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1
Karzilov, A. I. "The respiratory system biomechanical homeostasis and its maintenance mechanisms in normal conditions and at obstructive pulmonary diseases." Bulletin of Siberian Medicine 6, no. 1 (March 30, 2007): 13–38. http://dx.doi.org/10.20538/1682-0363-2007-1-13-38.
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Parameters of breathing biomechanics in healthy persons (n = 20), patients with bronchial asthma (n = 30) and chronic obstruc-tive pulmonary disease (n = 30) are analyzed during electrical stimulation of the diaphragm. Methodology of homeostatic parame-ters searching and their classification is offered. Descriptive and comparative analyses are performed. Homeostatic parameters of biomechanics describing the condition of elastic and non -elastic properties of respiratory system, of respiratory muscles, of general pulmonary hysteresis, breathing regulation are differentiated. Basic homeostatic parameter is the ratio of inspiratory capacity to the lungs elastic recoil. The model of lungs with the biomechanical buffer and retractive-elastic- surfactant complex of lungs is offered. Biomechanical homeostasis idea of respiratory system as ability of an organism to support in dynamics balance normal and patho-logical conditions essentially important for preservation of respiratory system biomechanical parameters in admissible limits is for-mulated.
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Roe, Simon. "Understanding the Limits of Biomechanical Testing." Veterinary and Comparative Orthopaedics and Traumatology 31, no. 02 (February 2018): vi—vii. http://dx.doi.org/10.1055/s-0038-1637025.
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Al-Eisawi, Khaled W., Carter J. Kerk, and Jerome J. Congleton. "Wrist strength limitations to manual exertion capability." Occupational Ergonomics 1, no. 2 (April 1, 1998): 107–21. http://dx.doi.org/10.3233/oer-1998-1203.
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This study evaluated wrist strength limitations to manual exertion capability in two-dimensional static biomechanical modeling. The researchers hypothesized that wrist strength does not limit manual exertion capability - an assumption commonly made in many strength biomechanical models. An experiment was conducted on 15 right-handed males of college age. Isometric wrist flexion strength was measured at two elbow angles: 90 degree and 135 degree and in two wrist positions: neutral and 45 degree extended. Isometric wrist radial deviation strength was measured at the same two elbow angles and in two wrist positions: neutral and 30 degree ulnarly deviated. Minimum wrist strength limits for which wrist strength does not limit maximal moments about the elbow in manual hand exertions were calculated and compared to their corresponding measured wrist strength moments using paired t-tests. In general, wrist strength was non-limiting. However, wrist flexion strength in the 45 degree extended wrist posture was limiting. Weak-wrist subjects showed more wrist strength limitations than strong-wrist subjects.
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Leitner, Christoph, Pascal A. Hager, Harald Penasso, Markus Tilp, Luca Benini, Christian Peham, and Christian Baumgartner. "Ultrasound as a Tool to Study Muscle–Tendon Functions during Locomotion: A Systematic Review of Applications." Sensors 19, no. 19 (October 5, 2019): 4316. http://dx.doi.org/10.3390/s19194316.
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Movement science investigating muscle and tendon functions during locomotion utilizes commercial ultrasound imagers built for medical applications. These limit biomechanics research due to their form factor, range of view, and spatio-temporal resolution. This review systematically investigates the technical aspects of applying ultrasound as a research tool to investigate human and animal locomotion. It provides an overview on the ultrasound systems used and of their operating parameters. We present measured fascicle velocities and discuss the results with respect to operating frame rates during recording. Furthermore, we derive why muscle and tendon functions should be recorded with a frame rate of at least 150 Hz and a range of view of 250 mm. Moreover, we analyze why and how the development of better ultrasound observation devices at the hierarchical level of muscles and tendons can support biomechanics research. Additionally, we present recent technological advances and their possible application. We provide a list of recommendations for the development of a more advanced ultrasound sensor system class targeting biomechanical applications. Looking to the future, mobile, ultrafast ultrasound hardware technologies create immense opportunities to expand the existing knowledge of human and animal movement.
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Al-Eisawi, Khaled W., Carter J. Kerk, and Jerome J. Congleton. "Limitations of Wrist Strength to Manual Exertion Capability in 2D Biomechanical Modeling." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 38, no. 10 (October 1994): 559–63. http://dx.doi.org/10.1177/154193129403801004.
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The objective of this study is to evaluate the assumption in biomechanical models that wrist strength does not limit manual exertion capability. An experiment was designed and run on right-handed males to test isometric elbow flexion strength at two included elbow angles: 90° and 135° and in two forearm positions: supinated and mid between supination and pronation. Isometric wrist flexion strength was also measured at the same elbow angles and at two wrist positions in the flexion/extension plane: neutral and 45° extended. Isometric wrist radial deviation strength was measured at the same two elbow angles and at two wrist positions in the radial/ulnar deviation plane: neutral and 30° ulnarly deviated. An equation was developed to calculate the theoretical minimum wrist strength limits for which wrist strength does not limit maximal moments about the elbow. These calculated limits were compared to the corresponding measured wrist strength moments. In general, wrist strength was found to be non-limiting, but in some specific circumstances, it can be limiting. Among the posture/exertion combinations tested, only wrist flexion strength in the extended wrist posture was found to be limiting. There was some evidence that strong-wrist people show less wrist strength limitations than weak-wrist people in some postures. It was also found that the neutral wrist posture is not associated with the highest wrist strength.
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Bonnette, Scott, Christopher A. DiCesare, Adam W. Kiefer, Michael A. Riley, Kim D. Barber Foss, Staci Thomas, Katie Kitchen, Jed A. Diekfuss, and Gregory D. Myer. "Injury Risk Factors Integrated Into Self-Guided Real-Time Biofeedback Improves High-Risk Biomechanics." Journal of Sport Rehabilitation 28, no. 8 (November 1, 2019): 831–39. http://dx.doi.org/10.1123/jsr.2017-0391.
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Context:Existing anterior cruciate ligament (ACL) injury prevention programs have failed to reverse the high rate of ACL injuries in adolescent female athletes.Objective:This investigation attempts to overcome factors that limit efficacy with existing injury prevention programs through the use of a novel, objective, and real-time interactive visual feedback system designed to reduce the biomechanical risk factors associated with ACL injuries.Design:Cross-over study.Setting:Medical center laboratory.Participants:A total of 20 females (age = 19.7 [1.34] y; height = 1.74 [0.09] m; weight = 72.16 [12.45] kg) participated in this study.Methods:Participants performed sets of 10 bodyweight squats in each of 8 training blocks (ie, 4 real-time and 4 control blocks) and 3 testing blocks for a total of 110 squats. Feedback conditions were blocked and counterbalanced with half of participants randomly assigned to receive the real-time feedback block first and half receiving the control (sham) feedback first.Results:Heat map analysis revealed that during interaction with the real-time feedback, squat performance measured in terms of key biomechanical parameters was improved compared with performance when participants squatted with the sham stimulus.Conclusions:This study demonstrates that the interactive feedback system guided participants to significantly improve movement biomechanics during performance of a body weight squat, which is a fundamental exercise for a longer term ACL injury risk reduction intervention. A longer training and testing period is necessary to investigate the efficacy of this feedback approach to effect long-term adaptations in the biomechanical risk profile of athletes.
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Deban, Stephen M., Roi Holzman, and Ulrike K. Müller. "Suction Feeding by Small Organisms: Performance Limits in Larval Vertebrates and Carnivorous Plants." Integrative and Comparative Biology 60, no. 4 (July 13, 2020): 852–63. http://dx.doi.org/10.1093/icb/icaa105.
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Abstract Suction feeding has evolved independently in two highly disparate animal and plant systems, aquatic vertebrates and carnivorous bladderworts. We review the suction performance of animal and plant suction feeders to explore biomechanical performance limits for aquatic feeders based on morphology and kinematics, in the context of current knowledge of suction feeding. While vertebrates have the greatest diversity and size range of suction feeders, bladderworts are the smallest and fastest known suction feeders. Body size has profound effects on aquatic organismal function, including suction feeding, particularly in the intermediate flow regime that tiny organisms can experience. A minority of tiny organisms suction feed, consistent with model predictions that generating effective suction flow is less energetically efficient and also requires more flow-rate specific power at small size. Although the speed of suction flows generally increases with body and gape size, some specialized tiny plant and animal predators generate suction flows greater than those of suction feeders 100 times larger. Bladderworts generate rapid flow via high-energy and high-power elastic recoil and suction feed for nutrients (relying on photosynthesis for energy). Small animals may be limited by available muscle energy and power, although mouth protrusion can offset the performance cost of not generating high suction pressure. We hypothesize that both the high energetic costs and high power requirements of generating rapid suction flow shape the biomechanics of small suction feeders, and that plants and animals have arrived at different solutions due in part to their different energy budgets.
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JHOU, SHU-YU, KAO-SHANG SHIH, PO-SHENG HUANG, FANG-YU LIN, and CHING-CHI HSU. "BIOMECHANICAL ANALYSIS OF DIFFERENT SURGICAL STRATEGIES FOR THE TREATMENT OF ROTATIONALLY UNSTABLE PELVIC FRACTURE USING FINITE ELEMENT METHOD." Journal of Mechanics in Medicine and Biology 19, no. 02 (March 2019): 1940015. http://dx.doi.org/10.1142/s0219519419400153.
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A rotationally unstable pelvic fracture can lead to loss of function and limit moving ability. Immediate fracture fixation is needed for patients with the pelvic fractures. However, it may be difficult to evaluate different surgical strategies for the fracture treatments due to variations in patients’ anatomies and surgical techniques. Thus, the purpose of the present study was to analyze the biomechanical performances of the intact, injured, and treated pelvises based on different physiological movements of the spine using finite element method. Three-dimensional musculoskeletal finite element models of the spine-pelvis-femur complex were developed. The intact pelvis, the rotationally unstable pelvis, and six types of pelvic fixation techniques were analyzed. Additionally, seven types of physiological movements of the spine were also considered. The results showed that the posterior iliosacral screws combined with lower and anterior plate (PIS-LAP) had good fixation stability, lower plate stress, and lower pelvic stress. However, the PIS-LAP increased the stress of the posterior iliosacral screws. The right lateral bending, left lateral bending, and flexion significantly affect all the biomechanical performances compared to the other physiological movements of the spine. The present study can provide engineers and surgeons with the understanding of the biomechanics of various fixation techniques during different physiological movements for the treatment of rotationally unstable pelvic fractures.
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Byrd, Charisma, and MinHyuk Kwon. "The Effect of Hand-Held Technology on Thumb Biomechanics." Journal of Health, Sports, and Kinesiology 2, no. 1 (January 31, 2021): 7–8. http://dx.doi.org/10.47544/johsk.2021.2.1.7.
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The rise of portable units calls attention to the impact of device design and it challenges to biomechanical capabilities of the thumb and increased musculoskeletal discomfort. The purpose of this critiqued article, therefore, is to understand the significance of thumb biomechanics on hand-held technology and upper extremity pain. Healthy sixteen right-handed participants (21-40 years) performed a multitude of swiping gestures with the thumb of their right hand on 8’’ and 10’’ tablets (Samsung Galaxy III). The swiping gestures differed in swipe direction (outward v. inward), swipe orientation (horizontal v. vertical), swipe location (4 swipe zones), and swipe length (short v. long). Data was acquired using a custom Android application, thumb/wrist posture and forearm muscle activity was quantified using three-dimensional motion analysis and surface electromyograph, respectively. Data was analyzed using repeated measures of ANOVA. Self-reported perceived wrist and hand discomfort was measured using a visual analogue scale after each trial. Swiping actions closest to the palm rendered less pain, decreased forearm muscle activity, neutral thumb biomechanics and wrist posture. The left zones had greatest metacarpal (16) and carpometacarpal abduction (10) and topmost wrist movement, ulnar deviation (18) and extension (14) (Table 1), compared to the right zones. Regarding tablet orientation, portrait mode of both devices amassed more muscle activity related to landscape mode. The limits of upper extremities and thumb biomechanics can be seen in specific swipe locations of hand-held technology. The p-values for wrist extension (p < 0.01) and ulnar deviation (p < 0.03) on tablet size and orientation quantitatively illustrate the poor wrist posture commonly adopted by users under these conditions. Swipe zone results proved users had best performance and lower discomfort rates when gestures were performed near the palm. Carpometacarpal abduction data found high joint angles during trials on the left side of the tablet and no movement (0) on the right side. This constant biomechanical exertion to swipe in out-of-reach areas may lead to musculoskeletal disorders or pain. The results suggest tablet hardware and user interface design to allow for neutral thumb and wrist posture while accounting for decreased muscle demands. The purpose of the study was to identify the effect of hand-held technology on thumb biomechanics, thumb/wrist posture, and forearm muscle activity. The findings demonstrated increased user performance and lower musculoskeletal pain while performing gestures closer to the palm. The authors’ ability to pinpoint the specific location where users experienced greatest extension, abduction, pain, and forearm muscle activation (top left zone) was one of the articles supreme strengths. Nonetheless, the study should be considered within context of its limitations. A limitation within the experiment was the criteria to be a participant. The study did not inquire about the amount of time users usually spent on their device in a normal week, this may give evidence to the biomechanical loads their thumb and upper extremities are accustomed to. A suggestion for research design is to improve participant criterion. Users thumb strength can be quantified with the pinch test or examined through manual muscle tests to indicate a correlation between thumb strength and participant perception of fatigue post-trial(s).
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KAMAL, ZEINAB, and GHOLAMREZA ROUHI. "A PARAMETRIC INVESTIGATION OF THE EFFECTS OF CERVICAL DISC PROSTHESES WITH UPWARD AND DOWNWARD NUCLEI ON SPINE BIOMECHANICS." Journal of Mechanics in Medicine and Biology 16, no. 07 (November 2016): 1650092. http://dx.doi.org/10.1142/s0219519416500925.
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This work aimed at investigating the influence of Baguera and Discocerv cervical disc prostheses, with mobile downward center of rotation (COR) and fixed upward COR, respectively, on the biomechanical behavior of C4–C6 cervical spine. For this purpose, using computed tomography (CT) data, a parametric nonlinear finite element (FE) model of intact C4–C6 spinal segments was developed, and an artificial disc was implanted at C5–C6 level. To assess the influence of implants on the biomechanics of cervical spine, the FE models were analyzed in flexion, extension, lateral bending, and axial rotation, and the results were presented in the range of motion (ROM) curves, and torsional stiffness. Results of this study, in agreement with the literature, suggested that both Baguera and Discocerv implants might be able to preserve the motion, and limit the alteration of the biomechanics of adjacent levels. Except for the possible confliction of adjacent vertebrae at the implanted level with Baguera implant in lateral bending, results of this study also indicated that the movability and downward COR of Baguera disc prosthesis caused ROMs of the implanted segment to be more similar to the intact model than Discocerv implant. Moreover, the upward COR of Discocerv implant may result in over-distraction on facets in the maximal flexion, with the ratio of 1.22 versus 1.36, and consequently facet syndrome during extension for Bageura and Discocerv disc prostheses, respectively.
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Behjati, Mohamad, and Navid Arjmand. "Biomechanical Assessment of the NIOSH Lifting Equation in Asymmetric Load-Handling Activities Using a Detailed Musculoskeletal Model." Human Factors: The Journal of the Human Factors and Ergonomics Society 61, no. 2 (September 17, 2018): 191–202. http://dx.doi.org/10.1177/0018720818795038.
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Objective: To assess adequacy of the National Institute for Occupational Safety and Health (NIOSH) Lifting Equation (NLE) in controlling lumbar spine loads below their recommended action limits during asymmetric load-handling activities using a detailed musculoskeletal model, that is, the AnyBody Modeling System. Background: The NIOSH committee employed simplistic biomechanical models for the calculation of the spine compressive loads with no estimates of the shear loads. It is therefore unknown whether the NLE would adequately control lumbar compression and shear loads below their recommended action limits during asymmetric load-handling activities. Method: Twenty-four static stoop lifting tasks at different load asymmetry angles, heights, and horizontal distances were performed by one normal-weight (70 kg) and one obese (93 kg) individual. For each task, the recommended weight limit computed by the NLE and body segment angles measured by a video-camera system (VICON) were prescribed in the participant-specific models developed in the AnyBody Modeling System that estimated spinal loads. Results: For both individuals, the NLE adequately controlled L5-S1 loads below their recommended action limits for all activities performed in upright postures. Both individuals, however, experienced compressive and/or shear L5-S1 loads beyond the recommended action limits when lifting was performed near the floor with large load asymmetry. Conclusion: The NLE failed to control spinal loads below the recommended limits during asymmetric lifting tasks performed near the floor. Application: The NLE should be used with caution for extreme tasks involving load handling near the floor with large load asymmetry.
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CHAFFIN, D. B., and G. B. PAGE. "Postural effects on biomechanical and psychophysical weight-lifting limits." Ergonomics 37, no. 4 (April 1994): 663–76. http://dx.doi.org/10.1080/00140139408963681.
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Balbinot, Gustavo, Clarissa Pedrini Schuch, Milton Antonio Zaro, and Marco Aur�lio Vaz. "Low-cost piezoelectric footswitch system for measuring temporal parameters during walking." International Journal of Engineering & Technology 3, no. 1 (February 18, 2014): 75. http://dx.doi.org/10.14419/ijet.v3i1.1733.
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Human walking is one of the most investigated biomechanical events, and gait analysis depends on accurate measurement of heel strike (HS) and toe off (TO). The purpose of this study was to construct and validate a low-cost footswitch system for the measurement of temporal gait parameters. Ten young healthy subjects participated of the validation and test of the footswitch system with two different footwear, Bland-Altman analysis showed 98% and 95% of validation data within the limits of agreement, for HS and TO respectively (mean difference of 16ms1ms and 20ms9ms) and the temporal parameters measured during treadmill walking at a speed of 4.5km.h-1 showed results similar to those found in the literature for normal walking. The outcomes confirm low CoVs for the instrumented athletic and instability shoe, respectively: (1.520.61)% and (1.900.73)% for contact time, (2.170.95)% and (2.570.95)% for balance time, (0.840.28)% and (1.120.53)% for stride time. The low-cost footswitch system described and validated in the present study has an important practical applicability, mostly for emerging and developing countries biomechanics labs. Keywords: Footswitch System, Gait Analysis, Locomotion, Low-Cost, Walk.
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Hartmann, Bastian, Gabriele Marchi, Paolo Alberton, Zsuzsanna Farkas, Attila Aszodi, Johannes Roths, and Hauke Clausen-Schaumann. "Early Detection of Cartilage Degeneration: A Comparison of Histology, Fiber Bragg Grating-Based Micro-Indentation, and Atomic Force Microscopy-Based Nano-Indentation." International Journal of Molecular Sciences 21, no. 19 (October 6, 2020): 7384. http://dx.doi.org/10.3390/ijms21197384.
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We have determined the sensitivity and detection limit of a new fiber Bragg grating (FBG)-based optoelectronic micro-indenter for biomechanical testing of cartilage and compared the results to indentation-type atomic force microscopy (IT-AFM) and histological staining. As test samples, we used bovine articular cartilage, which was enzymatically degraded ex vivo for five minutes using different concentrations of collagenase (5, 50, 100 and 500 µg/mL) to mimic moderate extracellular matrix deterioration seen in early-stage osteoarthritis (OA). Picrosirius Red staining and polarization microscopy demonstrated gradual, concentration-dependent disorganization of the collagen fibrillar network in the superficial zone of the explants. Osteoarthritis Research Society International (OARSI) grading of histopathological changes did not discriminate between undigested and enzymatically degraded explants. IT-AFM was the most sensitive method for detecting minute changes in cartilage biomechanics induced by the lowest collagenase concentration, however, it did not distinguish different levels of cartilage degeneration for collagenase concentrations higher than 5 µg/mL. The FBG micro-indenter provided a better and more precise assessment of the level of cartilage degeneration than the OARSI histological grading system but it was less sensitive at detecting mechanical changes than IT-AFM. The FBG-sensor allowed us to observe differences in cartilage biomechanics for collagenase concentrations of 100 and 500 µg/mL. Our results confirm that the FBG sensor is capable of detecting small changes in articular cartilage stiffness, which may be associated with initial cartilage degeneration caused by early OA.
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Singh, Devender. "Obesity Effects on Maximum Acceptable Weights of Lift." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 51, no. 15 (October 2007): 918–22. http://dx.doi.org/10.1177/154193120705101511.
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The aim of this paper was to investigate the effects of obesity on the maximum acceptable weights of lift (MAWL) Two obesity levels were considered: non-obese (18.5 kg/m2≤BMI≤24.9 kg/m2) and extremely obese (BMI≥ 40 kg/m2). Each obesity level had 10 male participants. The participants determined their MAWL for 18 different lifting task conditions (6 lifting frequencies × 3 lifting heights). An ANOVA was conducted to determine the effects of obesity level, lifting height, lifting frequency and their interactions on MAWL. In general, the ANOVA results revealed that obesity does not reduce MAWL. This indicates that there may not be a need to develop new psychophysical lifting limits for the obese worker population. However, in order to develop comprehensive lifting limit guidelines for the obese worker population, future studies should investigate the biomechanical and physiological based lifting tolerance limits for them.
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Qin, Xiao, Mengyao Yu, Haixia Zhang, Xinyan Chen, and Lin Li. "The Mechanical Interpretation of Ocular Response Analyzer Parameters." BioMed Research International 2019 (July 16, 2019): 1–11. http://dx.doi.org/10.1155/2019/5701236.
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Purpose. Ocular Response Analyzer (ORA) is one of the most widely used devices in clinic, while the mechanical interpretations of parameters obtained from ORA have not been understood completely. The aim of this research is to explore the mechanical interpretation of ORA parameters. Methods. Rabbits aged 3-24 months were measured with ORA in vivo and corneal strips uniaxial tensile tests to get ORA parameters and corneal biomechanical parameters (corneal elastic modulus, relaxation time, and relaxation limit). The mechanical interpretation of ORA parameters was cognized preliminarily by analyzing the correlation between ORA parameters and corneal biomechanical parameters. On the other hand, finite element method was applied to simulate ORA measurements with different corneal biomechanical parameters to obtain quantitative relationship between ORA parameters and corneal biomechanical parameters further. Results. Biomechanical experimental results showed that Corneal Resistance Factor (CRF) was correlated with corneal elastic modulus and relaxation limit significantly, while the significant correlations between Corneal Hysteresis (CH) and corneal biomechanical parameters were not observed. Results of finite element analysis showed that both CH and CRF were correlated with corneal elastic modulus, relaxation limit, and relaxation time significantly. Besides, corneal elastic modulus was positively correlated with upslop1 and upslop2 and negatively correlated with w2. Conclusions. For all ORA parameters, CH, CRF, the upslope, and the width of the peaks are parameters which may reflect corneal elastic properties. It is viable to cognize mechanical interpretation of ORA parameters by the comparisons of the data from ORA and biomechanical tests of rabbits with different ages and the simulations of ORA based on finite element methods. Further studies are needed to confirm the mechanical interpretation.
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Batticciotto, A., S. Olivieri, R. Talotta, A. Cappelli, A. Preda, and P. Sarzi-Puttini. "AB0667 ACHILLES PAIN PERSISTENCE IN PATIENTS AFFECTED BY SPONDYLOARTHRITIS: ULTRASONOGRAPHIC AND BIOMECHANICAL STUDY." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 1628.2–1629. http://dx.doi.org/10.1136/annrheumdis-2020-eular.5891.
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Background:Enthesis anatomy and biomechanics have a key role in Spondyloarthritis (SpA) pathogenesis (1) but few data are available about the influence of structural and biomechanical changes of Achilles tendon (AT) on persisting pain in longstanding SpA patients.Objectives:To correlate AT pain in longstanding SpA patients with ultrasonographic detectable disorders and biomechanical abnormalities.Methods:We performed a monocentric cross-sectional analysis including 35 consecutive patients affected by SpA (13 with Psoriatic Arthritis, 9 with Enteropathic SpA, 6 with Ankylosing Spondylitis and 7 with Undifferentiated SpA) under treatment with anti- TNF agents. A rheumatologic clinical and clinimetric evaluation (AT VAS pain, BASDAI, BASFI, HAQ), an ultrasound study of AT according to the Madrid Sonographic Enthesis Index (MASEI) score and a podiatrist biomechanical evaluation [Foot posture index (FPI), degree of ankle dorsiflexion with the knee extended and flexed] were performed.Results:Study population (13 F; 22 M; mean age 54.9 ±13.9 years; mean disease duration 9.5 ± 5.0 years; mean BMI 25.8 ±4.4) showed a mean AT VAS pain of 3.4 ± 2.2, a mean HAQ of 0.6 ± 0.6, a mean BASDAI of 3.3 ±2.1 and a mean BASFI of 2.2 ±1.9. At the ultrasonographic evaluation 47% (33/70) of the AT entheses analysed presented a dishomogeneous echostructure, 31% (22/70) structural thickness, 53% (37/70) calcifications, 10% (7/70) erosions, 44% (31/70) a retrocalcanear bursitis. A power Doppler positivity was found only in 0.07% (5/70) of the AT.At the biomechanical evaluation 50% (35/70) of the feet showed a FPI score between 0 and + 5 (neutral foot), 46% (32/70) a FPI score between +6 and +9 (slight foot pronation) and 6% (4/70) a FPI score between -1 and -4 (slight foot supination).The mean degree of ankle dorsiflexion with extended knee was 8.4 ± 3.9 with the 61% (43/70) of the patients with a maximum dorsiflexion < 10° of whom 46% (20/43) do not recover after the knee flexion.We found a between the mean degree of left ankle dorsiflexion with extended/flexed knee both with ultrasound-revealed left AT enthesis calcifications (p=0.014/0.037) and with left AT enthesis thickness (p=0.049/0.035), and a significant association between the mean degree of right ankle dorsiflexion and extended/flexed knee and ultrasound-revealed right AT calcifications (p=0.008/0.012). Moreover, we noticed an inverse correlation between the mean overall degree of ankle dorsiflexion with extended/flexed knee and the BASFI values (p=0.007/0.004). AT VAS pain was statistically related with Achilles PDUS signal persistence (p=0.048) but not with US signs of chronic entesopathy or biomechanical alterations [calcification (p=0.39), erosions (p=0.74)]. The limits of the study were the low number of patients recruited and the lack of a control group.Conclusion:In this monocentric study on a cohort of SpA patients, we demonstrated a statistically significant correlation between ankle–subtalar joint complex biomechanics alterations, ultrasonographic signs of chronic enthesopathy and clinimetric index of functional disability. Residual Achilles pain seems to be related to US signs of active enthesitis.References:[1]The enthesis organ concept and its relevance to the spondyloarthropathies. Benjamin, M and McGonagle, D. s.l.: Adv Exp Med Biol, 2009, Vol. 649.[2]The Synovio-entheseal Complex and Its Role in Tendon and Capsular Associated Inflammation. McGonagle, E D, Aydin, SZ and Tan, AL. 0, s.l.: J Rheumatol Suppl, 2012, Vol. 89Disclosure of Interests:None declared
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Driss, Tarak, and Henry Vandewalle. "The Measurement of Maximal (Anaerobic) Power Output on a Cycle Ergometer: A Critical Review." BioMed Research International 2013 (2013): 1–40. http://dx.doi.org/10.1155/2013/589361.
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The interests and limits of the different methods and protocols of maximal (anaerobic) power () assessment are reviewed: single all-out testsversusforce-velocity tests, isokinetic ergometersversusfriction-loaded ergometers, measure of during the acceleration phase or at peak velocity. The effects of training, athletic practice, diet and pharmacological substances upon the production of maximal mechanical power are not discussed in this review mainly focused on the technical (ergometer, crank length, toe clips), methodological (protocols) and biological factors (muscle volume, muscle fiber type, age, gender, growth, temperature, chronobiology and fatigue) limiting in cycling. Although the validity of the Wingate test is questionable, a large part of the review is dedicated to this test which is currently the all-out cycling test the most often used. The biomechanical characteristics specific of maximal and high speed cycling, the bioenergetics of the all-out cycling exercises and the influence of biochemical factors (acidosis and alkalosis, phosphate ions…) are recalled at the beginning of the paper. The basic knowledge concerning the consequences of the force-velocity relationship upon power output, the biomechanics of sub-maximal cycling exercises and the study on the force-velocity relationship in cycling by Dickinson in 1928 are presented in Appendices.
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IVANCEVIC, VLADIMIR, and SANJEEV SHARMA. "COMPLEXITY IN HUMAN AND HUMANOID BIOMECHANICS." International Journal of Humanoid Robotics 05, no. 04 (December 2008): 679–98. http://dx.doi.org/10.1142/s0219843608001571.
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We propose the following complexity conjecture: in a combined biomechanical system, where the action of Newtonian laws cannot be neglected, it is the mechanical part that determines the lower limit of complexity of the combined system, commonly defined as the number of mechanical degrees of freedom. The biological part of such a system, being "more intelligent", naturally serves as a "controller" for the "nonintelligent" mechanical "plant". Although, in some special cases, the behavior of the combined system might have a "simple" output, a realistic internal state space analysis shows that the total system complexity represents either the superposition, or a kind of "macroscopic entanglement" of the two partial complexities. Neither "mutual canceling" nor "averaging" of the mechanical degrees of freedom generally occurs in such a biomechanical system. The combined system has both dynamical and control complexities. The "realistic" computational model of such a system also has its own computational complexity. We demonstrate the validity of the above conjecture using the example of the physiologically realistic computer model. We further argue that human motion is the simplest well-defined example of a general human behavior, and discuss issues of simplicity versus predictability/controllability in complex systems. Further, we discuss self-assembly in relation to conditioned training in human/humanoid motion. It is argued that there is a significant difference in the observational resolution of human motion while one is watching "subtle" movements of a human hands playing a piano versus "coarse" movements of a human crowd at a football stadium from an orbital satellite. Techniques such as cellular automata can model the coarse crowd motion, but not the subtle hierarchical neural control of the dynamics of human hands playing a piano. Therefore, we propose the observational resolution as a new measure of biomechanical complexity. Finally, there is a possible route to apparent simplicity in biomechanics, in the form of oscillatory synchronization, both external (kinematical) and internal (control).
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Herbort, Oliver. "Where to Grasp a Tool?" Zeitschrift für Psychologie 220, no. 1 (January 2012): 37–43. http://dx.doi.org/10.1027/2151-2604/a000089.
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Biomechanical and environmental constraints limit body movements and tool use actions. However, in the case of tool use, such constraints can often be overcome by adjusting a tool’s tool transformation to the requirements of the intended tool use action. The research presented here examined whether participants grasped a lever at different positions, thus modifying the lever’s tool transformation, to accommodate speed and accuracy requirements of different tasks. Participants were asked to quickly track a sequence of targets with the lever. If accuracy requirements were high, participants compensated for limits in the accuracy of hand movements by grasping the lever at a position that enabled precise control of the lever. If accuracy requirements were low, participants compensated for limits in hand speed by grasping the lever at a position that enabled fast lever movements with comparatively slow hand movements. This task-dependent grasp selection was only present after participants had practiced the tasks. The data show that in addition to adapting to fixed tool transformations, participants also actively controlled tool transformations to facilitate tool use actions.
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Dudley, Robert. "Limits to human locomotor performance: phylogenetic origins and comparative perspectives." Journal of Experimental Biology 204, no. 18 (September 15, 2001): 3235–40. http://dx.doi.org/10.1242/jeb.204.18.3235.
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SUMMARYStudies of human exercise physiology have been conducted from a largely ahistorical perspective. This approach usefully elucidates proximate limits to locomotor performance, but ignores potential sources of biomechanical and physiological variation that derive from adaptation to ancestral environments. Phylogenetic reconstruction suggests that multiple hominoid lineages, including that leading to Homo sapiens, evolved in African highlands at altitudes of 1000–2000m. The evolution of human locomotor physiology therefore occurred under conditions of hypobaric hypoxia. In contrast to present-day humans running on treadmills or exercising in otherwise rectilinear trajectories, ancestral patterns of hominid locomotion probably involved intermittent knuckle-walking over variable terrain, occasional bouts of arboreality and an evolving capacity for bipedalism. All such factors represent potential axes of locomotor variation at present unstudied in extant hominoid taxa. As with humans, hummingbirds evolved in mid-montane contexts but pose an extreme contrast with respect to body size, locomotor mode and metabolic capacity. Substantial biomechanical and physiological challenges are associated with flight in hypobaria. Nonetheless, hummingbird lineages demonstrate a progressive invasion of higher elevations and a remarkable tolerance to hypoxia during hovering. Upregulation of aerobic capacity and parallel resistance to hypoxia may represent coupled evolutionary adaptations to flight under high-altitude conditions.
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Hirsch, BE. "Structural biomechanics of the foot bones." Journal of the American Podiatric Medical Association 81, no. 7 (July 1, 1991): 338–43. http://dx.doi.org/10.7547/87507315-81-7-338.
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The structure of the tarsal and metatarsal bones reflects the functional demands placed on them. Their shape and the arrangement of compact and trabecular bone within them help them resist the normal forces of everyday life. When the limits of their strength are exceeded, failure can occur.
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Alamin, Todd, John P. Kleimeyer, James R. Woodall, Vijay Agarwal, Angus Don, and Derek Lindsey. "Improved biomechanics of two alternative kyphoplasty cementation methods limit vertebral recollapse." Journal of Orthopaedic Research® 36, no. 12 (September 7, 2018): 3225–30. http://dx.doi.org/10.1002/jor.24127.
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Udelson, Daniel. "Biomechanics of male erectile function." Journal of The Royal Society Interface 4, no. 17 (May 3, 2007): 1031–48. http://dx.doi.org/10.1098/rsif.2007.0221.
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Two major branches of engineering mechanics are fluid mechanics and structural mechanics, with many practical problems involving the effect of the first on the second. An example is the design of an aircraft's wings to bend within reasonable limits without breaking under the action of lift forces exerted by the air flowing over them; another is the maintenance of the structural integrity of a dam designed to hold back a water reservoir which would exert very large forces on it. Similarly, fluid and structural mechanics are involved in the engineering analysis of erectile function: it is the hydraulic action of increased blood flow into the corpora cavernosa that creates the structural rigidity necessary to prevent collapse of the penile column.
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Felicita, A. Sumathi. "Quantification of intrusive/retraction force and moment generated during en-masse retraction of maxillary anterior teeth using mini-implants: A conceptual approach." Dental Press Journal of Orthodontics 22, no. 5 (October 2017): 47–55. http://dx.doi.org/10.1590/2177-6709.22.5.047-055.oar.
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ABSTRACT Objective: The aim of the present study was to clarify the biomechanics of en-masse retraction of the upper anterior teeth and attempt to quantify the different forces and moments generated using mini-implants and to calculate the amount of applied force optimal for en-masse intrusion and retraction using mini-implants. Methods: The optimum force required for en-masse intrusion and retraction can be calculated by using simple mathematical formulae. Depending on the position of the mini-implant and the relationship of the attachment to the center of resistance of the anterior segment, different clinical outcomes are encountered. Using certain mathematical formulae, accurate measurements of the magnitude of force and moment generated on the teeth can be calculated for each clinical outcome. Results: Optimum force for en-masse intrusion and retraction of maxillary anterior teeth is 212 grams per side. Force applied at an angle of 5o to 16o from the occlusal plane produce intrusive and retraction force components that are within the physiologic limit. Conclusion: Different clinical outcomes are encountered depending on the position of the mini-implant and the length of the attachment. It is possible to calculate the forces and moments generated for any given magnitude of applied force. The orthodontist can apply the basic biomechanical principles mentioned in this study to calculate the forces and moments for different hypothetical clinical scenarios.
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Molimard, Jérôme, Rebecca Bonnaire, Reynald Convert, Woo Suck Han, and Paul Calmels. "Role and limit of biomechanical modeling in the study of medical devices." Annals of Physical and Rehabilitation Medicine 59 (September 2016): e25-e26. http://dx.doi.org/10.1016/j.rehab.2016.07.058.
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Baritz, Mihaela Ioana, and Diana Laura Cotoros. "Oscillatory Movements Analysis at Knee Level." Applied Mechanics and Materials 436 (October 2013): 271–76. http://dx.doi.org/10.4028/www.scientific.net/amm.436.271.
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Some theoretical and experimental considerations upon the biomechanics of oscillatory flexion-extension movements developed at knee level of human subjects, without previous detected pathologies are presented in this paper. Thus, the first part of the paper is referring to the analysis of aspects related to the locomotion system biomechanics concerning the flexion-extension movement at knee level and also to the setting of various samples of subjects out of which the examples for the proposed methodology application will be selected. In the second part of the paper, the analysis structures required for the recording and assessment of oscillatory movements biomechanics at knee level are developed and presented. In the third part, the results and conclusions regarding the behavior and performance limits of movements at knee level are presented and processed.
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Weston, Eric B., Alexander Aurand, Jonathan S. Dufour, Gregory G. Knapik, and William S. Marras. "Biomechanically-Determined Guidelines for Occupational Pushing and Pulling." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 61, no. 1 (September 2017): 914–15. http://dx.doi.org/10.1177/1541931213601708.
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Background: In an attempt to reduce heavy lifting exposures, the manual materials handling burden has shifted towards pushing and pulling. Pushing and pulling may pose a biomechanical risk due to excessive loads placed onto the lumbar spine, particularly in anterior/posterior (A/P) shear (Knapik and Marras 2009). The only risk limits available in the scientific literature for pushing and pulling were psychophysically-determined, relying on the assumption that subjective perception of an individual’s maximum acceptable external forces corresponds to biomechanical tolerance (Snook and Ciriello 1991). However, individuals are unlikely able to sense biomechanical loading on critical tissues in the spine due to the lack of nociceptors in the intervertebral disc (Adams et al. 1996). As such, the objective of this study was to create a set of biomechanically-determined risk limits for occupational pushing and pulling that are protective of the low back. Methods: Sixty-two subjects (31 male, 31 female) performed occupational pushing and pulling tasks in a laboratory. Subjects performed three types of exertions (one-handed pull, two-handed pull, two-handed push) at three handle heights (32 in., 40 in., 48 in.) and in one of two directions (straight or turn). Subjects pushed or pulled on custom-built hand transducers connected to an overhead braking system via a rig while performing each exertion. To document a wide range of pushing and pulling exposures, the braking system incrementally increased the linear or rotational resistance proportional to the subject’s changes from the initial global position throughout each trial; subjects exerted up to a maximum voluntary exertion. Dependent measures consisted of the magnitude and direction of three-dimensional forces recorded at the hands, turning torques, net joint moments calculated at each shoulder, and three-dimensional spinal loads (compression, A/P shear, lateral shear) at the superior and inferior endplates of each spinal level extending from T12/L1 to L5/S1, as calculated by a dynamic EMG-driven biomechanical spine model (Knapik and Marras 2009; Hwang et al. 2016a; Hwang et al. 2016b). Multiple linear regression techniques correlated spinal loads with hand force or turning torque in order to develop biomechanically-determined hand force and turning torque limits. The values for straight two-handed pushing and pulling were also compared to psychophysically-determined thresholds developed by Snook and Ciriello (1991). Results and Discussion: The independent measures (exertion type, handle height, and exertion direction) and their interactions significantly influenced dependent measures of hand force, turning torque, shoulder moment, and spinal load. In agreement with Knapik and Marras (2009), spinal loads most frequently exceeded tissue tolerance limits for spinal loading (NIOSH 1981; Gallagher and Marras 2012) in A/P shear. The biomechanically-determined limits developed from this work are up to 30% lower than the closest psychophysically-derived equivalents (Snook and Ciriello 1991). Conclusion: Psychophysically-derived hand force limits are not protective enough of biomechanical risk imposed onto the lumbar spine during pushing and pulling. The biomechanically-determined pushing and pulling guidelines proposed herein provide a more objective and conservative indication of risk and should be implemented moving forward.
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Maiden, Nicholas R., and Roger W. Byard. "Unpredictable tensile strength biomechanics may limit thawed cadaver use for simulant research." Australian Journal of Forensic Sciences 48, no. 1 (April 13, 2015): 54–58. http://dx.doi.org/10.1080/00450618.2015.1025842.
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Baritz, Mihaela Ioana, Laura Diana Cotoros, Ileana Ciobanu, and Raluca Muntean. "Forces Distribution Analysis Developed in the Plantar Surface in Simulation Case of Controlled Blocking of Joints." Applied Mechanics and Materials 656 (October 2014): 642–49. http://dx.doi.org/10.4028/www.scientific.net/amm.656.642.
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Some theoretical and experimental considerations upon the biomechanics of the movements developed at foot level of human subjects without previous detected pathologies are presented in this paper. Thus, the first part of the paper is referring to the analysis of aspects related to the biomechanics of the locomotion system, aspects concerning the forces distribution at plantar surface level and also concerning the setting of various samples of subjects out of which the examples for the proposed methodology application will be selected. In the second part of the paper, the analysis structures required for the recording and assessment of simulation cases with blocked joints movements’ biomechanics at knee and ankle level are developed and presented. In the third part, the results and conclusions regarding the behavior and performance limits of forces and pressures at plantar surface level are presented and processed.
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NOROTTE, GILLES. "THE “PENDULUM LAW” - HOW TO EXPLAIN THE COLUMN SHAPE BASED ON COMMON ANOMALIES? PART II." Coluna/Columna 17, no. 1 (March 2018): 51–54. http://dx.doi.org/10.1590/s1808-185120181701172494.
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ABSTRACT In Part I, the author defines an organizational law of the body schema: the “pendulum law”, describing an ideal biomechanical structure of the spine. Thus, he shows how the common variations and anomalies, whether isolated or associated, modify the standard biomechanical scheme. The variations of isolated “curl/roll up” of the sacrum. Anomalies of the lumbosacral joint in the sagittal (LSS) and/or rotational (LSR) plan. Anomalies of stabilization of the capsule of the hip joint and the sacro-diaphyseal angle. Specific anomalies with grade 1 spondylolysis (SL). Segmental anomalies of the vertebral discs in flexion (Rx). Associated anomalies (SL + Rx + ASL= Rx). The interest of studying the impact on the vertical construction of the vertebral column, according to the “ideal” scheme is to establish the physiological limits of this gravitational law, to identify the anomalies, to classify schemes and types, and the biomechanical degenerative consequences.
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Kovacı, Halim, Ali Fatih Yetim, and Ayhan Çelik. "Biomechanical analysis of spinal implants with different rod diameters under static and fatigue loads: an experimental study." Biomedical Engineering / Biomedizinische Technik 64, no. 3 (May 27, 2019): 339–46. http://dx.doi.org/10.1515/bmt-2017-0236.
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Abstract Spinal implants are commonly used in the treatment of spinal disorders or injuries. However, the biomechanical analyses of them are rarely investigated in terms of both biomechanical and clinical perspectives. Therefore, the main purpose of this study is to investigate the effects of rod diameter on the biomechanical behavior of spinal implants and to make a comparison among them. For this purpose, three spinal implants composed of pedicle screws, setscrews and rods, which were manufactured from Ti6Al4V, with diameters of 5.5 mm, 6 mm and 6.35 mm were used and a bilateral vertebrectomy model was applied to spinal systems. Then, the obtained spinal systems were tested under static tension-compression and fatigue (dynamic compression) conditions. Also, failure analyses were performed to investigate the fatigue behavior of spinal implants. After static tension-compression and fatigue tests, it was found that the yield loads, stiffness values, load carrying capacities and fatigue performances of spinal implants enhanced with increasing spinal rod diameter. In comparison to spinal implants with 5.5 mm rods, the fatigue limits of implants showed 13% and 33% improvements in spinal implants having 6 mm and 6.35 mm rods, respectively. The highest static and fatigue test results were obtained from spinal implants having 6.35 mm rods among the tested implants. Also, it was observed that the increasing yield load and stiffness values caused an increase in the fatigue limits of spinal implants.
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Grabowski, Alena M., Craig P. McGowan, William J. McDermott, Matthew T. Beale, Rodger Kram, and Hugh M. Herr. "Running-specific prostheses limit ground-force during sprinting." Biology Letters 6, no. 2 (November 4, 2009): 201–4. http://dx.doi.org/10.1098/rsbl.2009.0729.
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Running-specific prostheses (RSP) emulate the spring-like behaviour of biological limbs during human running, but little research has examined the mechanical means by which amputees achieve top speeds. To better understand the biomechanical effects of RSP during sprinting, we measured ground reaction forces (GRF) and stride kinematics of elite unilateral trans-tibial amputee sprinters across a range of speeds including top speed. Unilateral amputees are ideal subjects because each amputee's affected leg (AL) can be compared with their unaffected leg (UL). We found that stance average vertical GRF were approximately 9 per cent less for the AL compared with the UL across a range of speeds including top speed ( p < 0.0001). In contrast, leg swing times were not significantly different between legs at any speed ( p = 0.32). Additionally, AL and UL leg swing times were similar to those reported for non-amputee sprinters. We infer that RSP impair force generation and thus probably limit top speed. Some elite unilateral trans-tibial amputee sprinters appear to have learned or trained to compensate for AL force impairment by swinging both legs rapidly.
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Bozkurt, Celal, Alpaslan Şenköylü, Erdem Aktaş, Baran Sarıkaya, Serkan Sipahioğlu, Rıza Gürbüz, and Muharrem Timuçin. "Biomechanical Evaluation of a Novel Apatite-Wollastonite Ceramic Cage Design for Lumbar Interbody Fusion: A Finite Element Model Study." BioMed Research International 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/4152543.
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Objectives. Cage design and material properties play a crucial role in the long-term results, since interbody fusions using intervertebral cages have become one of the basic procedures in spinal surgery. Our aim is to design a novel Apatite-Wollastonite interbody fusion cage and evaluate its biomechanical behavior in silico in a segmental spinal model. Materials and Methods. Mechanical properties for the Apatite-Wollastonite bioceramic cages were obtained by fitting finite element results to the experimental compression behavior of a cage prototype. The prototype was made from hydroxyapatite, pseudowollastonite, and frit by sintering. The elastic modulus of the material was found to be 32 GPa. Three intact lumbar vertebral segments were modelled with the ANSYS 12.0.1 software and this model was modified to simulate a Posterior Lumbar Interbody Fusion. Four cage designs in different geometries were analyzed in silico under axial loading, flexion, extension, and lateral bending. Results. The K2 design had the best overall biomechanical performance for the loads considered. Maximum cage stress recorded was 36.7 MPa in compression after a flexion load, which was within the biomechanical limits of the cage. Conclusion. Biomechanical analyses suggest that K2 bioceramic cage is an optimal design and reveals essential material properties for a stable interbody fusion.
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Dalingwater, John E. "Biomechanical approaches to eurypterid cuticles and chelicerate exoskeletons." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 76, no. 2-3 (1985): 359–64. http://dx.doi.org/10.1017/s0263593300010567.
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ABSTRACTMicrostructural features of eurypterid cuticles are analysed from a biomechanical viewpoint: some fibrous elements are now considered to resemble the macrofibres of extant arthropod cuticles; possible preferred orientation zones in Mycterops are related to directional stresses; pore canals are not viewed as acting as crack-stoppers but laminae (sensu Dennell 1978) may have served this function. Could some eurypterids have walked on land?—this problem is approached by using extant Limulus as a model. It leads on to the use of scaling exponents to determine the limits that possessing an exoskeleton places on the size of land arthropods: moulting may be the limiting factor. Possible critical factors limiting the size of aquatic arthropods are discussed briefly.
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Wainwright, Peter C. "Biomechanical limits to ecological performance: mollusc‐crushing by the Caribbean hogfish, Lachnolaimus maximus (Labridae)." Journal of Zoology 213, no. 2 (October 1987): 283–97. http://dx.doi.org/10.1111/j.1469-7998.1987.tb03704.x.
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Stubbs, Christopher J., Douglas D. Cook, and Karl J. Niklas. "A general review of the biomechanics of root anchorage." Journal of Experimental Botany 70, no. 14 (January 30, 2019): 3439–51. http://dx.doi.org/10.1093/jxb/ery451.
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Abstract With few exceptions, terrestrial plants are anchored to substrates by roots that experience bending and twisting forces resulting from gravity- and wind-induced forces. Mechanical failure occurs when these forces exceed the flexural or torsional tolerance limits of stems or roots, or when roots are dislodged from their substrate. The emphasis of this review is on the general principles of anchorage, how the mechanical failure of root anchorage can be averted, and recommendations for future research.
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O'Shea, Geoffrey. "Cranial factors in neocortical evolution." Behavioral and Brain Sciences 26, no. 5 (October 2003): 566. http://dx.doi.org/10.1017/s0140525x03350125.
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Our understanding of paleoneurology can benefit through considerations of how ontogenetic patterns of skull suture ossification can limit the phylogenetic expansion of underlying brain tissue to specific regions. Additionally, the influence of biochemical, rather than biomechanical, mechanisms on skull suture morphogenesis enable a reconceptualization of the skull as an independent evolutionary system from the brain.
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Sivakumar, Samyuktha, Boopathi Thangavel, and Manimaran Sekar. "Apical reference point - A clinical perspective." Journal of Academy of Dental Education 7 (August 5, 2021): 2–5. http://dx.doi.org/10.25259/jade_2_2021.
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The clinicians face various challenges in trying to find the optimum working length during root canal treatment. Unless proper biomechanical preparation up to the apical limit is done, reinfection of the canal occurs. Apical reference point must be measured with at most care as to avoid any damage to the surrounding periodontal tissues during the treatment.
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Pukšec, Mirjana, Damir Semenski, Damir Ježek, Mladen Brnčić, Sven Karlović, Antonia Jakovčević, Goran Bosanac, and Martin Jurlina. "Biomechanical Comparison of the Temporalis Muscle Fascia, the Fascia Lata, and the Dura Mater." Journal of Neurological Surgery Part B: Skull Base 80, no. 01 (June 19, 2018): 023–30. http://dx.doi.org/10.1055/s-0038-1661349.
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AbstractThe purpose of our research is to prove that elastic biomechanical characteristics of the temporalis muscle fascia are comparable to those of the fascia lata, which makes the temporalis muscle fascia adequate material for dural reconstruction in the region of the anterior cranial fossa. Fifteen fresh human cadavers, with age range from 33 to 83 years (median age: 64 years; mean age: 64.28 years), were included in the biomechanical study. Biomechanical stretching test with the comparison of elasticity among the tissues of the temporalis muscle fascia, the fascia lata, and the dura was performed. The samples were stretched up to the value of 6% of the total sample length and subsequently were further stretched to the maximum value of force. The value of extension at its elastic limit for the each sample was extrapolated from the force–extension curve and was 6.3% of the total sample length for the fascia lata (stress value of 14.61 MPa), 7.4% for the dura (stress value of 6.91 MPa), and 8% for the temporalis muscle fascia (stress value of 2.09 MPa). The dura and temporalis muscle fascia shared the same biomechanical behavior pattern up to the value of their elastic limit, just opposite to that of the fascia lata, which proved to be the stiffest among the three investigated tissues. There was a statistically significant difference in the extension of the samples at the value of the elastic limit for the fascia lata in comparison to the temporalis muscle fascia and the dura (p = 0.002; Kruskal–Wallis test). Beyond the value of elastic limit, the temporalis muscle fascia proved to be by far the most elastic tissue in comparison to the fascia lata and the dura. The value of extension at its maximum value of force for the each sample was extrapolated from the force–extension curve and was 9.9% of the sample's total length for the dura (stress value of 10.02 MPa), 11.2% for the fascia lata (stress value of 23.03 MPa), and 18.5% (stress value of 3.88 MPa) for the temporalis muscle fascia. There was a statistically significant difference in stress values at the maximum value of force between the dura and the temporalis muscle fascia (p = 0.001; Mann–Whitney U test) and between the dura and the fascia lata (p < 0.001; Mann–Whitney U test). Because of its elasticity and similarity in its mechanical behavior to the dura, the temporalis muscle fascia can be considered the most suitable tissue for dural reconstruction.
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BABBS, CHARLES F. "A NEW BIOMECHANICAL HEAD INJURY CRITERION." Journal of Mechanics in Medicine and Biology 06, no. 04 (December 2006): 349–71. http://dx.doi.org/10.1142/s021951940600200x.
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This paper presents a new analysis of the physics of closed head injury caused by intense acceleration of the head. At rest a 1 cm gap filled with cerebrospinal fluid (CSF) separates the adult human brain from the skull. During impact, whole head acceleration induces artificial gravity within the skull. Because its density differs slightly from that of CSF, the brain accelerates, strikes the inner aspect of the rigid skull, and undergoes viscoelastic deformation. Analytical methods for a lumped parameter model of the brain predict internal brain motions that correlate well with published high-speed photographic studies. The same methods predict a truncated hyperbolic strength-duration curve for impacts that produce a given critical compressive strain. A family of such curves exists for different critical strains. Each truncated hyperbolic curve defines a head injury criterion (HIC) or threshold for injury, which is little changed by small offsetting corrections for curvature of the brain and for viscous damping. Such curves predict results of experimental studies of closed head injury, known limits for safe versus dangerous falls, and the relative resistance of smaller versus larger animals to acceleration of the head. The underlying theory provides improved understanding of closed head injury and better guidance to designers of protective equipment and to those extrapolating research results from animals to man.
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DAGGFELDT, KARL. "MUSCLE BULGING REDUCES MUSCLE FORCE AND LIMITS THE MAXIMAL EFFECTIVE MUSCLE SIZE." Journal of Mechanics in Medicine and Biology 06, no. 03 (September 2006): 229–39. http://dx.doi.org/10.1142/s0219519406001947.
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A biomechanical model was generated in order to investigate the possible mechanisms behind reductions in muscle performance due to muscle bulging. It was shown that the proportion of fiber force contributing to the total muscle force is reduced with fiber bulging and that the cause of this reduction is due to the intramuscular pressure (IMP) created by the bulging fibers. Moreover, it was established that the amount of IMP generated muscle force reduction is determined by the extent to which muscle thickening restricts muscle fibers from shortening, thereby limiting their power contribution. It was shown that bulging can set a limit to the maximal size a muscle can take without losing force and power producing capability. Possible effects, due to bulging, on maximal muscle force in relation to both muscle length and muscle shortening velocity were also demonstrated by the model.
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Steinmetz, Michael P., Thomas E. Mroz, and Edward C. Benzel. "Craniovertebral Junction." Neurosurgery 66, suppl_3 (March 1, 2010): A7—A12. http://dx.doi.org/10.1227/01.neu.0000366109.85796.42.
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Abstract THE CRANIOVERTEBRAL JUNCTION is a complex region that incorporates the occiput–C1–C2 portions of the spine. It is a transition between the cranium and the mobile cervical spine that permits significant motion. The motions afforded and the anatomy are vastly different at the occiput–C1 and C1–C2 articulations. These differences make treating pathology in this region very difficult. Problems include bony fixation of the cranium and the cervical spine (specifically C1 and C2), which limits complex motions, and limited bony sites available for arthrodesis. A thorough knowledge of the normal anatomy and biomechanics is required for fixation of this region. Moreover, an understanding of pathologic motions and the biomechanics of fixation is needed for successful construct design and good patient outcome.
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Logishetty, K., R. J. van Arkel, K. C. G. Ng, S. K. Muirhead-Allwood, J. P. Cobb, and J. R. T. Jeffers. "Hip capsule biomechanics after arthroplasty." Bone & Joint Journal 101-B, no. 4 (April 2019): 426–34. http://dx.doi.org/10.1302/0301-620x.101b4.bjj-2018-1321.r1.
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Aims The hip’s capsular ligaments passively restrain extreme range of movement (ROM) by wrapping around the native femoral head/neck. We determined the effect of hip resurfacing arthroplasty (HRA), dual-mobility total hip arthroplasty (DM-THA), conventional THA, and surgical approach on ligament function. Materials and Methods Eight paired cadaveric hip joints were skeletonized but retained the hip capsule. Capsular ROM restraint during controlled internal rotation (IR) and external rotation (ER) was measured before and after HRA, DM-THA, and conventional THA, with a posterior (right hips) and anterior capsulotomy (left hips). Results Hip resurfacing provided a near-native ROM with between 5° to 17° increase in IR/ER ROM compared with the native hip for the different positions tested, which was a 9% to 33% increase. DM-THA generated a 9° to 61° (18% to 121%) increase in ROM. Conventional THA generated a 52° to 100° (94% to 199%) increase in ROM. Thus, for conventional THA, the capsule function that exerts a limit on ROM is lost. It is restored to some extent by DM-THA, and almost fully restored by hip resurfacing. In positions of low flexion/extension, the posterior capsulotomy provided more normal function than the anterior, possibly because the capsule was shortened during posterior repair. However, in deep flexion positions, the anterior capsulotomy functioned better. Conclusion Native head-size and capsular repair preserves capsular function after arthroplasty. The anterior and posterior approach differentially affect postoperative biomechanical function of the capsular ligaments. Cite this article: Bone Joint J 2019;101-B:426–434.
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Torres-Netto, Emilio A., Sabine Kling, Nikki Hafezi, Paolo Vinciguerra, J. Bradley Randleman, and Farhad Hafezi. "Oxygen Diffusion May Limit the Biomechanical Effectiveness of Iontophoresis-Assisted Transepithelial Corneal Cross-linking." Journal of Refractive Surgery 34, no. 11 (November 1, 2018): 768–74. http://dx.doi.org/10.3928/1081597x-20180830-01.
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Salam, Rudi, Mohammad Iqbal, and Iskandar Hasanuddin. "Desain dan Analisis Artificial Exoskeleton pada Prajurit TNI." Jurnal Optimasi Sistem Industri 17, no. 2 (October 30, 2018): 135. http://dx.doi.org/10.25077/josi.v17.n2.p135-142.2018.
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Soldier’s activities resulted in too much workload received by the body, especially in the back and waist. These conditions produce a high risk of musculoskeletal disorders especially if conducted continuously. The soldiers must carry a backpack containing supplies during training weighing up to 40 kg on average. All activities are conducted manually until the training is finish. Thus, the purposes of this study are to reduce spinal injury by identifying factors resulting from lifting loads that exceed the limits of the body, calculate the maximum load limit that can be carried by a soldier, and produce artificial exoskeleton as a tool for the Indonesian Armed Forces. The study used anthropometry, biomechanics, and physiological approach in solving the problem. The results show that the safe load can be carried by the soldiers is 30.46 kg. The body parts that feel the complaint are the upper neck, back, shoulder, buttocks. In addition, this study can produce a design of an artificial exoskeleton with the following dimensions: chest thickness 23 cm, chest width 32 cm, back length 52 cm. The soldiers can increase the force load by 9% of the initial weight of the load using this design.
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Green, P. A., M. J. McHenry, and A. Rico-Guevara. "Mechanoethology: The Physical Mechanisms of Behavior." Integrative and Comparative Biology 61, no. 2 (June 14, 2021): 613–23. http://dx.doi.org/10.1093/icb/icab133.
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Abstract Research that integrates animal behavior theory with mechanics—including biomechanics, physiology, and functional morphology—can reveal how organisms accomplish tasks crucial to their fitness. Despite the insights that can be gained from this interdisciplinary approach, biomechanics commonly neglects a behavioral context and behavioral research generally does not consider mechanics. Here, we aim to encourage the study of “mechanoethology,” an area of investigation intended to encompass integrative studies of mechanics and behavior. Using examples from the literature, including papers in this issue, we show how these fields can influence each other in three ways: (1) the energy required to execute behaviors is driven by the kinematics of movement, and mechanistic studies of movement can benefit from consideration of its behavioral context; (2) mechanics sets physical limits on what behaviors organisms execute, while behavior influences ecological and evolutionary limits on mechanical systems; and (3) sensory behavior is underlain by the mechanics of sensory structures, and sensory systems guide whole-organism movement. These core concepts offer a foundation for mechanoethology research. However, future studies focused on merging behavior and mechanics may reveal other ways by which these fields are linked, leading to further insights in integrative organismal biology.
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Ruiz, Siul A., and Dani Or. "Biomechanical limits to soil penetration by earthworms: direct measurements of hydroskeletal pressures and peristaltic motions." Journal of The Royal Society Interface 15, no. 144 (July 2018): 20180127. http://dx.doi.org/10.1098/rsif.2018.0127.
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Burrows resulting from earthworm activity are important for supporting various physical and ecological soil processes. Earthworm burrowing activity is quantified using models for earthworm penetration and cavity expansion that consider soil moisture and mechanical properties. Key parameters in these models are the maximal pressures exerted by the earthworm's hydroskeleton (estimated at 200 kPa). We designed a special pressure chamber that directly measures the pressures exerted by moving earthworms under different confining pressures to delineate the limits of earthworm activity in soils at different mechanical and hydration states. The chamber consists of a Plexiglas prism fitted with inner flexible tubing that hosts the earthworm. The gap around the tubing is pressurized using water, and the earthworm's peristaltic motion and concurrent pressure fluctuations were recorded by a camera and pressure transducer. A model that links the earthworm's kinematics with measured pressure fluctuations was developed. Resulting maximal values of radial pressures for anecic and endogeic earthworms were 130 kPa and 195 kPa, respectively. Mean earthworm peristaltic frequencies were used to quantify burrowing rates that were in agreement with previous results. The study delineates mechanical constraints to soil bioturbation by earthworms by mapping the elastic behaviour in the measurement chamber onto the expected elasto-viscoplastic environment of natural soils.
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Yuan, Yvonne V., and David D. Kitts. "Calcium absorption and bone utilization in spontaneously hypertensive rats fed on native and heat-damaged casein and soya-bean protein." British Journal of Nutrition 71, no. 4 (April 1994): 583–603. http://dx.doi.org/10.1079/bjn19940165.
Full textAbstract:
The effects of dietary protein on Ca bioavailability and utilization in bone were examined in male spontaneously hypertensive rats (SHR) fed on diets containing either casein (200 g/kg (control), 60 g/kg or heat-damaged (HD) 200 g/kg) or soya-bean protein isolate (200 g/kg (control), 60 g/kg, or HD 200 g/kg). Casein was heat-damaged to limit caseinophosphopeptide (CPP) production in order to evaluate casein enhancement of Ca bioavailability. All diets contained an adequate level of Ca (5 g/kg). A 24 h mineral balance study was performed when animals were 10 weeks old, followed by measurement of in situ paracellular Ca disappearance, femur mineralization and biomechanics at 14 weeks of age. Digestibility of soya-bean and both HD proteins estimated in vitro was reduced compared with native casein. Animals fed on HD and 60 g/kg protein diets exhibited decreased (P < 0.05) body weight gain, dry matter intake and feed efficiency compared with controls. The ileal disappearance of 45Ca was lower (P < 0.05) in animals fed on HD casein and all the soya-bean protein diets. Ca balance was not strongly affected by dietary treatments. A significant (P < 0.05) interaction between protein source and reduced protein intake was observed for femur calcification and physical measurements. Femur bending failure energy and biomechanical force measurements were reduced (P < 0.05) in HD and 60 g/kg casein and soya-bean protein fed animals. These findings suggest that whole-body Ca homeostatic mechanisms were involved in compensating for reduced Ca bioavailability and retention from casein diets modified to reduce protein digestibility and CPP production.
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Manista, Gregory C., and Alaa A. Ahmed. "Stability limits modulate whole-body motor learning." Journal of Neurophysiology 107, no. 7 (April 1, 2012): 1952–61. http://dx.doi.org/10.1152/jn.00983.2010.
Full textAbstract:
Our daily movements exert forces upon the environment and also upon our own bodies. To control for these forces, movements performed while standing are usually preceded by anticipatory postural adjustments (APAs). This strategy is effective at compensating for an expected perturbation, as it reduces the need to compensate for the perturbation in a reactive manner. However, it can also be risky if one anticipates the incorrect perturbation, which could result in movements outside stability limits and a loss of balance. Here, we examine whether the margin for error defined by these stability limits affects the amount of anticipation. Specifically, will one rely more on anticipation when the margin for error is lower? Will the degree of anticipation scale with the margin for error? We took advantage of the asymmetric stability limits (and margins for error) present in the sagittal plane during upright stance and investigated the effect of perturbation direction on the magnitude of APAs. We also compared anticipatory postural control with the anticipatory control observed at the arm. Standing subjects made reaching movements to multiple targets while grasping the handle of a robot arm. They experienced forward or backward perturbing forces depending on the target direction. Subjects learned to anticipate the forces and generated APAs. Although subjects had the biomechanical capacity to adapt similarly in the forward and backward directions, APAs were reduced significantly in the backward direction, which had smaller stability limits and a smaller margin for error. Interestingly, anticipatory control produced at the arm, where stability limits are not as relevant, was not affected by perturbation direction. These results suggest that stability limits modulate anticipatory control, and reduced stability limits lead to a reduction in anticipatory postural control.