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Background Postural sway during quiet standing has been shown as a useful task to assess risk of falling in older adults. While the risk of falling is consistently reported to be higher in older females than males, the sex-related differences in postural sway are not consistent across the studies. Research question What are the effects of age and sex on postural sway during quiet standing during different stance conditions? Methods We examined the effects of age (40 young and 34 older adults), sex (37 males and 37 females), and their interaction on the postural sway during different stance conditions. We compared the center of pressure (CoP) velocity, amplitude and frequency during parallel (eyes open and eyes closed) and semi-tandem (eyes open) stances. Results Our results suggest that postural sway is similar between sexes in young participants, while older males exhibit larger postural sway than older female participants (10/21 outcomes). Older female participants exhibited lower CoP amplitude (but larger total and anterior-posterior CoP velocity) compared to young female participants. We also found that the increase in the postural sway with increasing task difficulty is more pronounced in older vs. young adults. Significance This study shows that ageing-related changes in postural sway are sex- and task-specific. Researchers and clinicians need to be aware of these effects when comparing groups or monitoring changes in time.

Eccentric training proved to be effective in hamstring injury prevention ; however, little is known about effects of eccentric hamstring training at long muscle length on hamstring flexibility. Hence, the aim was to evaluate the effect of eccentric training at long muscle lengths on flexibility and passive properties of the hamstring muscles. 34 physically active young adults were randomized to either the control or intervention group (6 weeks of eccentric hamstring training at long muscle length ; control group resumed with their usual activities). Maximal passive hip flexion range of motion (ROM), passive hamstring stiffness, shear modulus and tendon length of the biceps femoris long head (BFlh) were measured pre- and post-intervention. A significant time × group effect was observed for maximal passive hip ROM. Post-hoc testing revealed a significant increase in the intervention group (+11.2% ; p < 0.001 ; d = 1.55). Additionally, a significant time effect was shown for shear modulus in a relaxed position (p < 0.001). No significant interaction was shown for other parameters. Results indicate that eccentric hamstring training at long muscle length elicits large gains in hamstring flexibility, which are most likely not related to changes in passive hamstring stiffness or BFlh distal tendon length.

The advanced communication networks require heterogeneous emerging technologies to be combined while enabling various future applications. The integration of 5G wireless and optical technology is considered an unavoidable approach to reach this goal. Based on 5G mobile communications and densification of cells, the upcoming idea of smart city becomes feasible and put on a lot of attention from the research community due to its effect on everyday life’s improvement and modernization. The concept of a smart city should support everything from electrical grids to traffic management and requires the transmission of a huge amount of data. Smart city planning with a reliable communication infrastructure that can provide stringent network requirements is unfeasible without the joint of optical and wireless technologies. This paper aims to provide an overview of recent developments of advanced optical networking to provide 5G transport networks and their applications in connecting a huge number of devices in future smart city infrastructures. The implementation of optical technologies in 5G core networking open numerous questions of how wireless and optical can coexist to provide sophisticated future applications, such as the smart city concept. Within this research, we will provide the answers to some of the key related questions.

Karuc, J, Mišigoj-Duraković, M, Šarlija, M, Marković, G, Hadžić, V, Trošt-Bobić, T, and Sorić, M. Can injuries be predicted by functional movement screen in adolescents? The application of machine learning. J Strength Cond Res 35(4): 910-919, 2021-This study used machine learning (ML) to predict injuries among adolescents by functional movement testing. This research is a part of the CRO-PALS study conducted in a representative sample of adolescents and analyses for this study are based on nonathletic (n = 364) and athletic (n = 192) subgroups of the cohort (16-17 years). Sex, age, body mass index (BMI), body fatness, moderate-to-vigorous physical activity (MVPA), training hours per week, Functional Movement Screen (FMS), and socioeconomic status were assessed at baseline. A year later, data on injury occurrence were collected. The optimal cut-point of the total FMS score for predicting injury was calculated using receiver operating characteristic curve. These predictors were included in ML analyses with calculated metrics: area under the curve (AUC), sensitivity, specificity, and odds ratio (95% confidence interval [CI]). Receiver operating characteristic curve analyses with associated criterium of total FMS score12 showed AUC of 0.54 (95% CI: 0.48-0.59) and 0.56 (95% CI: 0.47-0.63), for the nonathletic and athletic youth, respectively. However, in the nonathletic subgroup, ML showed that the Naïve Bayes exhibited highest AUC (0.58), whereas in the athletic group, logistic regression was demonstrated as the model with the best predictive accuracy (AUC: 0.62). In both subgroups, with given predictors: sex, age, BMI, body fat percentage, MVPA, training hours per week, socioeconomic status, and total FMS score, ML can give a more accurate prediction then FMS alone. Results indicate that nonathletic boys who have lower-body fat could be more prone to suffer from injury incidence, whereas among athletic subjects, boys who spend more time training are at a higher risk of being injured. Conclusively, total FMS cut-off scores for each subgroup did not successfully discriminate those who suffered from those who did not suffer from injury, and, therefore, our research does not support FMS as an injury prediction tool.

Downlink transmission techniques for multiuser (MU) multiple-input multiple-output (MIMO) systems have been comprehensively studied during the last two decades. The well-known low complexity linear precoding schemes are currently deployed in long-term evolution (LTE) networks. However, these schemes exhibit serious shortcomings in scenarios when users’ channels are strongly correlated. The nonlinear precoding schemes show better performance, but their complexity is prohibitively high for a real-time implementation. Two-stage precoding schemes, proposed in the standardization process for 5G new radio (5G NR), combine these two approaches and present a reasonable trade-off between computational complexity and performance degradation. Before applying the precoding procedure, users should be properly allocated into beamforming subgroups. Yet, the optimal solution for user selection problem requires an exhaustive search which is infeasible in practical scenarios. Suboptimal user grouping approaches have been mostly focused on capacity maximization through greedy user selection. Recently, overlapping user grouping concept was introduced. It ensures that each user is scheduled in at least one beamforming subgroup. To the best of our knowledge, the existing two-stage precoding schemes proposed in literature have not considered overlapping user grouping strategy that solves user selection, ordering, and coverage problem simultaneously. In this paper, we present a two-stage precoding technique for MU-MIMO based on the overlapping user grouping approach and assess its computational complexity and performance in IoT-oriented 5G environment. The proposed solution deploys two-stage precoding in which linear zero forcing (ZF) precoding suppresses interference between the beamforming subgroups and nonlinear Tomlinson-Harashima precoding (THP) mitigates interuser interference within subgroups. The overlapping user grouping approach enables additional capacity improvement, while ZF-THP precoding attains balance between the capacity gains and suffered computational complexity. The proposed algorithm achieves up to 45% higher MU-MIMO system capacity with lower complexity order in comparison with two-stage precoding schemes based on legacy user grouping strategies.

Objectives This study examined the relationship between functional movement and physical activity (PA) levels in adolescents. Design Cross-sectional study. Setting This research is a part of the CRO-PALS longitudinal study conducted in a random sample of adolescents in Zagreb at the Faculty of Kinesiology, University of Zagreb, Croatia. Participants Seven hundred and twenty-five adolescents aged between 16 and 17 years were included. Main outcome measure Total Functional Movement Screen score (total FMS score). Results After adjusting for age, body fat and SES, both VPA and MVPA showed minor but significant effects on total FMS score among girls (β = 0.011, p = 0.001, β = 0.005, p = 0.006, respectively), but not in boys (β = 0.004, p = 0.158; β = 0.000, p = 0.780). Regarding PA type, volleyball and dance improved total FMS score (β = 1.003, p = 0.071; β = 0.972, p = 0.043, respectively), while football was associated with lower FMS score (β = −0.569, p = 0.118). Conclusion Results suggest that the PA level is positively associated with the functional movement in adolescent girls, but not in boys, where the type of PA moderates these associations. Therefore, functional movement patterns incorporated into physical education curriculum could be beneficial to the musculoskeletal health of the children.

Recently, the two-point method of force–velocity (F–V) profiling of multi-joint human movements has been introduced and validated. In this study, we investigated the validity of estimating the jumping F–V profile using only bodyweight jump and isometric maximal voluntary contraction (MVC) task. Participants (n = 30) performed 3 repetitions of squat (SJ) and counter-movement jumps (CMJ), each at loads that were progressively increased by 10 kg increments, with the number of loads depending on the individual’s ability. Then, 3 isometric MVC trials were performed in 3 knee angles (30°, 60° and 90°). F–V profiling of SJ and CMJ were performed using the multiple-point method, the two-point method, and the novel Jump-MVC method. The results showed poor to fair validity of the novel Jump-MVC method for assessing jumping F–V profile (most ICC 10%, significant systematic bias present, and the presence of proportional bias). The exception was the estimation of theoretical maximal power, which was highly valid for both SJ and CMJ (ICC = 0.91–0.95; CV = 5.0–6.3%). In contrast, validity of the two-point method was excellent (all ICC > 0.90; CV = 2–6%). Although additional studies are needed, present results suggest that the F–V profiling of vertical jumps should be performed using the two-point method with distal loads.

Networks with distributed sensors, e.g. cognitive radio networks or wireless sensor networks enable large-scale deployments of cooperative automatic modulation classification (AMC). Existing cooperative AMC schemes with centralised fusion offer considerable performance increase in comparison to single sensor reception. Previous studies were generally focused on AMC scenarios in which multipath channel is assumed to be static during a signal reception. However, in practical mobile environments, time-correlated multipath channels occur, which induce large negative influence on the existing cooperative AMC solutions. In this paper, we propose two novel cooperative AMC schemes with the additional intra-sensor fusion, and show that these offer significant performance improvements over the existing ones under given conditions.

The paper analyzes the dependence of the stiffness of the support frames of the cranes with loading-unloading trolley on the change of geometrical parameters of the frames. The calculation model of the frames with transverse stiffness was formed because it additionally stiffens the supporting surface of the frames for connection with the axial-radial bearing. The relations of characteristic geometrical sizes of longitudinal and transverse elements were established, at which the necessary stiffness of the frames of loading-unloading trolley was achieved. Also, the variables and constants of geometric size were introduced, as well as the constant values of appropriate coefficients, the variation of which provides the possibility to form the optimal structure of the frames of loading-unloading trolley.

The specific problem that occurs in multi- criteria decision-making (MCDM) processes is ranking a number of alternatives using complex criteria functions (the hierarchical structure of criteria) whose values must consider the impacts of all-important characteristics and parameters of alternatives. The problem becomes more complex by increasing the number of levels of sub- criteria functions (degree of decomposition). This paper proposes an extended procedure based on the mean values conversion of the net outranking flow of sub-criterion functions obtained by modified PROMETHEE methods. The actual value of criterion functions is used only at the last level, and transformed values of the net outranking flow for generating a final rank of alternatives are introduced at other levels. This procedure provides a more objective comparison of the impact of various individual criteria to rank the alternatives and easier making of unique solution, where the impact of decision-maker (DM) experience and subjective estimation is minimised in the selection. Applicability and practicability of the presented procedure for solving the selection problem of a logistics warehouse location are demonstrated in the analysis of a case study example.

Amongst others, the deformation criterion is to be fulfilled in the process of steel structure design. Often, it can be more restrictive than the stress criterion. Although the stress state is within the permissible limit, excessive structure deformation can lead the additional load to emerge in the carrying structure and cause improper operation and shorter life of attached devices and equipment. For that reason, besides other requirements, the allowable deformation limits of the steel carrying structure are defined. The stress-strain analysis of the structure is usually conducted by utilization of finite element method (FEM) in the early phase of the design process. Alternatively, this paper shows the application procedure of the finite difference method (FDM) for the deflection determination on the simple elastically restrained cantilever beam with continuously varying box-like cross-section and linear change of section height. Dependence of the deflection on the design parameters is obtained through programming in MATLAB and the comparison is made with the results from the finite element model built in ANSYS. The results from both numerical approaches showed excellent compliance.

This research has presented the built-up column analysis with batten, applied to crane runaway support, where stability is put in the foreground. Also, optimization of all essential geometrical parameters of the built-up column was performed for a given height of the crane column and changing the load capacity. The chord members were composed of as-welded I-sections instead of fabricated hot rolled sections witch are commonly used in these constructions. The mass of the built-up columns, which consists of the chord and Web members (battens) members, was taken as the goal function in this research. Additional stability and load capacity conditions were used as constraint functions, as well as specific design recommendations. The optimization procedure was performed in the Ms. EXCEL software package, using the GRG2 algorithm because certain benefits are essential in this optimization problem. In this way, the justification of applying the proposed model of calculation and optimization was shown because the necessary geometrical parameters can be reached very quickly when designing these types of structures, considering that there are a large number of variables and constraint functions. It is also shown how the mass of the column changes and the optimal geometric parameters when the compression force on the column of the runaway crane support increases.

This study compared biomechanical characteristics and physiological responses during rowing on three devices: (i) stable ergometer (STE), (ii) transversally compliant ergometer (TCE) and (iii) frontally compliant ergometer (FCE). Eleven young competitive rowers completed a 2000 meter simulated race under each of the ergometer conditions in a randomized order. Stroke rate, average force, power output, velocity and amplitude of the handle and stretcher or seat, heart rate and blood lactate were measured at 500 m intervals. Force and power at the stretcher were significantly lower (p < 0.03) for TCE, while stroke rate and velocities of the handle and the seat were higher (p < 0.01). No significant differences were observed between STE and FCE in biomechanical parameters. The lowest rowing performance was observed in FCE (p = 0.007), and was accompanied with the highest average heart rate (p = 0.031). Our findings indicate that in TCE, rowers modified their technique, but were able to maintain physiological strain and performance. In contrast, FCE had no effect on rowing biomechanics, but decreased rowing performance and increased physiological strain. It seems plausible that transversal, but not frontal compliance, elicited a biomechanical technique that might reduce the discrepancy between a rowing ergometer and on-water rowing.

Smart city concept gained a lot of attention from the research community due to its effect on everyday life. The implementation of smart city applications requires a reliable smart infrastructure. New applications set high requirements on the communication network infrastructure such as low latency, high bandwidth, availability, and security. This paper aims to provide an overview of key developments in optical networking for 5G transport and their application in connecting a huge number of devices in smart infrastructures. Requirements on optical networks to support 5G transport, development activities, and research directions are pointed out in this paper.

Modelling the dynamic behaviour of elevators with high lifting velocities (contemporary elevators in building construction and mine elevators) is a complex task and an important step in the design process and creating conditions for safe and reliable exploitation of these machines. Due to high heights and lifting velocities, the standard procedures for dynamic exploitation are not adequate. The study presents the method of forming a dynamic model to analyse nonstationary vibrations of a rope with time-varying length with nonholonomic boundary conditions in the position where the rope is connected with the cabin (cage) and in the upcoming point of its winding onto the pulley (drum). A unique method was applied to identify the basic parameters of the dynamic model (stiffness and damping) based on experimental measures for a concrete elevator. Due to the verification of this procedure, the experiment was conducted on a mine elevator in RTB Bor, Serbia. Using the obtained computer-experimental results, the simulations of the dynamic behaviour of an empty and loaded cage were shown. In addition, the study shows the specific method as the basis for forming a control program that would enable the decrease in vertical vibrations during an elevator starting and braking mode.

Wheat and corn are main source of carbohydrates in the human and domestic animals diet. Growing need for the production of quality proteins dictates the use of other cereals for this purpose. Cyprinids (Cyprinidae) are the most common fish in world aquaculture. In the numerous experiments were performed with the replacement of wheat and corn with other cereals in feed mixtures for these species. It has been established that the value of cereals for this purpose can be ranked: wheat > triticale > corn > barley > rye > sorghum > millet.

Background: Ankle sprain is the most common acute time-loss injury in volleyball and occurs mainly during landing from a jump. Therefore we have evaluated the role of quadriceps strength and countermovement jump height on ankle sprain occurrence, as these intrinsic modifiable risk factors were not yet evaluated. We have also hypothesised that presence of quadriceps strength asymmetry could be a possible risk factor for ankle sprains in male volleyball players. Methods: This was a prospective cohort study. Male volleyball players (N = 99) from Slovenian national league participated in the study. Before the start of the season, all participants completed a preseason questionnaire and underwent evaluation of vertical jump performance and bilateral isokinetic strength of the quadriceps (Q) and hamstrings (H). During the subsequent season the players reported acute time loss injuries because of ankle sprain through a weekly questionnaire. Results: We have registered 19 ankle sprains during the season. Overall ankle sprain incidence was 0.41±0.24 per 1000 h. Previous ankle sprain (odd ratio 0.86 ; 95% CI 0.25 - 2.89, p = 0.802) and jump height (1.05 ; 95% C.I. 0.94 - 1.19, p = 0.393) were not significant risk factors, while Q strength asymmetry was a significant predictor of an ankle sprain (odd ratio 0.956 ; 95% CI 0.919-0.995, p = 0.026). Compared with the uninjured players, the injured players had higher right concentric Q strength, higher Q strength asymmetry, and lower concentric right H-Q strength ratio (all p

In this research, the problem of calculating the necessary static quantities of the main girder with the box crosssection of the double-beam bridge crane with two trolleys were analyzed. The aim is to determine the critical position on the girder due to the action of all loads in the vertical plane, as a function of input parameters, and to obtain expressions for calculating deflections in the vertical and horizontal planes, as well as bending moments in these planes, ie maximum (total) stress in the girder. Verification of the results was carried out in the SAP2000 software package, with proved a quite good correlation between the results obtained, for the proposed method of the calculation model of the box-girder, in the mentioned software package. The goal of this research is primarily to show how the application of the SAP2000 software package in an easy, fast and simple way can perform the dimensioning and design of this type of carrying structures, taking into account important static conditions that must be satisfied. By applying the proposed modelling method and using a certain module in the mentioned software package, the designer easily achieves the preliminary geometric values of the girder in the initial design phase, where he can completely rely on the obtained results. Also, all geometric quantities necessary for further phases in the design and calculation are obtained. Guidelines are given on how to prepare a calculation model in this software package for these types of carrying structures, as well as recommendations related to the design of these types of carrying structures made of S355 material.

Velocity and intensity in business surroundings are continuously accelerating and it is no longer possible, as it used to be, to plan linearly and make strategic decisions. Instead, it is necessary to adapt to more agile planning methods and evaluations of market opportunities. For the last couple of years, the method of Business model canvas has become vastly popular, especially in the start-up community. However, this method at its essence does not take account for strategic positions, meaning it doesn't consider analysis of the competitors and their offers, which make it unsuited for already established companies - incumbents. For these reasons this paper is based on the idea that the classical method of strategic planning should be merged with the Business model canvas method to achieve the most out of both approaches. The suggested new method is being developed step by step, through recognition of individual metamodels and afterwards their synthesis, across shared elements, to a completely new method. To prove this new method works and assure its dynamic aspect, a demonstrational prototype in MS Access tool has been created.

The paper presents implementation of LoRa Mapper system developed for the purpose of determining network coverage of LoRaWAN (and other) networks by using LoRa measurement modules. This system combines device for measuring of achieved coverage, and complete software (server and user application) for processing of received packets, i.e. for the visualization of the obtained measurement data. The main goal was to enable a simpler coverage mapping for LoRaWAN networks, although it is possible to simultaneously measure coverage of other wireless networks, and to achieve this with the satisfactory quality at the lowest possible cost. The paper explains the concept of LoRa Mapper operation, the method of implementation, and gives first results of testing this system in real-life conditions.

This study examined the association between functional movement (FM) and adiposity in adolescent population (16&ndash, 17 years). This study was conducted in a representative sample of urban adolescents as the part of the CRO-PALS longitudinal study (n = 652). Body mass index (BMI), a sum of four skinfolds (S4S), waist and hip circumference were measured, and FM was assessed via Functional Movement ScreenTM (FMSTM). Furthermore, total FMSTM screen was indicator of FM with the composite score ranged from 7 to 21, with higher score indicating better FM. Multilevel analysis was employed to determine the relationship between different predictors and total FMS score. In boys, after controlling for age, moderate-to-vigorous physical activity, socioeconomic status, and total FMS score was inversely associated with BMI (&beta, = &minus, 0.18, p &lt, 0.0001), S4S (&beta, 0.04, p &lt, 0.0001), waist circumference (&beta, 0.08, p &lt, 0.0001), and hip circumference (&beta, 0.09, p &lt, 0.0001). However, among girls, in adjusted models, total FMS score was inversely associated with S4S (&beta, 0.03, p &lt, 0.0001), while BMI (&beta, 0.05, p = 0.23), waist circumference (&beta, 0.04, p = 0.06), and hip circumference: &beta, 0.01, p = 0.70) failed to reach statistical significance. Results showed that the association between adiposity and FM in adolescence is sex-specific, suggesting that boys with overweight and obesity could be more prone to develop dysfunctional movement patterns. Therefore, exercise interventions directed toward correcting dysfunctional patterns should be sex-specific, targeting more boys with excess weight rather than adolescent girls with excess weight.

This paper presents analysis and optimization of the geometric parameters of T and I cross-sections of crane hook, observed for the most critical location of its structure. The reduction of the cross-sectional area of crane hook was set as the goal in this study. The stresses at characteristic points of the most critical cross-section are taken as constraint functions, calculated according to Winkler-Bach theory, and some geometric conditions are set, too. Two metaheuristic algorithms based on the laws of physics, Charged System Search (CSS) algorithm and Thermal Exchange Optimization (TEO) algorithm, were selected for optimization methods, using by MATLAB software package. The goal of this research is to show that the proposed cross-sections give significant savings in comparison to standard crane hook, wherein the one standard capacity was observed. Both observed cross-sections were analyzed in two variants, and the comparison of their optimization results was performed to show which one achieves the best results. Also, the comparison of the applied optimization algorithms was performed.

A field trial was conducted on an acid pseudogley soil during the 2011/12, 2012/13 and 2013/14 growing seasons to evaluate grain yield and its components in four triticale cultivars ('Favorit', 'Tango', 'Odisej' and 'KG-20'). The highest values of grain yield, 1,000-grain weight, number of grains per spike, spike length and plant height in all cultivars were obtained in the year characterised by moderate temperatures during grain filling and high amounts of rainfall in the second part of the growing season. 'Favorit' gave the highest grain yield, the largest number of grains per spike, the lowest 1,000-grain weight and the smallest plant height. The highest 1,000-grain weight and the lowest number of grains per spike were found in 'Tango'. 'KG-20' had the greatest plant height and the lowest average grain yield during the three experimental years, with the lowest grain yield achieved in the driest year, and the highest in the wettest year. 'Odisej' exhibited a high grain yield, fewer grains per spike, and the lowest grain weight per spike compared to the other cultivars.

The paper presents the connection of rotating platforms in building and transport machines depending on the type of driving mechanism. A special attention is paid to axial-radial bearings having big diameters made by prominent manufacturers. There are some necessary conditions which have to be met by supporting frames because working capacity of the bearings depends on them. Also, the law of distribution of load of moment of external forces is proposed because it provides identification of maximum load as a starting basis for further research on determination of optimal laws of distribution of acting forces which are caused by the moment of forces.

The paper’s purpose is to analyze the provisions of the first Soviet Constitution in terms of the relationship between the legislative and executive political institutions, and to examine whether and to what extent the principle of unity of powers had been prescribed. The analysis is based on the legal method, since the competences and the relationship of legislative and executive institutions had been explicitly prescribed by the Constitution. It also contains an analysis of the theoretical approach of the Marxist theoreticians to the system of government. The conclusion is that the Constitution of the Russian Socialist Federal Soviet Republic prescribed the principle of democratic unity of powers, and the system of assembly government, which had been based on the superiority of the representative body over the executive. However, it had not been a “clear” system of assembly government, since the executive (Sovnarkom [the Soviet of People’s Commissars]) had some important competences. Although th...

Hamstring strain injuries during sprinting or stretching frequently occur at long-muscle length. Yet, previous research has mainly focused on studying the effectiveness of eccentric hamstring strengthening at shorter muscle length on hamstring performance, morphology, and hamstring strain injury risk factors. Here, we evaluated the effects of 6-week eccentric hamstring training at long-muscle length on functional and architectural characteristics of the hamstrings. Healthy and injury-free participants (n = 40 ; age 23.7 +/- 2.5 years) were randomly assigned to control or intervention group. Training intervention consisted of 12 sessions with two eccentric hamstring exercises in a lengthened position. Outcome measures included isokinetic and isometric knee flexion peak torque, Nordic hamstring exercise peak torque, voluntary activation level, and countermovement jump performance. Ultrasonography was used to determine muscle thickness, pennation angle, and fascicle length of biceps femoris long head (BFlh). A significant time x group interaction effect was observed for all measured parameters except countermovement jump performance and muscle thickness. The training intervention resulted in increased concentric and eccentric knee flexion peak torque at 60 degrees/s (d = 0.55- 0.62, P = .02 and .03) and concentric peak torque at 180 degrees/s (d = 0.99, P = .001), increased isometric knee flexion peak torque (d = 0.73, P = .008) and Nordic hamstring exercise peak torque (d = 1.19, P < .001), increased voluntary activation level (d = 1.29, P < .001), decreased pennation angle (d = 1.31, P < .001), and increased fascicle length (d = 1.12, P < .001) of BFlh. These results provide evidence that short-term eccentric hamstring strengthening at long-muscle length can have significant favorable effects on various architectural and functional characteristics of the hamstrings.

IntroductionThe prevalence of overweight subjects in military cohorts increases despite the obligatory army physical fitness test (APFT) requirements and the negative consequences of possible test failure due to the increased body mass index (BMI). Studies that have examined the association of BMI with baseline fitness in the military are showing conflicting evidence. The primary aim of the study is to examine BMI effects on baseline fitness that was measured by APFT and additional functional performance tests (FT) (vertical countermovement jump with and without load, loaded prone plank, single-leg hamstring bridge test and pull-ups). Our secondary goal is to explore if regular strength training modifies the BMI effect on baseline fitness.MethodsA cross-sectional study on a sample of 118 male infantry soldiers that have performed APFT and FT was carried out. Body mass and body height measurements were used to calculate BMI, and to categorise participants into BMI ranks. Two independent categorical variables (BMI rank and strength training) were used to evaluate their influence on dependent variables of physical performance acquired from APFT and FT.ResultsA significantly large size effect of BMI rank (F=1.69, p=0.037; effect size (ES)=0.15) and regular strength training (F=2.66, p=0.006; ES=0.21) on physical performance was found. It was shown that strength training had a medium ES on push-up and pull-up performance, as well as on the overall APFT score and loaded plank.ConclusionsThe importance of regular strength training and normal BMI for better overall baseline fitness in infantry members was highlighted. Most importantly, it was shown that performance is not affected in overweight soldiers who are performing regular strength training in addition to their daily physical training.Trial registration numberNCT03415464

The current study aims to investigate the acute effects of light aerobic activity, static stretching (SS), strengthening and explosive exercises on lower-body muscular performance and range of motion (ROM). Dose-response effect of SS on performance and ROM was also studied. Nineteen young male soccer players (age: 13.9 ± 0.46 years) participated in a cross-over randomized trial. Participants performed 5-minute aerobic activity, followed by seven bouts of SS of calf, quadriceps, adductor and hamstring muscles lasting 20 seconds each. Additionally, two sets of strengthening and explosive exercises were performed after SS in the experimental condition. Power and strength were assessed by counter-movement jump (CMJ) and maximal voluntary contraction of hip adductors, while 3 flexibility tests were used for assessing ROM of lower body. Repeated-measures ANOVA revealed an increase in CMJ performance after aerobic activity, followed by a decrease after SS in a dose-dependent manner that continued to be present 15 minutes post-SS. Strengthening and explosive exercises did not neutralize the acute negative effects of SS on CMJ performance. No significant acute effect of selected interventions on maximal and explosive strength of hip adductors was observed. Finally, sit-and-reach and hip abduction ROM increased after aerobic activity and continued to increase throughout the SS protocol, and was preserved 15 minutes post-SS. Our results confirm that SS can impair lower-body power in young soccer players, and that these negative effects last at least 15 minutes. Excessive use of SS, as performed in this study, should be avoided during warm-up of young soccer players.

The aim of this study was to prospectively examine the association between isometric hip adductor strength and between-limb strength asymmetry to groin injuries in male professional soccer players. Isometric hip adductor strength and between-limb strength asymmetry of 45 professional outfield soccer players from three First Division teams were tested during the 2017/2018 preseason. Players were then monitored throughout the 2017/2018 season for groin injuries. Ten groin injuries were recorded. When compared with uninjured players, players who sustained groin injury had significantly lower strength of respective muscle groups and significantly higher between-limb strength asymmetries (all p &lt, 0.05, ES = 1.16 and 0.88, mean % difference = 26% and 51%). Isometric hip adductor strength had a significant inverse relationship with the incidence of occurring groin injuries (p = 0.016). No significant relationship between hip adductor strength asymmetry and the incidence of future groin injury was observed (p = 0.09). Finally, players&rsquo, age and previous groin injury were not significantly associated with the incidence of future groin injuries (all p &gt, 0.05). These results generally suggest that isometric adductor strength is a significant predictor of future groin injuries in men&rsquo, s professional football, however, due to the relatively low sample size, further studies are required.