scholarly journals Development of a Cost-effective Biomechanical System for the Assessment of Kinematic and Kinetic Parameters in Soccer Players During a Lower Limb Pointing Task

2021 ◽  
Author(s):  
MARCELO GUIMARAES SILVA ◽  
Henrique Martins Rocha ◽  
Cathrine Katsigianni
Keyword(s):  
Kinetic Parameters ◽  
Lower Limb ◽  
Simultaneous Measurement ◽  
Center Of Mass ◽  
Cost Effective ◽  
Calibration Procedure ◽  
Soccer Players ◽  
Combined System ◽  
Pointing Task ◽  
Body Center

Abstract PurposeThe main aim of the present study was to describe the development of a non-commercial biomechanical system designed for the simultaneous measurement of kinematic and kinetic parameters during a lower limb pointing task. The task was performed by two groups of soccer players (10 novices and 10 experts, aged 16-19 years) and the differences between the two groups, in terms of these parameters, were also assessed. MethodsThe calibration procedure of the combined system is presented in this paper. The system measured the Centre of Pressure (CoP) and body Center of Mass (CoM) displacements, kicking duration and the acceleration of the kicking leg. ResultsThe margin of error found for kinematic and kinetic calibration was less than 1%. Furthermore, the expert players presented decreased CoP and CoM displacements and kicking duration and acceleration of the kicking leg compared to the novices. ConclusionThe combined system provides an effective method for the simultaneous measurement of kinematic and kinetic parameters associated with kicking and may contribute to the development of intervention studies for the improvement of balance and kicking performance in sports.

scholarly journals Morphological Changes of the Hip Commonly Associated With Femoroacetabular Impingement Are Not Correlated With Rotational Range of Hip Motion in Elite Soccer Athletes

2021 ◽  
pp. 194173812097366
Author(s):  
André Orlandi Bento ◽  
Guilherme Falótico ◽  
Keelan Enseki ◽  
Ronaldo Alves Cunha ◽  
Benno Ejnisman ◽  
...  
Keyword(s):  
Femoroacetabular Impingement ◽  
Lower Limb ◽  
Clinical Relevance ◽  
Morphological Changes ◽  
Alpha Angle ◽  
Soccer Players ◽  
Level Of Evidence ◽  
Rotational Movement ◽  
Professional Soccer ◽  
Significant Difference

Background: Morphological changes characteristic of femoroacetabular impingement (FAI) are common in soccer players. However, the clinical relevance of such anatomical variations is still not well-defined. Hypothesis: We hypothesized that high alpha angle values and/or acetabular retroversion index (ARI) are correlated with rotational range of motion (ROM) of the hip and that there are clinical-radiological diferences between the dominant lower limb (DLL) and nondominant lower limb (NDLL) in professional soccer players. Study Design: Cross-sectional. Level of Evidence: Level 3. Methods: A total of 59 male professional soccer players (average age 25.5 years, range 18-38 years) were evaluated in the preseason. As main outcome measures, we evaluated the alpha angle and the ARI and hip IR and ER ROM with radiographic analysis. Results: The measurements taken on DLL and NDLL were compared and a significant difference was found between the sides in the ER ( P = 0.027), where the DLL measures were 1.54° (95% CI, 0.18-2.89) greater than the NDLL. There were no significant differences between the sides in the measures of IR ( P > 0.99), total ROM ( P = 0.07), alpha angle ( P = 0.250), and ARI ( P = 0.079). The correlations between the rotation measurements and the alpha angle in each limb were evaluated and the coefficient values showed no correlation; so also between the ARI and rotation measures. Conclusion: Morphological changes of the femur or acetabulum are not correlated with hip IR and ER ROM in male professional soccer players. ER on the dominant side was greater than on the nondominant side. There was no significant difference in the other measurements between sides. Clinical Relevance: In clinical practice, it is common to attribute loss of hip rotational movement to the presence of FAI. This study shows that anatomical FAI may not have a very strong influence on available hip rotational movement in professional soccer athletes.

scholarly journals Neural silences can be localized rapidly using noninvasive scalp EEG

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alireza Chamanzar ◽  
Marlene Behrmann ◽  
Pulkit Grover
Keyword(s):  
Center Of Mass ◽  
Cost Effective ◽  
Human Head ◽  
Head Model ◽  
Cortical Function ◽  
Scalp Eeg ◽  
Localization Algorithms ◽  
Important Benefit ◽  
Eeg Recordings ◽  
Detection And Localization

AbstractA rapid and cost-effective noninvasive tool to detect and characterize neural silences can be of important benefit in diagnosing and treating many disorders. We propose an algorithm, SilenceMap, for uncovering the absence of electrophysiological signals, or neural silences, using noninvasive scalp electroencephalography (EEG) signals. By accounting for the contributions of different sources to the power of the recorded signals, and using a hemispheric baseline approach and a convex spectral clustering framework, SilenceMap permits rapid detection and localization of regions of silence in the brain using a relatively small amount of EEG data. SilenceMap substantially outperformed existing source localization algorithms in estimating the center-of-mass of the silence for three pediatric cortical resection patients, using fewer than 3 minutes of EEG recordings (13, 2, and 11mm vs. 25, 62, and 53 mm), as well for 100 different simulated regions of silence based on a real human head model (12 ± 0.7 mm vs. 54 ± 2.2 mm). SilenceMap paves the way towards accessible early diagnosis and continuous monitoring of altered physiological properties of human cortical function.

scholarly journals Effect of foot–floor friction on the external moment about the body center of mass during shuffling gait: a pilot study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takeshi Yamaguchi ◽  
Kei Shibata ◽  
Hiromi Wada ◽  
Hiroshi Kakehi ◽  
Kazuo Hokkirigawa
Keyword(s):  
Friction Surface ◽  
Center Of Mass ◽  
Young Male ◽  
The Body ◽  
Low Friction ◽  
Surface Conditions ◽  
Normal Gait ◽  
External Moment ◽  
Body Center ◽  
Floor Condition

AbstractHerein, we investigated the effect of friction between foot sole and floor on the external forward moment about the body center of mass (COM) in normal and shuffling gaits. Five young male adults walked with normal and shuffling gaits, under low- and high-friction surface conditions. The maximum external forward moment about the COM (MEFM-COM) in a normal gait appeared approximately at initial foot contact and was unaffected by floor condition. However, MEFM-COM in a shuffling gait under high-friction conditions exceeded that under low-friction conditions (p < 0.001). Therein, MEFM-COM increased with an increasing utilized coefficient of friction at initial foot contact; this effect was weaker during a normal gait. These findings indicate that increased friction between foot sole and floor might increase tripping risk during a shuffling gait, even in the absence of discrete physical obstacles.

scholarly journals Modeling and optimization of radish root extract drying as peroxidase source using spouted bed dryer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shahrbanoo Hamedi ◽  
M. Mehdi Afsahi ◽  
Ali Riahi-Madvar ◽  
Ali Mohebbi
Keyword(s):  
Kinetic Parameters ◽  
Flow Rate ◽  
Air Flow ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interactive Effects ◽  
Root Extract ◽  
Air Flow Rate ◽  
Spouted Bed ◽  
Radish Root

AbstractThe main advantages of the dried enzymes are the lower cost of storage and longer time of preservation for industrial applications. In this study, the spouted bed dryer was utilized for drying the garden radish (Raphanus sativus L.) root extract as a cost-effective source of the peroxidase enzyme. The response surface methodology (RSM) was used to evaluate the individual and interactive effects of main parameters (the inlet air temperature (T) and the ratio of air flow rate to the minimum spouting air flow rate (Q)) on the residual enzyme activity (REA). The maximum REA of 38.7% was obtained at T = 50 °C and Q = 1.4. To investigate the drying effect on the catalytic activity, the optimum reaction conditions (pH and temperature), as well as kinetic parameters, were investigated for the fresh and dried enzyme extracts (FEE and DEE). The obtained results showed that the optimum pH of DEE was decreased by 12.3% compared to FEE, while the optimum temperature of DEE compared to FEE increased by a factor of 85.7%. Moreover, kinetic parameters, thermal-stability, and shelf life of the enzyme were considerably improved after drying by the spouted bed. Overall, the results confirmed that a spouted bed reactor can be used as a promising method for drying heat-sensitive materials such as peroxidase enzyme.

Analytic Optimization of Cost Effective Thermoelectric Generation on Top of Rankine Cycle

2013 ◽  
Author(s):  
Kazuaki Yazawa ◽  
Yee Rui Koh ◽  
Ali Shakouri
Keyword(s):  
Steam Turbine ◽  
Fuel Efficiency ◽  
Cost Effective ◽  
Rankine Cycle ◽  
Energy Conversion Efficiency ◽  
Design Parameters ◽  
Steam Temperature ◽  
Combined System ◽  
Fuel Consumption Rate ◽  
The Impact

Thermoelectric (TE) generators have a potential advantage of the wide applicable temperature range by a proper selection of materials. In contrast, a steam turbine (ST) as a Rankine cycle thermodynamic generator is limited up to more or less 630 °C for the heat source. Unlike typical waste energy recovery systems, we propose a combined system placing a TE generator on top of a ST Rankine cycle generator. This system produces an additional power from the same energy source comparing to a stand-alone steam turbine system. Fuel efficiency is essential both for the economic efficiency and the ecological friendliness, especially for the global warming concern on the carbon dioxide (CO2) emission. We report our study of the overall performance of the combined system with primarily focusing on the design parameters of thermoelectric generators. The steam temperature connecting two individual generators gives a trade-off in the system design. Too much lower the temperature reduces the ST performance and too much higher the temperature reduces the temperature difference across the TE generator hence reduces the TE performance. Based on the analytic modeling, the optimum steam temperature to be designed is found near at the maximum power design of TE generator. This optimum point changes depending on the hours-of-operation. It is because the energy conversion efficiency directly connects to the fuel consumption rate. As the result, physical upper-limit temperature of steam for ST appeared to provide the best fuel economy. We also investigated the impact of improving the figure-of-merit (ZT) of TE materials. As like generic TE engines, reduction of thermal conductivity is the most influential parameter for improvement. We also discuss the cost-performance. The combined system provides the payback per power output at the initial and also provides the significantly better energy economy [$/KWh].

scholarly journals Energy Sustainability Study of a Rural ICT Telecenter at the Bario Highland

2007 ◽  
Author(s):  
Mohammad Omar Abdullah ◽  
Voon Chun Yung ◽  
Audra Anak Jom ◽  
Alvin Yeo Wee ◽  
Martin Anyi ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Fuel Cell ◽  
Power Systems ◽  
Alternative Energy ◽  
Cost Effective ◽  
Energy Resources ◽  
Successful Implementation ◽  
Combined System ◽  
Pv System ◽  
Simple Method

The eBario project has won the eAsia Award and the Mondialogo Engineering Award in 2004 and 2005 respectively for it’s successful implementation of an Information and Telecommunications Technology Center (ICT) and solar renewable energy-incentive rural community project at the Bario Highland of Sarawak, East Malaysia, Borneo (http://www.unimas.my/ebario/). Although solar photovoltaic (PV) energy has been opted for power generation at the ICT Telecenter for the past five years, there is still a need to investigate the cost-effectiveness of the current energy setup as well as to conduct sustainability study taking into account factors such as system efficiency, weather, costs of fuel, operating costs, as well as to explore the feasibility of implementing alternative energy resources for the rural ICT Telecenter. Recent theoretical study conducted has shown that renewable combined power systems are more sustainable in terms of supplying electricity to the ICT Telecenter, and in a more cost-effective way compared to a standalone PV system which is subject to the cloud and the recent dense haze problems. For that purpose, two combined power systems are being put into consideration namely PV-Hydro and PV-Hydro-Fuel Cell, where the total simulated annualized cost for these two system configurations are US$10,847 and US$76,010 respectively as far as the present location is concerned. The PVHydro-Fuel Cell produces electrical energy at the amount of 3,577 kWh/yr while the annual energy consumption is 3,203 kWhr/yr. On the other hand, PV-Hydro produces 3,789 kWhr/yr of electricity annually load which consumes energy at 3,209 kWhr/yr. Results thus obtained has shown that the PVHydro scheme is expected to have advantages over the existing PV standalone system. Firstly, it is more cost-effective. Secondly, it provides the best outcomes for the local indigenous community and the natural highland environments both for now and the future. Thirdly, it also able to relate the continuity of both economic and social aspects of the local society as a whole. As the combined PV-Hydro system had been chosen, plus for completeness purposes, the present paper also discussed the custom design and construction of a small waterwheel breast-shot hydro-generator, suited to the local location and existing water energy resources. Energy saving design calculations and Sankey diagram showing the energy flows for the new combined system are also given herein. Finally, the energy system performance equations and the performance curves introduced in this study provide a new simple method of evaluating renewable energy systems.

scholarly journals Different strategies for pharmacological thromboprophylaxis for lower-limb immobilisation after injury: systematic review and economic evaluation

2019 ◽  
Vol 23 (63) ◽  
pp. 1-190 ◽  
Author(s):  
Abdullah Pandor ◽  
Daniel Horner ◽  
Sarah Davis ◽  
Steve Goodacre ◽  
John W Stevens ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lower Limb ◽  
Meta Analysis ◽  
Cost Effective ◽  
Health Technology ◽  
Risk Of Bleeding ◽  
Prognostic Accuracy ◽  
Risk Predictors ◽  
Qaly Threshold ◽  
Pharmacological Thromboprophylaxis

Background Thromboprophylaxis can reduce the risk of venous thromboembolism (VTE) during lower-limb immobilisation, but it is unclear whether or not this translates into meaningful health benefit, justifies the risk of bleeding or is cost-effective. Risk assessment models (RAMs) could select higher-risk individuals for thromboprophylaxis. Objectives To determine the clinical effectiveness and cost-effectiveness of different strategies for providing thromboprophylaxis to people with lower-limb immobilisation caused by injury and to identify priorities for future research. Data sources Ten electronic databases and research registers (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Review of Effects, the Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluation Database, Science Citation Index Expanded, ClinicalTrials.gov and the International Clinical Trials Registry Platform) were searched from inception to May 2017, and this was supplemented by hand-searching reference lists and contacting experts in the field. Review methods Systematic reviews were undertaken to determine the effectiveness of pharmacological thromboprophylaxis in lower-limb immobilisation and to identify any study of risk factors or RAMs for VTE in lower-limb immobilisation. Study quality was assessed using appropriate tools. A network meta-analysis was undertaken for each outcome in the effectiveness review and the results of risk-prediction studies were presented descriptively. A modified Delphi survey was undertaken to identify risk predictors supported by expert consensus. Decision-analytic modelling was used to estimate the incremental cost per quality-adjusted life-year (QALY) gained of different thromboprophylaxis strategies from the perspectives of the NHS and Personal Social Services. Results Data from 6857 participants across 13 trials were included in the meta-analysis. Thromboprophylaxis with low-molecular-weight heparin reduced the risk of any VTE [odds ratio (OR) 0.52, 95% credible interval (CrI) 0.37 to 0.71], clinically detected deep-vein thrombosis (DVT) (OR 0.40, 95% CrI 0.12 to 0.99) and pulmonary embolism (PE) (OR 0.17, 95% CrI 0.01 to 0.88). Thromboprophylaxis with fondaparinux (Arixtra®, Aspen Pharma Trading Ltd, Dublin, Ireland) reduced the risk of any VTE (OR 0.13, 95% CrI 0.05 to 0.30) and clinically detected DVT (OR 0.10, 95% CrI 0.01 to 0.94), but the effect on PE was inconclusive (OR 0.47, 95% CrI 0.01 to 9.54). Estimates of the risk of major bleeding with thromboprophylaxis were inconclusive owing to the small numbers of events. Fifteen studies of risk factors were identified, but only age (ORs 1.05 to 3.48), and injury type were consistently associated with VTE. Six studies of RAMs were identified, but only two reported prognostic accuracy data for VTE, based on small numbers of patients. Expert consensus was achieved for 13 risk predictors in lower-limb immobilisation due to injury. Modelling showed that thromboprophylaxis for all is effective (0.015 QALY gain, 95% CrI 0.004 to 0.029 QALYs) with a cost-effectiveness of £13,524 per QALY, compared with thromboprophylaxis for none. If risk-based strategies are included, it is potentially more cost-effective to limit thromboprophylaxis to patients with a Leiden thrombosis risk in plaster (cast) [L-TRiP(cast)] score of ≥ 9 (£20,000 per QALY threshold) or ≥ 8 (£30,000 per QALY threshold). An optimal threshold on the L-TRiP(cast) receiver operating characteristic curve would have sensitivity of 84–89% and specificity of 46–55%. Limitations Estimates of RAM prognostic accuracy are based on weak evidence. People at risk of bleeding were excluded from trials and, by implication, from modelling. Conclusions Thromboprophylaxis for lower-limb immobilisation due to injury is clinically effective and cost-effective compared with no thromboprophylaxis. Risk-based thromboprophylaxis is potentially optimal but the prognostic accuracy of existing RAMs is uncertain. Future work Research is required to determine whether or not an appropriate RAM can accurately select higher-risk patients for thromboprophylaxis. Study registration This study is registered as PROSPERO CRD42017058688. Funding The National Institute for Health Research Health Technology Assessment programme.

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