Kinematic Sequence Research Articles

Impact Position Variability in Golfers of Differing Skill Level

This study examined the variable error (VE) for the golf impact position of high and low skilled golfers. A consistent shot type was employed by 20 golfers from 2 skill groups over 10–15 shots with a midiron. Analysis reported similar positional variability across categories. Significant differences were found for the whole group in VE of the distance of various body segments to the ball (p < .001) where variability reduced across the distance of the ball to the midpoint of the stance, compared with the pelvis and shoulders. Alignment variability significantly decreased toward distal segments of the kinematic sequence with VE for the alignment of stance relative to pelvis compared with stance relative to shoulders and pelvis relative to shoulders showing reduced levels (p < .001) in the low skilled golfers. Tilt variability in the frontal plane around the sagittal/anterior-posterior (AP) axis also presented significantly reduced levels from the pelvis to the shoulders (p < .001) with no effect of skill le...

Sequence of onset latency of body segments when turning on-the-spot in people with stroke

BackgroundTurning around is a common activity of daily living. The location of a target may be known or unknown while angle and direction may vary prior to turning. A stroke can compromise coordination of body movement during turning. ObjectivesTo investigate the effect of target predictability, turn angle and turn direction on the kinematic sequence of rotation of body segments in people with stroke and healthy controls when turning on-the-spot. MethodsTen people with stroke (age: 66±10 years; 8 males) and 10 age-matched controls (age: 65±8 years; 6 males) were asked to either turn to a specific light (predictable condition) or locate and turn to a random light (unpredictable condition) placed at 45°, 90° or 135° to the right or left when a light in front extinguished. ResultsPeople with stroke initiated movement of the segments significantly later than the controls (p=0.014). The sequence of onset of rotation of the segments was not different between both groups. Target predictability affected the sequence of the segments; the eyes, head and shoulder started moving simultaneously when turning to unpredictable targets while the head and shoulder started moving before the eyes when turning to predictable targets. The sequence was also different across the three turn angles for each predictability condition. However, the sequence remained the same when turning to both sides in each group.Conclusion Similarities between the groups may be because the time since the stroke was long and therefore some recovery of function may have occurred. Slowness of movement in people with stroke may predispose them to falls.

Address Position Variability in Golfers of Differing Skill Level

This study aimed to determine whether differences in variability at address exist between golfers of low and high handicaps. A consistent shot type was employed by 20 golfers from 2 skill groups over 10--15 shots with a midiron. Kinematics analysis revealed only one significant difference between skill levels: the alignment relationship between the stance and shoulders, with the high skill golfers demonstrating reduced variability. Whole group variability was significantly reduced between the distance of the ball and the midpoint of the stance, pelvis and shoulders. Alignment variability also significantly decreased toward distal segments of the kinematic sequence where variable error decreased between the alignment of stance relative to shoulders and pelvis relative to shoulders with no effect of skill level. Results suggest the more distal segments of the kinematic sequence present a greater need for reduced detrimental variability. Coaches should ensure that golfers understand the importance of shoulder alignment in relation to the stance and how on course slopes and lies can influence the positions presented at address for distal segments of the golf swing kinematic sequence.

Flow-dependent porosity and other biomechanical properties of mysticete baleen

Despite its vital function in a highly dynamic environment, baleen is typically assumed to be a static material. Its biomechanical and material properties have not previously been explored. Thus I tested sections of baleen from bowhead whales, Balaena mysticetus, and humpback whales, Megaptera novaeangliae, alone or in groups representing miniature 'racks', in a flow tank through which water and buoyant particles circulated with variable flow velocity. Kinematic sequences were recorded through an endoscopic camera or viewing window. One set of experiments investigated particle capture; another series analyzed biomechanical behavior, including fringe spacing, movement and interaction. Baleen fringe porosity directly correlates, in a mostly linear fashion, with velocity of incident water flow. However, undulation and interaction of fringes (especially of bowheads) at higher flow velocities can decrease porosity. Fringe porosity depends on distance from the baleen plate. Porosity also varies, with fringe length, by position along the length of an individual plate. Plate orientation, which varied from 0 to 90 deg relative to water flow, is crucial in fringe spacing and particle capture. At all flow velocities, porosity is lowest with plates aligned parallel to water flow. Turbulence introduced when plates rotate perpendicular to flow (as in cross-flow filtration) increases fringe interaction, so that particles more easily strike fringes yet more readily dislodge. Baleen of bowhead whales, which feed by continuous ram filtration, differs biomechanically from that of humpbacks, which use intermittent lunge filtration. The longer, finer fringes of bowhead baleen readily form a mesh-like mat, especially at higher flow velocities, to trap tiny particles.

A study of pedestrian and bicyclist exposure to head injury in passenger car collisions based on accident data and simulations

The objective was to assess head injury risks and kinematics of adult pedestrians and bicyclists in primary impact to the passenger cars and secondary impact to the ground using real world accident data and computer reconstructions of the accidents. For this purpose, a subsample of 402 pedestrians and 940 bicyclists from the GIDAS database, Germany, was used for the statistical analysis, from which 22 pedestrian and 18 bicyclist accidents were further selected for reconstruction. PC-Crash was used to calculate impact conditions, such as vehicle impact velocity, vehicle kinematic sequence, and thrown distance. These conditions were employed to identify the initial conditions in reconstruction in MADYMO program. A comparable analysis was conducted based on the results from accident analysis and computer reconstructions for the impact configurations and the resulting injury patterns of pedestrians and bicyclists in view of head injury risks. Differences in HIC, head-relative impact velocity, linear acceleration, maximum angular velocity and acceleration, contact force, thrown distance, Wrap Around Distance (WAD), and head contact time were evaluated. Injury risk curves were generated by using a logistic regression model for vehicle impact velocity. The results indicate that bicyclists suffered less severe injuries compared with severity of pedestrian injuries. In the selected samples, the AIS 2+ and AIS 3+ head injury risks for pedestrians are 50% probability at impact speed of 38.87km/h and 54.39km/h respectively, while for bicyclists at 53.66km/h and 58.89km/h respectively. The findings of high injury risks suggested that in the area with high frequency car-pedestrian accidents, the vehicle speed limit should be 40km/h, while in the area with high frequency car-cyclist accidents the vehicle speed limit should be 50km/h.

Three-dimensional kinematic analysis of the golf swing using instantaneous screw axis theory, Part 2: golf swing kinematic sequence

Recent studies have measured body segment rotation to study the kinematic sequence of the downswing. However, this sequence has yet to be determined relative to an instantaneous screw axis (ISA), free to change position and orientation during motion to reflect shifts in a segment’s dominant axis of rotation. In Part 2 of this two-part study, the objectives were to compute the amplitude of segment angular velocity relative to the corresponding ISA of that segment and verify if the magnitude of segment angular velocity followed the proximal to distal sequence of the summation of speeds principle. Results indicate that the kinematic sequence of 2 of the 5 subjects analyzed supports the summation of speeds principle, where the sequence in which the maximum angular velocity about the pelvis, shoulders and left arm occurred, for one subject, at 68.2 ± 3.2, 72.8 ± 1.7 and 100 ± 0.0% of the downswing.

Elite golfers' kinematic sequence in full-swing and partial-swing shots

The aim of this study was to investigate whether kinematic proximal-to-distal sequencing (PDS) and speed-summation are common characteristics of both partial and full-swing shots in golf players of different skill levels and genders. A total of 45 golfers participated, 11 male tournament professionals, 21 male and 13 female elite amateurs. They performed partial shots with a wedge to targets at three submaximal distances, 40, 55 and 70 m, and full-swing shots with a 5 iron and a driver for maximal distance. Pelvis, upper torso and hand movements were recorded in 3D with an electromagnetic tracking system (Polhemus Liberty) at 240 Hz and the magnitude of the resultant angular velocity vector of each segment was computed. The results showed a significant proximal-to-distal temporal relationship and a concomitant successive increase in maximum (peak) segment angular speed in every shot condition for both genders and levels of expertise. A proximal-to-distal utilization of interaction torques is indicated. Using a common PDS movement strategy in partial and full-swing golf shots appears beneficial from mechanical and control points of view and could serve the purpose of providing both high speed and accuracy.

Structure and development of an anastomosing network of ductile shear zones

A detailed structural analysis of an anastomosing shear zone network in metagabbros from the Archean Rainy Lake zone (Canada) revealed the existence of prevalent dextral and minor sinistral conjugate shear zones with the obtuse angle (>130°) facing the main shortening direction. A typology of shear zone intersections, confluences, and other features shows that all shears formed during a single deformation event, with dextral and sinistral shears being active together or in an alternating fashion. In spite of the difficulty of establishing a complete kinematic sequence, early and late shears can be distinguished. The final angular pattern between dextral and sinistral shears is not an original feature. Dextral and sinistral shears formed at nearly right angles, and the angles progressively opened towards the extension direction as a result of increasing strain. The obtuse angles were achieved by the combined effects of continued shearing on newly forming shears and internal deformation of the lozenge-shaped domains of lesser-deformed rock bounded by the shears. Through time, there was an increasing prevalence of dextral shears over sinistral ones. The studied pattern and sequential analysis indicate that the bulk deformation was noncoaxial with a deformation regime evolving from a pure shear-dominated dextral transpression to a higher vorticity dextral transpression.

Forward modeling the kinematic sequence of the central Himalayan thrust belt, western Nepal

The Himalayan thrust belt is often cited as an example of a thrust system that propagated from hinterland to foreland; however, this kinematic sequence is not well documented, and the process of formation of the thrust belt has not been well supported. This study uses forward modeling and timing data to reveal a detailed view of the evolution of the central Himalayan thrust belt from the footwall of the South Tibetan detachment system southward to the Main Frontal thrust. By using a reasonable configuration of undeformed stratigraphy, the surface deformation in western Nepal can be dynamically reproduced, confirming that the cross sections from which the undeformed sections were derived are viable and propagated from hinterland to foreland. In addition, this study yields detailed step-by-step reconstructions of three cross sections and is the first of its kind in any thrust belt system. These detailed views are useful for understanding and bracketing erosion data, the basin sediments, and geodynamic models. Modeling shortening estimates are between 495 and 733 km from the Main Frontal thrust to the South Tibetan detachment system, and are within the range predicted for shortening in western Nepal obtained from balanced cross sections (485–743 km). Thus, the Himalayan thrust belt in western Nepal is essentially a forward-propagating thrust belt from hinterland to foreland, with minor out-of-sequence (

Sequence of thrusting and syntectonic sedimentation in the eastern Sub-Atlas thrust belt (Dadès and Mgoun valleys, Morocco)

A series of balanced cross-sections across the Sub-Atlas thrust belt and the northern Ouarzazate basin are used to illustrate the structural geometry and the timing of deformation at the southern front of the High Atlas Mountains of Morocco. The selected area is among the best sedimentary records of mountain building of the entire orogenic system. The study of the relationships between thrusts and synorogenic continental formations enables the unraveling of kinematic sequences and the proposal of a relative chronology of deformation. Active thrusting in the area occurred in a rather continuous fashion from the Oligocene to the Pliocene, punctuated by a major erosional phase imprecisely placed in late Oligocene to early Miocene times. Detrital sedimentary facies indicate that uplift in the hinterland of the High Atlas, to the north of the Sub-Atlas belt, was taking place already by mid Eocene times, although it might have commenced locally even earlier. Within the Sub-Atlas zone, the exposed faults did not propagate in a simple piggy-back fashion but show evidence of a complex, synchronous sequence with events of fault reactivation and out-of-sequence thrusting.

Kinematic sequence stratigraphy of the European Cenozoic Rift System and Alpine Foreland Basin: correlation with Mediterranean and Atlantic plate-boundary events

AbstractA review of the sequence stratigraphic development of the Tertiary basins of the North and West Alpine Foreland domains shows that their structural and depositional history was episodically affected by brief tectonic phases. These were associated with intermittent deformation events induced by the collisional convergence and compressional coupling of the Apulian and Iberian microplates with the European Plate. The plate kinematics-related episodicity was essentially isochronously recorded in the basin fills of the Alpine Foreland region. These are generally correlative with changes in eustatic sea level. The ensuing correlative successions of so-called Cenozoic Rift and Foredeep (CRF) sequences and phases can be traced throughout the European Cenozoic Rift System and Alpine Foreland Basin. Their temporal correlation indicates that, apparently, the changes in the plate collision-related stress regime of the Alpine Foreland were repeatedly accompanied by coeval changes in eustatic sea level. To test and substantiate the validity of this inferred causal relationship between intraplate deposition, plate kinematics and eustacy, the tectono-sedimentary evolution of the basins of the Mediterranean plate-boundary zone has been analysed in conjunction with a review of the plate-boundary events in the North Atlantic. Within the uncertainty range of available datings, synchroneity could thus be demonstrated for the punctuated tectonostratigraphic development of basins of the western Mediterranean (comprising the Liguro-Provençal Basin, Valencia Trough, Sardinia Rift and Tyrrhenian Basin), the Apenninic-Calabrian Arc, the Betic domain (including the Alboran Basin) and the North and West Alpine Foreland regions. Similar temporal correlations of plate tectonicsrelated events near the Mid-Atlantic Ridge in the North Atlantic and tectonostratigraphic sequences and phases of the Alpino-Pyrenean Foreland basins are further evidence of a common causal mechanism. The driving mechanisms appear to have been the northward drift of Africa and the resulting mechanical coupling of Apulia and Iberia with the southern passive margin of Europe, as well as the stepwise opening of the North Atlantic and accompanying episodic plate re-organisations of the Mid-Atlantic Ridge.

골프스윙시 기술수준에 따른 신체분절의 Kinematic sequence 분석

골프스윙시 기술수준에 따른 신체분절의 Kinematic sequence 분석

ABSTRACT: Kinematic Sequences and Systems Tracts: A Perspective from Growth Strata

ABSTRACT: Kinematic Sequences and Systems Tracts: A Perspective from Growth Strata

Stereotypic leg searching movements in the stick insect: kinematic analysis, behavioural context and simulation.

Insects are capable of efficient locomotion in a spatially complex environment, such as walking on a forest floor or climbing in a bush. One behavioural mechanism underlying such adaptability is the searching movement that occurs after loss of ground contact. Here, the kinematic sequence of leg searching movements of the stick insect Carausius morosus is analysed. Searching movements are shown to be stereotypic rhythmic movement sequences consisting of several loops. The typical loop structure allows the mean tarsus trajectory to be calculated using a feature-based averaging procedure. Thus, it is possible to describe the common underlying structure of this movement pattern. Phase relationships between joint angles, analysed for searching front legs, indicate a central role for the thorax-coxa joint in searching movements. Accordingly, the stereotyped loop structure of searching differs between front-, middle- and hindlegs, with leg-specific patterns being caused by differing protraction/retraction movements in the thorax-coxa joint. A simple artificial neural network that had originally been devised to generate simple swing movements allows two essential features of empirical searching trajectories to be simulated: (i) cyclic movements and (ii) the smooth transition into a search trajectory as a non-terminated swing movement. It is possible to generate several loops of a middle-leg search, but the precise size and shape of the loops fall short of a real-life approximation. Incorporation of front-leg retraction or hind-leg protraction during searching will also require an extension to the current model. Finally, front-leg searching occurs simultaneously with antennal movements. Also, because leg searching movements are a local behaviour, the legs remaining on the ground continue their stance phase, causing a forward shift of the body, including the searching leg. As a result of this shift, the centre of the searched space is close to the anterior extreme position of the tarsus during walking, representing the location of most likely ground contact according to past experience. Therefore, the behavioural relevance of searching movements arises from the combined actions of several limbs.

Une caractérisation de l'émission acoustique des véhicules au cours des déplacements

Traffic noise is usually measured at fixed points whereas in reality vehicles move and generate noise throughout their trip. This paper therefore puts forward a new method of identifying noise emissions which takes account of the trip as a whole. We have made use of the concept of standard kinematic sequences (which are the elements which form all car trips) and have introduced a new acoustic index to characterize the noise emissions of a vehicle during a sequence. We have achieved this by adapting conventional highway acoustic indices to the way sequences are defined and used. We have calculated examples of these indices from acoustic recordings of isolated vehicles on a test track and from standard sequences.

Tectonic applications of magnetic susceptibility and its anisotropy

Anisotropy of low field magnetic susceptibility (AMS) is a versatile petrofabric tool. For magnetite, AMS primarily defines grain-shape anisotropy; for other minerals, AMS expresses crystallographic control on magnetic properties. Thus, we may infer the orientation-distribution of a dominant mineral from the AMS of a rock. AMS principal directions can record current directions from sediment, flow-directions from magma, finite-strain directions from tectonized rocks and stress-directions from low-strain, low-temperature, neotectonic environments. AMS measurements may reveal some aspects of the strain-path, where carefully selected.For example, we may compare different parts of a heterogeneously strained domain, different minerals in a homogeneously strained site, AMS with schistosity/mineral lineation, and AMS with remanence-anisotropy. Such measurements isolate the orientation-distributions of different minerals, adding a temporal scale to the kinematic sequence. Normally, we can interpret the principal directions of AMS distributions as a physically significant direction, such as a current direction, magmatic flow or finite-strain axis. However, calibrating the AMS ellipsoid shape against the magnitude of the controlling physical process is very difficult. Primarily, this is because the shape of the AMS ellipsoid combines contributions from several minerals whose individual AMS ellipsoids are of different shape. Thus, small variations in the proportions of minerals change the shape of the rock's AMS ellipsoid, even if the alignment process were of constant intensity. In deformed rocks, AMS is more strain-sensitive than calcite twinning or the alignment of calcite or quartz c-axes. Not all AMS fabrics relate to crystallographic or grain alignment. First, displacement fabrics generate AMS where an isotropic matrix of high susceptibility displaces unevenly spaced objects of low susceptibility and suitable scales. Second, AMS location fabrics occur where sub-isometric magnetite grains are close enough, in certain directions, for their demagnetizing fields to interact. This accounts for the AMS of many magnetite-dominated signals where there is no aligned magnetite. Third, the AMS of single-domain magnetite is inverse to shape so that such grains may oppose the AMS contribution of parallel minerals. Finally, transitional sedimentary-tectonic or magmatic-tectonic fabrics yield smeared, temporal sequences of AMS principal directions that cannot be immediately attributed to a single alignment process. These transitional AMS ellipsoids mix primary and secondary AMS components, making it difficult to characterize either component. However, such fabric combinations may permit us to recognize the sense of shearing in flow processes.

Actual car use and operating conditions as emission parameters: derived urban driving cycles

A large-scale experiment has been carried out within the European DRIVE Project to identify actual vehicle use conditions. Fifty-eight privately-owned cars — 13 models, in 6 European cities — were equipped with sensors and data acquisition systems and studied under actual use conditions with their own drivers during 1-month period. A wide range of variables were measured and continuously recorded in order to define engine and vehicle operating conditions. Vehicle and engine speeds, engine and ambient temperatures, and fuel consumption have been recorded at 1-s time intervals over 73 000 km and 8200 trips. The data obtained yielded very accurate information on the actual car use which provided a wide image of normal European driving. This database enabled the analysis of car use characteristics and operating conditions which probably influence pollutant emissions and fuel consumption: daily vehicle use, trip characteristics (trip length, duration, etc.), speed and accelerations used, engine running conditions (engine speeds, choke use, etc.), thermal conditions. Traffic conditions have been characterized through splitting recorded speed profiles into ‘kinematic sequences’, between successive stops. Factorial analysis and classifying techniques enabled characterization of these sequences and linking of the different sequence types. A set of driving cycles for realistic emission measurements has been drawn up using these data, representing the different traffic conditions and driving patterns observed, while taking into account the influence of the vehicle type, driver's behaviour and geographical location, as well as the detailed records of engine operations. Vehicle uses were very frequent and often short. Time spent at rest or at low speed is very significant. Short trips, low temperatures, accelerations, and more generally urban traffic conditions, caused significant increases in fuel consumption.

Regional kinematics inferred from magnetic subfabrics in Archean rocks of Northern Ontario, Canada

Strain analysis, observations of L-S fabrics and studies of the anisotropy of magnetic susceptibility (AMS) and of anisotropy of isothermal remanence (AIRM) reveal a sequence of progressive fabric development during regional deformation. L-S fabrics of quartz and feldspar grains are most transposed in regional transpression whereas the AMS subfabrics, controlled by the properties of late metamorphic silicates, record a later orientation of the ambient stress field. Anisotropy of magnetic remanence is caused by the still younger minerals, magnetite and pyrrhotite. Its anisotropy is less transposed than the AMS subfabric. Consequently the relative orientations of the three types of fabric yield a kinematic sequence of subfabrics developed during transpression. The L-S fabrics are most transposed, the AMS less transposed and the AIRM fabrics least transposed toward the plane of regional flattening. The results indicate that the deformation recorded by the three subfabrics was non-coaxial in the most general sense, with all three principal directions spinning with respect to the rocks during progressive straining.

Cycles de conduite réalistes pour la mesure des émissions de polluannts et consommation des véhicules légers sur banc à rouleaux

Fuel consumption and pollutant emissions from vehicles are mainly a function of the vehicle's use (journey type, frequency, etc.…) and of the vehicle's operating conditions (speed, engine speed, rates of acceleration, temperature conditions, etc…) and depend on both the traffic conditions and the individual behaviour of the driver. Thus, a realistic assessment of emissions, pollution reduction methods and the effectiveness of emission control technologies cannot be carried out without taking into account the actual operating conditions of the vehicles. For that reason, a project modem (Modelling of Emissions and Fuel Consumption in Urban Areas — DRIVE project UI053) has been carried out within the EC DRIVE (Dedicated Road Infrastructure for Vehicle Safety in Europe — EEC research programme — DGXIII) programme to develop models of vehicle emissions in terms of traffic operations. Part of the project was a large scale experiment to measure engine and vehicle operating conditions during normal driving. A total of 58 private cars were equipped with sensors and data acquisition systems to record details of their use by their owners over a period of about 1 month. Over 8200 trips were monitored, covering more than 73 000 km of travel, during which the vehicle speed, engine, speed temperatures and other variables were recorded at 1-s intervals. ‘Kinematic sequences’ were defined as the periods between two successive stops of the vehicle and these were used to characterized the traffic conditions, which were assumed to be homogeneous throughout each ‘sequence’. The main categories of sequences (urban, non-urban and motorway) were identified by factorial analysis and classifying techniques and each sequence was assigned to a category. An analysis of the way in which the sequences were linked during a trip and statistics on trip lengths were used to develop realistic and statistically significant test cycles representing different urban traffic conditions. The cycles were created by recombining real sequences, randomly selected in accordance with the results of the statistical analyses. These cycles were then used on a chassis dynamometer for accurate measurements of exhaust emissions and fuel consumption on a large sample of vehicles. This paper describes the statistical analysis of the vehicle operation data and the development of the test cycles.

The deep structure of the central Alps inferred from both geophysical and geological data

ABSTRACTGravity surveys of the past century established that mountains have roots, seismic refraction lines shot in the second half of this century confirmed the downbulge of the Moho under the Alps, and recent reflection traverses provided new details on the behaviour of crustal layers in the deep part of the Alps. However, geophysical data are ambiguous geologically. For models of the root in terms of rock distribution to be tectonophysically acceptable, they must be the retrodeformable result of kinematic sequence that fits the geological surface data. For a cross‐section through the Swiss Alps based on refraction data and somewhat modified by the recent reflection traverses, a kinematic model compatible with large‐scale geological data may be obtained by the superposition of three Neogene phases with alternating vergence. Although Alpine collision is largely dextrally compressive in the central Alps, the N‐S component may be discussed in a cross‐section. Particularly puzzling geophysical features include a high‐velocity body in the middle crust and the disappearance of the layered foreland crust in the root. In order to account for these phenomena, it is proposed that the crustal root is interpreted as the result of complex reshuffling of middle and lower crustal masses as well as large‐scale phase transformations. The mid‐crustal highvelocity body is interpreted as a delaminated section of the lower crust of the Adria plate that was wedged into the middle crust of the Alps in the middle Miocene. The disappearance of the foreland lower crust is attributed to eclogitization attendant on the subduction of continental crust. Material balance estimates suggest that during Alpine collision large volumes of continental crust have disappeared through subduction.