• rehabilitation
• biomedical engineering

• Humans
• Robotics
• Aged
• Male
• Female
• Gait/physiology
• Walking/physiology
• Sitting Position
• Wearable Electronic Devices
• Arm/physiology
• Biomechanical Phenomena
• Accidental Falls/prevention & control

• JP24K00844 Japan Society for the Promotion of Science, Japan

• auditory imagery
• electroencephalography
• neural entrainment
• proficient imagers
• sensorimotor synchronization
• visual imagery

• Humans
• Male
• Female
• Imagination/physiology
• Young Adult
• Adult
• Electroencephalography/methods
• Psychomotor Performance/physiology
• Auditory Perception/physiology
• Acoustic Stimulation/methods
• Visual Perception/physiology
• Electromyography
• Photic Stimulation/methods

• P20 GM103650 NIGMS NIH HHS
• P20GM103650 NIGMS NIH HHS

• Hamstring extensibility
• Hamstring flexibility
• Movement asymmetry
• Musculoskeletal dysfunction

• arm‐leg coupling
• assistive device
• biomechanics
• lower limb disorder
• neural coupling
• spinal cord injury
• walking

• Humans
• Spinal Cord Injuries/rehabilitation
• Spinal Cord Injuries/physiopathology
• Gait/physiology
• Arm/physiology
• Leg
• Walking/physiology
• Biomechanical Phenomena/physiology
• Self-Help Devices
• Gait Disorders, Neurologic/rehabilitation
• Gait Disorders, Neurologic/physiopathology

• cutaneous reflexes
• interlimb coordination
• locomotion
• spinal cord injury

• Animals
• Cats
• Hindlimb/physiology
• Forelimb/physiology
• Reflex/physiology
• Locomotion/physiology
• Muscle, Skeletal/physiology
• Spinal Cord Injuries/physiopathology
• Movement/physiology
• Female
• Male
• Skin/innervation

• R01 NS110550 NINDS NIH HHS

• Cross education
• directionality of global training
• rehabilitation
• unilateral training

• Middle Aged
• Humans
• Female
• Leg/physiology
• Resistance Training
• Exercise/physiology
• Knee/physiology
• Lower Extremity
• Muscle, Skeletal/physiology
• Muscle Strength/physiology
• Isometric Contraction/physiology

• neurology
• neurological disorders
• parkinson's disease
• motor control
• bone quality and biomechanics

• Humans
• Levodopa/pharmacology
• Levodopa/therapeutic use
• Biomechanical Phenomena
• Dopamine
• Upper Extremity
• Acceleration
• Parkinson Disease/drug therapy

• CDS 000606 Ministero Sviluppo Economico; Contratto di sviluppo industriale Farmaceutica e Diagnostica
• (Investimento 3.1.M4. C2), project IR0000011 European Union "NextGenerationEU", EBRAINS-Italy of PNRR
• No. 945539 (SGA3) European Union's Horizon 2020
• 826421 Human Brain Project
• European Union “NextGenerationEU”, EBRAINS-Italy of PNRR
• European Union’s Horizon 2020

• GAITRite® Walkway System
• bipedal locomotion
• cell phone
• evolutionary biology
• gait

• TUG
• gait
• instrumented timed-up-and-go
• joint velocity
• motor control
• polyneuropathy
• whole-body motion capture

• Cerebral palsy
• Cycling
• Pendulum test
• Presynaptic inhibition
• Spasticity

• cutaneous reflexes
• interlimb coordination
• locomotion
• modulation
• split-belt treadmill

• R01 NS110550 NINDS NIH HHS
• Natural Sciences and Engineering Research Council of Canada
• National Institutes of Health

• H-reflex
• Lokomat
• Robotic gait orthosis
• Somatosensory input
• Transcranial magnetic stimulation

• H-reflex
• hyperreflexia
• locomotion
• spinal reflexes
• task-dependent modulation

• P2C HD086844 NICHD NIH HHS
• P41 EB018783 NIBIB NIH HHS
• R01 NS114279 NINDS NIH HHS
• U01 NS108916 NINDS NIH HHS
• Medical University of South Carolina | Doscher Neurorehabilitation Research Program
• New York State Spinal Cord Injury Research Trust
• HHS | NIH | National Institute of Biomedical Imaging and Bioengineering (NIBIB)
• HHS | NIH | National Institute of Neurological Disorders and Stroke (NINDS)
• South Carolina Spinal Cord Injury Research Fund (SCIRF)
• HHS | NIH | Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

• cervical spinal cord injury
• electrical stimulation
• epidural
• motor evoked potentials
• myelopathy

• Animals
• Humans
• Electromyography
• Spinal Cord/physiology
• Muscle, Skeletal/physiology
• Forelimb
• Spinal Cord Injuries
• Electric Stimulation
• Spinal Cord Stimulation

• R01 NS124224 NINDS NIH HHS
• 1R01NS124224 NINDS NIH HHS
• HHS | NIH | National Institute of Neurological Disorders and Stroke (NINDS)
• Travis Roy Foundation (TRF)

• Electromyography
• Humans
• Information Theory
• Muscles
• Stroke
• Stroke Rehabilitation/methods
• Upper Extremity

• R01 HD071978 NICHD NIH HHS
• 1R01HD071978 NIH HHS

• double support
• interlimb
• lower limbs
• poststroke adults
• walking

• Adult
• Biomechanical Phenomena
• Exercise Test
• Gait/physiology
• Humans
• Kinetics
• Walking/physiology
• Young Adult

• UI52102020 Fundação para a Ciência e Tecnologia

• High-density surface EMG
• Locomotion
• Task-dependent

Mimicking the native extracellular matrix (ECM) as a cell culture scaffold has long attracted scientists from the perspective of supramolecular chemistry for potential application in regenerative medicine. However, the development of the next-generation synthetic materials that mimic key aspects of ECM, with hierarchically oriented supramolecular structures, which are simultaneously highly dynamic and responsive to external stimuli, remains a major challenge. Herein, we present supramolecular assemblies formed by motor amphiphiles (MAs), which mimic the structural features of the hydrogel nature of the ECM and additionally show intrinsic dynamic behavior that allow amplifying molecular motions to macroscopic muscle-like actuating functions induced by light. The supramolecular assembly (named artificial muscle) provides an attractive approach for developing responsive ECM mimetic scaffolds for human bone marrow-derived mesenchymal stem cells (hBM-MSCs). Detailed investigations on the photoisomerization by nuclear magnetic resonance and UV–vis absorption spectroscopy, assembled structures by electron microscopy, the photoactuation process, structural order by X-ray diffraction, and cytotoxicity are presented. Artificial muscles of MAs provide fast photoactuation in water based on the hierarchically anisotropic supramolecular structures and show no cytotoxicity. Particularly important, artificial muscles of MAs with adhered hBM-MSCs still can be actuated by external light stimulation, showing their ability to convert light energy into mechanical signals in biocompatible systems. As a proof-of-concept demonstration, these results provide the potential for building photoactuating ECM mimetic scaffolds by artificial muscle-like supramolecular assemblies based on MAs and offer opportunities for signal transduction in future biohybrid systems of cells and MAs.

Background: Interlimb neural coupling implies that arm swing should be included during gait training to improve rehabilitation outcomes. We previously developed several systems for production of walking with arm swing, but the reaction forces on the foot sole during usage of the systems were not satisfactory and there was potential to improve control system performance. This work aimed to design and technically evaluate a novel system for producing walking with synchronised arm and leg movement and with dynamic force loading on the foot soles.

Methods: The robotic system included a passive curved treadmill and a trunk frame, upon which the rigs for the upper and lower limbs were mounted. Ten actuators and servocontrollers with EtherCAT communication protocol controlled the bilateral shoulder, elbow, hip, knee and ankle joints. Impedance control algorithms were developed and ran in an industrial PC. Flexible pressure sensors recorded the plantar forces on the foot soles. The criteria of implementation and responsiveness were used to formally evaluate the technical feasibility of the system.

Results: Using impedance algorithms, the system produced synchronous walking with arm swing on the curved treadmill, with mean RMS angular tracking error <2° in the 10 joint profiles. The foot trajectories relative to the hip presented similar shapes to those during normal gait, with mean RMS displacement error <1.5 cm. A force pattern that started at the heel and finished at the forefoot was observed during walking using the system, which was similar to the pattern from overground walking.

Conclusion: The robotic system produced walking-like kinematics in the 10 joints and in the foot trajectories. Integrated with the curved treadmill, the system also produced walking-like force patterns on the foot soles. The system is considered feasible as far as implementation and responsiveness are concerned. Future work will focus on improvement of the mechanical system for future clinical application.

• Balance and stability
• CPG
• EMG patterns
• Equilibrium-point hypothesis
• Human locomotion
• Posture-movement problem
• Referent body configuration

Most human movements require coordinated activation of multiple muscles. Although many studies reported associations between arm, leg, and trunk muscles during functional tasks, their neural interaction mechanisms still remain unclear. Therefore, the aim of our study was to investigate arm-trunk or arm-leg neural interactions in the corticospinal tract during different arm muscle contractions. Specifically, we examined corticospinal excitability of the erector spinae (ES; trunk extensor), rectus abdominis (RA; trunk flexor), and tibialis anterior (TA; leg) muscles while participants exerted: (1) wrist flexion and (2) wrist extension isometric contraction at various contraction intensity levels ranging from rest to 50% of maximal voluntary contraction (MVC) effort. Corticospinal excitability was assessed using motor evoked potentials (MEPs) elicited through motor cortex transcranial magnetic stimulation (TMS). Results showed that ES MEPs were facilitated even at low contractions (>5% MVC) during wrist flexion and extension, while stronger contractions (>25% MVC) were required to facilitate RA MEPs. The extent of facilitation of ES MEPs depended on contraction intensity of wrist extension, but not flexion. Moreover, TA MEPs were facilitated at low contractions (>5% MVC) during wrist flexion and extension, but contraction intensity dependence was only shown during stronger wrist extension contractions (>25% MVC). In conclusion, trunk extensor corticospinal excitability seems to depend on the task and the intensity of arm contraction, while this is not true for trunk flexor and leg muscles. Our study therefore demonstrated task- and intensity-dependent neural interactions of arm-trunk connections, which may underlie anatomic and/or functional substrates of these muscle pairs.

• arm-trunk interaction
• corticospinal pathway
• motor evoked potential
• transcranial magnetic stimulation

• Body stability
• Dynamic balance
• Kinesthesia
• Plantar sensation
• Postural control

• Aged
• Aged, 80 and over
• Female
• Humans
• Lower Extremity/innervation
• Lower Extremity/physiology
• Male
• Muscle Strength/physiology
• Postural Balance/physiology
• Proprioception/physiology

• abobotulotoxin
• central pattern generator
• cerebral palsy
• locomotion
• spasticity

• Motor behaviour
• Motor control
• Pedal rate
• Preferred pedalling frequency
• Rhythmic movement

• PNF
• Total Hip Arthroplasty
• clinical reasoning
• gait rehabilitation
• motor control
• motor learning

• Arms
• Assistive device
• Coordination
• Energetics
• Gait rehabilitation
• Legs
• Locomotion biomechanics
• Walking

For patients with gait impairment due to neurological disorders, body weight-supported treadmill training (BWSTT) has been widely used for gait rehabilitation. On a conventional (passive) treadmill that runs at a constant speed, however, the level of patient engagement and cortical activity decreased compared with gait training on the ground. To increase the level of cognitive engagement and brain activity during gait rehabilitation, a self-paced (active) treadmill is introduced to allow patients to actively control walking speed, as with overground walking.

To validate the effects of self-paced treadmill walking on cortical activities, this paper presents a clinical test with stroke survivors. We hypothesized that cortical activities on the affected side of the brain would also increase during active walking because patients have to match the target walking speed with the affected lower limbs. Thus, asymmetric gait patterns such as limping or hobbling might also decrease during active walking.

Although the clinical test was conducted in a short period, the patients showed higher cognitive engagement, improved brain activities assessed by electroencephalography (EEG), and decreased gait asymmetry with the self-paced treadmill. As expected, increases in the spectral power of the low γ and β bands in the prefrontal cortex (PFC), premotor cortex (PMC), and supramarginal gyrus (SG) were found, which are possibly related to processing sensory data and planning voluntary movements. In addition, these changes in cortical activities were also found with the affected lower limbs during the swing phase. Since our treadmill controller tracked the swing speed of the leg to control walking speed, such results imply that subjects made substantial effort to control their affected legs in the swing phase to match the target walking speed.

The patients also showed reduced gait asymmetry patterns. Based on the results, the self-paced gait training system has the potential to train the symmetric gait and to promote the related cortical activities after stroke.

Trial registration Not applicable

• Cortical activation
• Electroencephalography
• Gait asymmetry
• Gait training
• Self-paced treadmill
• Stroke rehabilitation

• adaptation
• bipedal walking
• cutaneous afferents
• human
• locomotor network

• interlimb neural coupling
• locomotion
• spinal reflex

This study evaluates the effect of combined epidural electrical stimulation (EES) applied above (C5) and below (L2) the spinal cord injury (SCI) at T8–9 combined with motor training on the restoration of sensorimotor function in mini pigs. The motor evoked potentials (MEP) induced by EES applied at C5 and L2 levels were recorded in soleus muscles before and two weeks after SCI. EES treatment started two weeks after SCI and continued for 6 weeks led to improvement in multiple metrics, including behavioral, electrophysiological, and joint kinematics outcomes. In control animals after SCI a multiphasic M-response was observed during M/H-response testing, while animals received EES-enable training demonstrated the restoration of the M-response and H-reflex, although at a lower amplitude. The joint kinematic and assessment with Porcine Thoracic Injury Behavior scale (PTIBS) motor recovery scale demonstrated improvement in animals that received EES-enable training compared to animals with no treatment. The positive effect of two-level (cervical and lumbar) epidural electrical stimulation on functional restoration in mini pigs following spinal cord contusion injury in mini pigs could be related with facilitation of spinal circuitry at both levels and activation of multisegmental coordination. This approach can be taken as a basis for the future development of neuromodulation and neurorehabilitation therapy for patients with spinal cord injury.

• epidural electrical stimulation
• mini pigs
• spinal cord injury
• translesional network

• Central pattern generator
• Movement
• Neural control
• Sural nerve

• Adult
• Electric Stimulation
• Electromyography
• Female
• Humans
• Leg
• Locomotion
• Male
• Muscle, Skeletal
• Reflex
• Walking

Arm cycling is commonly used in rehabilitation settings for individuals with motor impairments in an attempt to facilitate neural plasticity, potentially leading to enhanced motor function in the affected limb(s). Studies examining the neural control of arm cycling, however, typically cycle using a set cadence and power output. Given the importance of motor output intensity, typically represented by the amplitude of electromyographic (EMG) activity, on neural excitability, surprisingly little is known about how arm muscle activity is modulated using relative workloads. Thus, the objective of this study was to characterize arm muscle activity during arm cycling at different relative workloads. Participants (n = 11) first completed a 10-second maximal arm ergometry sprint to determine peak power output (PPO) followed by 11 randomized trials of 20-second arm cycling bouts ranging from 5–50% of PPO (5% increments) and a standard 25 W workload. All submaximal trials were completed at 60 rpm. Integrated EMG amplitude (iEMG) was assessed from the biceps brachii, brachioradialis, triceps brachii, flexor carpi radialis, extensor carpi radialis and anterior deltoid of the dominant arm. Arm cycling was separated into two phases, flexion and extension, relative to the elbow joint for all comparisons. As expected, iEMG amplitude increased during both phases of cycling for all muscles examined. With the exception of the triceps brachii and extensor carpi radialis, iEMG amplitudes differed between the flexion and extension phases. Finally, there was a linear relationship between iEMG amplitude and the %PPO for all muscles during both elbow flexion and extension.

• Cycling
• Elbow extension
• Elbow flexion
• Electromyography
• Sprint
• Upper-limb

• Performance
• exertion
• mental rehearsal
• motor cognition

• Adult
• Energy Metabolism
• Exercise/physiology
• Exercise/psychology
• Female
• Heart Rate/physiology
• Humans
• Imagination
• Lactic Acid/blood
• Male
• Muscle Fatigue/physiology
• Oxygen Consumption/physiology
• Perception/physiology
• Physical Exertion/physiology
• Psychometrics
• Self Report
• Young Adult

The first years of life represent an important phase of maturation of the central nervous system, processing of sensory information, posture control and acquisition of the locomotor function. Cerebral palsy (CP) is the most common group of motor disorders in childhood attributed to disturbances in the fetal or infant brain, frequently resulting in impaired gait. Here we will consider various findings about functional maturation of the locomotor output in early infancy, and how much the dysfunction of gait in children with CP can be related to spinal neuronal networks vs. supraspinal dysfunction. A better knowledge about pattern generation circuitries in infancy may improve our understanding of developmental motor disorders, highlighting the necessity for regulating the functional properties of abnormally developed neuronal locomotor networks as a target for early sensorimotor rehabilitation. Various clinical approaches and advances in biotechnology are also considered that might promote acquisition of the locomotor function in infants at risk for locomotor delays.

• abnormal development
• cerebral palsy
• early development of locomotion
• neuromuscular pattern generation
• rehabilitation
• spinal locomotor output

• cutaneous
• fatigue
• motor neuron
• spinal cord
• submaximal

• excitability
• finger tapping frequency
• modulatory effects
• movement priming

• Spinal cord injury
• calcium
• contusion
• locomotion
• magnetic field stimulation
• pain

• cutaneous reflex
• locomotion
• neural control
• sensory feedback
• walking

• Cross-education
• cutaneous
• electrical stimulation
• electromyography
• plasticity
• reflexes
• resistance training

• Adult
• Electric Stimulation
• Electromyography
• Feedback, Sensory
• Female
• Humans
• Male
• Muscle Contraction
• Muscle Strength
• Muscle, Skeletal/physiology
• Reflex
• Wrist/physiology
• Young Adult

• Heart and Stroke Foundation of Canada
• Natural Sciences and Engineering Research Council of Canada

Evaluating the strength of the small muscles of the foot may be useful in a variety of clinical applications but is challenging from a methodology standpoint. Previous efforts have focused primarily on the functional movement of toe flexion, but clear methodology guidelines are lacking. A novel foot doming test has also been proposed, but not fully evaluated. The purposes of the present study were to assess the repeatability and comparability of several functional foot strength assessment techniques.

Forty healthy volunteers were evaluated across two testing days, with a two-week doming motion practice period between them. Seven different measurements were taken using a custom toe flexion dynamometer (seated), custom doming dynamometer (standing), and a pressure mat (standing). Measurements from the doming dynamometer were evaluated for reliability (ICCs) and a learning effect (paired t-tests), while measurements from the toe flexion dynamometer and pressure mat were evaluated for reliability and comparability (correlations). Electromyography was also used to descriptively assess the extent of muscle isolation in all measurements.

Doming showed excellent within-session reliability (ICCs > 0.944), but a clear learning effect was present, with strength (p < 0.001) and muscle activity increasing between sessions. Both intrinsic and extrinsic muscles were engaged during this test. All toe flexion tests also showed excellent reliability (ICCs > 0.945). Seated toe flexion tests using the dynamometer were moderately correlated to standing toe flexion tests on a pressure mat (r > 0.54); however, there were some differences in muscle activity. The former may better isolate the toe flexors, while the latter appeared to be more functional for many pathologies. On the pressure mat, reciprocal motion appeared to display slightly greater forces and reliability than isolated toe flexion.

This study further refines potential methodology for foot strength testing. These devices and protocols can be duplicated in the clinic to evaluate and monitor rehabilitation progress in clinical populations associated with foot muscle weakness.

• Doming
• Extrinsic foot muscles
• Intrinsic foot muscles
• Short foot exercise
• Toe flexion

Over the expanse of evolutionary history, humans, and predecessor Homo species, ran to survive. This legacy is reflected in many deeply and irrevocably embedded neurological and biological design features, features which shape how we run, yet were themselves shaped by running.

Smoothness is a widely recognised feature of healthy, proficient movement. Nevertheless, although the term ‘smoothness’ is commonly used to describe skilled athletic movement within practical sporting contexts, it is rarely specifically defined, is rarely quantified and remains barely explored experimentally. Elsewhere, however, within various health-related and neuro-physiological domains, many manifestations of movement smoothness have been extensively investigated. Within this literature, smoothness is considered a reflection of a healthy central nervous system (CNS) and is implicitly associated with practiced coordinated proficiency; ‘non-smooth’ movement, in contrast, is considered a consequence of pathological, un-practiced or otherwise inhibited motor control.

Despite the ubiquity of running across human cultures, however, and the apparent importance of smoothness as a fundamental feature of healthy movement control, to date, no theoretical framework linking the phenomenon of movement smoothness to running proficiency has been proposed. Such a framework could, however, provide a novel lens through which to contextualise the deep underlying nature of coordinated running control. Here, we consider the relevant evidence and suggest how running smoothness may integrate with other related concepts such as complexity, entropy and variability. Finally, we suggest that these insights may provide new means of coherently conceptualising running coordination, may guide future research directions, and may productively inform practical coaching philosophies.