity or 60 min of moderate to vigorous intensity. Physical activities could be split and cumulated. Active movement should be partly performed in schools as a subject of Physical and Sports education, organized in clubs and leisure time. Recommended physical activities include strength training, for its beneficial effects on healthy physical growth, correct body-control, which is fundamental for every physical movement and sport. Our recommendation and guidelines provide basic information for parents and teachers to gauge sufficient physical activities of children. [ABSTRACT FROM AUTHOR]

Copyright of Rehabilitation & Physical Medicine / Rehabilitace a Fyzikální Lékařství is the property of Czech Medical Association of JE Purkyne and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We have developed an advanced version of our yield estimation method [Ferencz et al., 2004, Crop yield estimation by satellite remote sensing. International Journal of Remote Sensing, 25, pp. 4113–4149], that is able to provide reliable forecasts for corn and wheat, several weeks before the harvest. The forecasting method is based on the data of the Advanced Very High Resolution Radiometer (AVHRR) instruments of the National Oceanic and Atmospheric Administration's (NOAA) Polar Orbiting Environmental Satellites (POES). The method was applied to Hungary between the years 1996 and 2000. The forecasted yield values are all within 5% reliability with respect to the actual yield data produced by classic (non-satellite based) methods and provided by the Hungarian Statistical Office, with the exception of 1997, where the absolute error is about 8%. [ABSTRACT FROM PUBLISHER]

Two methods for estimating the yield of different crops in Hungary from satellite remote sensing data are presented. The steps of preprocessing the remote sensing data (for geometric, radiometric, atmospheric and cloud scattering correction) are described. In the first method developed for field level estimation, reference crop fields were selected by using Landsat Thematic Mapper (TM) data for classification. A new vegetation index (General Yield Unified Reference Index (GYURI)) was deduced using a fitted double-Gaussian curve to the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) data during the vegetation period. The correlation between GYURI and the field level yield data for corn for three years was R 2 =0.75. The county-average yield data showed higher correlation ( R 2 =0.93). A significant distortion from the model gave information of the possible stress of the field. The second method presented uses only NOAA AVHRR and officially reported county-level yield data. The county-level yield data and the deduced vegetation index, GYURRI, were investigated for eight different crops for eight years. The obtained correlation was high ( R 2 =84.6-87.2). The developed robust method proved to be stable and accurate for operational use for county-, region- and country-level yield estimation. The method is simple and inexpensive for application in developing countries, too. [ABSTRACT FROM AUTHOR]

Abstract: The preliminary results of a collaborative study on the amplitude variation of 24kHz sub-ionospheric NAA VLF transmitter signals transmitted from Cutler, Maine (Lat. 44.6°N, Long. 67.2°W) and monitored simultaneously at Budapest (Lat. 47.5°N, Long. 19.17°E), Hungary and Agra (Lat. 27.2°N, Long. 78°E), India are presented. The time segments of the propagation paths are so chosen that they lie in the post-midnight hours over Budapest and sunrise hours over Agra. The results show that the amplitude at Budapest decreases after midnight hours by about 3dB whereas the same at Agra increases by 5dB during sunrise normally. The anomalous enhancements and reductions in the amplitude variation during the three month period of July–September 2002 along Cutler–Agra great circle path (GCP) are examined in the light of seismic, solar flares, and magnetic storm effects. It is found that the occasional amplitude reductions are caused by earthquakes (M >5) which occurred along the GCP, and the enhancements are caused by solar flares. The magnetic storms do not seem to influence the data except in the case when associated with large solar flares. [Copyright &y& Elsevier]

While classical resistance exercise is an effective way to improve strength and control postural sway, it may not be suitable for some elderly individuals with specific health disorders (e.g., aneurysms). Therefore, there is a need to explore alternative modalities. The study aimed to evaluate the effects of sensorimotor training on muscle strength and postural control in the female elderly population and subsequently compare these effects with a traditional combined resistance-endurance training program. A total of 34 healthy, active elderly women aged from 65 to 75 years, (average age 72.7 ± 4.4 years, height 161.6 ± 5.1 cm, and weight 66.9 ± 8.4 kg) were randomly assigned to three groups undergoing different 10-week interventions: the resistance-endurance training (RET, n = 11), the sensorimotor training (SMT, n = 12) and the control group (COG, n = 11). Prior to and after the interventions all participants underwent tests of maximal voluntary contraction of the dominant and non-dominant leg; postural sway tests with open and closed eyes; novel visual feedback balance test; 10-meter maximal walking speed (10 mMWS) and stair climb test. A T-test and repeated measures ANOVA were used, followed by the Bonferroni post hoc test, to compare the pre and post-measurements and assess differences in gains between groups. Results showed a significant main effect of time on strength ( p < 0.001). In addition, significant differences in time × group interaction on strength ( p < 0.01), postural control ( p < 01), and ascendant and descended vertical speed ( p < 0.001) were observed. Besides, the RET group improved significantly the maximal voluntary contraction of both dominant (16.3%, p ≤ 0.01) and non-dominant leg (10.9%, p ≤ 0.05). SMT group improved maximal voluntary contraction of both dominant (16.6%, p ≤ 0.001) and non-dominant leg (12.7%, p ≤ 0.01). In addition, they also improved mean velocity of the centre of pressure (COP) in postural sway test with eyes open (24.2%, p ≤ 0.05) as well as eyes closed (29.2%, p ≤ 0.05), mean distance of COP in novel visual feedback balance test (37.5%, p ≤ 0.001), ascendant and descended vertical velocity (13.6%, p ≤ 0.001 and 17.8%, p ≤ 0.001, respectively). Results show not only resistance training but sensorimotor intervention boosts strength too. This intervention also enhances postural control and functional abilities for both ascending and descending movements., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Varjan, Žiška Böhmerová, Oreská, Schickhofer and Hamar.)

A well-synchronized circadian system is a manifestation of an individual's health. A gradual weakening of the circadian timing function characterizes aging. Regular exercise has been suggested as a modality to improve many detrimental changes associated with aging. Therefore, we aim to examine the benefits and risks of lifelong endurance exercise on age-dependent changes in the circadian time-keeping function, the performance of the muscular system and health status. The study protocol has a comparative cross-sectional design, including groups of senior (65 to 75 years old, n=16) and young (20-30 years old, n=16) endurance runners and triathletes. Age-matched groups of young and elderly sedentary men are included as controls. The circadian function is evaluated mainly by measurement of urinary 6-sulphatoxymelatonin, a metabolite of the hormone melatonin shown to participate in the modulation of sleep cycles. The 6-sulphatoxymelatonin will be assessed in urine samples collected upon awakening in the morning and in the late evening, as a marker of melatonin production. In addition, sleep/activity rhythms and sleep quality will be measured by wrist actigraphy. Performance of the muscular system will be assessed by examination of muscular strength and quantifying of gene expression in the skeletal muscle tissue samples. Health status and age-induced reduction in immune function are to be analysed via the balance of pro- and anti-inflammatory immune markers in the plasma and skeletal muscle, body composition, bone density and physical fitness.

Aging is associated with a decline in physical capabilities and several other health-related conditions. One of the most common age-related processes is sarcopenia. Sarcopenia is usually accompanied with a decline in skeletal muscle mass and physical functioning. A decrease in these markers usually impacts basic daily living activities (DLAs), which become somewhat harder to accomplish for older individuals. Several research studies have examined the demands of DLA in older individuals with results indicating that activities such as walking, sitting, standing, stair climbing, stair descending, and running generate high demands on older adults. The forces that act on individuals are in most cases equal or multiple times higher relative to their body mass. For instance, it was reported that the GRF (ground reaction force) during stair descent ranged from 1.43 to 1.50 of BW (body weight) in an older population. Even higher demands were recorded during other related activities. These demands of DLA raise the question of appropriate rehabilitative or training management procedures. During the past decades, an eccentric form of resistance training gained popularity due to its effectiveness and lower metabolic demands, which seems to be an appropriate method to develop and maintain a basic level of strength capabilities in higher age. Multiple factors of eccentric training have been examined including modality of exercise, intensity, frequency, and safety of the elderly. Several modalities of eccentric exercise have been shown to be effective including traditional methods, as well as machine-based ones, with or without using some equipment. The studies included in this review varied in intensity from low to high; however, the most frequently used intensity was ≥50% of the maximal eccentric strength during two or three eccentric sessions per week. Importantly, the prevalence of injury of older adults appears to have been low to none, highlighting the safety of this approach. In summary, eccentric training prescriptions for older adults should consider the demands of DLA and the characteristics of the elderly for appropriate management of training recommendations.

Regular physical activity, recommended by the WHO, is crucial in maintaining a good physical fitness level and health status and slows down the effects of aging. However, there is a lack of knowledge of whether lifelong endurance running, with a volume and frequency above the WHO limits, still brings the same benefits, or several negative effects too. The present study aims to examine the protentional benefits and risks of lifelong endurance running training in Master male athletes, as this level of physical activity is above the WHO recommendations. Within the study, four main groups of participants will be included: (1) endurance-trained master athletes, (2) endurance-trained young athletes, (3) young sedentary adults, and (4) elderly sedentary. Both groups of athletes are strictly marathon runners, who are still actively running. The broad spectrum of the diagnostic tests, from the questionnaires, physical fitness testing, and blood sampling to muscle biopsy, will be performed to obtain the possibility of complexly analyzing the effects of lifelong endurance physical activity on the human body and aging. Moreover, the study will try to discover and explain new relationships between endurance running and diagnostic parameters, not only within aging.

Context: Despite growing interest in quantifying and correcting vitamin D inadequacy in basketball players, a critical synthesis of these data is yet to be performed to overcome the low generalizability of findings from individual studies., Objective: To provide a comprehensive analysis of data in basketball pertaining to (1) the prevalence of vitamin D inadequacy; (2) the effects of vitamin D supplementation on 25-hydroxyvitamin D [25(OH)D] concentration (and its association with body composition), bone health, and performance; and (3) crucial aspects that warrant further investigation., Data Sources: PubMed, MEDLINE, ERIC, Google Scholar, SCIndex, and ScienceDirect databases were searched., Study Selection: After screening, 15 studies were included in the systematic review and meta-analysis., Study Design: Systematic review and meta-analysis., Level of Evidence: Level 3., Data Extraction: The prevalence of vitamin D inadequacy, serum 25(OH)D, body composition, stress fractures, and physical performance were extracted., Results: The pooled prevalence of vitamin D inadequacy for 527 basketball players in 14 studies was 77% ( P < 0.001; 95% CI, 0.70-0.84). Supplementation with 4000 IU/d and 4000 IU/wk (absolute mean difference [AMD]: 25.39 nmol/L; P < 0.001; 95% CI, 13.44-37.33), as well as 10,000 IU/d (AMD: 100.01; P < 0.001; 95% CI, 70.39-129.63) vitamin D restored 25(OH)D to normal concentrations. Body composition data revealed inverse correlations between changes in serum 25(OH)D (from pre- to postsupplementation) and body fat ( r = -0.80; very large). Data concerning positive impacts of vitamin D supplementation on bone health and physical performance remain sparse., Conclusion: The high proportion of vitamin D inadequacy underscores the need to screen for serum 25(OH)D in basketball players. Although supplementation restored vitamin D sufficiency, the beneficial effects on bone health and physical performance remain sparse. Adiposity can modulate 25(OH)D response to supplementation.

Background: The purpose of this scoping review was to analyze the evidence of acute and long-term effects of the application of leg-press strength training with or without serial stretch-loading stimuli on various biomechanical and physiological outcomes., Methods: This review was performed in accordance with PRISMA for Scoping Reviews recommendations, and two researchers independently searched the following databases: PubMed, Web of Science, Scopus, ScienceDirect, ProQuest, Cochrane, and Google Scholar. All studies that used unique leg-press device for testing, acute responses and long-term adaptation were included in this review, irrespective of the measured outcomes. A total of 13 studies were included in this review, with 5 focused on the testing capabilities of the device and acute training responses and 8 focused on the long-term adaptations in various physical and physiological outcomes., Results: Regarding the acute responses after leg-press strength training with or without serial stretch-loading stimuli, visible changes were observed in the muscle force, rate of force development, and hormonal concentrations between pre- and postmenopausal women (only one study). Long-term studies revealed different training adaptations after performing leg-press strength training with unique serial stretch-loading stimuli. A positive trend for leg-press strength training with serial stretch-loading was recorded in the young population and athletes; however, more variable training effects favoring one or the other approach were achieved in the older population., Conclusions: In summary, this review shows the uniqueness and usability of a leg-press device that is capable of various exercising modes, including special serial stretch-loading stimuli. The use of this device can serve as a positive addition to training regiments, and the main application appears to be suitable for rehabilitation needs.

In 2013 we presented results showing that at the histological level lifelong increased physical activity promotes reinnervation of muscle fibers in aging muscles. Indeed, in muscle biopsies from 70-year old men with a lifelong history of high-level physical activity, we observed a considerable increase in fiber-type groupings (F-TG), almost exclusively of the slow type. Slow-type transformation by denervation-reinnervation in senior sportsmen seems to fluctuate from those with scarce fiber-type transformation and groupings to almost fully transformed muscle, going through a process in which isolated fibers co-expressing fast and slow Myosin Heavy Chains (MHCs) seems to fill the gaps. Taken together, our results suggest that, beyond the direct effects of aging on the muscle fibers, changes occurring in skeletal muscle tissue appear to be largely, although not solely, a result of sparse denervation-reinnervation. The lifelong exercise allows the body to adapt to the consequences of the age-related denervation and to preserve muscle structure and function by saving otherwise lost muscle fibers through recruitment to different, mainly slow, motor units. These beneficial effects of high-level life-long exercise on motoneurons, specifically on the slow type motoneurones that are those with higher daily activity, and on muscle fibers, serve to maintain size, structure and function of muscles, delaying the functional decline and loss of independence that are commonly seen in late aging. Several studies of independent reserchers with independent analyses confirmed and cited our 2013 results. Thus, the results we presented in our paper in 2013 seem to have held up rather well.

Background/aims: Walking speed (WS) is an objective measure of physical capacity and a modifiable risk factor of morbidity and mortality in the elderly. In this study, we (i) determined effects of 3-month supervised aerobic-strength training on WS, muscle strength, and habitual physical activity; (ii) evaluated capacity of long-term (21 months) training to sustain higher WS; and (iii) identified determinants of WS in the elderly., Methods: Volunteers (F 48/M 14, 68.4 ± 7.1 years) completed either 3-month aerobic-strength (3 × 1 h/week, n = 48) or stretching (active control, n = 14) intervention (study A). Thirty-one individuals (F 24/M 7) from study A continued in supervised aerobic-strength training (2 × 1 h/week, 21 months) and 6 (F 5/M 1) became nonexercising controls., Results: Three-month aerobic-strength training increased preferred and maximal WS (10-m walk test, p < 0.01), muscle strength (p < 0.01) and torque (p < 0.01) at knee extension, and 24-h habitual physical activity (p < 0.001), while stretching increased only preferred WS (p < 0.03). Effect of training on maximal WS was most prominent in individuals with baseline WS between 1.85 and 2.30 m·s-1. Maximal WS measured before intervention correlated negatively with age (r = -0.339, p = 0.007), but this correlation was weakened by the intervention (r = -0.238, p = 0.06). WS progressively increased within the first 9 months of aerobic-strength training (p < 0.001) and remained elevated during 21-month intervention (p < 0.01). Cerebellar gray matter volume (MRI) was positively associated with maximal (r = 0.54; p < 0.0001) but not preferred WS and explained >26% of its variability, while age had only minor effect., Conclusions: Supervised aerobic-strength training increased WS, strength, and dynamics of voluntary knee extension as well as habitual physical activity in older individuals. Favorable changes in WS were sustainable over the 21-month period by a lower dose of aerobic-strength training. Training effects on WS were not limited by age, and cerebellar cortex volume was the key determinant of WS., (© 2021 S. Karger AG, Basel.)

Neuromuscular training in young athletes improves performance and decreases the risk of injuries during sports activities. These effects are primarily ascribed to the enhancement of muscle strength and power but also balance, speed and agility. However, most studies have failed to demonstrate significant improvement in these abilities. This is probably due to the fact that traditional tests do not reflect training methods (e.g., plyometric training vs. isometric or isokinetic strength testing, dynamic balance training vs. static balance testing). The protocols utilized in laboratories only partially fulfill the current needs for testing under sport-specific conditions. Moreover, laboratory testing usually requires skilled staff and a well equipped and costly infrastructure. Nevertheless, experience demonstrates that high-technology and expensive testing is not the only way to proceed. A number of physical fitness field tests are available today. However, the low reliability and limited number of parameters retrieved from simple equipment used also limit their application in competitive sports. Thus, there is a need to develop and validate a functional assessment platform based on portable computerized systems. Variables obtained should be directly linked to specific features of particular sports and capture their complexity. This is essential for revealing weak and strong components of athlete performance and design of individually-tailored exercise programs. Therefore, identifying the drawbacks associated with the assessment of athlete performance under sport-specific conditions would provide a basis for the formation of an innovative approach to their long-term systematic testing. This study aims (i) to review the testing methods used for the evaluation of the effect of neuromuscular training on sport-specific performance in young athletes, (ii) to introduce stages within the Sport Longlife Diagnostic Model, and (iii) to propose future research in this topic. Analysis of the literature identified gaps in the current standard testing methods in terms of their low sensitivity in discriminating between athletes of varied ages and performance levels, insufficent tailoring to athlete performance level and individual needs, a lack of specificity to the requirements of particular sports and also in revealing the effect of training. In order to partly fill in these gaps, the Sport Longlife Diagnostic Model was proposed.

It has been clearly established that maximal force and power is lower in the morning compared to noon or afternoon hours. This morning neuromuscular deficit can be diminished by regularly training in the morning hours. However, there is limited and contradictory information upon hypertrophic adaptations to time-of-day-specific resistance training. Moreover, no cellular or molecular mechanisms related to muscle hypertrophy adaptation have been studied with this respect. Therefore, the present study examined effects of the time-of-day-specific resistance training on muscle hypertrophy, phosphorylation of selected proteins, hormonal concentrations and neuromuscular performance. Twenty five previously untrained males were randomly divided into a morning group (n = 11, age 23 ± 2 yrs), afternoon group (n = 7, 24 ± 4 yrs) and control group (n = 7, 24 ± 3 yrs). Both the morning and afternoon group underwent hypertrophy-type of resistance training with 22 training sessions over an 11-week period performed between 07:30-08:30 h and 16:00-17:00 h, respectively. Isometric MVC was tested before and immediately after an acute loading exclusively during their training times before and after the training period. Before acute loadings, resting blood samples were drawn and analysed for plasma testosterone and cortisol. At each testing occasion, muscle biopsies from m. vastus lateralis were obtained before and 60 min after the acute loading. Muscle specimens were analysed for muscle fibre cross-sectional areas (CSA) and for phosphorylated p70S6K, rpS6, p38MAPK, Erk1/2, and eEF2. In addition, the right quadriceps femoris was scanned with MRI before and after the training period. The control group underwent the same testing, except for MRI, between 11:00 h and 13:00 h but did not train. Voluntary muscle strength increased significantly in both the morning and afternoon training group by 16.9% and 15.2 %, respectively. Also muscle hypertrophy occurred by 8.8% and 11.9% (MRI, p < 0.001) and at muscle fibre CSA level by 21% and 18% (p < 0.01) in the morning and afternoon group, respectively. No significant changes were found in controls within these parameters. Both pre- and post-training acute loadings induced a significant (p < 0.001) reduction in muscle strength in all groups, not affected by time of day or training. The post-loading phosphorylation of p70S6Thr421/Ser424 increased independent of the time of day in the pre-training condition, whereas it was significantly increased in the morning group only after the training period (p < 0.05). Phosphorylation of rpS6 and p38MAPK increased acutely both before and after training in a time-of-day independent manner (p < 0.05 at all occasions). Phosphorylation of p70S6Thr389, eEF2 and Erk1/2 did not change at any time point. No statistically significant correlations were found between changes in muscle fibre CSA, MRI and cell signalling data. Resting testosterone was not statistically different among groups at any time point. Resting cortisol declined significantly from pre- to post-training in all three groups (p < 0.05). In conclusion, similar levels of muscle strength and hypertrophy could be achieved regardless of time of the day in previously untrained men. However, at the level of skeletal muscle signalling, the extent of adaptation in some parameters may be time of day dependent.

Background: Canine hepatic copper content has been increasing. Recognition of canine copper-associated hepatopathies is becoming more common., Objectives: The purpose of the study was to assess the diagnostic performance of Wright-Giemsa (WG) and rhodanine staining for detection of increased canine hepatic copper following a proposed cytologic protocol for semi-quantitative evaluation of liver aspirates and the effect of previous WG staining., Methods: Retrospectively, 40 canine hepatic WG-stained cytology cases were rhodanine stained. Diagnostic performance of WG staining for increased hepatic copper was evaluated. A rhodanine-stained cytologic copper grading system was developed. Prospectively, 67 canine liver samples with quantitative copper measurement, a WG-then rhodanine-stained slide, and a non-WG rhodanine-stained slide were used to assess the performance of the grading system and the effect of previous WG staining., Results: Copper was not described in 40 retrospective cases on initial cytologic evaluation; 8/40 cases had increased copper content after rhodanine staining or quantitative copper assessment. Prior WG staining and destaining significantly affected the cytologic copper grade but not the diagnostic performance as measured by receiver-operating characteristic curve analysis. Quantitative copper concentration and previously WG-stained copper grade were moderately correlated (n = 67, ρ = .79 [.68-.87]). For detection of ≥ 600 ppm, dry weight (dw) copper, sensitivity was .75 and specificity was .97. For detection of ≥ 1500 ppm, dw copper, sensitivity was 1.0 and specificity was .97., Conclusions: Wright-Giemsa staining alone does not reliably detect hepatic copper. Grading of rhodanine-stained canine hepatic cytologic samples demonstrates acceptable diagnostic performance for detection of copper content., (© 2016 American Society for Veterinary Clinical Pathology.)

Systematic physical activity increases physical fitness and exercise capacity that lead to the improvement of health status and athletic performance. Considerable effort is devoted to identifying new biomarkers capable of evaluating exercise performance capacity and progress in training, early detection of overtraining, and monitoring health-related adaptation changes. Recent advances in OMICS technologies have opened new opportunities in the detection of genetic, epigenetic and transcriptomic biomarkers. Very promising are mainly small non-coding microRNAs (miRNAs). miRNAs post-transcriptionally regulate gene expression by binding to mRNA and causing its degradation or inhibiting translation. A growing body of evidence suggests that miRNAs affect many processes and play a crucial role not only in cell differentiation, proliferation and apoptosis, but also affect extracellular matrix composition and maintaining processes of homeostasis. A number of studies have shown changes in distribution profiles of circulating miRNAs (c-miRNAs) associated with various diseases and disorders as well as in samples taken under physiological conditions such as pregnancy or physical exercise. This overview aims to summarize the current knowledge related to the response of blood c-miRNAs profiles to different modes of exercise and to highlight their potential application as a novel class of biomarkers of physical performance capacity and training adaptation., Competing Interests: The authors declare no conflict of interest.

Background/Study Context: The study estimates the reliability of peak velocity and peak power during chair rising and chair jumping tests and their ability to discriminate between different age and physical activity level groups., Methods: Physically active and sedentary individuals (N = 262) of different ages (young: 22.9 ± 2.0 years, range: 21-25 years; older: 63.1 ± 1.8 years, range: 61-65 years) performed, in random order, chair rising and chair jumping tests on a force plate. Randomly selected young subjects performed both tests repeatedly on two different occasions separated by 1 week. From the sitting position with the arms crossed on the chest, they either stand up completely (chair rising test), or jump as high as possible (chair jumping test)., Results: The test-retest reliability of peak power and peak velocity during chair rising as well as chair jumping was excellent, with high intraclass correlation coefficients (ICCs; .90-.98) and low standard error of measurement (SEM; 7.0-9.1%). Post hoc analysis revealed significant differences in peak power and peak velocity between the sedentary and physically active young and older subjects. However, greater coefficients of variation for both parameters were found for chair jumping than chair rising (21.1-40.2% vs. 11.0-15.2%). Additionaly, there were moderate correlations of peak power and peak velocity between chair rising and chair jumping (r = .42-.49). There were greater within- and between-group differences in peak force and peak power and a steeper increase in their values during the initial phase of chair jumping than chair rising., Conclusion: Both chair rising and chair jumping tests provide reliable data and are valid indicators of lower body power in young and older adults. However, jumping from a chair is a more sensitive measure of strength and power performance than chair rising.

Aim: The study compares the reliability of peak power (Ppeak) and mean power in acceleration (Pmean acc) and entire concentric phase (Pmean total) of chest presses on the bench and unstable Swiss ball with different weights., Methods: A group of 32 fit men performed over 2 testing sessions 3 trials of barbell chest presses on the bench and Swiss ball, without and with countermovement, with weights of 40, 60 and 80% 1RM., Results: High values of correlation coefficients (above .80) and no significant differences between trials signify stability of measurement under both stable and unstable conditions. When chest presses were performed on the bench, ICC and SEM% values were in range .97 to .98 and 7.6 to 7.7%, respectively for Pmean total, .96 to .98 and 9.1 to 9.6%, respectively for Pmean acc, and .94 to .97 and 9.2 to 10.0%, respectively for Ppeak. Their values during chest presses on a Swiss ball ranged from .93 to .96 and 8.4 to 9.1%, respectively for Pmean total, from .87 to .90 and 11.7 to 12.2%, respectively for Pmean acc, and from .79 to .82 and 12.1 to 13.4%, respectively for Ppeak at weights of 40 and 60% 1RM, and from .70 to .76 and 17.6 to 19.8%, respectively at weight of 80% 1RM., Conclusion: Measurement of peak and mean power during unstable chest presses provides reliable data comparable to those obtained during bench presses under all conditions tested. However, peak values of power measured during unstable chest presses with weights ≥80% 1RM should be interpreted with caution.

Aging is a multifactorial irreversible process associated with significant decline in muscle mass and neuromuscular functions. One of the most efficient methods to counteract age-related changes in muscle mass and function is physical exercise. An alternative effective intervention to improve muscle structure and performance is electrical stimulation. In the present work we present the positive effects of physical activity in elderly and a study where the effects of a 8-week period of functional electrical stimulation and strength training with proprioceptive stimulation in elderly are compared.

Sarcopenia is the age-related loss of muscle mass and function, reducing force generation and mobility in the elderlies. Contributing factors include a severe decrease in both myofiber size and number as well as a decrease in the number of motor neurons innervating muscle fibers (mainly of fast type) which is sometimes accompanied by reinnervation of surviving slow type motor neurons (motor unit remodeling). Reduced mobility and functional limitations characterizing aging can promote a more sedentary lifestyle for older individuals, leading to a vicious circle further worsening muscle performance and the patients' quality of life, predisposing them to an increased risk of disability, and mortality. Several longitudinal studies have shown that regular exercise may extend life expectancy and reduce morbidity in aging people. Based on these findings, the Interreg IVa project aimed to recruit sedentary seniors with a normal life style and to train them for 9 weeks with either leg press (LP) exercise or electrical stimulation (ES). Before and at the end of both training periods, all the subjects were submitted to mobility functional tests and muscle biopsies from the Vastus Lateralis muscles of both legs. No signs of muscle damage and/or of inflammation were observed in muscle biopsies after the training. Functional tests showed that both LP and ES induced improvements of force and mobility of the trained subjects. Morphometrical and immunofluorescent analyses performed on muscle biopsies showed that ES significantly increased the size of fast type muscle fibers (p<0.001), together with a significant increase in the number of Pax7 and NCAM positive satellite cells (p<0.005). A significant decrease of slow type fiber diameter was observed in both ES and LP trained subjects (p<0.001). Altogether these results demonstrate the effectiveness of physical exercise either voluntary (LP) or passive (ES) to improve the functional performances of aging muscles. Here ES is demonstrated to be a safe home-based method to counteract fast type fiber atrophy, typically associated with aging skeletal muscle.

Paper deals with backgrounds and principles of universal linear motor driven leg press dynamometer and concept of serial stretch loading. The device is based on two computer controlled linear motors mounted to the horizontal rails. As the motors can keep either constant resistance force in selected position or velocity in both directions, the system allows simulation of any mode of muscle contraction. In addition, it also can generate defined serial stretch stimuli in a form of repeated force peaks. This is achieved by short segments of reversed velocity (in concentric phase) or acceleration (in eccentric phase). Such stimuli, generated at the rate of 10 Hz, have proven to be a more efficient means for the improvement of rate of the force development. This capability not only affects performance in many sports, but also plays a substantial role in prevention of falls and their consequences. Universal linear motor driven and computer controlled dynamometer with its unique feature to generate serial stretch stimuli seems to be an efficient and useful tool for enhancing strength training effects on neuromuscular function not only in athletes, but as well as in senior population and rehabilitation patients.

This review focuses on investigations into postural sway response to different forms of exercise, and particularly those dealing with physiological mechanisms of post-exercise balance impairment. The findings of relevant studies combined with our research results show that postural sway response to exercise depends on its type, intensity, duration and intensity of proprioceptive stimulation. Differences in postural sway were also observed after exercise with different forms of muscle contraction and those with different activation of muscle fibres. In general, fatigue is associated with post-exercise balance impairment. Such an effect is usually a consequence of prolonged exercise. However, findings proved that after short-term intensive exercises, hyperventilation, rather than fatigue, is responsible for increased postural sway. Significant differences in balance impairment were also found after exercises that induced the same ventilation but with a different intensity of muscle contractions eliciting a different level of proprioceptive stimulation, such as calf rises versus jumps and cycling versus running. Thus, in addition to fatigue and hyperventilation, impairment of somatosensory inputs also very likely plays a role in increased post-exercise postural sway. Based on this literature review, possible physiological mechanisms of post-exercise balance impairment identified so far may be fatigue, hyperventilation, deterioration of functions of mechanoreceptors, proprioceptors, vestibular apparatus and visual cues, muscle damage, dehydration, hyperthermia and dizziness. These findings can be explored in a more practical setting in the field of sport, clinical medicine and rehabilitation.

The histologic features of aging muscle suggest that denervation contributes to atrophy, that immobility accelerates the process, and that routine exercise may protect against loss of motor units and muscle tissue. Here, we compared muscle biopsies from sedentary and physically active seniors and found that seniors with a long history of high-level recreational activity up to the time of muscle biopsy had 1) lower loss of muscle strength versus young men (32% loss in physically active vs 51% loss in sedentary seniors); 2) fewer small angulated (denervated) myofibers; 3) a higher percentage of fiber-type groups (reinnervated muscle fibers) that were almost exclusive of the slow type; and 4) sparse normal-size muscle fibers coexpressing fast and slow myosin heavy chains, which is not compatible with exercise-driven muscle-type transformation. The biopsies from the old physically active seniors varied from sparse fiber-type groupings to almost fully transformed muscle, suggesting that coexpressing fibers appear to fill gaps. Altogether, the data show that long-term physical activity promotes reinnervation of muscle fibers and suggest that decades of high-level exercise allow the body to adapt to age-related denervation by saving otherwise lost muscle fibers through selective recruitment to slow motor units. These effects on size and structure of myofibers may delay functional decline in late aging.

The study evaluates the effect of weight lifted on power in the concentric phase of resistance exercises on stable and unstable surfaces. A group of 19 fit men performed randomly on different days 3 reps of (a) barbell chest presses on the bench and Swiss ball, and (b) barbell squats on stable base and BOSU ball. Exercises were performed without and with countermovement (CM) using maximal effort in concentric phase. Initial weight of 20 kg was increased by 10 kg or 5 kg (at higher loads) up to at least 85% of previously established 1RM under stable conditions. Results showed no significant differences in mean power in the concentric phase of stable and unstable CM chest presses at lower weights lifted (from 20 to 50 kg). However, its values were significantly higher during chest presses on the bench than on Swiss ball while lifting higher weights (from 60 to 90 kg). Similarly, mean power in the concentric phase of squats was significantly higher on stable base than on BOSU ball at higher weights lifted (from 60 to 90 kg). Though a set of data showed significant differences, the effect sizes≤0.7 suggest no practically meaningful differences. It may be concluded that unstable base compromises the power in the concentric phase of resistance exercises, however, only at higher weights lifted.

The study evaluates a reaction time in the Agility Test under simulated competitive and noncompetitive conditions. A group of 16 fit men performed, in random order, 2 versions of the Agility Test: non-competitive Agility Single and Agility Dual in form of simulated competition. In both cases, subjects had to touch, as fast as possible, with either the left or the right foot 1 of 4 mats located in 4 corners outside of an 80 cm square. Mats had to be touched in accordance with the location of the stimulus in one of the corners of the screen. The test consisted of 20 visual stimuli with random generation of their location on the screen and time generation from 500 to 2,500 milliseconds. The result was total reaction time (RT) for all 20 reactions measured by a PC-based system FiTRO Agility Check. Results showed significantly (p < 0.01) better RT in the Agility Dual than in the Agility Single Test (690.6 ± 83.8 milliseconds and 805.8 ± 101.1 milliseconds, respectively). Further comparisons of RT under noncompetitive and simulated competitive conditions for the best 8 subjects proceeded in the second match showed a decrease from 781.3 ± 111.2 milliseconds to 693.6 ± 97.8 milliseconds in the first match and to 637.0 ± 53.0 milliseconds in the second match. It may be concluded that RT is better when the Agility Test is performed in simulated competitive than noncompetitive conditions. The Agility Test in form of competition may be used for children and young athletes to enhance their attention level and motivation.

Aim: The study compares the power outputs in concentric phase of chest presses and squats performed without and with countermovement on stable and unstable support surface, respectively., Methods: A group of 16 physical education students performed randomly in four different days 3 repetitions of: 1) barbell chest presses on the bench and Swiss ball, respectively, and 2) barbell squats on stable support base and Bosu ball, respectively. Exercises were performed without and with countermovement (CM) using maximal effort in concentric phase of lifting. Initial weight of 20 kg increased by 10 kg or 5 kg (at higher loads) up to at least 85% of previously established 1RM under stable conditions. A PC based system FiTRO Dyne Premium was used to monitor force and velocity and to calculate power. As a parameter of the capability to use elastic energy was considered the difference in mean power in concentric phase of weight exercises (ΔP) performed with and without CM., Results: There were higher power outputs in concentric phase of CM chest presses as compared to those performed from quiet position on the chest under both stable and unstable conditions. This enhancement of power due to CM was rather modest at lower weights and become more pronounced with increasing weights reaching a maximum at 57.1% 1RM on stable and at 47.6% 1RM on unstable support surface. Lifting heavier weights not only failed to increase the enhancing effect but led to its decline. Similar trend was observed during squats with maximal enhancement of power in concentric phase of lifting at about 80% 1RM under both conditions. The ΔP was significantly lower during chest presses on Swiss ball than on the bench, however, only at higher weights lifted (≥60% 1RM). On the other hand, the ΔP during squats performed on Bosu ball and on stable support base did not differ significantly across all weights lifted., Conclusion: The ability to utilize elastic energy during CM chest presses is more profoundly compromised under unstable than stable conditions, namely at higher weights lifted. On the other hand, there is similar enhancement of power in concentric phase of CM squats on stable and unstable support surface regardless of weights lifted. Besides the type of exercise, this may be ascribed to different degree of instability of devices used (Swiss ball vs. Bosu ball).

The study compares power outputs in the concentric phase of chest presses and squats performed in the interval mode on stable and unstable surface, respectively. A group of 16 physical education students performed randomly on different days 6 sets of 8 repetitions of (a) chest presses on the bench and Swiss ball, respectively, and (b) squats on stable support base and Bosu ball, respectively, with 2 minutes of rest period between sets. The exercises were performed with previously established 70% of 1 repetition maximum under stable conditions. A PC-based system FiTRO Dyne Premium was used to monitor force and velocity and to calculate power. The results showed significantly lower power outputs when resistance exercises were performed on an unstable than a stable support base. In the initial set, mean power in concentric phase of lifting decreased more profoundly under unstable than under stable conditions during both chest presses (13.2 and 7.7%, respectively) and squats (10.3 and 7.2%, respectively). In the final set, the reduction rates of mean power in the concentric phase of chest presses were significantly (p < 0.05) greater on the Swiss ball than on the bench (19.9 and 11.8%, respectively). On the other hand, there were no significant differences in decline of mean power in the concentric phase of squats on the Bosu ball and on stable support base (11.4 and 9.6%, respectively). It may be concluded that power outputs during resistance exercises is more profoundly compromised under unstable than under stable conditions, and this effect is more evident for barbell chest presses on the Swiss ball than for barbell squats on the Bosu ball. These findings have to be taken into account when instability resistance exercises are implemented into the training program, namely, for sports that require production of maximal force in short time.

Objective: To compare the effects of isokinetic (ISO-K) and vibrational-proprioceptive (VIB) trainings on muscle mass and strength., Methods: In 29 ISO-K- or VIB-trained young athletes we evaluated: force, muscle fiber morphometry, and gene expression of muscle atrophy/hypertrophy cell signaling., Results: VIB training increased the maximal isometric unilateral leg extension force by 48·1%. ISO-K training improved the force by 24·8%. Both improvements were statistically significant (P⩿0·01). The more functional effectiveness of the VIB training in comparison with the ISO-K training was shown by the statistical significance changes only in VIB group in: rate of force development in time segment 0-50 ms (P<0·001), squat jump (P<0·05) and 30-m acceleration running test (P<0·05). VIB training induced a highly significant increase of mean diameter of fast fiber (+9%, P<0·001), but not of slow muscle fibers (-3%, not significant). No neural cell adhesion molecule-positive (N-CAM(+)) and embryonic myosin heavy chain-positive (MHC-emb(+)) myofibers were detected. VIB induced a significant twofold increase (P<0·05) of the skeletal muscle isoform insulin-like growth factor-1 (IGF-1) Ec mRNA. Atrogin-1 and muscle ring finger-1 (MuRF-1) did not change, but myostatin was strongly downregulated after VIB training (P<0·001). Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) expression increased in post-training groups, but only in VIB reached statistical significance (+228%, P<0·05)., Discussion: We demonstrated that both trainings are effective and do not induce muscle damage. Only VIB-trained group showed statistical significance increase of hypertrophy cell signaling pathways (IGF-1Ec and PGC-1α upregulation, and myostatin downregulation) leading to hypertrophy of fast twitch muscle fibers.

Aim: The study evaluates the effect of 6-week combined agility-balance training on neuromuscular performance in basketball players., Methods: Subjects divided into experimental (EG, n = 17) and control group (CG, n = 17) underwent a combined agility-balance training (in duration of 30 min) for a period of 6 weeks (4-5 sessions/week). Both groups performed reaction tasks similar to game-like situations, however EG on wobble boards and CG on stable surface. Prior to and after the training parameters of agility, balance, speed of step initiation, strength differentiation accuracy, and explosive power of lower limbs were evaluated. Postural stability was assessed under both static and dynamic conditions (wobble board) with eyes open and eyes closed, respectively. The velocity of the centre of pressure (COP) was registered at 100 Hz by means of posturography system FiTRO Sway check based on dynamometric platform. Using FiTRO Reaction check simple and multi-choice reaction times were measured. The same system was applied to evaluate the agility performance including reaction and movement task. Speed of step initiation was measured using FiTRO Dyne Premium. Jumping abilities were evaluated by means of FiTRO Jumper (10-seconds maximal jumps, Countermovement jump, Squat jump, Drop jump). Using the same system, the subject´s ability to match 50 % of their maximal height of the jump was evaluated., Results: Results showed that a combined agility-balance training improved dynamic balance not only under visual control but also in eyes closed conditions. Training also increased run-out speed that likely contributed to better agility performance, reduced ground contact time during drop jump, and improved the ability to differentiate the force of muscle contraction during repeated jumps. However, such training has been found to be insufficient to improve both simple and multi-choice reaction time, and jumping performance. On the other hand, control group failed to show any significant improvement in examined abilities except for enhancement of jumping performance (Pact, Δ CMJ & SJ)., Conclusion: It may be concluded that balance exercises performed simultaneously with reaction tasks represent an effective means for improvement of neuromuscular performance in elite athletes.

Transmissible spongiform encephalopathies (TSEs) are a family of neurodegenerative diseases characterized by their long incubation periods, progressive neurological changes, and spongiform appearance in the brain. There is much evidence to show that TSEs are caused by an isoform of the normal cellular surface prion protein PrPC. The normal function of PrPC is still unknown, but it exhibits properties of a cupro-protein, capable of binding up to six copper ions. There are two differing views on copper's role in prion diseases. While one view looks at the PrPC copper-binding as the trigger for conversion to PrPSc, the opposing viewpoint sees a lack of PrPC copper-binding resulting in the conformational change into the disease causing isoform. Manganese and zinc have been shown to interact with PrPC as well and have been found in abnormal levels in prion diseases. This review addresses the interaction between select trace elements and the PrPC.