Influence Motor Control Research Articles

How mind wandering influences motor control: The modulating role of movement difficulty

It has been found that mind wandering can impair motor control. However, it remains unclear whether the impact of mind wandering on motor control is modulated by movement difficulty and its associated neural mechanisms. To address this issue, we manipulated movement difficulty using handedness and finger dexterity separately in two signal-response tasks with identical experiment designs, in which right-handed participants performed key-pressing and key-releasing movements with the specified fingers, and they had to intermittently report whether their attention was “On task” or “Off task.” Key-releasing with the right index finger (RI) had a faster reaction time and stronger contralateral delta-theta (1–7 Hz) functional connectivity than with the left index (LI) in Experiment 1, and mind wandering only reduced the contralateral delta-theta functional connectivity and midfrontal delta-theta activity for key-releasing with RI. Key-pressing with right index and middle fingers (RIR) had a faster reaction time and stronger midfrontal delta-theta activity than with right index and ring fingers (RIR) in Experiment 2, and mind wandering only reduced the midfrontal delta-theta activity for key-pressing with RIM. Theta oscillations are vital in motor control. These findings suggest that mind wandering only impairs the motor control of relatively simple movements without affecting the difficult ones. It supports the notion that mind wandering competes for executive resources with the primary task. Moreover, the quantity of executive resources recruited for a task and how these resources are allocated is contingent upon the task difficulty, which may determine whether mind wandering would interfere with motor control.

Tetrahydrocannabinol and dopamine D1 receptor.

Dopamine is a hormone that is released by the adrenal gland and influences motor control and motivation. Dopamine is known to have 5 receptors which are D1, D2, D3, D4 and D5, which are further categorized into 2 families: D1 family and D2 family. The D1 family is known to play a role in motivation and motor control whereas the D2 family is known to affect attention and sleep. THC, a type of cannabinoid, can lead to feelings of euphoria, anxiety, fear, distrust, or panic. THC is known to affect dopamine in regions such as the anterior cingulate cortex (ACC), and plays a role in fundamental cognitive processes. Although there is a vast amount of research between the relationship of THC on dopamine, there continues to be limited research in relation to THC on dopamine receptors. The D1 receptor plays a role in several essential functions, such as memory, attention, impulse control, regulation of renal function, and locomotion. Accordingly, this review is intended to summarize the relationship between THC and D1 receptors, highlighting key gaps in the literature and avenues for future research.

Subsensory stochastic electrical stimulation targeting muscle afferents alters gait control during locomotor adaptations to haptic perturbations

Subsensory noise stimulation targeting sensory receptors has been shown to improve balance control in healthy and impaired individuals. However, the potential for application of this technique in other contexts is still unknown. Gait control and adaptation rely heavily on the input from proprioceptive organs in the muscles and joints. Here we investigated the use of subsensory noise stimulation as a means to influence motor control by altering proprioception during locomotor adaptations to forces delivered by a robot. The forces increase step length unilaterallyand trigger an adaptive response that restores the original symmetry. Healthy participants performed two adaptation experiments, one with stimulation applied to the hamstring muscles and one without. We found that participants adapted faster but to a lesser extent when undergoing stimulation. We argue that this behavior is because of the dual effect that the stimulation has on the afferents encoding position and velocity in the muscle spindles.

Recent developments in muscle synergy analysis in young people with neurodevelopmental diseases: A Systematic Review.

The central nervous system simplifies motor control by sending motor commands activating groups of muscles, known as synergies. Physiological locomotion can be described as a coordinated recruitment of four to five muscle synergies. The first studies on muscle synergies in patients affected by neurological diseases were on stroke survivors. They showed that synergies can be used as biomarkers for motor impairment as they vary in patients with respect to healthy people. Likewise, muscle synergy analysis has been applied to developmental diseases (DD). The need for a comprehensive view of the present findings is crucial for comparing results achieved so far and promote future directions in the field. In the present review, we screened three scientific databases and selected thirty-six papers investigating muscle synergies extracted from locomotion in children affected by DD. Thirty-one articles investigate how cerebral palsy (CP) influences motor control, the currently exploited method in studying motor control in CP and finally the effects of treatments in these patients in terms of synergies and biomechanics; two articles investigate how muscle synergies vary in Duchenne muscular dystrophy (DMD), and three other articles assess other developmental pathologies, such as chronic and acute neuropathic pain. For CP, most of the studies demonstrate that the number of synergies is lower and that the synergy composition varies in the affected children with respect to normal controls. Still, the predictability of treatment's effects and the etiology of muscle synergy variation are open questions, as it has been reported that treatments minimally modify synergies, even if they improve biomechanics. The application of different algorithms in extracting synergies might bring about more subtle differences. Considering DMD, no correlation was found between non-neural muscle weakness and muscle modules' variation, while in chronic pain a decreased number of synergies was observed as a possible consequence of plastic adaptations. Even if the potential of the synergistic approach for clinical and rehabilitation practices is recognized, there is not full consensus on protocols nor widely accepted guidelines for the systematic clinical adoption of the method in DD. We critically commented on the current findings, on the methodological issues and the relative open points, and on the clinical impact of muscle synergies in neurodevelopmental diseases to fill the gap for applying the method in clinical practice.

Emotional body postures affect inhibitory control only when task-relevant.

A classical theoretical frame to interpret motor reactions to emotional stimuli is that such stimuli, particularly those threat-related, are processed preferentially, i.e., they are capable of capturing and grabbing attention automatically. Research has recently challenged this view, showing that the task relevance of emotional stimuli is crucial to having a reliable behavioral effect. Such evidence indicated that emotional facial expressions do not automatically influence motor responses in healthy young adults, but they do so only when intrinsically pertinent to the ongoing subject's goals. Given the theoretical relevance of these findings, it is essential to assess their generalizability to different, socially relevant emotional stimuli such as emotional body postures. To address this issue, we compared the performance of 36 right-handed participants in two different versions of a Go/No-go task. In the Emotional Discrimination task, participants were required to withhold their responses at the display of emotional body postures (fearful or happy) and to move at the presentation of neutral postures. Differently, in the control task, the same images were shown, but participants had to respond according to the color of the actor/actress' t-shirt, disregarding the emotional content. Results showed that participants made more commission errors (instances in which they moved even though the No-go signal was presented) for happy than fearful body postures in the Emotional Discrimination task. However, this difference disappeared in the control task. Such evidence indicates that, like facial emotion, emotional body expressions do not influence motor control automatically, but only when they are task-relevant.

"Tricking the Brain" Using Immersive Virtual Reality: Modifying the Self-Perception Over Embodied Avatar Influences Motor Cortical Excitability and Action Initiation.

To offer engaging neurorehabilitation training to neurologic patients, motor tasks are often visualized in virtual reality (VR). Recently introduced head-mounted displays (HMDs) allow to realistically mimic the body of the user from a first-person perspective (i.e., avatar) in a highly immersive VR environment. In this immersive environment, users may embody avatars with different body characteristics. Importantly, body characteristics impact how people perform actions. Therefore, alternating body perceptions using immersive VR may be a powerful tool to promote motor activity in neurologic patients. However, the ability of the brain to adapt motor commands based on a perceived modified reality has not yet been fully explored. To fill this gap, we “tricked the brain” using immersive VR and investigated if multisensory feedback modulating the physical properties of an embodied avatar influences motor brain networks and control. Ten healthy participants were immersed in a virtual environment using an HMD, where they saw an avatar from first-person perspective. We slowly transformed the surface of the avatar (i.e., the “skin material”) from human to stone. We enforced this visual change by repetitively touching the real arm of the participant and the arm of the avatar with a (virtual) hammer, while progressively replacing the sound of the hammer against skin with stone hitting sound via loudspeaker. We applied single-pulse transcranial magnetic simulation (TMS) to evaluate changes in motor cortical excitability associated with the illusion. Further, to investigate if the “stone illusion” affected motor control, participants performed a reaching task with the human and stone avatar. Questionnaires assessed the subjectively reported strength of embodiment and illusion. Our results show that participants experienced the “stone arm illusion.” Particularly, they rated their arm as heavier, colder, stiffer, and more insensitive when immersed with the stone than human avatar, without the illusion affecting their experienced feeling of body ownership. Further, the reported illusion strength was associated with enhanced motor cortical excitability and faster movement initiations, indicating that participants may have physically mirrored and compensated for the embodied body characteristics of the stone avatar. Together, immersive VR has the potential to influence motor brain networks by subtly modifying the perception of reality, opening new perspectives for the motor recovery of patients.

Influence of imagery-based suggestions on performance during the training of professional firefighters

AbstractObjectivesFor several decades, a growing number of studies have highlighted that imagery-based suggestions, can efficiently influence motor control and perception. In the present study, we tested whether imagery-based suggestions without hypnotic induction might influence physical resistance performance and effort perception in the context of French firefighters’ usual training.MethodsA group of 18 male firefighters had to keep the wall-sit posture as long as they could while listening to different scripts. In the first condition, imagery was related to Lightness. In the second one, it was related to Heaviness. In the Control condition, they just had to listen and pay attention to series of two-digit numbers.ResultsResults showed that the participants kept the posture longer in the Lightness condition than in the Heaviness one. Furthermore the effort was perceived as less difficult in the Lightness condition in comparison to the Heaviness and the Control ones. Moreover in the Lightness condition, the higher the participants scored in visual and kinesthetic imagery tasks (MIQ-R), the less they rated the exercise as difficult.ConclusionsImagery-based suggestions significantly influenced both physical resistance performance and effort perception without any prior hypnotic induction. Further studies are necessary to better understand the factors that modulate this influence.

Linking Pain and Motor Control: Conceptualization of Movement Deficits in Patients With Painful Conditions.

This Perspective proposes that approaching PRMD from a contemporary motor control perspective will uncover key mechanisms, identify treatment targets, inform assessments, and innovate treatments across sensory-perceptual, cognitive, and motor domains, all of which have the potential to improve movement and functional outcomes in patients with painful conditions.

Trunk Angle Modulates Feedforward and Feedback Control during Single-Limb Squatting.

Trunk positioning and unexpected perturbations are high-risk conditions at the time of anterior cruciate ligament injury. The influence of trunk positioning on motor control responses to perturbation during dynamic performance is not known. We tested the influence of trunk position on feedforward and feedback control during unexpected perturbations while performing a novel single-limb squatting task. We also assessed the degree that feedforward control was predictive of feedback responses. In the flexed trunk condition, there were increased quadriceps (p < 0.026) and gluteus medius long-latency reflexes (p < 0.001) and greater quadriceps-to-hamstrings co-contraction during feedforward (p = 0.017) and feedback (p = 0.007) time bins. Soleus long-latency reflexes increased more than 100% from feedforward muscle activity regardless of trunk condition. Feedforward muscle activity differentially predicted long-latency reflex responses depending on the muscle (R2: 0.47–0.97). These findings support the concept that trunk positioning influences motor control responses to perturbation and that feedback responses may be invariant to the feedforward control strategy.

Frozen in (e)motion: How reactive motor inhibition is influenced by the emotional content of stimuli in healthy and psychiatric populations

Efficient inhibitory control is vital. However, environmental cues can influence motor control especially in an emotional context. One common task to measure inhibitory control is the stop-signal task (SST), which asks participants to respond to go stimuli knowing that on some trials a stop signal will be presented, requiring them to inhibit their response. This paradigm estimates the ability to inhibit already-initiated responses by calculating participants' stop-signal reaction times (SSRT), an index of inhibitory control. Here, we aim to review the existing, often contradictory, evidence on the influence of emotional stimuli on the inhibitory process. We aim to discuss which factors may reveal an interference as well as an advantage of emotional stimuli on action inhibition performance. Finally, we review the existing evidence that has investigated the effect of such stimuli on action inhibition in the psychiatric population. Important factors are the relevance, the intensity and the valence of the emotional stimulus, as well as the affected component of the motor control. From all this evidence, it is clear that understand precisely how emotion is integrated into core executive functions, such as inhibitory control, is essential not only for cognitive neuroscience, but also for refining neurocognitive models of psychopathology.

The effect of experimental pain on the excitability of the corticospinal tract in humans: A systematic review and meta-analysis.

Pain influences motor control. Previous reviews observed that pain reduces the excitability of corticospinal projections to muscles tested with transcranial magnetic stimulation. However, the independent effect of the type of pain models (tonic, phasic), pain location and tissues targeted (e.g. muscle, skin) remains unexplored. The objective of this review was to determine the influence of experimental pain and of different methodological factors on the corticospinal excitability. Three electronic databases were searched: Embase, Pubmed and Web of Science. Meta-analyses were conducted in three consecutive steps to reduce methodological variability: (a) all studies; (b) same pain location; (c) same tissues, pain location and muscle state. Strength of evidence was assessed for each analysis performed. Forty studies were included in the review and 26 in the meta-analysis as it focused only on studies using tonic pain. Overall, there was conflicting/moderate evidence of a diminution of corticospinal excitability during and after tonic pain. When considering only pain location, tonic hand and face pain induced a reduction in corticospinal excitability (limited evidence). Both muscle and cutaneous hand pain reduced corticospinal excitability (limited/conflicting evidence). Similar results were observed for phasic pain (limited evidence). Our results confirm the inhibitory effect of pain on corticospinal excitability for both tonic and phasic pain. This reduction was specific to hand and face pain. Also, both cutaneous and muscle hand pain reduced excitability. The strength of evidence remains limited/conflicting. More high-quality studies are needed to confirm our conclusions. This study adds evidence on the effect of specific factors on the modulation of corticospinal excitability during/after experimental pain. The reduction in corticospinal excitability was driven by hand and face pain. We confirmed previous results that muscle pain reduces corticospinal excitability and provided evidence of a similar effect for cutaneous pain. Both models may inform on the influence of different types of pain on motor control. Future studies are needed to determine the origin of the effect of pain.

Awareness of voluntary action, rather than body ownership, improves motor control

Awareness of the body is essential for accurate motor control. However, how this awareness influences motor control is poorly understood. The awareness of the body includes awareness of visible body parts as one’s own (sense of body ownership) and awareness of voluntary actions over that visible body part (sense of agency). Here, I show that sense of agency over a visible hand improves the initiation of movement, regardless of sense of body ownership. The present study combined the moving rubber hand illusion, which allows experimental manipulation of agency and body ownership, and the finger-tracking paradigm, which allows behavioral quantification of motor control by the ability to coordinate eye with hand movements. This eye–hand coordination requires awareness of the hand to track the hand with the eye. I found that eye–hand coordination is improved when participants experience a sense of agency over a tracked artificial hand, regardless of their sense of body ownership. This improvement was selective for the initiation, but not maintenance, of eye–hand coordination. These results reveal that the prospective experience of explicit sense of agency improves motor control, suggesting that artificial manipulation of prospective agency may be beneficial to rehabilitation and sports training techniques.

Precisely timed dopamine signals establish distinct kinematic representations of skilled movements.

Brain dopamine is critical for normal motor control, as evidenced by its importance in Parkinson Disease and related disorders. Current hypotheses are that dopamine influences motor control by 'invigorating' movements and regulating motor learning. Most evidence for these aspects of dopamine function comes from simple tasks (e.g. lever pressing). Therefore, the influence of dopamine on motor skills requiring multi-joint coordination is unknown. To determine the effects of precisely timed dopamine manipulations on the performance of a complex, finely coordinated dexterous skill, we optogenetically stimulated or inhibited midbrain dopamine neurons as rats performed a skilled reaching task. We found that reach kinematics and coordination between gross and fine movements progressively changed with repeated manipulations. However, once established, rats transitioned abruptly between aberrant and baseline reach kinematics in a dopamine-dependent manner. These results suggest that precisely timed dopamine signals have immediate and long-term influences on motor skill performance, distinct from simply 'invigorating' movement.

Integration of Swimming-Related Synaptic Excitation and Inhibition by olig2+ Eurydendroid Neurons in Larval Zebrafish Cerebellum.

The cerebellum influences motor control through Purkinje target neurons, which transmit cerebellar output. Such output is required, for instance, for larval zebrafish to learn conditioned fictive swimming. The output cells, called eurydendroid neurons (ENs) in teleost fish, are inhibited by Purkinje cells and excited by parallel fibers. Here, we investigated the electrophysiological properties of glutamatergic ENs labeled by the transcription factor olig2. Action potential firing and synaptic responses were recorded in current clamp and voltage clamp from olig2+ neurons in immobilized larval zebrafish (before sexual differentiation) and were correlated with motor behavior by simultaneous recording of fictive swimming. In the absence of swimming, olig2+ ENs had basal firing rates near 8 spikes/s, and EPSCs and IPSCs were evident. Comparing Purkinje firing rates and eurydendroid IPSC rates indicated that 1-3 Purkinje cells converge onto each EN. Optogenetically suppressing Purkinje simple spikes, while preserving complex spikes, suggested that eurydendroid IPSC size depended on presynaptic spike duration rather than amplitude. During swimming, EPSC and IPSC rates increased. Total excitatory and inhibitory currents during sensory-evoked swimming were both more than double those during spontaneous swimming. During both spontaneous and sensory-evoked swimming, the total inhibitory current was more than threefold larger than the excitatory current. Firing rates of ENs nevertheless increased, suggesting that the relative timing of IPSCs and EPSCs may permit excitation to drive additional eurydendroid spikes. The data indicate that olig2+ cells are ENs whose activity is modulated with locomotion, suiting them to participate in sensorimotor integration associated with cerebellum-dependent learning.SIGNIFICANCE STATEMENT The cerebellum contributes to movements through signals generated by cerebellar output neurons, called eurydendroid neurons (ENs) in fish (cerebellar nuclei in mammals). ENs receive sensory and motor signals from excitatory parallel fibers and inhibitory Purkinje cells. Here, we report electrophysiological recordings from ENs of larval zebrafish that directly illustrate how synaptic inhibition and excitation are integrated by cerebellar output neurons in association with motor behavior. The results demonstrate that inhibitory and excitatory drive both increase during fictive swimming, but inhibition greatly exceeds excitation. Firing rates nevertheless increase, providing evidence that synaptic integration promotes cerebellar output during locomotion. The data offer a basis for comparing aspects of cerebellar coding that are conserved and that diverge across vertebrates.

First person – Trace Stay

ABSTRACTFirst Person is a series of interviews with the first authors of a selection of papers published in Disease Models & Mechanisms, helping early-career researchers promote themselves alongside their papers. Trace Stay is first author on ‘In vivo cerebellar circuit function is disrupted in an mdx mouse model of Duchenne muscular dystrophy’, published in DMM. Trace conducted the research described in this article while a PhD student in Roy V. Sillitoe's lab at the Baylor College of Medicine, Houston, TX, USA. He is now a postdoctoral scholar in the lab of Jennifer L. Raymond at Stanford University, Stanford, CA, USA, investigating how the cerebellum interacts with sensory input to influence motor control and more cognitive processing.

Effects of Sensorimotor Rhythm Modulation on the Human Flexor Carpi Radialis H-Reflex.

People can learn over training sessions to increase or decrease sensorimotor rhythms (SMRs) in the electroencephalogram (EEG). Activity-dependent brain plasticity is thought to guide spinal plasticity during motor skill learning; thus, SMR training may affect spinal reflexes and thereby influence motor control. To test this hypothesis, we investigated the effects of learned mu (8–13 Hz) SMR modulation on the flexor carpi radialis (FCR) H-reflex in 6 subjects with no known neurological conditions and 2 subjects with chronic incomplete spinal cord injury (SCI). All subjects had learned and practiced over more than 10 < 30-min training sessions to increase (SMR-up trials) and decrease (SMR-down trials) mu-rhythm amplitude over the hand/arm area of left sensorimotor cortex with ≥80% accuracy. Right FCR H-reflexes were elicited at random times during SMR-up and SMR-down trials, and in between trials. SMR modulation affected H-reflex size. In all the neurologically normal subjects, the H-reflex was significantly larger [116% ± 6 (mean ± SE)] during SMR-up trials than between trials, and significantly smaller (92% ± 1) during SMR-down trials than between trials (p < 0.05 for both, paired t-test). One subject with SCI showed similar H-reflex size dependence (high for SMR-up trials, low for SMR-down trials): the other subject with SCI showed no dependence. These results support the hypothesis that SMR modulation has predictable effects on spinal reflex excitability in people who are neurologically normal; they also suggest that it might be used to enhance therapies that seek to improve functional recovery in some individuals with SCI or other CNS disorders.

The effect of fidget spinners on fine motor control

Fidgeting, defined as the generation of small movements through nervousness or impatience, is one of cardinal characteristic of ADHD. While fidgeting is, by definition, a motor experience still nothing is known about the effects of fidgeting on motor control. Some forms of fidgeting involve also the manipulation of external objects which, through repetition, may become automatic and second nature. Both repetition and practice are important for the acquisition of motor skills and, therefore, it is plausible that the repetitive manipulation of objects may influence motor control and performance. As such, fidget spinners, by being diffuse and prone to repetitive usage, may represent interesting tool for improving motor control. In this study we examine the effect of fidget spinners on fine motor control, evaluated by a spiral-tracing task. We show that the use of fidget spinner indeed seems to have a favorable effect on fine motor control, at least in the short term, although this effect does not seem to be in any way inherent to fidget spinners themselves as much as to object manipulation in general. However, due to their widespread usage, fidget spinner may have the advantage of being an enjoyable means for improving fine motor control.

Laterality recognition of images, motor performance, and aspects related to pain in participants with and without wrist/hand disorders: An observational cross-sectional study

ObjectiveMusculoskeletal disorders are associated with altered sensory, proprioceptive and cognitive processes. Sensory processes affect the internal cortical representation of the body in space, the body schema, which in turn influences motor control. The purpose of this study was to determine if participants with wrist/hand disorders had impaired performance on a task associated with the body schema, the Left/Right Judgement Task (LRJT) and secondly how LRJT performance, motor performance, disability, pain and related aspects are associated. MethodsFifteen healthy control participants and 15 participants with hand/wrist pain were asked to determine the laterality of images of hands. Measures of motor performance (Purdue Pegboard test), self-reported disability (Australian Canadian Hand Index), and pain related aspects (pain intensity, symptom duration, pain interference and affective distress) were recorded. ResultsParticipants with wrist/hand pain scored lower on all segments of the Purdue Pegboard test. There were differences in LRJT performance between groups for both Accuracy (p = 0.03) and Reaction Time (RT) (p < 0.01). There was no correlation between RT and Accuracy with pain intensity, pain duration, and disability. Both motor performance (r = 0.58–0.64) and LRJT performance Accuracy (r = 0.59) and RT (r = −0.56) were correlated with affective distress. A significant correlation was observed between RT and motor performance in healthy control participants (r = −0.56, p = 0.03) but not in participants with wrist/hand pain (r = −0.26, p = 0.44). ConclusionsLRJT and motor performance was correlated with affective distress in participants with wrist/hand pain suggestive of complex interactions between cognitive-affective processes and sensorimotor integration.

Motor dexterity and strength depend upon integrity of the attention-control system

Attention control (or executive control) is a higher cognitive function involved in response selection and inhibition, through close interactions with the motor system. Here, we tested whether influences of attention control are also seen on lower level motor functions of dexterity and strength-by examining relationships between attention control and motor performance in healthy-aged and hemiparetic-stroke subjects (n = 93 and 167, respectively). Subjects undertook simple-tracking, precision-hold, and maximum force-generation tasks, with each hand. Performance across all tasks correlated strongly with attention control (measured as distractor resistance), independently of factors such as baseline performance, hand use, lesion size, mood, fatigue, or whether distraction was tested during motor or nonmotor cognitive tasks. Critically, asymmetric dissociations occurred in all tasks, in that severe motor impairment coexisted with normal (or impaired) attention control whereas normal motor performance was never associated with impaired attention control (below a task-dependent threshold). This implies that dexterity and force generation require intact attention control. Subsequently, we examined how motor and attention-control performance mapped to lesion location and cerebral functional connectivity. One component of motor performance (common to both arms), as well as attention control, correlated with the anatomical and functional integrity of a cingulo-opercular "salience" network. Independently of this, motor performance difference between arms correlated negatively with the integrity of the primary sensorimotor network and corticospinal tract. These results suggest that the salience network, and its attention-control function, are necessary for virtually all volitional motor acts while its damage contributes significantly to the cardinal motor deficits of stroke.

Rehabilitation for Shoulder Instability - Current Approaches.

Background:The shoulder relies predominantly on dynamic muscular control to provide stability. Successful treatment is highly dependent upon the correct clinical diagnosis, identification of anatomical structural defects and abnormal movement patterns so that rehabilitation programs can be designed accordingly and individualised to the patient.Method: A systematic outline is provided to guide the clinician on how to identify muscular insufficiencies both local to the shoulder joint and global muscles that can influence shoulder instability. Management is based on expert experience and current literature.Results:The Stanmore classification helps to correctly diagnose the type of instability and prioritise management. Symptom modification tests can help to guide management, however assessing individual muscle groups local to glenohumeral control is also recommended.Conclusion:Physical and psychosocial factors can influence motor control in the presence of pain and injury. A multi-disciplinary approach is required to avoid recurrence of symptoms with rehabilitation focusing on kinetic chain, scapular and gleno-humeral control.