Quantitative Kinematic Research Articles

Quantitative finite strain and kinematic analyses of Dahomeyide orogenic belt (Benino-Nigerian shield) around Igarra, southwestern Nigeria

The Igarra area (including Sebe-Ogbe and Otuo) in Igarra schist belt, southwestern Nigeria exposes a good section of the Dahomeyide orogenic belt (Benino-Nigerian shield). The area provides an opportunity to investigate quantitative finite strain, types of strain and strain ellipsoid, kinematic vorticity number (Wk) and proportions of pure and simple shear components from metaconglomerate outcrops. Measurements of the long, short and intermediate axes of deformed clasts in the metaconglomerates were carried out. The angular relationships between a constant reference line and the long axes of some of the clasts were determined. Combined strain in two dimensions (2-D) and three dimensions (3-D) analyses involving the Rf/ɸ (Phi), centre to centre (Fry) and Flinn methods were performed on the data with the aid of Ellipsefit software to generate Flinn, the tear-drop shaped diagrams and finite strain ellipsoids. The kinematic vorticity numbers were estimated in order to quantify the amount of shear. The results indicated that the rocks in the Dahomeyide orogenic belt around Igarra have ellipticity in initial state (Ri) and true strain (Rs) of 3.6 and 4.4, respectively. The Ri and Rs for Otuo are 2.43 and 3.35, respectively while the values for Sebe-Ogbe are 1.96 and 3.16, respectively. The results of centre to centre method showed strain ellipses with different orientations from near horizontal to vertical, while the Flinn diagram showed that the rocks in the three areas have both constrictional and flattening strains corresponding to prolate and oblate strain ellipsoids, respectively which are characteristic of L-S tectonites. The kinematic vorticity number (WK or Wm) for the locations are 0.97 (Igarra), 0.79 (Sebe-Ogbe) and 0.97 (Otuo). These probably suggest homogeneous subsimple shear transpressional deformation involving approximately 42% pure shear and 58% simple shear for Sebe-Ogbe and 17% pure shear and 83% simple shear for both Igarra and Otuo. The state of strain of the rocks at Igarra, Otuo and Sebe-Ogbe was relatively high and increased towards the south from Igarra (north) to Sebe-Ogbe (south) where there is highest strain probably due to clast support nature of the metaconglomerates where the clasts acted as single rigid body, and influence of contact metamorphism. The implication of this is that the rocks at Igarra have undergone less deformation than those at Otuo which in turn have undergone less deformation than those at Sebe-Ogbe.

Reliability Of Quantitative Kinematics From A Portable Hand-held Device

The current gold standard for assessing kinematics is three-dimensional (3D) motion analysis. However, the equipment required to accomplish this is not generally available in sport or clinical settings. Portable handheld devices (PD) are available that synchronize multiple two-dimensional video views to qualitatively evaluate complex sport skills. However, the use of quantitative kinematic analysis on PD compared to standard computer software (CS) has not been investigated. PURPOSE: To investigate the intra- and inter-rater reliability of PD compared to an open source CS. METHODS: Twenty-seven collegiate male soccer players (height:179.8±5.6cm, mass: 75.9±6.9kg) were analyzed (120 Hz) during a drop vertical jump from a 30-cm box. PD and CS were separately used to 1) select a single frame from the frontal plane view when both knees were visually the most medial during landing and 2) digitize and record the frontal plane knee angle from hip, knee and ankle joint centers to estimate lower extremity valgus. Reliability between systems and reliability between testers were established with intraclass correlations (ICC2,k, ICC3,k, respectively). Precision was calculated with standard error of measurement (SEM). RESULTS: Intra-rater reliability was 0.993 [95% CI 0.985, 0.997] with SEM of 1.09 on the right, and 0.971 [95% CI 0.938, 0.987] SEM of 2.69 on the left limb. Inter-rater reliability on the right side was 0.979 [95% CI 0.954, 0.990] with SEM of 1.97 for the right limb and 0.978 [95% CI 0.943, 0.990] with SEM of 2.37 on the left, respectively. CONCLUSION: In collegiate male soccer players, PD exhibited excellent intra- and inter-rater reliability. The data indicates that it might be a useful tool to integrate into a screening protocol to quickly estimate lower extremity valgus. However, future analyses should compare traditional 3D motion analysis to determine validity.

2D Kinematic Quantification of Soil Particles around Growing Plant Root based on Optical Mechanics

The quantitative kinematic description of the surrounding soil particles during root growth is a technical challenge and biologically important. In this study, a two-dimensional camera-based imaging system was used to observe micro scale interactions between plant roots and soil particles. Maize root tip was imaged during ingress into the soils. This produced a series of two-dimensional images that represent temporal resolution of the geometric soil and root configurations at the micrometer scale. These images were used as inputs for full-field kinematic quantification methods, which enabled the analysis of two-dimensional deformation of the soils around elongating root. Correlation-based discrete object tracking and contour updating were used to track the shapes and the locations of soil particles and soil aggregates, while incremental digital image correlation was proposed to extract deformation and strain field within soil particle and soil aggregate. These techniques allowed the full-field displacements and strains of the soil to be quantified and the changes in shapes of soil particles to be visualized. Experimental results show that the presented shape tracking scheme, incremental digital image correlation and the research findings will be useful for the measurement and quantification of soil particle kinematics of soil-root physical interactions.

Comparison across vehicles of passenger head kinematics in abrupt vehicle maneuvers

Objective: Studies of vehicle occupant motions in response to abrupt vehicle maneuvers have demonstrated movements that may result in changes in the level of protection for the occupant if a crash subsequently occurs. The previous studies have typically used a single vehicle. The current study assesses whether the patterns of occupant head movement are different across passenger vehicle types.Method: Data collection was conducted on a closed test track with the same driver for all trials. A passenger sedan, a minivan, and a pickup truck were equipped with inertial measurement units to quantify vehicle dynamics. Head location was tracked using Microsoft Kinect v2 sensor and a novel methodology that fits 3 D head scan data to the depth data acquired in the vehicle. Twelve men and women with a wide range of body size and age were recruited. The primary purpose of the study was obfuscated by telling the participants that the focus was on vehicle ride motion. Participants sat in the right front seat and wore the vehicle belt. The first event during the test track route was a hard brake (approximately 1 g) to a stop from 35 mph (56 kph). Within the space of approximately 5 min the participants also experienced two aggressive, right-going lane changes, a sharp right turn with simultaneous hard braking, and a second hard braking event. The vehicles were presented in random order for each participant. This paper presents comparison across vehicles of head motions in the braking and lane-change maneuvers.Results: Accelerations were similar across the vehicles for both braking and lane-change events. The means (standard deviations) of forward head-CG excursion in the first braking event were 162 (54), 112 (39), and 176 (46) mm for the minivan, passenger car, and truck, respectively. The forward head excursion in the passenger car was found to be significantly smaller than in the other two vehicles using a paired t-test (p < 0.01). Across vehicles, the mean excursion in the second braking exposure was smaller than in the first (p < 0.01). In the first lane change event, the mean (SD) inboard head excursions were 126 (51), 110 (49), and 140 (68) mm; the values were not significantly different across vehicles or in the second lane-change event. A detailed investigation did not reveal an explanation for the smaller head excursions in the passenger car.Discussion: This is the first quantitative occupant kinematics study to compare responses across vehicles. Although a significant difference was found between vehicles, the overall responses are similar to those observed in a previous study.Conclusions: The results confirm previous studies showing large variance in excursions across occupants. Further study is needed to understand the factors that affect responses across vehicles.

Kinematic Metrics from a Wireless Stylus Quantify Tremor and Bradykinesia in Parkinson's Disease.

A fundamental challenge in the clinical care of Parkinson disease (PD) is the current dependence on subjective evaluations of tremor and bradykinesia. New technologies offer the ability to evaluate motor deficits using purely objective measures. The aim of this study was to develop and evaluate the efficacy of a wireless stylus (Cleveland Clinic Stylus) with an embedded motion sensor to quantitatively assess tremor and bradykinesia in patients with PD with subthalamic nucleus (STN) deep brain stimulation (DBS). Twenty-one subjects were tested in various on and off DBS conditions while holding the Cleveland Clinic Stylus while at rest, maintaining a postural hold, and during a movement task. Kinematic metrics were calculated from the motion sensor data, including 3D angular velocity and 3D acceleration data, and were compared between the on and off conditions. Generalized estimating equations (GEEs) were used to determine the relationship between kinematic metrics and MDS-Unified Parkinson's Disease Rating Scale Motor III (UPDRS-III) subscores. Kinematic metrics from the rest and postural tasks were significantly related to the UPDRS-III subscores of tremor (p < 0.001 for all metrics), and kinematic metrics from the movement task were significantly related to the UPDRS-III subscore of bradykinesia (p < 0.001 for 3/7 metrics). Kinematic metrics (7/9) showed a significant effect of stimulation setting (range: p < 0.03– < 0.0001) across the three tasks, indicating significant improvements from DBS in these measures. The Cleveland Clinic Stylus provided quantitative kinematic measures of tremor and bradykinesia severity and detected significant improvements in these measures from medication and DBS therapy. This low-cost, easy-to-use tool can provide objective measures that will improve clinical care of PD patients by providing a more reliable and objective evaluation of movement symptoms, disease progression, and effects of therapy in and outside the clinical setting.

Unstable coupling of body sway with imposed motion precedes visually induced motion sickness

Motion sickness is preceded by differences in the quantitative kinematics of body sway between individuals who (later) become sick and those who do not. In existing research, this effect has been demonstrated only in measures of body sway, relative to the earth. However, body sway can become coupled with imposed oscillatory motion of the illuminated environment, and the nature of this coupling may differ between individuals who become sick and those who do not. We asked whether body sway would become coupled to complex oscillations of the illuminated environment, and whether individual differences in such coupling might be precursors of motion sickness. Standing participants (women) were exposed to complex oscillation of the illuminated environment. We examined the strength of coupling as a function of time during exposure. Following exposure, some participants reported motion sickness. The nature and temporal evolution of coupling differed between participants who later reported motion sickness and those who did not. Our results show that people can couple the complex dynamics of body sway with complex imposed motion, and that differences in the nature of this coupling are related to the risk of motion sickness.

Comparison between subtalar joint quantitative kinematic 4-D CT parameters in healthy volunteers and patients with joint stiffness or chronic ankle instability: A preliminary study

Objectiveto compare quantitative kinematic 4-D CT parameters between healthy volunteers and pathologic patients (joint stiffness or chronic ankle instability). MethodsThirteen healthy volunteers without previous ankle trauma, 18 patients with clinical subtalar joint stiffness and 10 patients with chronic ankle instability diagnosed based on clinical and imaging findings were prospectively evaluated with 4-D CT. This study was approved by the local ethics committee and all patients signed an informed consent. The subtalar joint was evaluated during a prono-supination cycle. Two angles and two distances between the talus and the calcaneus were measured semi-automatically and independently by two readers. Measurement variations were compared in these three different groups. ResultsThere were statistically significant differences between axial and coronal talocalcaneal angles of healthy volunteers and patients with joint stiffness (p < 0.0001). The best sensitivities and specificities for the identification of subtalar joint stiffness were 92–100% and 74–94%. Mean and maximal posterior calcaneal facet uncovering were significantly lower in patients with chronic ankle instability patients compared to healthy volunteers (p < 0.006) with sensitivities and specificities of 92–95% and 80–92% respectively. ConclusionQuantitative analysis in 4D CT can provide an objective criteria for the differentiation between healthy volunteers and patients with subtalar joint stiffness and chronic ankle instability.

Improved Kinematics and Motor Control in a Longitudinal Study of a Complex Therapy Movement in Chronic Stroke.

Impaired motor control post-stroke is typically measured using clinical assessments employing categorical and subjective scoring. We investigated quantitative kinematic parameters of a complex movement with therapy in chronic stroke. Tri-axial accelerometry of the more-affected arm of 24 patients was recorded during early- (day 2-3) and late- (days 12-14) therapy, and for 13 patients at 6-month follow-up. Clinical assessments included the classification of motor-function as low, moderate, or high. Kinematic parameters were measured during Wii-baseball swings to assess the effect of time and the level of motor-function. Clinical tests improved over time (all p < 0.01). Increased acceleration magnitude over time was significant only at proximal sensors (p < 0.05), and there was an effect of motor-function at distal sensors (p < 0.05). Normalized velocity decreased (p < 0.05) at all sensors over time. Peak acceleration and peak deceleration increased over time, predominately at proximal sensors. Kinematic parameters provide an objective and quantitative measure of change in motor-function that is not possible with clinical assessments. The complex patterns of change were not consistent between and within levels of motor-function but reflected improved motor control that was sustained over time. These data emphasize the potential for ongoing improvements in motor capacity in chronic stroke with additional rehabilitation.

Scapholunate instability: improved detection with semi-automated kinematic CT analysis during stress maneuvers.

To evaluate the diagnostic performance of radioulnar deviation (RUD) and clenching fist (CF) maneuvers for the evaluation of scapholunate dissociation (SLD) using quantitative kinematic CT. Thirty-seven patients with suspected scapholunate instability were prospectively evaluated with kinematic CT. Two radiologists independently evaluated the SLD during RUD and CF maneuvers. Various dynamic parameters describing SLD were compared (maximal value, variation coefficient and range) in patients with and without scapholunate ligament ruptures confirmed by CT arthrography. SLD in CF varied from 3.17 ± 0.38 to 3.24 ± 0.80 mm in controls and from 4.11 ± 0.77 and 4.01 ± 0.85 mm in patients with scapholunate ligament ruptures for reader 1 and 2 (p < 0.009). SLD in RUD varied from 3.35 ± 0.51 and 3.01 ± 0.78 mm in controls and from 4.51 ± 1.26 to 4.42 ± 1.75 mm in patients with scapholunate ligament ruptures for reader 1 and 2 (p varied from 0.001 to 0.002). The inter-observer variability was better for RUD (ICC = 0.85 versus 0.6 for RUD and CF respectively). Analysis of SLD using kinematic CT has shown significant measurement differences between the groups with or without scapholunate instability with good diagnostic performance. • Kinematic CT can quantitatively assess scapholunate dissociation. • SLD analysis on kinematic CT has excellent reproducibility with radioulnar deviation maneuver. • Scapholunate dissociation was significantly different in patients with and without instability. • Diagnostic performance for scapholunate instability identification was better with radioulnar deviation.

Reconstructing Greater India: Paleogeographic, kinematic, and geodynamic perspectives

Key in understanding the geodynamics governing subduction and orogeny is reconstructing the paleogeography of ‘Greater India’, the Indian plate lithosphere that subducted since Tethyan Himalayan continental collision with Asia. Here, we discuss this reconstruction from paleogeographic, kinematic, and geodynamic perspectives and isolate the evolution scenario that is consistent with all three. We follow recent constraints advocating a ~58 Ma initial collision and update a previous kinematic restoration of intra-Asian shortening with a recently proposed model that reconciles long-debated large and small estimates of Indochina extrusion. Our new reconstruction is tested against paleomagnetic data, and against seismic tomographic constraints on paleo-subduction zone locations. The resulting restoration shows ~1000–1200 km of post-collisional intra-Asian shortening, leaving a 2600–3400 km wide Greater India. From a paleogeographic, sediment provenance perspective, Eocene sediments in the Lesser Himalaya and on undeformed India may be derived from Tibet, suggesting that all Greater Indian lithosphere was continental, but may alternatively be sourced from the contemporaneous western Indian orogen unrelated to India-Asia collision. A quantitative kinematic, paleomagnetic perspective prefers major Cretaceous extension and a ‘Greater India Basin’ opening within Greater India, but data uncertainty may speculatively allow for minimal extension. Finally, from a geodynamic perspective, assuming a fully continental Greater India would require that subduction rates close to 20 cm/yr was driven by a down-going lithosphere-crust assemblage more buoyant than the mantle, which seems physically improbable. We conclude that the Greater India Basin scenario is the only sustainable one from all three perspectives. We infer that old pre-collisional lithosphere rapidly entered the lower mantle sustaining high subduction rates, whilst post-collisional continental and young Greater India basin lithosphere did not, inciting the rapid India-Asia convergence deceleration ~8 Myr after collision. Subsequent absolute northward slab migration and overturning caused flat slab subduction, Tibetan shortening, arc migration and arc volume decrease.

Investigation of a Planetary Rover Locomotion System with Wheel-walking Propulsion by Applying the Method of Object-oriented Modeling

Objectives: The study aims to identify the capabilities of the locomotion systems based on the wheel-walking propulsion as the means of improving the mobility and maneuverability of the planetary rovers. Method: Principal method of this study is represented by object-oriented modeling that helps undertake complex investigation of the object. Findings: Current importance of the study is predetermined by the intensive investigations of celestial bodies assisted by mobile robotic systems and planetary rovers that are delivered to the surface of the planet. The study considers the opportunities provided by computerized modeling for the purposes of estimating the behavior of a planetary rover in the process of overcoming such obstructions as escarp, sloping surface of hard and loose soils and sinusoidal profile of surface that imitates coarse irregularities of the relief. The locomotion system under investigation is represented by a four-wheeled platform equipped with the two-lever wheel-walking mechanisms. The algorithms have been suggested for controlling the actuator mechanisms of the locomotion systems in the course of overcoming the obstacles under consideration. Improvements: The results make it possible to evaluate qualitative and quantitative kinematic and force requirements to the drives of the locomotion systems of planetary rovers and are of practical engineering significance.

Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis.

Action sport cameras (ASC) are currently adopted mainly for entertainment purposes but their uninterrupted technical improvements, in correspondence of cost decreases, are going to disclose them for three-dimensional (3D) motion analysis in sport gesture study and athletic performance evaluation quantitatively. Extending this technology to sport analysis however still requires a methodologic step-forward to making ASC a metric system, encompassing ad-hoc camera setup, image processing, feature tracking, calibration and 3D reconstruction. Despite traditional laboratory analysis, such requirements become an issue when coping with both indoor and outdoor motion acquisitions of athletes. In swimming analysis for example, the camera setup and the calibration protocol are particularly demanding since land and underwater cameras are mandatory. In particular, the underwater camera calibration can be an issue affecting the reconstruction accuracy. In this paper, the aim is to evaluate the feasibility of ASC for 3D underwater analysis by focusing on camera setup and data acquisition protocols. Two GoPro Hero3+ Black (frequency: 60Hz; image resolutions: 1280×720/1920×1080 pixels) were located underwater into a swimming pool, surveying a working volume of about 6m3. A two-step custom calibration procedure, consisting in the acquisition of one static triad and one moving wand, carrying nine and one spherical passive markers, respectively, was implemented. After assessing camera parameters, a rigid bar, carrying two markers at known distance, was acquired in several positions within the working volume. The average error upon the reconstructed inter-marker distances was less than 2.5mm (1280×720) and 1.5mm (1920×1080). The results of this study demonstrate that the calibration of underwater ASC is feasible enabling quantitative kinematic measurements with accuracy comparable to traditional motion capture systems.

Hans Laubscher (1924–2015)

Geologische Vereinigung in recognition of his research on the kinematics and mass balancing of tectonic systems. Hans Laubscher was born on 11 January 1924, in Muttenz, near Basel. After attending the Classical Gymnasium in Basel, he enrolled at the University of Basel and obtained his PhD degree in Geology in 1947 at the age of 23. He then worked for 10 years with an oil company in the southern foreland of the Venezuelan Andes, first as junior field geologist, and then as a geophysicist and staff geologist combining, as he put it, “dirty geology with clean physics”. In 1958, he returned to the Geological Institute in Basel, obtained his Habilitation with a paper on neptunian sandstone dykes and—after a year as guest professor at the University of Illinois in Urbana—was appointed successor of Louis Vonderschmitt as the Head of the Institute in Basel. It was during Laubscher’s tenure from 1966 to 1989 that this institute gained international recognition, one might add, despite its relatively limited resources. Hans Laubscher was not intimidated by the complexities of mountain belts; early on in his career, he liked to unravel what he called “tectonic knots” that evolve from the interference of different orogenic systems. Already during his PhD work, he was intrigued by the folds, thrusts and strikeslip faults in the Caquerelle Zone of the central Jura Mountains. When he returned to Basel from South America, he began to study the Jura Mountains as a tectonic system. In the 1960s, long before balancing profiles became fashionable, he recognized that accurately balanced cross sections are necessary in order to understand the kinematics and mechanics of fold-and-thrust belts. Armed with only paper, scissors and thread (before the days of computers), he constrained shortening in the Jura Mountains by the curvimetric and volumetric analysis of the folds. His brilliant quantitative kinematic reconstruction confirmed Buxtorf’s idea of decollement of the sedimentary cover above a rigid Hans P. Laubscher, Professor emeritus of Geology at the University of Basel, passed away on 2 July 2015, in Riehen, Switzerland. A leading tectonician and one of the great Alpine geologists of our time, he spent his career combining careful fieldwork with deep insight into the theoretical and experimental aspects of tectonics. At the centre of his research was the analysis of tectonic systems, from small-scale folds to mountain belts and the global puzzle of lithospheric plates through geologic time. In 1993, Hans Laubscher received the Gustav Steinmann Medal of the

A plate tectonic scenario for the Iapetus and Rheic oceans

The tectonics, dynamics, and biogeographic landscape of the early Paleozoic were dominated by the opening and expansion of one large ocean—the Rheic—and the diminution to terminal closure of another—Iapetus. An understanding of the evolution of these oceans is thus central to an understanding of the early Paleozoic, but their chronicle also presents a rich temporal profile of the Wilson cycle, illustrating continental-scale rifting, microcontinent formation, ocean basin development, arc accretion, and continent–continent collision. Nevertheless, contemporary paleogeographic models of the Iapetus and Rheic oceans remain mostly schematic or spatiotemporally disjointed, which limits their utility and hinders their testing. Moreover, many of the important kinematic and dynamic aspects of the evolution of these oceans are impossible to unambiguously resolve from a conceptual perspective and the existing models unsurprisingly present a host of contradictory scenarios. With the specific aim to resolve some of the uncertainties in the evolution of this early Paleozoic domain, and a broader aim to instigate the application of quantitative kinematic models to the early Paleozoic, I present a new plate tectonic model for the Iapetus and Rheic oceans. The model has realistic tectonic plates, which include oceanic lithosphere, that are defined by explicit and rigorously managed plate boundaries, the nature and kinematics of which are derived from geological evidence and plate tectonic principles. Accompanying the presentation and discussion of the plate model, an extensive review of the underlying geological and paleogeographic data is also presented.

Dyslexic children fail to comply with the rhythmic constraints of handwriting

In this study, we sought to demonstrate that deficits in a specific motor activity, handwriting, are associated to Developmental Dyslexia. The linguistic and writing performance of children with Developmental Dyslexia, with and without handwriting problems (dysgraphia), were compared to that of children with Typical Development. The quantitative kinematic variables of handwriting were collected by means of a digitizing tablet. The results showed that all children with Developmental Dyslexia wrote more slowly than those with Typical Development. Contrary to typically developing children, they also varied more in the time taken to write the individual letters of a word and failed to comply with the principles of isochrony and homothety. Moreover, a series of correlations was found among reading, language measures and writing measures suggesting that the two abilities may be linked. We propose that the link between handwriting and reading/language deficits is mediated by rhythm, as both reading (which is grounded on language) and handwriting are ruled by principles of rhythmic organization.

Kinematic, finite strain and vorticity analysis of the Sisters Shear Zone, Stewart Island, New Zealand

The Sisters Shear Zone (SSZ) on Stewart Island, New Zealand, is a greenschist-facies extensional shear zone active prior to and possibly during the development of the Pacific–Antarctica spreading ridge at ∼76 Ma. We report quantitative kinematic and rotation data as well as apatite fission-track (AFT) ages from the SSZ. Early kinematic indicators associated with the NNE-trending stretching lineation formed under upper greenschist-facies metamorphism and show alternating top-to-the-NNW and top-to-the-SSE senses of shear. During progressive exhumation lowermost greenschist-facies and brittle-ductile kinematic indicators depict a more uniform top-to-the-SSE sense of shear in the topmost SSZ just below the detachment plane. Deformed metagranites in the SSZ allow the reconstruction of deformation and flow parameters. The mean kinematic vorticity number (Wm) ranges from 0.10 to 0.89; smaller numbers prevail in the deeper parts of the shear zone with a higher degree of simple shear deformation in the upper parts of the shear zone (deeper and upper parts relate to present geometry). High finite strain intensity correlates with low Wm and high Wm numbers near the detachment correlate with relatively weak strain intensity. Finite strain shows oblate geometries. Overall, our data indicate vertical and possibly temporal variations in deformation of the SSZ. Most AFT ages cluster around 85–75 Ma. We interpret the AFT ages to reflect the final stages of continental break-up just before and possibly during the initiation of sea-floor spreading between New Zealand and Antarctica.

Three Dimensional Digital Modelling of Human Spine Anthropometrics and Kinematics from Meta-Analysis. How Relevant is Existing Anatomical Research?

Objective: This research aims to provide a complete spine digital model, including vertebral anthropometrics, posture and kinematics to inform biomechanics models. Background: There is limited integration of published literature on quantitative anatomy, anthropometrics and posture data in current digital models. Most studies Preclude the interconnected nature of the spine. Method: A literature review from the disciplines of anatomy, manipulative therapy, anthropometrics, occupational ergonomics, biomechanics and forensic science was conducted. The data was unified into a single normative model of the sub-axial spine using a normalisation protocol. A related kinematics meta-analysis was conducted. Results: 2D orthographic drawings were produced from 590 individual measurements, informing a 3D model. New data relating to vertebral spatial coordinates are published. The kinematics data was applied to the 3D model, interconnecting spine regions. Range of Motion [ROM] ratios of movement were calculated throughout the spine. Intervertebral measurements were extrapolated, providing new data. To the best of our knowledge this digital model is the first to quantify skeletal anthropometrics, posture and kinematics. Conclusion: The model data and the limitations discussed provide a roadmap for other spine model researchers. New basic science anatomical research is needed, revisiting quantitative anatomy and kinematics studies, using interrelated 3D digital technologies, within a standardised protocol framework for researcher to adhere to. From usercentric design, biomechanical engineering to rehabilitation care, quantification of spine anthropometrics at vertebral level and their spatial profile under motion is key. Existing publications in biomechanics, by computer scientists and mathematicians often limits to a few studies or excludes the basic science of human spine anatomy, vertebral anthropometrics, posture and kinematics, choosing to focus on functional mathematics principles. The present research provides a unified model and a potentially powerful tool in quantifying and visualising these attributes. It complements biomechanics research towards better informed and more complex models of the spine.

Passive Marker Based Optical System for Gait Kinematics for Lower Extremity

Human gait quantification assists in physical therapy, sport science and medical diagnostics. Most gait capture systems use direct measurement techniques to acquire specific motion information, but at high cost for hardware and the subject's natural motion is hindered due to the presence of cables or other components. To overcome these limitations, this paper introduces an alternative by using passive marker based optical gait analysis system developed at RAMAN Lab at Malaviya National Institute of Technology, Jaipur. The co-ordinates of markers were obtained by using a simple arrangement consisting of a camera, 5 reflective passive markers and a personal computer. From the analyses, kinematic gait parameters i.e. joint angles and walking speed can be obtained. The main benefits are that it doesn’t consume excessive time and complexity required for marker placement, the need for a controlled environment to acquire high quality data, the high cost for the markers, and also the effect of the markers on the subject's movement is reduced. The prototype of the system provides decent quantitative kinematics gait parameters i.e. joint angles. The quantitative data specified by this system can help Healthcare professionals for better understanding of Indian patient's gait pathology, treatment and rehabilitation

Strain memory of 2D and 3D rigid inclusion populations in viscous flows — What is clast SPO telling us?

We model the development of shape preferred orientation (SPO) of a large population of two- and three-dimensional (2D and 3D) rigid clasts suspended in a linear viscous matrix deformed by superposed steady and continuously non-steady plane strain flows to investigate the sensitivity of clasts to changing boundary conditions during a single or superposed deformation events. Resultant clast SPOs are compared to one developed by an identical initial population that experienced a steady flow history of constant kinematic vorticity and reached an identical finite strain state, allowing examination of SPO sensitivity to deformation path. Rotation paths of individual triaxial inclusions are complex, even for steady plane strain flow histories. It has been suggested that the 3D nature of the system renders predictions based on 2D models inadequate for applied clast-based kinematic vorticity gauges. We demonstrate that for a large population of clasts, simplification to a 2D model does provide a good approximation to the SPO predicted by full 3D analysis for steady and non-steady plane strain deformation paths. Predictions of shape fabric development from 2D models are not only qualitatively similar to the more complex 3D analysis, but they display the same limitations of techniques based on clast SPO commonly used as a quantitative kinematic vorticity gauge. Our model results from steady, superposed, and non-steady flow histories with a significant pure shearing component at a wide range of finite strain resemble predictions for an identical initial population that experienced a single steady simple shearing deformation. We conclude that individual 2D and 3D clasts respond instantaneously to changes in boundary conditions, however, in aggregate, the SPO of a population of rigid inclusions does not reflect the late-stage kinematics of deformation, nor is it an indicator of the unique ‘mean’ kinematic vorticity experienced by a deformed rock volume.

Kinematic analysis of upper extremity movement during drinking in hemiplegic subjects

BackgroundIt is necessary to analyze the kinematic properties of a paralyzed extremity to quantitatively determine the degree of impairment of hemiplegic people during functional activities of daily living (ADL) such as a drinking task. This study aimed to identify the kinematic differences between 16 hemiplegic and 32 able-bodied participants in relation to the task phases when drinking with a cup and the kinematic strategy used during motion with respect to the gravity direction. MethodsThe subjects performed a drinking task that was divided into five phases according to Murphy's phase definition: reaching, forward transport, drinking, backward transport, and returning. We found that the groups differed in terms of the movement times and the joint angles and angular velocities of the shoulder, elbow, and wrist joints. FindingsCompared to the control group, the hemiplegic participants had a larger shoulder abduction angle of at most 17.1° during all the phases, a larger shoulder flexion angle of 7.6° during the reaching phase, and a smaller shoulder flexion angle of 6.4° during the backward transporting phase. Because of these shoulder joint patterns, a smaller elbow pronation peak angle of at most 13.1° and a larger wrist extension peak angle of 12.0° were found in the motions of the hemiplegic participants, as compensation to complete the drinking task. The movement in the gravity direction during the backward transporting phase resulted in a 15.9% larger peak angular velocity for elbow extension in the hemiplegic participants compared to that of the control group. InterpretationThese quantitative kinematic patterns help provide an understanding of the movements of an affected extremity and can be useful in designing rehabilitation robots to assist hemiplegic people with ADL.