Locomotion Gaits Research Articles

Design and Control of a Flexible Exoskeleton to Generate a Natural Full Gait for Lower-Limb Rehabilitation

Abstract Strokes caused by cerebrovascular diseases often result in severe damage to locomotion, movement, and cognitive functions. Rehabilitation is an effective way to regain locomotion ability in daily life. However, there are mismatching biological joints, non-full rehabilitation gaits, and indirect joint feedback among conventional exoskeletons or devices. Hence, this paper proposed a novel flexible Bowden cable driving exoskeleton to achieve natural full walking gaits utilizing direct lower-limb movement feedback. First, complete flexible joint rotation kinematics was proposed by using a pair of agonism–antagonism flexible Bowden cables. Then, a personalized rehabilitation walking gait and feedforward proportional-integral-differential controller were adopted to drive the lower limbs to realize complete joint movement and natural full gait locomotion. Finally, a prototype was designed to verify the effectiveness. Mannequin and human tests were conducted, and the results show that the real walking gait is consistent with the reference natural human gait and that assistive torque was applied to humans to reduce muscle activation without significantly changing the foot pressure.

Design of Model-Based and Model-Free Robust Control Strategies for Lower Limb Rehabilitation Exoskeletons

Rehabilitation in the form of locomotion assistance and gait training through robotic exoskeletons requires both precision and accuracy to achieve effective results. The essential challenge is to ensure robust tracking of the reference signal, i.e., of the gait or locomotion. This paper presents the design of model-based (MB) and model-free (MF) robust control strategies to achieve desired performance and robustness in terms of transient behavior and steady-state/tracking error, implementable to the locomotion assistance and gait training by exoskeletons. The dynamic responses of the exoskeleton system were investigated with both the control strategies. The study was carried out with a variety of reference signals and performance was evaluated to identify the best suited approach for rehabilitation exoskeletons. In case of the model-based control, a mathematical model of the system was developed using a bond graph modeling technique and a lead compensated H-infinity reference gain controller was designed to ensure robust tracking performance. In the model-free control strategy, however, the system function is approximated using radial basis function neural networks (RBFNNs) and an adaptive proportional-derivative RBFNN controller was designed to achieve the desired results with minimum tracking error. Both strategies make the system robust and stable. However, the MF control strategy is faster for all reference inputs as compared to the MB control strategy i.e., faster to approach the peak value and settle, and rapidly approaches the zero steady-state/tracking error. The rise time in the case of a sinusoidal input for model-free control is 0.4 s faster than the rise time in model-based control. Similarly, the settling time is 3.9 s faster in the case of model-free control, which is a prominent difference and can provide better rehabilitation results.

A portable off‐road crawling hexapod robot

AbstractLegged robot has attracted wide attention because of its outstanding mobility and flexibility in the off‐road environment. Benefitting from the smooth foot trajectory and the discrete footholds, the robot can traverse the rough terrains with a great maneuverability. This paper studies a portable off‐road crawling hexapod robot with a flat structure of Schatz linkage. The proposed crawling hexapod robot could be stacked flatly with a compact size, which is good for storage and transportation. What's more, the robot could play an important role in the search and rescue mission. It could protect the operator from an incident like a collapsing wall. The robot has four locomotion gaits to meet different demands on rough terrains, including the hexapod gait, the tripod gait, the butterfly stroke gait, and the escape gait. A prototype of the robot system is fabricated. A series of experiments and simulated search and rescue missions are conducted, and the results verify that the robot could traverse through the rough terrain and complete the tasks required in the search and rescue mission.

Real-Time Locomotion on Soft Grounds With Dynamic Footprints

When we move on snow, sand, or mud, the ground deforms under our feet, immediately affecting our gait. We propose a physically based model for computing such interactions in real time, from only the kinematic motion of a virtual character. The force applied by each foot on the ground during contact is estimated from the weight of the character, its current balance, the foot speed at the time of contact, and the nature of the ground. We rely on a standard stress-strain relationship to compute the dynamic deformation of the soil under this force, where the amount of compression and lateral displacement of material are, respectively, parameterized by the soil’s Young modulus and Poisson ratio. The resulting footprint is efficiently applied to the terrain through procedural deformations of refined terrain patches, while the addition of a simple controller on top of a kinematic character enables capturing the effect of ground deformation on the character’s gait. As our results show, the resulting footprints greatly improve visual realism, while ground compression results in consistent changes in the character’s motion. Readily applicable to any locomotion gait and soft soil material, our real-time model is ideal for enhancing the visual realism of outdoor scenes in video games and virtual reality applications.

Decoupling and Reprogramming the Wiggling Motion of Midge Larvae Using a Soft Robotic Platform.

The efficient motility of invertebrates helps them survive under evolutionary pressures. Reconstructing the locomotion of invertebrates and decoupling the influence of individual basic motion are crucial for understanding their underlying mechanisms, which, however, generally remain a challenge due to the complexity of locomotion gaits. Herein, a magnetic soft robot to reproduce midge larva's key natural swimming gaits is developed, and the coupling effect between body curling and rotation on motility is investigated. Through the authors' systematically decoupling studies using programmed magnetic field inputs, the soft robot (named LarvaBot) experiences various coupled gaits, including biomimetic side-to-side flexures, and unveils that the optimal rotation amplitude and the synchronization of curling and rotation greatly enhance its motility. The LarvaBot achieves fast locomotion and upstream capability at the moderate Reynolds number regime. The soft robotics-based platform provides new insight to decouple complex biological locomotion, and design programmed swimming gaits for the fast locomotion of soft-bodied swimmers.

Reconfigurable Robotic System Design With Application to Cleaning and Maintenance

Abstract The design of cleaning and maintenance (CaM) robots is generally limited by their fixed morphologies, resulting in limited functions and modes of operation. Contrary to fixed shape robots, the design of reconfigurable robots presents unique challenges in designing their system, subsystems, and functionalities with the scope for innovative operational scenarios and achieving high performance in multiple modalities without compromise. This paper proposes a heuristic framework using three layers, namely input, formulation, and output layer, for designing reconfigurable robots with the aid of established transformation principles including expand/collapse, expose/cover, and fuse/divide observed in several products, services, and systems. We apply this heuristic framework approach to the novel design of a pavement CaM robotic system and subsystems, namely, (i) varying footprint, (ii) transmission, (iii) outer skin or cover, (iv) storage bin, (v) surface cleaning, and (vi) vacuum/suction and blowing. The advances in the design method using the heuristic approach are demonstrated by developing an innovative reconfigurable design for the CaM task. Kinematic analysis and control architecture enables the unique locomotion behavior and gaits, namely, (a) static reconfiguration and (b) reconfiguration while locomotion, supported by the control architecture. Experiments were conducted, and outcomes were discussed along with the failure mode analysis to support the design robustness and limitations through the observations made from the development to testing phase over one year. A detailed video demonstrating the design capabilities is linked.

Formulation of kinematics and gait locomotion for Hyper-Redundant robot

Robots with numerous excess degrees of freedom (DOF) are known as hyper-redundant. These robots resemble snakes or tentacles are suitable for use in extremely constrained situations as well as new modes of locomotion. This work discusses kinematic analysis of hyper-redundant (H-R) systems over solid terrain. The analysis is based on travelling wave gait which is used to model variety of locomotion for example: locomotion of flatworm or inchworm. The H-R locomotion describes displacement generated from internal bending or twisting of its mechanism. Kinematics of gait is formulated for both extensible and non-extensible H-R locomotion. Its kinematics is modelled using differential geometry of planar curves. Flatworm and inchworm locomotion has been idealized using travelling wave gait models. An H-R precise manipulation method of grasping wave is also introduced.

Deep Reinforcement Learning with Gait Mode Specification for Quadrupedal Trot-Gallop Energetic Analysis.

Quadruped system is an animal-like model which has long been analyzed in terms of energy efficiency during its various gait locomotion. The generation of certain gait modes on these systems has been achieved by classical controllers which demand highly specific domain-knowledge and empirical parameter tuning. In this paper, we propose to use deep reinforcement learning (DRL) as an alternative approach to generate certain gait modes on quadrupeds, allowing potentially the same energetic analysis without the difficulty of designing an ad hoc controller. We show that by specifying a gait mode in the process of learning, it allows faster convergence of the learning process while at the same time imposing a certain gait type on the systems as opposed to the case without any gait specification. We demonstrate the advantages of using DRL as it can exploit automatically the physical condition of the robots such as the passive spring effect between the joints during the learning process, similar to the adaptation skills of an animal. The proposed system would provide a framework for quadrupedal trot-gallop energetic analysis for different body structures, body mass distributions and joint characteristics using DRL.

Locomotion Synchronization and Gait Performance While Walking With an Overground Body Weight Support System.

Rehabilitation robotics offers new alternatives to patients and therapists to efficiently support walking training using Body Weight Support (BWS) systems. Automating the locomotion of overground BWS systems is one of the feasible approaches to free therapists from manual operation. However, the effect of locomotion control strategies of BWS system on participant's gait performance have not been studied sufficiently. For this reason, in this paper we introduced locomotion synchronization between a participant, a therapist, and a BWS system as control criteria, and investigated its effect on participant's gait performance during walking with an overground BWS system. In the experiment, four healthy participants walked with a BWS system under different BWS conditions, and with/without wearing orthosis which simulates asymmetric gait of actual patients. As the result, it was observed a significant relationship between locomotion synchronization and participants' gait performance, such as walking speed and step time.Clinical relevance - Controlling an overground BWS system's locomotion in synchronizing with the participant's gait has the potential to facilitate the effect of gait rehabilitation.

Neuroplasticity Mechanisms and Prospects for Personalized Rehabilitation Strategies in Patients with Motor and Cognitive Impairments

Aim. To highlight the most important areas of research on the problems of rehabilitation after stroke and the prospects for the development of new rehabilitation strategies, taking into account individual characteristics. Neuroplastic outcomes of anemic infarctions are presented by multi-pattern positive processes of synaptogenesis, sprouting, synthesis of neuroprotective proteins, and destructive effects of stress plasticity inducing dystonic disturbances, deterioration of stabilometric parameters and locomotor gait mechanisms with support deterioration [1]. Thus, specialists in neurorehabilitation should know the basics of fundamental neurophysiological processes in the central nervous system, interhemispheric networks of the brain, and optimize rehabilitation programs, taking into account individualized recovery profiles [2]. One of the factors influencing recovery after a stroke is nervous reorganization, which is proportional to the amount of damage [3]. The processes of neuroplasticity are studied from the standpoint of returning to the pre-stroke recovery model (with minor injuries) – forming “optimal” plasticity and compensatory strategies of “destructive” plasticity (with extensive hemispheric injuries). Micro-RNA (miRNA) are understudied in the neuroprotective reaction to cerebral ischemia. Another important modulator of stroke outcomes is the brain-derived neurotrophic factor (BDNF). Processing of the defective BDNF synthesis when the amino acid valine is replaced by methionine (val-met) that occurs during allelic disorders is of outstanding interest. Conclusion. Promising research areas for strategic approaches to rehabilitation after a stroke are the study of hemispheric introduction, miRNA and neuroprotection cascades; BDNF as an inducer of neuronal differentiation. Allelic BDNF polymorphisms induce lower recovery potential after stroke. Under certain environmental conditions motor learning can overcome the neuroplasticity deficit in the BDNF gene polymorphism. The studies have shown general patterns of positive effects of aerobic stimuli with enhanced BDNF secretion in the recovery of patients with cognitive and motor impairments; nevertheless, the onset period, intensity, duration and exercises rhythmicity have not been established in cerebral stroke. Future studies are likely to optimize rehabilitation profiles based on genetic characteristics.

Hopscotching jellyfish: combining different duty cycle kinematics can lead to enhanced swimming performance

Jellyfish (Medusozoa) have been deemed the most energy-efficient animals in the world. Their bell morphology and relatively simple nervous systems make them attractive to robotocists. Although, the science community has devoted much attention to understanding their swimming performance, there is still much to be learned about the jet propulsive locomotive gait displayed by prolate jellyfish. Traditionally, computational scientists have assumed uniform duty cycle kinematics when computationally modeling jellyfish locomotion. In this study we used fluid-structure interaction modeling to determine possible enhancements in performance from shuffling different duty cycles together across multiple Reynolds numbers and contraction frequencies. Increases in speed and reductions in cost of transport were observed as high as 80% and 50%, respectively. Generally, the net effects were greater for cases involving lower contraction frequencies. Overall, robust duty cycle combinations were determined that led to enhanced or impeded performance.

Generation of Direct-, Retrograde-, and Source-Wave Gaits in Multi-Legged Locomotion in a Decentralized Manner via Embodied Sensorimotor Interaction.

Multi-legged animals show several types of ipsilateral interlimb coordination. Millipedes use a direct-wave gait, in which the swing leg movements propagate from posterior to anterior. In contrast, centipedes use a retrograde-wave gait, in which the swing leg movements propagate from anterior to posterior. Interestingly, when millipedes walk in a specific way, both direct and retrograde waves of the swing leg movements appear with the waves' source, which we call the source-wave gait. However, the gait generation mechanism is still unclear because of the complex nature of the interaction between neural control and dynamic body systems. The present study used a simple model to understand the mechanism better, primarily how local sensory feedback affects multi-legged locomotion. The model comprises a multi-legged body and its locomotion control system using biologically inspired oscillators with local sensory feedback, phase resetting. Each oscillator controls each leg independently. Our simulation produced the above three types of animal gaits. These gaits are not predesigned but emerge through the interaction between the neural control and dynamic body systems through sensory feedback (embodied sensorimotor interaction) in a decentralized manner. The analytical description of these gaits' solution and stability clarifies the embodied sensorimotor interaction's functional roles in the interlimb coordination.

A 3D‐Printed Self‐Learning Three‐Linked‐Sphere Robot for Autonomous Confined‐Space Navigation

Robots In article number 2100039, Yong Lin Kong and co-workers present a 3D-printed, compact robot integrated with reinforcement learning that performs adaptable, autonomous crawling in a confined environment. Without prior knowledge of the environment, the scalable robot can learn effective locomotory gaits that enable navigation through confined and dynamic environments, addressing a key challenge for robotic biomedical diagnosis.

Yoshimura-origami Based Earthworm-like Robot With 3-dimensional Locomotion Capability.

Earthworm-like robots have received great attention due to their prominent locomotion abilities in various environments. In this research, by exploiting the extraordinary three-dimensional (3D) deformability of the Yoshimura-origami structure, the state of the art of earthworm-like robots is significantly advanced by enhancing the locomotion capability from 2D to 3D. Specifically, by introducing into the virtual creases, kinematics of the non-rigid-foldable Yoshimura-ori structure is systematically analyzed. In addition to exhibiting large axial deformation, the Yoshimura-ori structure could also bend toward different directions, which, therefore, significantly expands the reachable workspace and makes it possible for the robot to perform turning and rising motions. Based on prototypes made of PETE film, mechanical properties of the Yoshimura-ori structure are also evaluated experimentally, which provides useful guidelines for robot design. With the Yoshimura-ori structure as the skeleton of the robot, a hybrid actuation mechanism consisting of SMA springs, pneumatic balloons, and electromagnets is then proposed and embedded into the robot: the SMA springs are used to bend the origami segments for turning and rising motion, the pneumatic balloons are employed for extending and contracting the origami segments, and the electromagnets serve as anchoring devices. Learning from the earthworm’s locomotion mechanism--retrograde peristalsis wave, locomotion gaits are designed for controlling the robot. Experimental tests indicate that the robot could achieve effective rectilinear, turning, and rising locomotion, thus demonstrating the unique 3D locomotion capability.

Common motor patterns of asymmetrical and symmetrical bipedal gaits.

BackgroundSynergy modules have been used to describe activation of lower limb muscles during locomotion and hence to understand how the system controls movement. Walking and running have been shown shared synergy patterns suggesting common motor control of both symmetrical gaits. Unilateral skipping, an equivalent gait to the quadrupedal gallop in humans, has been defined as the third locomotion paradigm but the use by humans is limited due to its high metabolic cost. Synergies in skipping have been little investigated. In particular, to the best of our knowledge, the joint study of both trailing and leading limbs has never been addressed before.Research questionHow are organized muscle activation patterns in unilateral skipping? Are they organized in the same way that in symmetrical gaits? If yes, which are the muscle activation patterns in skipping that make it a different gait to walking or running? In the present research, we investigate if there are shared control strategies for all gaits in locomotion. Addressing these questions in terms of muscle synergies could suggest possible determinants of the scarce use of unilateral skipping in humans.MethodsElectromyographic data of fourteen bilateral muscles were collected from volunteers while performing walking, running and unilateral skipping on a treadmill. Also, spatiotemporal gait parameters were computed from 3D kinematics. The modular composition and activation timing extracted by non-negative matrix factorization were analyzed to detect similarities and differences among symmetrical gaits and unilateral skipping.ResultsSynergy modules showed high similarity throughout the different gaits and between trailing and leading limbs during unilateral skipping. The synergy associated with the propulsion force operated by calf muscles was anticipated in bouncing gaits. Temporal features of synergies in the leading leg were very similar to those observed for running. The different role of trailing and leading legs in unilateral skipping was reflected by the different timing in two modules. Activation for weight acceptance was anticipated and extended in the trailing leg, preparing the body for landing impact after the flight phase. A different behaviour was detected in the leading leg, which only deals with a pendular weight transference.SignificanceThe evidence gathered in this work supports the hypothesis of shared modules among symmetrical and asymmetrical gaits, suggesting a common motor control despite of the infrequent use of unilateral skipping in humans. Unilateral skipping results from phase-shifted activation of similar muscular groups used in symmetrical gaits, without the need for new muscular groups. The high and anticipated muscle activation in the trailing leg for landing could be the key distinctive event of unilateral skipping.

Targeting Paretic Propulsion and Walking Speed With a Soft Robotic Exosuit: A Consideration-of-Concept Trial.

Background: Soft robotic exosuits can facilitate immediate increases in short- and long-distance walking speeds in people with post-stroke hemiparesis. We sought to assess the feasibility and rehabilitative potential of applying propulsion-augmenting exosuits as part of an individualized and progressive training program to retrain faster walking and the underlying propulsive strategy.Methods: A 54-yr old male with chronic hemiparesis completed five daily sessions of Robotic Exosuit Augmented Locomotion (REAL) gait training. REAL training consists of high-intensity, task-specific, and progressively challenging walking practice augmented by a soft robotic exosuit and is designed to facilitate faster walking by way of increased paretic propulsion. Repeated baseline assessments of comfortable walking speed over a 2-year period provided a stable baseline from which the effects of REAL training could be elucidated. Additional outcomes included paretic propulsion, maximum walking speed, and 6-minute walk test distance.Results: Comfortable walking speed was stable at 0.96 m/s prior to training and increased by 0.30 m/s after training. Clinically meaningful increases in maximum walking speed (Δ: 0.30 m/s) and 6-minute walk test distance (Δ: 59 m) were similarly observed. Improvements in paretic peak propulsion (Δ: 2.80 %BW), propulsive power (Δ: 0.41 W/kg), and trailing limb angle (Δ: 6.2 degrees) were observed at comfortable walking speed (p's < 0.05). Likewise, improvements in paretic peak propulsion (Δ: 4.63 %BW) and trailing limb angle (Δ: 4.30 degrees) were observed at maximum walking speed (p's < 0.05).Conclusions: The REAL training program is feasible to implement after stroke and capable of facilitating rapid and meaningful improvements in paretic propulsion, walking speed, and walking distance.

Using Energy Shaping and Regulation for Limit Cycle Stabilization, Generation, and Transition in Simple Locomotive Systems

Abstract This paper explores new ways to use energy shaping and regulation methods in walking systems to generate new passive-like gaits and dynamically transition between them. We recapitulate a control framework for Lagrangian hybrid systems, and show that regulating a state varying energy function is equivalent to applying energy shaping and regulating the system to a constant energy value. We then consider a simple one-dimensional hopping robot and show how energy shaping and regulation control can be used to generate and transition between nearly globally stable hopping limit cycles. The principles from this example are then applied on two canonical walking models, the spring loaded inverted pendulum (SLIP) and compass gait biped, to generate and transition between locomotive gaits. These examples show that piecewise jumps in control parameters can be used to achieve stable changes in desired gait characteristics dynamically/online.

A Self-Contained 3D Biomechanical Analysis Lab for Complete Automatic Spine and Full Skeleton Assessment of Posture, Gait and Run.

Quantitative functional assessment of Posture and Motion Analysis of the entire skeleton and spine is highly desirable. Nonetheless, in most studies focused on posture and movement biomechanics, the spine is only grossly depicted because of its required level of complexity. Approaches integrating pressure measurement devices with stereophotogrammetric systems have been presented in the literature, but spine biomechanics studies have rarely been linked to baropodometry. A new multi-sensor system called GOALS-E.G.G. (Global Opto-electronic Approach for Locomotion and Spine-Expert Gait Guru), integrating a fully genlock-synched baropodometric treadmill with a stereophotogrammetric device, is introduced to overcome the above-described limitations. The GOALS-EGG extends the features of a complete 3D parametric biomechanical skeleton model, developed in an original way for static 3D posture analysis, to kinematic and kinetic analysis of movement, gait and run. By integrating baropodometric data, the model allows the estimation of lower limb net-joint forces, torques and muscle power. Net forces and torques are also assessed at intervertebral levels. All the elaborations are completely automatised up to the mean behaviour extraction for both posture and cyclic-repetitive tasks, allowing the clinician/researcher to perform, per each patient, multiple postural/movement tests and compare them in a unified statistically reliable framework.

Mechanical rotation at low Reynolds number via reinforcement learning

There is growing interest in the development of artificial microscopic machines that can perform complex maneuvers like swimming microorganisms for potential biomedical applications. At the microscopic scales, the dominance of viscous over inertial forces imposes stringent constraints on locomotion. In the absence of inertia, Purcell first proposed an elegant way to generate net translation using kinematically irreversible motions [E. M. Purcell, “Life at low Reynolds number,” Am. J. Phys. 45, 3–11 (1977)]. In addition to net translation, a more recent prototype known as Purcell's “rotator” has been proposed in Dreyfus et al. [“Purcell's “rotator”: Mechanical rotation at low Reynolds number,” Eur. Phys. J. B 47, 161–164 (2005)] as a mechanical implementation of net rotation at low Reynolds numbers. These ingenious designs rely on knowledge of the surrounding environment and the physics of locomotion within the environment, which may be incomplete or unclear in more complex scenarios. More recently, reinforcement learning has been used as an alternative approach to enable a machine to learn effective locomotory gaits for net translation based on its interaction with the surroundings. In this work, we demonstrate the use of reinforcement learning to generate net mechanical rotation at low Reynolds numbers without requiring prior knowledge of locomotion. For a three-sphere configuration, the reinforcement learning recovers the strategy proposed by Dreyfus et al. As the number of spheres increases, multiple effective rotational strategies emerge from the learning process. However, given sufficiently long learning processes, all machines considered in this work converge to a single type of rotational policies that consist of traveling waves of actuation, suggesting its optimality of the strategy in generating net rotation at low Reynolds numbers.

A QTL for conformation of back and croup influences lateral gait quality in Icelandic horses

BackgroundThe back plays a vital role in horse locomotion, where the spine functions as a spring during the stride cycle. A complex interaction between the spine and the muscles of the back contribute to locomotion soundness, gait ability, and performance of riding and racehorses. Conformation is commonly used to select horses for breeding and performance in multiple horse breeds, where the back and croup conformation plays a significant role. The conformation of back and croup plays an important role on riding ability in Icelandic horses. However, the genes behind this trait are still unknown. Therefore, the aim of this study was to identify genomic regions associated with conformation of back and croup in Icelandic horses and to investigate their effects on riding ability. One hundred seventy-seven assessed Icelandic horses were included in the study. A genome-wide association analysis was performed using the 670 K+ Axiom Equine Genotyping Array, and the effects of different haplotypes in the top associated region were estimated for riding ability and additional conformation traits assessed during breeding field tests.ResultsA suggestive quantitative trait loci (QTL) for the score of back and croup was detected on Equus caballus (ECA) 22 (p-value = 2.67 × 10− 7). Haplotype analysis revealed two opposite haplotypes, which resulted in higher and lower scores of the back and croup, respectively (p-value < 0.001). Horses with the favorable haplotype were more inclined to have a well-balanced backline with an uphill conformation and had, on average, higher scores for the lateral gaits tölt (p-value = 0.02) and pace (p-value = 0.004). This genomic region harbors three genes: C20orf85, ANKRD60 and LOC100056167. ANKRD60 is associated with body height in humans. C20orf85 and ANKRD60 are potentially linked to adolescent idiopathic scoliosis in humans.ConclusionsOur results show that the detected QTL for conformation of back and croup is of importance for quality of lateral gaits in Icelandic horses. These findings could result in a genetic test to aid in the selection of breeding horses, thus they are of major interest for horse breeders. The results may also offer a gateway to comparative functional genomics by potentially linking both motor laterality and back inclination in horses with scoliosis in humans.