Spatial distribution of major and trace elements in artificial lakes in Serbia: health risk indices and suitability of water for drinking and irrigation purposes.

Lakes and reservoirs are the main water resources for household, irrigation, and industrial use. Hence, it is necessary to control water pollution and have reliable information on water quality, which refers to its suitability for a particular purpose. The main objective of this study was to evaluate the suitability of water for drinking and irrigation purposes from ten artificial lakes on the territory of the Republic of Serbia. The physicochemical parameters were determined using standard analytical methods, whereas the optical emission spectrometry with inductively coupled plasma, ICP-OES, was used to determine the concentrations of 23 macro-, micro-, and trace elements in water. Health risk indices of drinking water and its suitability for irrigation purposes were evaluated. The results of physicochemical parameters, except for total organic matter, indicated that most samples were within the recommended values. Among analyzed elements, the concentration of Mg was elevated in the water of the lakes Srebrno and Prvonek. The results of health risk assessment clearly showed that there was no acute health risk (HQA < 1), whereas long-term risk (HQL) in the studied lakes was observed with respect to As (lakes Grliste and Srebrno), Mn (lakes Srebrno and Prvonek), Ni (Lake Vrutci), and Sr (Lake Grliste). The irrigation criteria indicated that the water from the examined lakes had satisfactory quality for this purpose, except for residual sodium carbonates (RSC). This criterion indicated low quality or unsuitability of the water in 7 lakes. The main outcomes provided valuable information on the suitability of water from the artificial lakes for intended uses.

Backheel Pass During Forward Running as a Mechanism of Severe Acute Hamstring Injury in Football: A Case Report.

ABSTRACT: Proximal hamstring tendon avulsions represent the most severe hamstring injury in sports and are typically sustained during stretch-related movements in closed kinetic chain: forced hip hyperflexion combined with knee extension. Here, we present the case study of the right-foot dominant professional football player with a severe proximal hamstring tendon avulsion injury and concomitant lower-grade injuries of hamstring muscle-tendon complex caused by a potentially new football-specific injury mechanism: right-foot backheel pass during forward running (ie, a kick directly backward). This mechanism involves a specific stretch-shortening cycle action of hamstring muscles in open-kinetic chain movement that has not yet been described in the scientific literature. Although further studies related to this football-specific hamstring injury mechanism are needed, clinicians and coaches working in football should be aware of it and potentially introduce additional injury mechanism-specific exercises and strategies for prevention of severe hamstring injuries which often require surgical intervention.

Quadriceps strength asymmetry as predictor of ankle sprain in male volleyball players.

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 hypothesized 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 (Odds Ratio: 0.86; 95% CI: 0.25-2.89, P=0.802) and jump height (1.05; 95% CI: 0.94-1.19, P=0.393) were not significant risk factors, while Q strength asymmetry was a significant predictor of an ankle sprain (Odds 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<0.03). CONCLUSIONS: Our results suggest that excessive concentric strength of the right Q, which leads to low H-Q strength ratio, and high bilateral Q strength asymmetry in favor of the right side, could be associated with increased risk of ankle sprains in male volleyball.

Effects of age, sex and task on postural sway during quiet stance.

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.

GIS-Based Forest Fire Susceptibility Zonation with IoT Sensor Network Support, Case Study-Nature Park Golija, Serbia.

The territory of the Republic of Serbia is vulnerable to various natural disasters, among which forest fires stand out. In relation with climate changes, the number of forest fires in Serbia has been increasing from year to year. Protected natural areas are especially endangered by wildfires. For Nature Park Golija, as the second largest in Serbia, with an area of 75,183 ha, and with MaB Reserve Golija-Studenica on part of its territory (53,804 ha), more attention should be paid in terms of forest fire mitigation. GIS and multi-criteria decision analysis are indispensable when it comes to spatial analysis for the purpose of natural disaster risk management. Index-based and fuzzy AHP methods were used, together with TOPSIS method for forest fire susceptibility zonation. Very high and high forest fire susceptibility zone were recorded on 26.85% (Forest Fire Susceptibility Index) and 25.75% (fuzzy AHP). The additional support for forest fire prevention is realized through an additional Internet of Thing (IoT)-based sensor network that enables the continuous collection of local meteorological and environmental data, which enables low-cost and reliable real-time fire risk assessment and detection and the improved long-term and short-term forest fire susceptibility assessment. Obtained results can be applied for adequate forest fire risk management, improvement of the monitoring, and early warning systems in the Republic of Serbia, but are also important for relevant authorities at national, regional, and local level, which will be able to coordinate and intervene in a case of emergency events.

Factorial Structure of Trunk Motor Qualities and Their Association with Explosive Movement Performance in Young Footballers.

This study examined the factorial structure of trunk motor qualities and their associations with explosive muscular performance of football players. Ninety-one young male football players (age: 15-21 years; body height: 1.78 ± 0.07 m; body mass: 70.3 ± 7.5 kg) performed a series of tests: four standing and four seated isometric trunk strength tests, seven trunk power (medicine ball throwing) tests, four trunk endurance tests and four explosive movement performance tests. A principal component factor analysis (PCA) was used to determine the structure of trunk motor qualities, and correlational analyses were used to assess linear associations between trunk motor qualities and explosive performance. The PCA revealed four independent factors-trunk power, standing and seated isometric trunk strength, and trunk muscle endurance. Only trunk power had significant moderate, logically positive associations with sprint and vertical jump performance (common variance: 25-36%), while other associations between trunk motor factors and explosive movement performance were generally low to very low. These results indicate that trunk muscle functions of football players can be described with three independent motor qualities-trunk power, trunk strength and trunk muscle endurance, with only trunk power being moderately associated with players' sprinting and jumping performance.

Effects of Nordic hamstring exercise combined with glider exercise on hip flexion flexibility and hamstring passive stiffness.

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.

Can Injuries Be Predicted by Functional Movement Screen in Adolescents? The Application of Machine Learning.

ABSTRACT: Karuc, J, Misigoj-Durakovic, M, Sarlija, M, Markovic, G, Hadzic, V, Trost-Bobic, T, and Soric, 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 score >12 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.

Relationship between force-velocity-power profiles and inter-limb asymmetries obtained during unilateral vertical jumping and singe-joint isokinetic tasks.

We explored the associations between force-velocity-power (FVP) profiles and inter-limb asymmetries in FVP profiles obtained during unilateral jumping and single-leg isokinetic knee extension and flexion tasks. Thirty (13 senior and 17 junior) basketball players performed unilateral jumps with different levels of unloading (0-40% body mass) and isokinetic knee extension and flexion at different angular velocities (60-300°/s) with each leg. Senior and junior basketball players exhibited similar jump performance, normalized knee extensor and flexor strength, and relatively similar jumping and isokinetic FVP profiles. No significant associations between unilateral jump and isokinetic knee extension and flexion FVP parameters were found (all r ≤ 0.26; p > 0.05). Inter-limb asymmetries had no or very weak associations with unilateral jump height (-0.2 < r < 0.2; all p > 0.1); also, inter-limb asymmetries in jump and isokinetic FVP parameters were generally weakly associated (median r < 0.1). Finally, unilateral jump height was weakly-to-moderately associated with isokinetic F0, jumping Pmax, and normalized knee extension isokinetic peak torque at 60°/s and 240°/s (r = 0.35-0.57). These results suggest that the generalizability of the FVP profile of isolated muscle groups to complex ballistic tasks is weak.

Association between trunk muscle strength and static balance in older women.

The aim of this study was to determine the relationship between trunk muscle strength and balance ability in both simple and dual-task conditions in older women. Sixty-seven older women (age: 67.2 ± 1.1 years) volunteered in this study. Each participant performed isometric trunk muscle strength testing in standing position (extension, flexion, and lateral flexion) and balance testing in semitandem stance for 30 seconds in two conditions: with and without an additional cognitive task (counting down by 3 from 300). Balance was quantified via force plate as a mean velocity of center of pressure (CoP) displacement over 30 seconds. We found a statistically significant correlation between the trunk extensor strength and mean velocity of CoP displacement, both without (r = 0.5, p < .05) and with an additional cognitive task (r = 0.4, p < .05). There were no statistically significant correlations between trunk flexor and lateral flexors strength and balance measures (r < 0.2; p > .05). These results indicate that trunk extensor muscle strength is related to balance ability of healthy older women. Although additional studies are needed, our findings suggest that trunk strength training could be of importance in prevention of falls and fall-related injuries in seniors.

Is Adiposity Associated with the Quality of Movement Patterns in the Mid-Adolescent Period?

This study examined the association between functional movement (FM) and adiposity in adolescent population (16-17 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 (ß = -0.18, p < 0.0001), S4S (ß = -0.04, p < 0.0001), waist circumference (ß = -0.08, p < 0.0001), and hip circumference (ß = -0.09, p < 0.0001). However, among girls, in adjusted models, total FMS score was inversely associated with S4S (ß = -0.03, p < 0.0001), while BMI (ß = -0.05, p = 0.23), waist circumference (ß = -0.04, p = 0.06), and hip circumference: ß = -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.

Force-velocity profile during vertical jump cannot be assessed using only bodyweight jump and isometric maximal voluntary contraction tasks.

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 < 0.5, most CV > 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.

Movement quality in adolescence depends on the level and type of physical activity.

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 (ß = 0.011, p = 0.001, ß = 0.005, p = 0.006, respectively), but not in boys (ß = 0.004, p = 0.158; ß = 0.000, p = 0.780). Regarding PA type, volleyball and dance improved total FMS score (ß = 1.003, p = 0.071; ß = 0.972, p = 0.043, respectively), while football was associated with lower FMS score (ß = -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.

Adductor Muscles Strength and Strength Asymmetry as Risk Factors for Groin Injuries among Professional Soccer Players: A Prospective Study.

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 < 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' age and previous groin injury were not significantly associated with the incidence of future groin injuries (all p > 0.05). These results generally suggest that isometric adductor strength is a significant predictor of future groin injuries in men's professional football; however, due to the relatively low sample size, further studies are required.

Effects of eccentric training at long-muscle length on architectural and functional characteristics of the hamstrings.

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 × 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°/s (d = 0.55-0.62, P = .02 and .03) and concentric peak torque at 180°/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.

Does Sex Dimorphism Exist in Dysfunctional Movement Patterns during the Sensitive Period of Adolescence?

This study aimed to investigate sex difference in the functional movement in the adolescent period. Seven hundred and thirty adolescents (365 boys) aged 16-17 years participated in the study. The participants performed standardized Functional Movement Screen™ (FMSTM) protocol and a t-test was used to examine sex differences in the total functional movement screen score, while the chi-square test was used to determine sex differences in the proportion of dysfunctional movement and movement asymmetries within the individual FMSTM tests. Girls demonstrated higher total FMSTM score compared to boys (12.7 ± 2.3 and 12.2 ± 2.4, respectively; p = 0.0054). Sex differences were present in several individual functional movement patterns where boys demonstrated higher prevalence of dysfunctional movement compared to girls in patterns that challenge mobility and flexibility of the body (inline lunge: 32% vs. 22%, df = 1, p = 0.0009; shoulder mobility: 47% vs. 26%, df = 1, p < 0.0001; and active straight leg raise: 31% vs. 9%, df = 1, p < 0.0001), while girls underperformed in tests that have higher demands for upper-body strength and abdominal stabilization (trunk stability push-up: 81% vs. 44%, df = 1, p < 0.0001; and rotary stability: 54% vs. 44%, df = 1, p = 0.0075). Findings of this study suggest that sex dimorphisms exist in functional movement patterns in the period of mid-adolescence. The results of this research need to be considered while using FMSTM as a screening tool, as well as the reference standard for exercise intervention among the secondary school-aged population.

Nordic Hamstring Strength of Highly Trained Youth Football Players and Its Relation to Sprint Performance.

Markovic, G, Sarabon, N, Boban, F, Zoric, I, Jelcic, M, Sos, K, and Scappaticci, M. Nordic hamstring strength of highly trained youth football players and its relation to sprint performance. J Strength Cond Res 34(3): 800-807, 2020-We aimed to characterize Nordic hamstring (NH) strength and bilateral NH strength asymmetry in highly trained youth footballers and to investigate the relationship between NH strength and sprint performance. Twenty-two adult and 133 highly trained youth footballers in the age groups U12-U18 participated in this study. Eccentric hamstring strength was assessed using the NH device. Youth footballers (n = 119) also performed 20-m sprint test. Age-related changes in absolute and relative NH strength, and bilateral NH strength asymmetry were analyzed using 1-way analysis of variance. The linear relationship between relative NH strength and sprint performance was established using a Pearson correlation analysis. Significant age-related increases (F = 3.6-18.9; all p < 0.01) in NH strength were reported for all units except N·kg (F = 1.9; p = 0.08). The largest differences in absolute NH strength were seen between U15 and U16 groups. Bilateral NH strength asymmetry varied from 8 to 16% (F = 1.8; p = 0.09) across all age groups. A large correlation between NH strength and sprint performance was observed (r = -0.52; p < 0.01). Our results indicate that NH strength increases nonlinearly with players' age, with the highest values observed in U16 group. Furthermore, bilateral NH strength asymmetry varied nonsignificantly between 8 and 16%. Finally, 27% of variance of sprint performance of youth footballers could be explained by relative NH strength. The reported NH strength data could be used as normative standards during testing and training of youth football players. Present results also suggest that coaches should pay close attention to eccentric hamstring function in youth footballers.

Kinematic and electromyographic analysis of variations in Nordic hamstring exercise.

The purpose of this study was to present and biomechanically evaluate several variations of the Nordic hamstring exercise (NHE), achieved by altering the slope of the lower leg support and by asumming different hip flexion angles. Electromyographic and 2D kinematic measurements were conducted to analyse muscle activity (biceps femoris, semitendinosus, gluteus maximus, erector spine and lateral head of the gastrocnemius), knee and hip joint torques during 6 variations of NHE. The study involved 18 adults (24.9 ± 3.7 years) with previous experience in resistance training, but with little or no experience with NHE. Increasing the slope of the lower leg support from 0° (standard NHE) to 20° and 40° enabled the participants to perform the exercise through a larger range of motion, while achieving similar peak knee and hip torques. Instructions for increased hip flexion from 0° (standard NHE) to 25°, 50° and 75° resulted in greater peak knee and hip torque, although the participants were not able to maintain the hip angle at 50° nor 75°. Muscle activity decreased or remained similar in all modified variations compared to the standard NHE for all measured muscles. Our results suggest that using the presented variations of NHE might contribute to optimization of hamstring injury prevention and rehabilitation programs, by providing appropriate difficulty for the individual's strength level and also allow eccentric strengthening at longer hamstring lengths.

Distributed Hybrid Two-Stage Multi-Sensor Fusion for Cooperative Modulation Classification in Large-Scale Wireless Sensor Networks.

Recent studies showed that the performance of the modulation classification (MC) is considerably improved by using multiple sensors deployed in a cooperative manner. Such cooperative MC solutions are based on the centralized fusion of independent features or decisions made at sensors. Essentially, the cooperative MC employs multiple uncorrelated observations of the unknown signal to gather more complete information, compared to the single sensor reception, which is used in the fusion process to refine the MC decision. However, the non-cooperative nature of MC inherently induces large loss in cooperative MC performance due to the unreliable measure of quality for the MC results obtained at individual sensors (which causes the partial information loss while performing centralized fusion). In this paper, the distributed two-stage fusion concept for the cooperative MC using multiple sensors is proposed. It is shown that the proposed distributed fusion, which combines feature (cumulant) fusion and decision fusion, facilitate preservation of information during the fusion process and thus considerably improve the MC performance. The clustered architecture is employed, with the influence of mismatched references restricted to the intra-cluster data fusion in the first stage. The adopted distributed concept represents a flexible and scalable solution that is suitable for implementation of large-scale networks.

Effect of Rowing Ergometer Compliance on Biomechanical and Physiological Indicators during Simulated 2,000-metre Race.

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.