Body Segment Contributions to Javelin Throwing during Final Thrust Phases

1994 ◽  
Vol 10 (2) ◽  
pp. 166-177 ◽  
Author(s):  
Mero Antti ◽  
Paavo V. Komi ◽  
Tapio Korjus ◽  
Enrique Navarro ◽  
Robert J. Gregor
Keyword(s):  
High Speed ◽  
Olympic Games ◽  
Center Of Mass ◽  
The Body ◽  
Body Segment ◽  
Male And Female ◽  
Body Center ◽  
Joint Center ◽  
The Right ◽  
Release Speed

This study investigated body segment contributions to javelin throwing during the last thrust phases. A 3-D analysis was performed on male and female javelin throwers during the finals of the 1992 Olympic Games in Barcelona. The subjects were videotaped from the right sight of the throwing area by two NAC high-speed cameras operating at 100 frames per second. Both men’s and women’s grip of javelin and body center of mass displayed a curved pathway to the right from the left (bracing) foot during the final foot contact. The position of the body center of mass decreased at the beginning of the final foot contact, but after the decrease period it began to increase. Simultaneously with the increase, the peak joint center speeds occurred in a proper sequence from proximal to distal segments and finally to the javelin at release. Release speed correlated significantly with throwing distance in both male and females.

An Automated Image-Based Method of 3D Subject Specific Body Segment Parameter Estimation

2008 ◽  
Author(s):  
Alison L. Sheets ◽  
Stefano Corazza ◽  
Thomas Andriacchi
Keyword(s):  
The Body ◽  
Regression Equations ◽  
Body Segment ◽  
Non Invasive ◽  
Subject Specific ◽  
Joint Center ◽  
The Right ◽  
Almost All ◽  
Body Segment Parameters ◽  
Application Specific

Recent studies have suggested that limb kinetics during swing or float phase movements are important for ACL injury analysis and injury prevention [1]. Kinetic (moment and force) calculations during swing phase can be sensitive to the accuracy of subject-specific body segment parameters (BSP) including mass and inertial properties. While numerous methods for estimating BSP have been implemented including regression equations [2,3], geometric body shape estimations, medical imaging and optimization approaches, they all have application specific limitations. Almost all of these BSP estimation approaches are limited by assumptions that: the mass center (CM) lies on the axis connecting the segment’s proximal and distal joint center, the body principle moments of inertia are aligned with the segment axes [4], and the right and left limbs are symmetric. These assumptions could introduce errors in 3D kinematic analysis. Non-invasive methods of measuring the exact geometry and volume of body segments have the potential to reduce most sources of error.

Three-dimensional acceleration of the body center of mass in people with transfemoral amputation: Identification of a minimal body segment network

2021 ◽  
Vol 90 ◽  
pp. 129-136
Author(s):  
Emeline Simonetti ◽  
Elena Bergamini ◽  
Joseph Bascou ◽  
Giuseppe Vannozzi ◽  
Hélène Pillet
Keyword(s):  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Body Segment ◽  
Transfemoral Amputation ◽  
Body Center

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

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

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

scholarly journals Morphometry of human tricuspid valve: A cadaveric study

2020 ◽  
Vol 11 (3) ◽  
pp. 4487-4491
Author(s):  
Kirti Chaudhary ◽  
Amey Dhatrak ◽  
Brij Raj Singh ◽  
Ujwal Gajbe
Keyword(s):  
Tricuspid Valve ◽  
The Body ◽  
Muscle Pathology ◽  
Male And Female ◽  
Unidirectional Flow ◽  
Significant Difference ◽  
Tissue Flaps ◽  
The Right ◽  
Cardiac Surgeons ◽  
Formalin Fixed

The cardiovascular system consists of a pump represented by the heart and blood vessels, which provide the route by which blood circulates to all parts of the body. William Harvey, in the 17th century, discovered that blood is pumped away from the heart, but it all returns to the heart after circulating in the body. A right ventricular function can be compromised by pressure or stress, often secondary to the right heart valve or muscle pathology. The valves maintain unidirectional flow and permit increased pressure to develop in the chambers. The tricuspid valve consists of three tissue flaps. It separates the right atria and the right ventricle. To measure morphometric measurements of an individual leaflet of the tricuspid valve of cadaveric human hearts. The material for the present study comprised of 50 formalin-fixed adult human hearts (35 males and 15 females) which were obtained from the Department of Anatomy from various medical colleges in Maharashtra. Statistical significant difference was found for the height of anterior and posterior leaflets between male and female hearts. The length of the septal leaflet was also found to be statistically significant between male and female hearts. The study will be helpful for cardiac surgeons in providing data for tricuspid valve complex, leaflets, cords and papillary muscles.

Long bone cross-sectional geometry

2020 ◽  
pp. 307-320
Author(s):  
Christopher B. Ruff ◽  
Ryan W. Higgins ◽  
Kristian J. Carlson
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Lateral Displacement ◽  
Center Of Mass ◽  
Gait Pattern ◽  
Locomotor Behavior ◽  
The Body ◽  
Long Bone ◽  
Cross Sectional ◽  
Body Center

Long bone diaphyseal cross-sectional geometries reflect the mechanical properties of the bones, and can be used to aid in inferences of locomotor behavior in extinct hominins. This chapter considers all available long bone diaphyseal and femoral neck cross-sections of specimens from Sterkfontein Member 4, and presents comparisons of these section properties and other cross-sectional dimensions with those of other early hominins as well as modern samples. The cross-sectional geometry of the Sterkfontein Member 4 long bone specimens suggests some similarities to, but also interesting differences in, mechanical loading of these elements relative to modern humans. The less asymmetric cortical bone distribution in the Sterkfontein femoral necks is consistent with other evidence above indicating an altered gait pattern involving lateral displacement of the body center of mass over the stance limb. The relatively very strong upper limb of StW 431 implies that arboreal behavior formed a significant component of its locomotor repertoire. Bipedal gait may have been less efficient and arboreal climbing more prevalent in the Sterkfontein hominins.

Time-To-Contact Analysis of Gait Stability in the Swing Phase of Walking in People With Multiple Sclerosis

Motor Control ◽  
2015 ◽  
Vol 19 (4) ◽  
pp. 289-311 ◽  
Author(s):  
Jebb G. Remelius ◽  
Richard E.A. van Emmerik
Keyword(s):  
Multiple Sclerosis ◽  
Center Of Mass ◽  
Swing Phase ◽  
The Body ◽  
Head Movements ◽  
Gait Stability ◽  
Time To Contact ◽  
Prospective Control ◽  
Body Center ◽  
All Speeds

This study investigated timing and coordination during the swing phase of swing leg, body center of mass (CoM) and head during walking people with multiple sclerosis (MS; n = 19) and controls (n = 19). The MS group showed differences in swing phase timing at all speeds. At imposed but not preferred speeds, the MS group had less time to prepare for entry into the unstable equilibrium, as the CoM entered this phase of swing earlier. Time-to-contact coupling, quantifying the coordination between the CoM and the swing foot, was not different between groups. The projection of head motion on the ground occurred earlier after toeoff and was positioned closer to the body in the MS group, illustrating increased reliance on visual exproprioception in which vision of the body in relation to the surface of support is established. Finally, prospective control, linking head movements to the swing foot time-to-contact and next step landing area, was impaired in the MS group at higher gait speeds.

scholarly journals Symmetry Analysis of Amputee Gait Based on Body Center of Mass Trajectory and Discrete Fourier Transform

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2392
Author(s):  
Claudia Ochoa-Diaz ◽  
Antônio Padilha L. Bó
Keyword(s):  
Center Of Mass ◽  
Sine Wave ◽  
The Body ◽  
Compensatory Mechanisms ◽  
Magnitude Spectrum ◽  
Functional Aspects ◽  
Gait Mechanics ◽  
Body Center ◽  
Main Components ◽  
Amputee Gait

The calculation of symmetry in amputee gait is a valuable tool to assess the functional aspects of lower limb prostheses and how it impacts the overall gait mechanics. This paper analyzes the vertical trajectory of the body center of mass (CoM) of a group formed by transfemoral amputees and non-amputees to quantitatively compare the symmetry level of this parameter for both cases. A decomposition of the vertical CoM into discrete Fourier series (DFS) components is performed for each subject’s CoM trajectory to identify the main components of each pattern. A DFS-based index is then calculated to quantify the CoM symmetry level. The obtained results show that the CoM displays different patterns along a gait cycle for each amputee, which differ from the sine-wave shape obtained in the non-amputee case. The CoM magnitude spectrum also reveals more coefficients for the amputee waveforms. The different CoM trajectories found in the studied subjects can be thought as the manifestation of developed compensatory mechanisms, which lead to gait asymmetries. The presence of odd components in the magnitude spectrum is related to the asymmetric behavior of the CoM trajectory, given the fact that this signal is an even function for a non-amputee gait. The DFS-based index reflects this fact due to the high value obtained for the non-amputee reference, in comparison to the low values for each amputee.

scholarly journals Can explicit visual feedback of postural sway efface the effects of sensory manipulations on mediolateral balance performance?

2016 ◽  
Vol 115 (2) ◽  
pp. 907-914 ◽  
Author(s):  
L. Eduardo Cofré Lizama ◽  
Mirjam Pijnappels ◽  
N. Peter Reeves ◽  
Sabine M. P. Verschueren ◽  
Jaap H. van Dieën
Keyword(s):  
Visual Feedback ◽  
Repeated Measures ◽  
Visual Information ◽  
Postural Sway ◽  
Center Of Mass ◽  
The Body ◽  
Body Center ◽  
Explicit Feedback ◽  
Dominant Frequencies ◽  
Visual Conditions

Explicit visual feedback on postural sway is often used in balance assessment and training. However, up-weighting of visual information may mask impairments of other sensory systems. We therefore aimed to determine whether the effects of somatosensory, vestibular, and proprioceptive manipulations on mediolateral balance are reduced by explicit visual feedback on mediolateral sway of the body center of mass and by the presence of visual information. We manipulated sensory inputs of the somatosensory system by transcutaneous electric nerve stimulation on the feet soles (TENS) of the vestibular system by galvanic vestibular stimulation (GVS) and of the proprioceptive system by muscle-tendon vibration (VMS) of hip abductors. The effects of these manipulations on mediolateral sway were compared with a control condition without manipulation under three visual conditions: explicit feedback of sway of the body center of mass (FB), eyes open (EO), and eyes closed (EC). Mediolateral sway was quantified as the sum of energies in the power spectrum and as the energy at the dominant frequencies in each of the manipulation signals. Repeated-measures ANOVAs were used to test effects of each of the sensory manipulations, of visual conditions and their interaction. Overall, sensory manipulations increased body sway compared with the control conditions. Absence of normal visual information had no effect on sway, while explicit feedback reduced sway. Furthermore, interactions of visual information and sensory manipulation were found at specific dominant frequencies for GVS and VMS, with explicit feedback reducing the effects of the manipulations but not effacing these.

WEAR OF THE RIGHT KNIFE OF THE PSKU SPEED PLOW AND TECHNOLOGICAL MEASURES TO INCREASE ITS DURABILITY

2021 ◽  
Vol 3 (144) ◽  
pp. 122-129
Author(s):  
Aleksandr M. Mikhal’chenkov ◽  
◽  
Natal’ya V. Sinyaya ◽  
Aleksandr M. Sluchevskiy ◽  
Nelli Yu. Kozhukhova
Keyword(s):  
High Speed ◽  
Crop Production ◽  
Technical Condition ◽  
The Body ◽  
Research Purpose ◽  
Back Side ◽  
Resistant Alloy ◽  
Blade Area ◽  
Working Bodies ◽  
The Right

The intensification of crop production has led to the creation of equipment for high-speed tillage. The high speed of plowing causes an increased intensity of wear of the working bodies of plows. The limit capacity of the vertical knife when processing loamy soils is about 30 hectares, after which the body must be subjected to repair (maintenance) operations. (Research purpose) The research purpose is in studying the wear of the right knives of the PSKU plow (geometry and location on the working surface), assessing the technical condition and develop measures to improve their durability. (Materials and methods) The right knife (plowshare) performs the function of a pruning element, its design corresponds to the design of the plowshare in the classic version, but with reduced dimensions. We carried out wear control in width and thickness on 14 parts. (Results and discussion) The knives after working 30 hectares are suitable for further use in width. The width of the solid layer deposited on the back side is about 7-8 millimeters, so additional surfacing of the abrasive-resistant alloy is necessary. The wear on the thickness of the knife cannot be the reason for its decommissioning, since the strength and rigidity are preserved, and the agrotechnical requirements for soil cultivation are not violated. (Conclusions) The residual width and thickness of the studied knives when plowing loam retain the normalized limits, which indicates the possibility of their further operation, but it is necessary to weld the cutting-blade part from the back with an abrasive- resistant alloy. The xiphoid wear is fused with an electrode that provides a roller hardness of about 50 HRC. A low level of wear rate of the part is achieved due to the hardness of the blade area 60 HRC.

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