Locomotion Characteristics Research Articles

MSBOTS: a multiple small biological organism tracking system robust against non-ideal detection and segmentation conditions.

Accurately tracking a group of small biological organisms using algorithms to obtain their movement trajectories is essential to biomedical and pharmaceutical research. However, object mis-detection, segmentation errors and overlapped individual trajectories are particularly common issues that restrict the development of automatic multiple small organism tracking research. Extending on previous work, this paper presents an accurate and generalised Multiple Small Biological Organism Tracking System (MSBOTS), whose general feasibility is tested on three types of organisms. Evaluated on zebrafish, Artemia and Daphnia video datasets with a wide variety of imaging conditions, the proposed system exhibited decreased overall Multiple Object Tracking Precision (MOTP) errors of up to 77.59%. Moreover, MSBOTS obtained more reliable tracking trajectories with a decreased standard deviation of up to 47.68 pixels compared with the state-of-the-art idTracker system. This paper also presents a behaviour analysis module to study the locomotive characteristics of individual organisms from the obtained tracking trajectories. The developed MSBOTS with the locomotive analysis module and the tested video datasets are made freely available online for public research use.

Tubulin Polymerization Promoting Protein Affects the Circadian Timing System in C57Bl/6 Mice.

The circadian timing system (CTS) is a complex set of cyclic cellular mechanisms which serve to synchronize discrete cell groups across multiple organ systems to adapt the bodys physiology to a (roughly) 24-hour clock. Many genes and hormones have been shown to be strongly associated with the CTS, some of which include the genes Bmal1, Period1, Period2, Cryptochrome1, and Cryptochrome2, and the hormone melatonin. Previous data suggest that microtubule dynamics play an important role in melatonin function as it relates to the CTS in vitro, though this relationship has never been explored in vivo. The purpose of this study was to determine whether disruption of microtubule regulation in C57Bl/6 mice results in measurable changes to the CTS. To study the potential effects of microtubule dynamics on the CTS in vivo, we utilized a mouse model of microtubule instability, knocked out for the tubulin polymerization promoting protein gene (Tppp -/-), comparing them to their wild type (WT) littermates in three categories: locomotor activity (in light/dark and dark/dark photoperiods), serial clock gene expression, and serial serum melatonin concentration. These comparisons showed differences in all three categories, including significant differences in locomotor characteristics under dark/dark conditions. Our findings support and extend previous reports that microtubule dynamics are a modulator of circadian rhythm regulation likely through a mechanism involving melatonin induced phase shifting.

Climbing for dummies: recommendation for multi‐specific fishways for the conservation of tropical eels and gobies

AbstractDams and other man‐made barriers impair upstream fish migration and thus threaten fish populations that need access to upper river reaches to complete their life cycle. For many years, fishways have been used to mitigate this impact. Fishways around the globe are typically built based on recommendations made for northern hemisphere species, particularly salmonids. These recommendations do not consider the locomotor characteristics and skills of other species, especially those living in the tropics. Among tropical species, freshwater eels and gobies of the Sicydiinae subfamily are important cultural and economic species that are particularly sensitive to the impact of man‐made barriers. Our experimental study aimed to test different substrates and slopes for ramp‐like fishways adapted to tropical eels and sicydiines. Among the five substrates tested for 368 eels Anguilla marmorata, elastomer pins appeared to be the most efficient. Elastomer pins also appeared to be more efficient than the fine concrete which is currently used in fishways for sicydiines (Sicyopterus lagocephalus, N = 1797, and Cotylopus acutipinnis, N = 1303). The slope had a lesser effect on the climbing success of sicydiines compared to substrate type, except for gradients greater than 50° that induced a slight decrease in success. Our results indicated that ramp‐like fishways fitted with 1.0 cm diameter elastomer pins, positioned in staggered rows with a diagonal spacing of 1.3 cm, wetted with low‐flow and angled less than 50°, are well adapted to accommodate the different locomotor characteristics and skills of tropical eels and sicydiines.

Comparative forelimb kinematics of the “pygmy” chameleon Brookesia superciliaris

Understanding the locomotor characteristics of early diverging “pygmy” or “leaf” chameleons can help to explain how their unique morphology is adapted to fit their environment and mode of life. However, nearly all quantitative studies of chameleon locomotion thus far have focused on the larger, highly arboreal “true” chameleons. Unlike “true chameleons, “pygmy” chameleons spend most of their time on the ground and are considered terrestrial. We investigated forearm kinematics in the Brown Leaf Chameleon Brookesia superciliaris to quantify and compare the locomotor characteristics of B. superciliaris relative to “true” chameleons such as Trioceros and Bradypodion. We predicted that elbow joint angles would be smaller in B. superciliaris, corresponding to a less upright posture, and that wrist range of motion would be more limited because of their simplified wrist structure. Kinematic data were collected from B. superciliaris and Trioceros jacksonii, a three horned chameleon native to east Africa. Markers were painted on the skin, and locomotion was recorded using four high speed cameras at 120 Hz while the chameleons traversed a horizontal dowel. Five events (recordings) for B. superciliaris and one event for T. jacksonii were analyzed. Markers on the elbow, forearm, wrist, and manual digits were tracked throughout one stride in each event. Outcome measures were range of motion at the wrist, elbow angle, and footfall patterns. Elbow joint angles in B. superciliaris at mid-stance and touch-down were similar to values reported in the literature forBradypodion pumilim, a larger arboreal chameleon found in parts of south Africa. The elbow joint angle of B. superciliaris at lift off was smaller when compared to B. pumilim. T. jacksonii had a much smaller elbow range of motion than B. superciliaris and B. pumilim. Wrist range of motion was similar between B. superciliaris and T. jacksonii. B. superciliaris used a lateral sequence walk with a lower step frequency and higher duty factor than T. jacksonii, which used a walking trot. Our results do not support the hypothesis that “pygmy” chameleons have more restricted ranges of motion at the wrist than “true” chameleons, but they indicate that the elbow is slightly more flexed and has a smaller range of motion. However, the greatest difference between the two groups was that B. superciliaris moved much more slowly and kept at least three feet in contact with the substrate, trading speed for increased stability. Thus, the transition to a fully arboreal way of life in “true” chameleons may have involved changes in limb kinematics as well as morphology.

Personalized rehabilitation assessment of locomotor functions in Parkinson disease using three-dimensional video analysis of motions

Parkinson disease (PD) is one of the most common neurodegenerative diseases. Its main clinical manifestation is movement disorders. The study of innovative objective methods for the diagnosis and rehabilitation of movement disorders in PD is relevant and in demand taking into account the slowly progressive course of the disease and the complex set of symptoms that subsequently forms a characteristic movement pattern. This article provides an example of a personalized rehabilitation assessment of biomechanical manifestations of the gait function of a patient with exacted diagnosis, stage 3.5 PD according to Hoehn and Yahr, by means of the method of three-dimensional motion video analysis using the Vicon Motion Capture Systems soft-hardware complex. The patient has postural and gait disorders. This method was applied after a rehabilitation course based on the activation of lifting the foot from the support surface (“back push”). Changes in the tempo and rhythm parameters of gait in a patient with PD in comparison to a healthy person were revealed: acceleration of walking pace with shortening of the length of single and double step, a decrease in the time of limb advancement, acceleration of the moment of heel rise and a decrease in walking pace. Analysis of the locomotion also revealed a decrease in the amplitude of flexion-extension in the coxofemoral joint, knee joint and tibio-tarsic on the side with more pronounced Parkinsonism. Insufficient knee flexion and hip extension, excessive dorsal flexion of the foot with insufficient plantar flexion were noted. Revealing the last features of locomotion in a particular case allows one to make a plan for a targeted personalized rehabilitation program for a given patient. Thus, the method of three-dimensional video analysis is a valuable diagnostic tool that makes it possible to objectively assess the existing violations of locomotion and identify the targets of rehabilitation.

Locomotion and righting behavior of sea stars: a study case on the bat star Asterina stellifera (Asterinidae)

Introduction: The locomotion behavior of an organism involves the integration of aspects like body symmetry, sensory and locomotor systems. Furthermore, various ecological factors seem to be related to locomotion characteristics, such as foraging strategy, migration trends, response to predators and competitors, and environmental stress. Objective: To analyze locomotion and the influence of body symmetry in the crawling and righting movements of the sea star Asterina stellifera. Methods: We carried out laboratory experiments in aquariums in the presence/absence of water current and on a horizontal and vertical surface. Results: The speed is similar to speed in other species of similar size. Both the speed and linearity of displacement were independent of individual body size. A water current leads to faster crawling and straight paths, but there is no rheotaxis: streams do not affect locomotion. Speed and linearity of displacement were independent of individual body size. The displacement pattern described here may be an adaptation of organisms that present dense populations in communities with high prey abundance, as is the case of A. stellifera. Conclusions: Like other asteroids, this species did not show an Anterior/Posterior plane of symmetry during locomotion, or righting movement: it does not tend to bilaterality.

Reconstructing the Intrinsic Statistical Properties of Intermittent Locomotion Through Corrections for Boundary Effects

Locomotion characteristics are often recorded within bounded spaces, a constraint which introduces geometry-specific biases and potentially complicates the inference of behavioural features from empirical observations. We describe how statistical properties of an uncorrelated random walk, namely the steady-state stopping location probability density and the empirical step probability density, are affected by enclosure in a bounded space. The random walk here is considered as a null model for an organism moving intermittently in such a space, that is, the points represent stopping locations and the step is the displacement between them. Closed-form expressions are derived for motion in one dimension and simple two-dimensional geometries, in addition to an implicit expression for arbitrary (convex) geometries. For the particular choice of no-go boundary conditions, we demonstrate that the empirical step distribution is related to the intrinsic step distribution, i.e. the one we would observe in unbounded space, via a multiplicative transformation dependent solely on the boundary geometry. This conclusion allows in practice for the compensation of boundary effects and the reconstruction of the intrinsic step distribution from empirical observations.

Combination of Defined CatWalk Gait Parameters for Predictive Locomotion Recovery in Experimental Spinal Cord Injury Rat Models.

In many preclinical spinal cord injury (SCI) studies, assessment of locomotion recovery is key to understanding the effectiveness of the experimental intervention. In such rat SCI studies, the most basic locomotor recovery scoring system is a subjective observation of animals freely roaming in an open field, the Basso Beattie Bresnahan (BBB) score. In comparison, CatWalk is an automated gait analysis system, providing further parameter specifications. Although together the CatWalk parameters encompass gait, studies consistently report single parameters, which differ in significance from other behavioral assessments. Therefore, we believe no single parameter produced by the CatWalk can represent the fully-coordinated motion of gait. Typically, other locomotor assessments, such as the BBB score, combine several locomotor characteristics into a representative score. For this reason, we ranked the most distinctive CatWalk parameters between uninjured and SC injured rats. Subsequently, we combined nine of the topmost parameters into an SCI gait index score based on linear discriminant analysis (LDA). The resulting combination was applied to assess gait recovery in SCI experiments comprising of three thoracic contusions, a thoracic dorsal hemisection, and a cervical dorsal column lesion model. For thoracic lesions, our unbiased machine learning model revealed gait differences in lesion type and severity. In some instances, our LDA was found to be more sensitive in differentiating recovery than the BBB score alone. We believe the newly developed gait parameter combination presented here should be used in CatWalk gait recovery work with preclinical thoracic rat SCI models.

Analysis of movement mechanics in the training process of sport horses

Article Details: Received: 2020-10-15 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.145-149 The aim of the study was to determine the effect of training process on changes of quantitative and qualitative indicators of the movement mechanics of sport horses. A load controller was used to evaluate the motion mechanics. The training load was divided into three stages with different lengths, speeds and degrees of load. Tested animals were 14 horses of Slovak Warmblood breed. Our results have shown that gradual increase of load in the tested horses resulted in better spaciousness of movement, which was reflected in the elongation of the horse´s stride, regular movement and significant energy of the pelvic limbs (p<0.05). From our findings we can state that the effect of gender did not have significant effect on the number and length of steps in each degree of load. We have noticed a significant difference (p<0.05) in the „number of steps“ parameter between the age categories of horses in the age up to 7 years (3.460±619) and the category aged up to 14 years (3.383±572). Gradual increase of the training load led to the economization of the movement and the long-term training process sled to the adaptation of the organism to repeated load. Keywords: horse, movement mechanics, training, treadmill, load References Arfuso, F. et al. (2016). Dynamic modulation of platelet aggregation, albumin and nonesterified fatty acids during physical exercise in Thoroughbred horses. Research in Veterinary Science , 104, 86-91. https://doi.org/10.1016/j.rvsc.2015.11.013 Barrey, E. (2016). Biomechanics of locomotion in the athletic horses. Veterian Key [online], 10. Retrieved June 20, 2019 from https://veteriankey.com/biomechanics-of-locomotion-in-the-athletic-horse/ Barrey, E. et al. (1993). Stride characteristics of overground versus treadmill locomotion in the saddle horse. Acta Anatomica ,146(2-3), 90-94. https://doi.org/10.1159/000147427 Becero, M. et al. (2020). Capacitive resistive electric transfer modifies gait pattern in horses exercised of treadmill. BMC Veterinary Research , 16, 10. https://doi.org/10.1186/s12917-020-2233-x Becker, A. C., Stock, K. F. & Distl, O. (2011). Genetic correlations between free movement and movement under rider in performance tests of German Warmblood horses. Livestock Science , 142(1-3), 245-252. https://doi.org/10.1016/j.livsci.2011.08.001 Clayton, H. M. (2004). The dynamic horse: a biomechanical guide to equine movement and performance . Madison, MI: Sport Horse Publications. ISBN 097476700X. Fredricson, I. et al. (1983). Treadmill for equine locomotion analysis. Equine Veterinary Journal , 15(2), 111-115. https://doi.org/10.1111/j.2042-3306.1983.tb01730.x Halo, M. et al. (2008). Genetic efficiency parameters of Slovak warm-blood horses. Arch. Tierz. , Dummerstorf 51 (2008) 1, 05-15. Halo, M. et al. (2008). Influence stres on the training process of the horses. Journal of Central European Agriculture Open Access , 9(1), 217-223. Leleu, C., Cotrel, C. & Barrey, E. (2005). Relationships between biomechanical variables and race performance in French Standardbred trotters. Livestock Production Science , 92(1), 39-46. https://doi.org/10.1016/j.livprodsci.2004.07.019 Mcbride, S. D. & Mills, D. S. (2012). Psychological factors affecting equine performance. BMC Veterinary Research , 8, 180. https://doi.org/10.1186/1746-6148-8-180 McGreevy, P. D. & McLean, A. N. (2007). Roles of learning theory and ethology in equitation. Journal of Veterinary Behavior: Clinical Applications and Research , 2(4), 108-118. https://doi.org/10.1016/j.jveb.2007.05.003 Mlynekova, E. et al (2016). Impact of training load on the heart rate of horses. Acta fytotechnica et zootechnica , 19, 2016(4):167-170. http://dx.doi.org/10.15414/afz.2016.19.04.167-170 Moore, J. (2010). General biomechanics: the horse as a biological machine. Journal of Equine Veterinary Science , 30(7), 379-383. https://doi.org/10.1016/j.jevs.2010.06.002 Parkes, R. S. V. et al. (2019). The Effect of Training on Stride Duration in a Cohors of Two-Year-Old and Three-Year-Old Thoroughbred Racehorses. Animals , 9(7), 466. https://doi.org/10.3390/ani9070466 Persson, S. G. P. (1967). On blood volume and working capacity in horses. Acta Veterinaria Scandinavica, 19(Suppl.), 9-189. Straub, R. & Hoppeler, U. (1989). Leistungstest im Feld und auf dem Laufband - Eine vergleichende Studie. 2 nd Congress of the world Equine Vet. Assoc . Essen: Equitana.

The effect of claw disorders on the locomotion activity of dairy cows

Article Details: Received: 2020-10-26 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.135-139 The purpose of the work was aimed at determining changes in locomotion activity of dairy cows with healthy claws, as opposed to cows suffering from claw disorders. To achieve this goal, Heatime RuminAct technical equipment was used. Data gathering took place at the dairy farm of University of Agriculture in Nitra, where locomotion activity was measured via Heatime RuminAct hardware with DataFlowTMII software. This data came from 87 dairy cows, whose locomotion activity was monitored during a period of 21 days. This period consisted of 10 days of monitoring before the claw trimming, monitoring during the day of the trimming, and afterwards, another 10 days of monitoring after the trimming was complete. Units of locomotion activity in 24 hours (u.24h -1 ) were used to formulate the locomotion activity of the dairy cows. Health conditions of claws of the dairy cows were recorded and based on the presence of claw disorders, the cows were divided into two groups - cows with observed claw disorders formed a group of 33 cows, and cows exhibiting no claw disorder related symptoms formed a group of 54 cows. Conclusions based on results from the data gathered confirm a crucial difference in locomotion activity between healthy cows and cows afflicted by claw disorders. Keywords: dairy cow, Heatime RuminAct, locomotion activity, claw health, claw disorders References Anil, L. et al. (2005). Pain detection and amelioration in animals on the farm: issues and options. Journal of Applied Animal Welfare Science , 8, 261-278. https://doi.org/10.1207/s15327604jaws0804_3 Beer, G. et al. (2016). Use of extended characteristics of locomotion and feeding behavior for automated identification of lame dairy cows. PLoS One , 11, e0155796. https://doi.org/10.1371/journal.pone.0155796 Bruijnis, M. R. et al. H. (2010). Assessing economic consequences of foot disorders in dairy cattle using a dynamic stochastic simulation model. Journal of Dairy Scienc e, 93(6), 2419-2432. https://doi.org/10.3168/jds.2009-2721 Flower, F. C. et al.(2006). Effect of hoof pathologies on subjective assessments of dairy cow gait. Journal of Dairy Science , 89, 139-146. https://doi.org/10.3168/jds.S0022-0302(06)72077-X Hudson, C. et al. (2008) H. Recognition and management of pain in cattle. In Practice, 30, 126-134. https://doi.org/ 10.1136/inpract.30.3.126 King, M. T. M. et al. (2017). Cow-level associations of lameness, behavior, and milk yield of cows milked in automated systems. Journal of Dairy Science , 100(6), 4818-4828. https://doi.org/10.3168/jds.2016-12281 Nechanitzky, K. et al. (2016). Analysis of behavioral changes in dairy cows associated with claw horn lesions. Journal of Dairy Science , 99(4), 2904-2914. https://doi.org/10.3168/jds.2015-10109 O'Callaghan, K. A. et al. (2003). Subjective and objective assessment of pain and discomfort due to lameness in dairy cattle. Animal Welfare , 12, 605-610. O'Leary, N. W. et al. (2020). Invited review: Cattle lameness detection with accelerometers. Journal of Dairy Science , 103(5), 3895-3911. https://doi.org/10.3168/jds.2019-17123 Shepley, E. et al. (2017). Validation of the ability of a 3D pedometer to accurately determine the number of steps taken by dairy cows when housed in tie-stalls. Agriculture (Basel), 7, 53. https://doi.org/10.3390/agriculture7070053 Stoddard, G. C. and Cramer, G. (2017). A Review of the Relationship Between Hoof Trimming and Dairy Cattle Welfare. Veterinary Clinics of North America: Food Animal Practice , 33(2), 365-375. https://doi.org/10.1016/j.cvfa.2017.02.012 Strapak, P. et al. (2013). Cattle Breeding . Nitra: Slovak University of Agriculture. In Slovak. Thorup, V. M. et al. (2015). Lameness detection via leg-mounted accelerometers on dairy cows on four commercial farms. Animal , 9, 1704-1712. https://doi.org/10.1017/S1751731115000890 Weigele, H. C. et al. (2018). Moderate lameness leads to marked behavioral changes in dairy cows. Journal of Dairy Science , 101(3), 2370-2382. https://doi.org/10.3168/jds.2017-13120

A Small Bipedal Trans-Scale Precision Positioning Stage Based on Inertial Stick-Slip Driving

The small size and high flexibility of the mobile platform is widely used in many fields such as electron scanning microscope (SEM), but the mobile platform still adopts the structure of guide rail at present and has the problem of large volume and poor flexibility, which cannot meet the requirements of SEM for small cavity. Therefore, this paper proposes a small bipedal trans-scale precision positioning stage based on the inertial stick-slip driving to achieve small size and high flexibility. The mobile platform consists of two piezoelectric actuators, a frame structure, two bottom plates, two pre-tightening screws, and magnets, and the volume is 15 mm × 10 mm × 9.5 mm. To investigate the locomotion characteristics of the mobile platform, a prototype is manufactured, and a series of experiments are carried out. The experimental results show that its linear motion velocity can reach 3.553 mm/s and its angular velocity can reach 462.72mrad/s, which means that the mobile platform has good motion performance.

Uticaj vučne sile i brzine kretanja na čvrstoću osovina lokomotive

The article presents the dependencies obtained when researching the load on the locomotive axles, depending on the traction force and the speed of movement of the locomotive. The traction characteristic of the locomotive is the relationship between the traction force achieved by the traction motors and the speed of movement, and it is different under different driving conditions. Different modes of operation of locomotive axles are considered. A simulation of the axles' behaviour has been developed. The strength and deformation characteristics of the locomotive axles under different loading modes are calculated. A comparative analysis of the strength characteristics of locomotives with different classes of transmission mechanisms has been made

Short communication: Claw block application improves locomotion and weight-bearing characteristics in cattle with foot diseases

In cattle with foot diseases, application of a block on the healthy partner claw is a common method of pain relief. The aim of this study was to evaluate the effect of wooden claw blocks on locomotion characteristics and weight distribution in healthy (group C; n = 17) versus lame (group L; n = 17) cattle. Group L was further subdivided into group L1 (lameness score ≤3; n = 7) and group L2 (lameness score >3; n = 10). We performed lameness scoring using a numeric rating system and measured locomotion characteristics using 2 accelerometers (400 Hz; kinematic outcome = stance phase duration; kinetic outcomes = foot load and toe-off) and a 4-scale weighing platform (difference of mean weight distribution across the limbs; ∆weight) before and after application of a claw block. We applied claw blocks to a randomly assigned lateral or medial claw of the fore or hindlimb in group C cows, and on the healthy partner claw in group L cows. Variables were expressed as differences across limbs. We used 1-way ANOVA to determine the differences between groups C and L and between groups L1 and L2 for ∆weight after application of the claw block. We performed paired t tests to compare variables before and after application of the claw block in groups C and L. Group L scored higher on the numeric rating system than group C (mean ± SD, 3.40 ± 0.62 vs. 1.87 ± 0.28) and showed greater differences in relative stance phase duration (16.34 ± 10.78% vs. 2.13 ± 1.94%), foot load (9.68 ± 8.06 g vs. 3.26 ± 3.69 g), toe-off (3.91 ± 3.14 g vs. 0.78 ± 0.66 g), and ∆weight (53.62 ± 28.85% vs. 8.52 ± 6.19%). In group C, we observed an increase of 12.17 percentage points in ∆weight after block application, from 8.52 ± 6.19% to 20.69 ± 17.01%. Compared with the baseline, group L showed a decrease in numeric rating system score (2.88 ± 0.49 vs. 3.40 ± 0.62) and a decrease in differences between the limbs in relative stance phase duration (7.66 ± 9.96% vs. 16.34 ± 10.78%) and foot load (4.26 ± 4.14 g vs. 9.68 ± 8.06 g) after application of a claw block. Group L2 showed smaller ∆weight after application of a claw block than group L1 (-7.8 ± 8.7% vs. 10.4 ± 7.6%). After block application in group L, we observed smaller differences across the limbs in variables measured to describe gait-cycle characteristics while walking, but no significant improvement while standing. We concluded that application of a claw block must be combined with other methods of pain relief, such as analgesic medication.

Forelimb joints contribute to locomotor performance in reindeer (Rangifer tarandus) by maintaining stability and storing energy.

Reindeer (Rangifer tarandus) have lengthy seasonal migrations on land and their feet possess excellent locomotor characteristics that can adapt to complex terrains. In this study, the kinematics and vertical ground reaction force (GRF) of reindeer forelimb joints (interphalangeal joint b, metacarpophalangeal joint c, and wrist joint d) under walk, trot 1, and trot 2 were measured using a motion tracking system and Footscan pressure plates. Significant differences among different locomotor activities were observed in the joint angles, but not in changes of the joint angles (αb, αc, αd) during the stance phase. Peak vertical GRF increased as locomotor speed increased. Net joint moment, power, and work at the forelimb joints were calculated via inverse dynamics. The peak joint moment and net joint power related to the vertical GRF increased as locomotor speed increased. The feet absorbed and generated more energy at the joints. During different locomotor activities, the contribution of work of the forelimbs changed with both gait and speed. In the stance phase, the metacarpophalangeal joint absorbed more energy than the other two joints while trotting and thus performed better in elastic energy storage. The joint angles changed very little (∼5°) from 0 to 75% of the stance phase, which reflected the stability of reindeer wrist joints. Compared to typical ungulates, reindeer toe joints are more stable and the stability and energy storage of forelimb joints contribute to locomotor performance in reindeer.

Improvement of traction capacity of industrial railway transport in the Arctic and on the continental shelf

The Russian Arctic is extremely rich in minerals (hydrocarbons, various minerals, precious metals, etc.). In modern conditions, it is of particular importance to develop vast territories located beyond the Arctic Circle, due to their special socio-economic, geopolitical and defense significance. The rapid development of the Yamal field needs a reliable and modern trunk railway. The project called the Northern Latitudinal Railway has been included in the Strategy for the Development of Railway Transport until 2030. At the temperatures below minus 20 °C, the use of ordinary sand to improve adhesion usually has low effect due to a significant increase in the hardness of ice and ice crust. It should be noted that given sand is present at the contact of ice-glazed rails and wheels, their metal–metal interaction is interrupted by of this sandwiched sand interlayer, which leads to a decrease in the traction characteristics of locomotives. To increase the adhesion coefficient in winter, the author has proposed an engineering solution protected by patent No. 2504492, which consists in the feed of pre-heated, for example, using an induction heater, dry quartz sand to the rail–wheel contact zone. This invention allows increasing the coefficient of adhesion and, consequently, the traction force of locomotives on average up to 10%. Currently, we are carrying out studies to solve the problem of removing ice deposits from the working surface of rails using innovative “sandless” methods that eliminate the need of using ordinary sand. The solution to the problem of removing ice from rails will contribute to the creation of a terrestrial year-round communication between Chukotka and the Barents Sea, which duplicates the Northern Sea Route.

Automated creation and tuning of personalised muscle paths for OpenSim musculoskeletal models of the knee joint.

Computational modelling is an invaluable tool for investigating features of human locomotion and motor control which cannot be measured except through invasive techniques. Recent research has focussed on creating personalised musculoskeletal models using population-based morphing or directly from medical imaging. Although progress has been made, robust definition of two critical model parameters remains challenging: (1) complete tibiofemoral (TF) and patellofemoral (PF) joint motions, and (2) muscle tendon unit (MTU) pathways and kinematics (i.e. lengths and moment arms). The aim of this study was to develop an automated framework, using population-based morphing approaches to create personalised musculoskeletal models, consisting of personalised bone geometries, TF and PF joint mechanisms, and MTU pathways and kinematics. Informed from medical imaging, personalised rigid body TF and PF joint mechanisms were created. Using atlas- and optimisation-based methods, personalised MTU pathways and kinematics were created with the aim of preventing MTU penetration into bones and achieving smooth MTU kinematics that follow patterns from existing literature. This framework was integrated into the Musculoskeletal Atlas Project Client software package to create and optimise models for 6 participants with incrementally increasing levels of personalisation with the aim of improving MTU kinematics and pathways. Three comparisons were made: (1) non-optimised (Model 1) and optimised models (Model 3) with generic joint mechanisms; (2) non-optimised (Model 2) and optimised models (Model 4) with personalised joint mechanisms; and (3) both optimised models(Model 3 and 4). Following optimisation, improvements were consistently shown in pattern similarity to cadaveric data in comparison (1) and (2). For comparison (3), a number of comparisons showed no significant difference between the two compared models. Importantly, optimisation did not produce statistically significantly worse results in any case.

Long ascending propriospinal neurons provide flexible, context-specific control of interlimb coordination.

Within the cervical and lumbar spinal enlargements, central pattern generator (CPG) circuitry produces the rhythmic output necessary for limb coordination during locomotion. Long propriospinal neurons that inter-connect these CPGs are thought to secure hindlimb-forelimb coordination, ensuring that diagonal limb pairs move synchronously while the ipsilateral limb pairs move out-of-phase during stepping. Here, we show that silencing long ascending propriospinal neurons (LAPNs) that inter-connect the lumbar and cervical CPGs disrupts left-right limb coupling of each limb pair in the adult rat during overground locomotion on a high-friction surface. These perturbations occurred independent of the locomotor rhythm, intralimb coordination, and speed-dependent (or any other) principal features of locomotion. Strikingly, the functional consequences of silencing LAPNs are highly context-dependent; the phenotype was not expressed during swimming, treadmill stepping, exploratory locomotion, or walking on an uncoated, slick surface. These data reveal surprising flexibility and context-dependence in the control of interlimb coordination during locomotion.

Indication of Electromagnetic Field Exposure via RBF-SVM Using Time-Series Features of Zebrafish Locomotion.

This paper introduces a novel model based on support vector machine with radial basis function kernel (RBF-SVM) using time-series features of zebrafish (Danio rerio) locomotion exposed to different electromagnetic fields (EMFs) to indicate the corresponding EMF exposure. A group of 14 adult zebrafish was randomly divided into two groups, 7 in each group; the fish of each group have the novel tank test under a sham or real magnetic exposure of 6.78 MHz and about 1 A/m. Their locomotion in the tests was videotaped to convert into the x, y coordinate time-series of the trajectories for reforming time-series matrices according to different time-series lengths. The time-series features of zebrafish locomotion were calculated by the comparative time-series analyzing framework highly comparative time-series analysis (HCTSA), and a limited number of the time-series features that were most relevant to the EMF exposure conditions were selected using the minimum redundancy maximum relevance (mRMR) algorithm for RBF-SVM classification training. Before this, ambient environmental parameters (AEPs) had little effect on the locomotion performance of zebrafish processed by the empirical method, which had been quantitatively verified by regression using another group of 14 adult zebrafish. The results have demonstrated that the purposed model is capable of accurately indicating different EMF exposures. All classification accuracies can be 100%, and the classification precision of several classifiers based on specific parameters and feature sets with specific dimensions can reach higher than 95%. The speculative reason for this result is that the specified EMF has affected the zebrafish neural aspect, which is then reflected in their behaviors. The outcomes of this study have provided a new indication model for EMF exposures and provided a reference for the investigation of the impact of EMF exposure.

Biopsychosocial determinants of visuospatial memory performance according to different spaces

Visuospatial memory (VSM) performance depends on intrinsic (biopsychosocial parameters) and extrinsic (space) factors. We aimed at characterizing the determinants of VSM performance according to space. Young healthy adults, 20 males and 41 females (23 ± 3 years old), were assessed for VSM performance through a pathway learning task, in reaching (eCorsi Block Tapping task) and walking space (Virtual Walking Corsi Task). We evaluated psychosocial factors through seven questionnaires – Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Fatigue Severity Scale, Profile of the Mood States, 2nd edition, short version, Coping Inventory for Stressful Situations, Measurement of Ambiguity Tolerance, Motives for Physical Activities Measure-Revised, mental rotation capabilities and locomotor characteristics (physical activity level through embedded trackers and the International Physical Activity Questionnaire, and gait parameters). The most explanatory biopsychosocial determinants of VSM performance were i) mental rotation capabilities and fatigue indicator in reaching space, and ii) mental rotation capabilities and physical activity level (tracked active energy expenditure only) in walking space. These results suggest that specific parameters should be preferred for the evaluation and strengthening of VSM capabilities in both reaching or walking spaces.

Locomotor characteristics of the women’s inaugural super league competition and the rugby league world cup

ABSTRACT Understanding the locomotor characteristics of competition can help rugby league (RL) coaches optimise training prescription. To date, no research exists on the locomotor characteristics of women’s RL. The aim was to compare whole match and peak locomotor characteristics of women’s RL competition at international (RL World Cup [WRLWC]) and domestic level (Super League [WSL]). Microtechnology data were collected from 58 players from 3-WSL clubs and 1-WRLWC team. Participants were classified into forwards (n = 30) and backs (n = 28). Partial least squares correlation analysis established which variables were important to discriminate between the level of competition (international vs. domestic) and positional group (forwards vs. backs). Linear mixed-effects models estimated the differences between standards of competition and positional group for those variables. International forwards were most likely exposed to greater peak 1-min average acceleration (standardised mean difference = 1.23 [0.42 to 2.04]) and peak 3-min average acceleration (1.13 [0.41 to 1.85]) than domestic forwards. International backs likely completed greater peak 1-min average acceleration (0.83 [0.08 to 1.58]) than domestic backs and possibly greater high-speed-distances (0.45 [−0.17 to 1.07]). Findings highlight the need for positional specific training across levels to prepare representative players for the increased match characteristics of international competition.