Displaying publications 21 - 40 of 251 in total

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  1. Fulltext Effects of powered ankle-foot orthoses mass distribution on lower limb muscle forces-a simulation study
    Marconi G, Gopalai AA, Chauhan S
    Med Biol Eng Comput, 2023 May;61(5):1167-1182.
    PMID: 36689083 DOI: 10.1007/s11517-023-02778-2
    This simulation study aimed to explore the effects of mass and mass distribution of powered ankle-foot orthoses, on net joint moments and individual muscle forces throughout the lower limb. Using OpenSim inverse kinematics, dynamics, and static optimization tools, the gait cycles of ten subjects were analyzed. The biomechanical models of these subjects were appended with ideal powered ankle-foot orthoses of different masses and actuator positions, as to determine the effect that these design factors had on the subject's kinetics during normal walking. It was found that when the mass of the device was distributed more distally and posteriorly on the leg, both the net joint moments and overall lower limb muscle forces were more negatively impacted. However, individual muscle forces were found to have varying results which were attributed to the flow-on effect of the orthosis, the antagonistic pairing of muscles, and how the activity of individual muscles affect each other. It was found that mass and mass distribution of powered ankle-foot orthoses could be optimized as to more accurately mimic natural kinetics, reducing net joint moments and overall muscle forces of the lower limb, and must consider individual muscles as to reduce potentially detrimental muscle fatigue or muscular disuse. OpenSim modelling method to explore the effect of mass and mass distribution on muscle forces and joint moments, showing potential mass positioning and the effects of these positions, mass, and actuation on the muscle force integral.
    Matched MeSH terms: Biomechanical Phenomena/physiology
  2. Fulltext Virtual Planning, Control, and Machining for a Modular-Based Automated Factory Operation in an Augmented Reality Environment
    Pai YS, Yap HJ, Md Dawal SZ, Ramesh S, Phoon SY
    Sci Rep, 2016 06 07;6:27380.
    PMID: 27271840 DOI: 10.1038/srep27380
    This study presents a modular-based implementation of augmented reality to provide an immersive experience in learning or teaching the planning phase, control system, and machining parameters of a fully automated work cell. The architecture of the system consists of three code modules that can operate independently or combined to create a complete system that is able to guide engineers from the layout planning phase to the prototyping of the final product. The layout planning module determines the best possible arrangement in a layout for the placement of various machines, in this case a conveyor belt for transportation, a robot arm for pick-and-place operations, and a computer numerical control milling machine to generate the final prototype. The robotic arm module simulates the pick-and-place operation offline from the conveyor belt to a computer numerical control (CNC) machine utilising collision detection and inverse kinematics. Finally, the CNC module performs virtual machining based on the Uniform Space Decomposition method and axis aligned bounding box collision detection. The conducted case study revealed that given the situation, a semi-circle shaped arrangement is desirable, whereas the pick-and-place system and the final generated G-code produced the highest deviation of 3.83 mm and 5.8 mm respectively.
    Matched MeSH terms: Biomechanical Phenomena
  3. Observation of Medium-Induced Modifications of Jet Fragmentation in Pb-Pb Collisions at sqrt[s_{NN}]=5.02  TeV Using Isolated Photon-Tagged Jets
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Dec 14;121(24):242301.
    PMID: 30608764 DOI: 10.1103/PhysRevLett.121.242301
    Measurements of fragmentation functions for jets associated with an isolated photon are presented for the first time in pp and Pb-Pb collisions. The analysis uses data collected with the CMS detector at the CERN LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Fragmentation functions are obtained for jets with p_{T}^{jet}>30  GeV/c in events containing an isolated photon with p_{T}^{γ}>60  GeV/c, using charged tracks with transverse momentum p_{T}^{trk}>1  GeV/c in a cone around the jet axis. The association with an isolated photon constrains the initial p_{T} and azimuthal angle of the parton whose shower produced the jet. For central Pb-Pb collisions, modifications of the jet fragmentation functions are observed when compared to those measured in pp collisions, while no significant differences are found in the 50% most peripheral collisions. Jets in central Pb-Pb events show an excess (depletion) of low (high) p_{T} particles, with a transition around 3  GeV/c. This measurement shows for the first time the in-medium shower modifications of partons (quark dominated) with well-defined initial kinematics. It constitutes a new well-controlled reference for testing theoretical models of the parton passage through the quark-gluon plasma.
    Matched MeSH terms: Biomechanical Phenomena
  4. Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2018 Nov 30;121(22):221802.
    PMID: 30547617 DOI: 10.1103/PhysRevLett.121.221802
    The first evidence of events consistent with the production of a single top quark in association with a photon is reported. The analysis is based on proton-proton collisions at sqrt[s]=13  TeV and recorded by the CMS experiment in 2016, corresponding to an integrated luminosity of 35.9  fb^{-1}. Events are selected by requiring the presence of a muon (μ), a photon (γ), an imbalance in transverse momentum from an undetected neutrino (ν), and at least two jets (j) of which exactly one is identified as associated with the hadronization of a b quark. A multivariate discriminant based on topological and kinematic event properties is employed to separate signal from background processes. An excess above the background-only hypothesis is observed, with a significance of 4.4 standard deviations. A fiducial cross section is measured for isolated photons with transverse momentum greater than 25 GeV in the central region of the detector. The measured product of the cross section and branching fraction is σ(pp→tγj)B(t→μνb)=115±17(stat)±30(syst)  fb, which is consistent with the standard model prediction.
    Matched MeSH terms: Biomechanical Phenomena
  5. Effects of utterance rate and length on the spatiotemporal index in Parkinson's disease
    Chu SY, Barlow SM, Lee J, Wang J
    Int J Speech Lang Pathol, 2020 04;22(2):141-151.
    PMID: 31213093 DOI: 10.1080/17549507.2019.1622781
    Purpose: To characterise labial articulatory pattern variability using the spatiotemporal index (STI) in speakers with idiopathic Parkinson's disease (PD) across different speaking rates and syllable-sentence conditions compared to age- and sex-matched healthy controls.Method: Ten speakers with mild-severe idiopathic PD and 10 controls produced "pa" and the Rainbow Passage at slow, typical and fast speech rates. Upper lip and lower lip kinematics were digitised during a motion capture system. Data were analysed using linear mixed modelling.Result: Regardless of the participant group, a high STI value was observed in the fast speech rate for the "pa" syllable condition, particularly for movements of the lower lip. As utterance rate increased, the control group showed the highest variability, followed by PD OFF and PD ON conditions. Syllable "pa" showed a greater STI value compared to both the first and second utterance of Rainbow Passage.Conclusion: PD manifests sufficient residual capacity to achieve near-normal motor compensation to preserve the consistency of lower lip movements during speech production. The lack of a significant difference in lip STI values between ON-OFF medication states suggests that dopaminergic treatment does not influence stability of speech for individuals with mild-moderate stage PD.
    Matched MeSH terms: Biomechanical Phenomena
  6. A state-of-the-art review on badminton lunge attributes
    Lee JJJ, Loh WP
    Comput Biol Med, 2019 05;108:213-222.
    PMID: 31005013 DOI: 10.1016/j.compbiomed.2019.04.003
    Good badminton lunge skills have been quantitatively described using biomechanical attributes at both static and dynamic phases. The measurement of badminton lunge attributes has often been complicated by various experimental protocols used. No review article has considered or critically reviewed the attributes that align with badminton lunge performance. This paper, hence, presents a review of badminton lunge postures governed by various determinant attributes. This review was performed by involving a number of relevant search engines. A total of 21 articles that fulfilled the predefined inclusion criteria were analysed. The lunge determinant attributes, such as time, lunge distance, plantar, ground reaction force, joint, dynamic balance and muscle attributes, had been examined. Contradictory findings in the dynamic balance attributes, specifically the relative displacement between the centre of mass and the centre of pressure, are presented in this paper. The findings showed that time, lunge distance and ground reaction force determined lunge performance. On the other hand, plantar, joint, dynamic balance and muscle attributes appeared useful in minimising injuries to ensure efficient lunge performance.
    Matched MeSH terms: Biomechanical Phenomena
  7. Fulltext Inertial Sensor-Based Instrumented Cane for Real-Time Walking Cane Kinematics Estimation
    Fernandez IG, Ahmad SA, Wada C
    Sensors (Basel), 2020 Aug 19;20(17).
    PMID: 32825029 DOI: 10.3390/s20174675
    Falls are among the main causes of injuries in elderly individuals. Balance and mobility impairment are major indicators of fall risk in this group. The objective of this research was to develop a fall risk feedback system that operates in real time using an inertial sensor-based instrumented cane. Based on inertial sensor data, the proposed system estimates the kinematics (contact phase and orientation) of the cane. First, the contact phase of the cane was estimated by a convolutional neural network. Next, various algorithms for the cane orientation estimation were compared and validated using an optical motion capture system. The proposed cane contact phase prediction model achieved higher accuracy than the previous models. In the cane orientation estimation, the Madgwick filter yielded the best results overall. Finally, the proposed system was able to estimate both the contact phase and orientation in real time in a single-board computer.
    Matched MeSH terms: Biomechanical Phenomena
  8. Investigation of EMG parameter for transtibial prosthetic user with flexion and extension of the knee and normal walking gait: A preliminary study
    Sobh KNM, Abd Razak NA, Abu Osman NA
    Proc Inst Mech Eng H, 2021 Apr;235(4):419-427.
    PMID: 33517847 DOI: 10.1177/0954411920985753
    Electromyography signal has been used widely as input for prosthetic's leg movements. C-Leg, for example, is among the prosthetics devices that use electromyography as the main input. The main challenge facing the industrial party is the position of the electromyography sensor as it is fixed inside the socket. The study aims to investigate the best positional parameter of electromyography for transtibial prosthetic users for the device to be effective in multiple movement activities and compare with normal human muscle's activities. DELSYS Trigno wireless electromyography instrument was used in this study to achieve this aim. Ten non-amputee subjects and two transtibial amputees were involved in this study. The surface electromyography signals were recorded from two anterior and posterior below the knee muscles and above the knee muscles, respectively: tibial anterior and gastrocnemius lateral head as well as rectus femoris and biceps femoris during two activities (flexion and extension of knee joint and gait cycle for normal walking). The result during flexion and extension activities for gastrocnemius lateral head and biceps femoris muscles was found to be more useful for the control subjects, while the tibial anterior and also gastrocnemius lateral head are more active for amputee subjects. Also, during normal walking activity for biceps femoris and gastrocnemius lateral head, it was more useful for the control subjects, while for transtibial amputee subject-1, the rectus femoris was the highest signal of the average normal walking activity (0.0001 V) compared to biceps femoris (0.00007 V), as for transtibial amputee subject-2, the biceps femoris was the highest signals of the average normal walking activity (0.0001 V) compared to rectus femoris (0.00004 V). So, it is difficult to rely entirely on the static positioning of the electromyography sensor within the socket as there is a possibility of the sensor to contact with inactive muscle, which will be a gap in the control, leading to a decrease in the functional efficiency of the powered prostheses.
    Matched MeSH terms: Biomechanical Phenomena
  9. Fulltext Muscles Affecting Minimum Toe Clearance
    Perera CK, Gopalai AA, Ahmad SA, Gouwanda D
    Front Public Health, 2021;9:612064.
    PMID: 34136448 DOI: 10.3389/fpubh.2021.612064
    The aim of this study was to investigate how the anterior and posterior muscles in the shank (Tibialis Anterior, Gastrocnemius Lateralis and Medialis), influence the level of minimum toe clearance (MTC). With aging, MTC deteriorates thus, greatly increasing the probability of falling or tripping. This could result in injury or even death. For this study, muscle activity retention taping (MART) was used on young adults, which is an accepted method of simulating a poor MTC-found in elderly gait. The subject's muscle activation was measured using surface electromyography (SEMG), and the kinematic parameters (MTC, knee and ankle joint angles) were measured using an optical motion capture system. Our results indicate that MART produces significant reductions in MTC (P < α), knee flexion (P < α) and ankle dorsiflexion (P < α), as expected. However, the muscle activity increased significantly, contrary to the expected result (elderly individuals should have lower muscle activity). This was due to the subject's muscle conditions (healthy and strong), hence the muscles worked harder to counteract the external restriction. Yet, the significant change in muscle activity (due to MART) proves that the shank muscles do play an important role in determining the level of MTC. The Tibialis Anterior had the highest overall muscle activation, making it the primary muscle active during the swing phase. With aging, the shank muscles (specifically the Tibialis Anterior) would weaken and stiffen, coupled with a reduced joint range of motion. Thus, ankle-drop would increase-leading to a reduction in MTC.
    Matched MeSH terms: Biomechanical Phenomena
  10. Fulltext The relationship between carrying activity and low back pain: a critical review of biomechanics studies
    Hanif Farhan, M. R., White, P. J, Warner, M., Adam, J. E.
    Jurnal Sains Kesihatan Malaysia, 2015;13(2):1-10.
    MyJurnal
    The aim of this review was to systematically explore the underlying musculoskeletal biomechanical mechanisms of carrying and to describe its potential relationship with low back pain. This literature review was carried out using AMED, CINAHL, Compendex and MEDLINE electronic databases. Articles published from 2004 to 2012 were selected for consideration. Articles were considered if at least one measurement of kinetics, kinematics or other related musculoskeletal parameters related to biomechanics were included within the study. After combining the main keywords, 677 papers were identified. However, only 10 studies met all the inclusion criteria. Age, body mass index, gender and level of physical activity were identified as the factors that may influence the biomechanics of carrying activity. Carrying a loaded backpack was reported leading to posterior pelvic tilt, reduced lumbar lordosis, but increased cervical lordosis, thoracic kyphosis and trunk forward lean. Furthermore, while carrying bilaterally, lumbo-pelvic coordination was also reported to be more in-phase, as well as reduced coordination variability in transverse plane. Future studies investigating the biomechanics of a standardized carrying activity for clinical test are recommended.
    Matched MeSH terms: Biomechanical Phenomena
  11. Mechanobiological modelling of tendons: Review and future opportunities
    Thompson MS, Bajuri MN, Khayyeri H, Isaksson H
    Proc Inst Mech Eng H, 2017 May;231(5):369-377.
    PMID: 28427319 DOI: 10.1177/0954411917692010
    Tendons are adapted to carry large, repeated loads and are clinically important for the maintenance of musculoskeletal health in an increasing, actively ageing population, as well as in elite athletes. Tendons are known to adapt to mechanical loading. Also, their healing and disease processes are highly sensitive to mechanical load. Computational modelling approaches developed to capture this mechanobiological adaptation in tendons and other tissues have successfully addressed many important scientific and clinical issues. The aim of this review is to identify techniques and approaches that could be further developed to address tendon-related problems. Biomechanical models are identified that capture the multi-level aspects of tendon mechanics. Continuum whole tendon models, both phenomenological and microstructurally motivated, are important to estimate forces during locomotion activities. Fibril-level microstructural models are documented that can use these estimated forces to detail local mechanical parameters relevant to cell mechanotransduction. Cell-level models able to predict the response to such parameters are also described. A selection of updatable mechanobiological models is presented. These use mechanical signals, often continuum tissue level, along with rules for tissue change and have been applied successfully in many tissues to predict in vivo and in vitro outcomes. Signals may include scalars derived from the stress or strain tensors, or in poroelasticity also fluid velocity, while adaptation may be represented by changes to elastic modulus, permeability, fibril density or orientation. So far, only simple analytical approaches have been applied to tendon mechanobiology. With the development of sophisticated computational mechanobiological models in parallel with reporting more quantitative data from in vivo or clinical mechanobiological studies, for example, appropriate imaging, biochemical and histological data, this field offers huge potential for future development towards clinical applications.
    Matched MeSH terms: Biomechanical Phenomena
  12. Fulltext Relative Modification of Prompt ψ(2S) and J/ψ Yields from pp to PbPb Collisions at sqrt[s_{NN}]=5.02  TeV
    Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, Brandstetter J, et al.
    Phys Rev Lett, 2017 Apr 21;118(16):162301.
    PMID: 28474955 DOI: 10.1103/PhysRevLett.118.162301
    The relative modification of the prompt ψ(2S) and J/ψ yields from pp to PbPb collisions, at the center-of-mass energy of 5.02 TeV per nucleon pair, is presented. The analysis is based on pp and PbPb data samples collected by the CMS experiment at the LHC in 2015, corresponding to integrated luminosities of 28.0  pb^{-1} and 464  μb^{-1}, respectively. The double ratio of measured yields of prompt charmonia reconstructed through their decays into muon pairs, (N_{ψ(2S)}/N_{J/ψ})_{PbPb}/(N_{ψ(2S)}/N_{J/ψ})_{pp}, is determined as a function of PbPb collision centrality and charmonium transverse momentum p_{T}, in two kinematic intervals: |y|<1.6 covering 6.5
    Matched MeSH terms: Biomechanical Phenomena
  13. Fulltext Geographic information system mapping in Pedro Vicente Maldonado Ecuadorian Scientific Station Antarctica Base (Greenwich Island) Antarctic Peninsular
    Fauzi, R., Salazar, D.M., Kadzim, R.M., Hussin, A., Burbano, L.
    ASM Science Journal, 2009;3(2):161-167.
    MyJurnal
    In this project, a Geographic Information System (GIS) was used to collect and compile various field data in the Pedro Vicente Maldonado Ecuadorian Scientific Station Antarctica Base area. The main source of data was obtained from a global positioning system (GPS) survey using kinematic GPS (GPS-RTK) which allowed continuous point mapping in the terrain. GPS units were utilized in the collection of spatial data for all field work. The co-ordinates obtained were used to produce a point map which was then exported into GIS software where the proximity of cartographic phenomena and boundaries were mapped. All the collected data were subsequently gathered to develop the GIS database which was then used to generate and compile different maps to test for spatial and temporal relationships. The output of the project comprises a GIS database, spatial maps and 3D terrain model of the area. The developed GIS database can be used with other ecological datasets to provide biogeographical information, potential range distribution and sampling adequacy. The database is also applicable to geographical management and multi-disciplinary research projects.
    Matched MeSH terms: Biomechanical Phenomena
  14. Fulltext Visual perception of kuda and sila service techniques in sepak takraw
    Mohamad Razali Abdullah, Saidon Amri, Suppiah, Pathmanathan K.
    Movement Health & Exercise, 2012;1(1):25-37.
    MyJurnal
    Two major types of services in sepak takraw are kuda and sila services. Even though both services are delivered at high speed, each is composed of different kinematic features. The purpose of the study was to determine the fundamental differences in perceptual strategies in
    anticipating the kuda and sila services. The receiver of the game in sepak takraw makes decisions under severe time constraint in both spatial and temporal uncertainty. The study examined two groups of 12 players each; the experts and the novices. Perceptual displays in anticipation of the
    kuda and sila services were prompted using video stimulations consisting of seven temporal occlusions t1 (240 milliseconds at pre-contact), t2 (160 milliseconds at pre-contact), t3 (80 milliseconds at pre-contact, t4 (0 millisecond at contact), t5 (80 milliseconds at post-contact), t6 (160
    milliseconds at post-contact), and t7 (no occlusion). Significant differences amongst expert players in anticipating kuda and sila services were at t1 F (14, 180) = 2.37; p < 0.05], t2 F (14, 180) = 5.60; p < 0.05], t3 F (14, 180) = 3.81; p < 0.05] and t4 F (14, 180) = 2.00; p < 0.05]. Similar comparisons at t5, t6, and t7 did not yield any significant differences. In addition, there were significant differences amongst novice players in anticipating kuda and sila services at t2 F (14,
    180) = 2.27; p < 0.05], t3 F (14, 180) = 1.94; p < 0.05], t4 F (14, 180) = 2.61; p < 0.05], and t5 F (14, 180) = 9.38; p < 0.05]. Overall findings revealed that expert players found it more difficult to anticipate kuda service compared to sila service at t1. Hence, the kuda service is more
    difficult to anticipate than sila service. Participants of this study demonstrated a more effective visual perceptual strategy to counter attack a sila service than they would with a kuda service.
    Matched MeSH terms: Biomechanical Phenomena
  15. Fulltext Cambered profile of a California sea lion's body
    Ul-Haque A, Asrar W, Omar AA, Sulaeman E, Mohamed Ali JS
    J Exp Biol, 2015 Apr 15;218(Pt 8):1270-1.
    PMID: 25911735 DOI: 10.1242/jeb.117556
    Matched MeSH terms: Biomechanical Phenomena
  16. Jumping in lantern bugs (Hemiptera, Fulgoridae)
    Burrows M, Ghosh A, Sutton GP, Yeshwanth HM, Rogers SM, Sane SP
    J Exp Biol, 2021 12 01;224(23).
    PMID: 34755862 DOI: 10.1242/jeb.243361
    Lantern bugs are amongst the largest of the jumping hemipteran bugs, with body lengths reaching 44 mm and masses reaching 0.7 g. They are up to 600 times heavier than smaller hemipterans that jump powerfully using catapult mechanisms to store energy. Does a similar mechanism also propel jumping in these much larger insects? The jumping performance of two species of lantern bugs (Hemiptera, Auchenorrhyncha, family Fulgoridae) from India and Malaysia was therefore analysed from high-speed videos. The kinematics showed that jumps were propelled by rapid and synchronous movements of both hind legs, with their trochantera moving first. The hind legs were 20-40% longer than the front legs, which was attributable to longer tibiae. It took 5-6 ms to accelerate to take-off velocities reaching 4.65 m s-1 in the best jumps by female Kalidasa lanata. During these jumps, adults experienced an acceleration of 77 g, required an energy expenditure of 4800 μJ and a power output of 900 mW, and exerted a force of 400 mN. The required power output of the thoracic jumping muscles was 21,000 W kg-1, 40 times greater than the maximum active contractile limit of muscle. Such a jumping performance therefore required a power amplification mechanism with energy storage in advance of the movement, as in their smaller relatives. These large lantern bugs are near isometrically scaled-up versions of their smaller relatives, still achieve comparable, if not higher, take-off velocities, and outperform other large jumping insects such as grasshoppers.
    Matched MeSH terms: Biomechanical Phenomena
  17. Fulltext Instantaneous, Dual-Frequency, Multi-GNSS Precise RTK Positioning Using Google Pixel 4 and Samsung Galaxy S20 Smartphones for Zero and Short Baselines
    Yong CZ, Odolinski R, Zaminpardaz S, Moore M, Rubinov E, Er J, et al.
    Sensors (Basel), 2021 Dec 13;21(24).
    PMID: 34960412 DOI: 10.3390/s21248318
    The recent development of the smartphone Global Navigation Satellite System (GNSS) chipsets, such as Broadcom BCM47755 and Qualcomm Snapdragon 855 embedded, makes instantaneous and cm level real-time kinematic (RTK) positioning possible with Android-based smartphones. In this contribution we investigate the instantaneous single-baseline RTK performance of Samsung Galaxy S20 and Google Pixel 4 (GP4) smartphones with such chipsets, while making use of dual-frequency L1 + L5 Global Positioning System (GPS), E1 + E5a Galileo, L1 + L5 Quasi-Zenith Satellite System (QZSS) and B1 BeiDou Navigation Satellite System (BDS) code and phase observations in Dunedin, New Zealand. The effects of locating the smartphones in an upright and lying down position were evaluated, and we show that the choice of smartphone configuration can affect the positioning performance even in a zero-baseline setup. In particular, we found non-zero mean and linear trends in the double-differenced carrier-phase residuals for one of the smartphone models when lying down, which become absent when in an upright position. This implies that the two assessed smartphones have different antenna gain pattern and antenna sensitivity to interferences. Finally, we demonstrate, for the first time, a near hundred percent (98.7% to 99.9%) instantaneous RTK integer least-squares success rate for one of the smartphone models and cm level positioning precision while using short-baseline experiments with internal and external antennas, respectively.
    Matched MeSH terms: Biomechanical Phenomena
  18. A triple compound pendulum model to analyse the effect of an ankle-foot orthosis on swing phase kinematics
    Marconi G, Gopalai AA, Chauhan S
    Med Eng Phys, 2023 Feb;112:103951.
    PMID: 36842774 DOI: 10.1016/j.medengphy.2023.103951
    Powered ankle-foot orthoses can be utilised to overcome gait abnormalities such as foot drop; however, normal gait is rarely restored with compensatory gait patterns arising and prevalence of gait asymmetry. Therefore, this study aims to determine the effect of orthosis mass and mass distribution on the swing phase of gait, to understand residual gait asymmetry with orthosis use. Using a triple compound pendulum model, which accounts for mass distribution of the limb and orthosis, the swing phase of gait is simulated in terms of natural dynamics and the effect of an orthosis on kinematic parameters is quantitatively determined. It was found that additional mass causes faster and shorter steps on the affected side due to rapid knee extension and reduced hip flexion, with particular actuator positions and natural cadence causing varying severity of these effects. Our study suggests that this model could be used as a preliminary design tool to identify subject specific optimum orthosis mass distribution of a powered ankle-foot orthosis, without the need for motion data or experimental trials. This optimisation intends to more accurately mimic natural swing phase kinematics, consequently allowing for the reduction in severity of gait asymmetry and the potential to improve rehabilitative outcomes.
    Matched MeSH terms: Biomechanical Phenomena
  19. Fulltext Intra-Rater Reliability and Minimal Detectable Change of Vertical Ground Reaction Force Measurement during Gait and Half-Squat Tasks on Healthy Male Adults
    Fairus FZ, Joseph LH, Omar B, Ahmad J, Sulaiman R
    Malays J Med Sci, 2016 Mar;23(2):21-7.
    PMID: 27547111 MyJurnal
    The understanding of vertical ground reaction force (VGRF) during walking and half-squatting is necessary and commonly utilised during the rehabilitation period. The purpose of this study was to establish measurement reproducibility of VGRF that reports the minimal detectable changes (MDC) during walking and half-squatting activity among healthy male adults.
    Matched MeSH terms: Biomechanical Phenomena
  20. Fulltext Analysis of Jumping-Landing Manoeuvers after Different Speed Performances in Soccer Players
    Daneshjoo A, Abu Osman NA, Sahebozamani M, Yusof A
    PLoS One, 2015;10(11):e0143323.
    PMID: 26599336 DOI: 10.1371/journal.pone.0143323
    PURPOSE: Running at high speed and sudden change in direction or activity stresses the knee. Surprisingly, not many studies have investigated the effects of sprinting on knee's kinetics and kinematics of soccer players. Hence, this study is aimed to investigate indices of injury risk factors of jumping-landing maneuvers performed immediately after sprinting in male soccer players.

    METHODS: Twenty-three collegiate male soccer players (22.1±1.7 years) were tested in four conditions; vertical jump (VJ), vertical jump immediately after slow running (VJSR), vertical jump immediately after sprinting (VJFR) and double horizontal jump immediately after sprinting (HJFR). The kinematics and kinetics data were measured using Vicon motion analyzer (100Hz) and two Kistler force platforms (1000Hz), respectively.

    RESULTS: For knee flexion joint angle, (p = 0.014, η = 0.15) and knee valgus moment (p = 0.001, η = 0.71) differences between condition in the landing phase were found. For knee valgus joint angle, a main effect between legs in the jumping phase was found (p = 0.006, η = 0.31), which suggests bilateral deficit existed between the right and left lower limbs.

    CONCLUSION: In brief, the important findings were greater knee valgus moment and less knee flexion joint angle proceeding sprint (HJFR & VJFR) rather than no sprint condition (VJ) present an increased risk for knee injuries. These results seem to suggest that running and sudden subsequent jumping-landing activity experienced during playing soccer may negatively change the knee valgus moment. Thus, sprinting preceding a jump task may increase knee risk factors such as moment and knee flexion joint angle.

    Matched MeSH terms: Biomechanical Phenomena
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