The effects of periodic and noisy tendon vibration on a kinesthetic targeting task.

Tendon vibration is used extensively to assess the role of peripheral mechanoreceptors in motor control, specifically, the muscle spindles. Periodic tendon vibration is known to activate muscle spindles and induce a kinesthetic illusion that the vibrated muscle is longer than it actually is. Noisy tendon vibration has been used to assess the frequency characteristics of proprioceptive reflex pathways during standing; however, it is unknown if it induces the same kinesthetic illusions as periodic vibration. The purpose of the current study was to assess the effects of both periodic and noisy tendon vibration in a kinesthetic targeting task. Participants (N = 15) made wrist extension movements to a series of visual targets without vision of the limb, while their wrist flexors were either vibrated with periodic vibration (20, 40, 60, 80, and 100 Hz), or with noisy vibration which consisted of filtered white noise with power between ~ 20 and 100 Hz. Overall, our results indicate that both periodic and noisy vibration can induce robust targeting errors during a wrist targeting task. Specifically, the vibration resulted in an undershooting error when moving to the target. The findings from this study have important implications for the use of noisy tendon vibration to assess proprioceptive reflex pathways and should be considered when designing future studies using noisy vibration.

Acute Stress Does Not Affect Motor Imagery Ability in Young, Healthy Participants: A Randomized Trial.

Motor imagery (MI) is the mental representation of a movement without its execution. It activates internal representations of the movement without external stimulus through different memory-related processes. Although acute stress is frequent in the population and affects supraspinal structures essential for memory functionality, it is still unknown how that stress affects MI capacity and temporal congruence (TC) between execution and movement imagination. This study aimed to discover how acute stress may influence MI capacity and TC in the subscales of internal and external visual imagery and kinesthetic imagery. A double-blind, randomized trial was conducted. Sixty-two young, healthy subjects (mean age = 20.65 [2.54]; 39 females and 23 males) unfamiliar with the assessment and uses of MI were recruited. Participants were assigned by stratified randomization to the stress group or the control group. Stress was induced by the Maastricht Acute Stress Test (MAST), while the control group performed the MAST control protocol. MI capacity and TC were assessed before (t1) and after (t2) MAST stress or control using the Movement Imagery Questionnaire-3 (MIQ-3). Electrodermal activity and heart rate variability were further recorded as control variables to assess stress induction. Thirty subjects in the stress group and 26 subjects in the control group were analyzed. No significant group differences were observed when comparing MI capacity or TC in any subscales. These findings suggest that acute stress does not significantly affect MI capacity or TC in young, healthy, non-experienced MI subjects. MI could thus be a relevant helpful technique in stressful situations.

The effect of a neck-specific exercise program on cervical kinesthesia for patients with chronic whiplash-associated disorders: a case-control study.

INTRODUCTION: Cervical kinesthesia is an important part of movement control and of great importance for daily function. Previous research on kinesthesia in whiplash-associated disorders (WAD) has focused on grades I-II. More research is needed on WAD grade III. The aim of this study was to investigate cervical kinesthesia in individuals with WAD grades II-III before and after a neck-specific exercise intervention and compare them to healthy controls. METHODS: A prospective, case-control study with a treatment arm (n = 30) and a healthy control arm (n = 30) was conducted in Sweden. The WAD group received a neck-specific exercise program for 12 weeks. The primary outcome to evaluate kinesthesia was neck movement control (the Fly test). Secondary outcomes were neck disability, dizziness and neck pain intensity before and after the Fly test. Outcomes were measured at baseline and post-treatment. The control arm underwent measurements at baseline except for the dizziness questionnaire. A linear mixed model was used to evaluate difference between groups (WAD and control) and over time, with difficulty level in the Fly test and gender as factors. RESULTS: Between-group analysis showed statistically significant differences in three out of five kinesthetic metrics (p = 0.002 to 0.008), but not for the WAD-group follow-up versus healthy control baseline measurements. Results showed significant improvements for the WAD-group over time for three out of five kinaesthesia metrics (p < 0.001 to 0.008) and for neck disability (p < 0.001) and pain (p = 0.005), but not for dizziness (p = 0.70). CONCLUSIONS: The exercise program shows promising results in improving kinesthesia and reducing neck pain and disability in the chronic WAD phase. Future research might benefit from focusing on adding kinesthetic exercises to the exercise protocol and evaluating its beneficial effects on dizziness or further improvement in kinesthesia. IMPACT STATEMENT: Kinesthesia can be improved in chronic WAD patients without the use of specific kinesthetic exercises. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03664934), first registration approved 11/09/2018.

Development and Validation of the Combined Action Observation and Motor Imagery Ability Questionnaire.

Combined use of action observation and motor imagery (AOMI) is an increasingly popular motor-simulation intervention, which involves observing movements on video while simultaneously imagining the feeling of movement execution. Measuring and reporting participant imagery-ability characteristics are essential in motor-simulation research, but no measure of AOMI ability currently exists. Accordingly, the AOMI Ability Questionnaire (AOMI-AQ) was developed to address this gap in the literature. In Study 1, two hundred eleven participants completed the AOMI-AQ and the kinesthetic imagery subscales of the Movement Imagery Questionnaire-3 and Vividness of Motor Imagery Questionnaire-2. Following exploratory factor analysis, an 8-item AOMI-AQ was found to correlate positively with existing motor-imagery measures. In Study 2, one hundred seventy-four participants completed the AOMI-AQ for a second time after a period of 7-10 days. Results indicate a good test-retest reliability for the AOMI-AQ. The new AOMI-AQ measure provides a valid and reliable tool for researchers and practitioners wishing to assess AOMI ability.

[The development of kinaesthetic competence in acute inpatient care: a feasibility study with a pre-posttest design]. / Die Entwicklung der Kinästhetikkompetenz in der stationären Akutpflege.

The development of kinaesthetic competence in acute inpatient care: a feasibility study with a pre-posttest design Abstract: Background: Most patients in acute care hospitals experience movement limitations due to surgery or a general deterioration of their condition. Therefore, nurses need a high level of competence in movement promotion. Aim: The aim of this study was to evaluate the feasibility of a three-day advanced kinaesthetics training course followed by six months of practical support to promote kinaesthetic competence in inpatient acute care and the competence development achieved as a result. Methods: The evaluation of the nurses' effectiveness was conducted using a pre- and post-measurement of kinaesthetic competence through a self-assessment questionnaire and an observation protocol. The evaluation of feasibility was done through a semi-structured questionnaire. Results: Eight nurses rated their kinaesthetics competence as good before (mean: 10,8 on a scale of 4-16) and very good after the intervention (mean: 13,2). The kinaesthetics trainer assessed the competence before as sufficient (mean: 9,4 on a scale of 4-16) and very good (mean: 14,5) after the practical support. The need to make practical support more flexible is highlighted in the qualitative data. Conclusion: The results demonstrate that a three-day training followed by six months of practical support has a positive impact on nurses' kinaesthetic competence.

Variation of corticospinal excitability during kinesthetic illusion induced by musculotendinous vibration.

Despite being studied for more than 50 years, the neurophysiological mechanisms underlying vibration (VIB)-induced kinesthetic illusions are still unclear. The aim of this study was to investigate how corticospinal excitability tested by transcranial magnetic stimulation (TMS) is modulated during VIB-induced illusions. Twenty healthy adults received vibration over wrist flexor muscles (80 Hz, 1 mm, 10 s). TMS was applied over the primary motor cortex representation of wrist extensors at 120% of resting motor threshold in four random conditions (10 trials/condition): baseline (without VIB), 1 s, 5 s, and 10 s after VIB onset. Means of motor-evoked potential (MEP) amplitudes and latencies were calculated. Statistical analysis found a significant effect of conditions (stimulation timings) on MEP amplitudes (P = 0.035). Paired-comparisons demonstrated lower corticospinal excitability during VIB at 1 s compared with 5 s (P = 0.025) and 10 s (P = 0.003), although none of them differed from baseline values. Results suggest a time-specific modulation of corticospinal excitability in muscles antagonistic to those vibrated, i.e., muscles involved in the perceived movement. An early decrease of excitability was observed at 1 s followed by a stabilization of values near baseline at subsequent time points. At 1 s, the illusion is not yet perceived or not strong enough to upregulate corticospinal networks coherent with the proprioceptive input. Spinal mechanisms, such as reciprocal inhibition, could also contribute to lower the corticospinal drive of nonvibrated muscles in short period before the illusion emerges. Our results suggest that neuromodulatory effects of VIB are likely time-dependent, and that future work is needed to further investigate underlying mechanisms.NEW & NOTEWORTHY The modulation of corticospinal excitability when perceiving a vibration (VIB)-induced kinesthetic illusion evolves dynamically over time. This modulation might be linked to the delayed occurrence and progressive increase in strength of the illusory perception in the first seconds after VIB start. Different spinal/cortical mechanisms could be at play during VIB, depending on the tested muscle, presence/absence of an illusion, and the specific timing at which corticospinal drive is tested pre/post VIB.

Integration of proprioception in upper limb prostheses through non-invasive strategies: a review.

Proprioception plays a key role in moving our body dexterously and effortlessly. Nevertheless, the majority of investigations evaluating the benefits of providing supplemental feedback to prosthetics users focus on delivering touch restitution. These studies evaluate the influence of touch sensation in an attempt to improve the controllability of current robotic devices. Contrarily, investigations evaluating the capabilities of proprioceptive supplemental feedback have yet to be comprehensively analyzed to the same extent, marking a major gap in knowledge within the current research climate. The non-invasive strategies employed so far to restitute proprioception are reviewed in this work. In the absence of a clearly superior strategy, approaches employing vibrotactile, electrotactile and skin-stretch stimulation achieved better and more consistent results, considering both kinesthetic and grip force information, compared with other strategies or any incidental feedback. Although emulating the richness of the physiological sensory return through artificial feedback is the primary hurdle, measuring its effects to eventually support the integration of cumbersome and energy intensive hardware into commercial prosthetic devices could represent an even greater challenge. Thus, we analyze the strengths and limitations of previous studies and discuss the possible benefits of coupling objective measures, like neurophysiological parameters, as well as measures of prosthesis embodiment and cognitive load with behavioral measures of performance. Such insights aim to provide additional and collateral outcomes to be considered in the experimental design of future investigations of proprioception restitution that could, in the end, allow researchers to gain a more detailed understanding of possibly similar behavioral results and, thus, support one strategy over another.

Utility and Usability of Two Forms of Supplemental Vibrotactile Kinesthetic Feedback for Enhancing Movement Accuracy and Efficiency in Goal-Directed Reaching.

Recent advances in wearable sensors and computing have made possible the development of novel sensory augmentation technologies that promise to enhance human motor performance and quality of life in a wide range of applications. We compared the objective utility and subjective user experience for two biologically inspired ways to encode movement-related information into supplemental feedback for the real-time control of goal-directed reaching in healthy, neurologically intact adults. One encoding scheme mimicked visual feedback encoding by converting real-time hand position in a Cartesian frame of reference into supplemental kinesthetic feedback provided by a vibrotactile display attached to the non-moving arm and hand. The other approach mimicked proprioceptive encoding by providing real-time arm joint angle information via the vibrotactile display. We found that both encoding schemes had objective utility in that after a brief training period, both forms of supplemental feedback promoted improved reach accuracy in the absence of concurrent visual feedback over performance levels achieved using proprioception alone. Cartesian encoding promoted greater reductions in target capture errors in the absence of visual feedback (Cartesian: 59% improvement; Joint Angle: 21% improvement). Accuracy gains promoted by both encoding schemes came at a cost in terms of temporal efficiency; target capture times were considerably longer (1.5 s longer) when reaching with supplemental kinesthetic feedback than without. Furthermore, neither encoding scheme yielded movements that were particularly smooth, although movements made with joint angle encoding were smoother than movements with Cartesian encoding. Participant responses on user experience surveys indicate that both encoding schemes were motivating and that both yielded passable user satisfaction scores. However, only Cartesian endpoint encoding was found to have passable usability; participants felt more competent using Cartesian encoding than joint angle encoding. These results are expected to inform future efforts to develop wearable technology to enhance the accuracy and efficiency of goal-directed actions using continuous supplemental kinesthetic feedback.

Relationship between the vividness of motor imagery and physical function in patients with subacute hemiplegic stroke: a cross-sectional preliminary study.

PURPOSE: The study aimed to clarify whether the vividness of motor imagery is related to lower limb function and walking ability in patients with hemiplegic stroke. MATERIALS AND METHODS: The study was a cross-sectional preliminary study. The subjects were 15 patients with hemiplegic stroke. The vividness of motor imagery was assessed using the kinesthetic and visual imagery questionnaire. The kinesthetic imagery (KI) involves the sensation of one's own movement, whereas the visual imagery (VI) involves the imagination of a third-person performing the self-movement. Their physical functions were assessed using the Brunnstrom recovery stage, stroke impairment assessment set, 10-m maximum walking speed test, and functional independence measure. KI and VI were compared using the t test. Correlation analysis was performed between KI or VI and various variables as well as between the motor imagery gap (difference between KI and VI) and various variables. RESULTS: KI was significantly lower than VI (p < .01). KI was correlated not only with lower limb function (r = 0.68) but also with walking speed (r = -0.64). The motor imagery gap was correlated with hip joint function (r = -0.53). CONCLUSIONS: KI and motor imagery gap were associated with lower limb function and walking ability.

Dataset with Tactile and Kinesthetic Information from a Human Forearm and Its Application to Deep Learning.

There are physical Human-Robot Interaction (pHRI) applications where the robot has to grab the human body, such as rescue or assistive robotics. Being able to precisely estimate the grasping location when grabbing a human limb is crucial to perform a safe manipulation of the human. Computer vision methods provide pre-grasp information with strong constraints imposed by the field environments. Force-based compliant control, after grasping, limits the amount of applied strength. On the other hand, valuable tactile and proprioceptive information can be obtained from the pHRI gripper, which can be used to better know the features of the human and the contact state between the human and the robot. This paper presents a novel dataset of tactile and kinesthetic data obtained from a robot gripper that grabs a human forearm. The dataset is collected with a three-fingered gripper with two underactuated fingers and a fixed finger with a high-resolution tactile sensor. A palpation procedure is performed to record the shape of the forearm and to recognize the bones and muscles in different sections. Moreover, an application for the use of the database is included. In particular, a fusion approach is used to estimate the actual grasped forearm section using both kinesthetic and tactile information on a regression deep-learning neural network. First, tactile and kinesthetic data are trained separately with Long Short-Term Memory (LSTM) neural networks, considering the data are sequential. Then, the outputs are fed to a Fusion neural network to enhance the estimation. The experiments conducted show good results in training both sources separately, with superior performance when the fusion approach is considered.

Neural Activity During Imagery Supports Three Imagery Abilities as Measured by the Movement Imagery Questionnaire-3.

Self-report and neural data were examined in 14 right-handed college-age males screened from a pool of 200 to verify neural activity during imagery and that the neural activity (area of brain) varies as a function of the imagery type. Functional magnetic resonance imaging data collected during real-time imagery of the three Movement Imagery Questionnaire-3 abilities indicated frontal areas, motor areas, and cerebellum active during kinesthetic imagery, motor areas, and superior parietal lobule during internal visual imagery, and parietal lobule and occipital cortex during external visual imagery. Central and imagery-specific neural patterns were found providing further biological validation of kinesthetic, internal visual, and external visual complementing results on females. Next, research should (a) compare neural activity between male participants screened by self-reported imagery abilities to determine if good imagers have more efficient neural networks than poor imagers and (b) determine if there is a statistical link between participants' neural activity during imagery and self-report Movement Imagery Questionnaire-3 scores.

[Kinaesthetics competence in specialized palliative care: Process evaluation of a quasi-experimental study]. / Kinästhetikkompetenz in der spezialisierten Palliative Care.

Kinaesthetics competence in specialized palliative care: Process evaluation of a quasi-experimental study Abstract. Background: To ensure professional symptom control in the context of palliative care, specific nursing skills are required. "Advanced Kinaesthetics in Palliative Care" (AdKinPal) is an education program intending to promote nurses' kinaesthetics competence in order to improve symptom management by means of nursing interventions. Aim: The aim of this article is to illuminate the process of the AdKinPal study in order to check the program's feasibility and to determine possible outcomes. Results may serve as a basis for revising the program with regard to further implementation. Methods: The process evaluation was part of a quasi-experimental study. We collected qualitative and quantitative data (interviews, observation protocols, questionnaire). For data interpretation, we used qualitative content analysis and descriptive quantitative analysis. Results: Overall, the participants valued the workshops and practical support as beneficial. Nevertheless, there were also inhibiting factors, such as workshop scheduling and location as well as working material. The participants questioned sustainable skills development. Conclusions: The first run of the education program was successful. To ensure sustainable competence development, adjustments are necessary for further implementation.

Efference copy in kinesthetic perception: a copy of what is it?

A number of notions in the fields of motor control and kinesthetic perception have been used without clear definitions. In this review, we consider definitions for efference copy, percept, and sense of effort based on recent studies within the physical approach, which assumes that the neural control of movement is based on principles of parametric control and involves defining time-varying profiles of spatial referent coordinates for the effectors. The apparent redundancy in both motor and perceptual processes is reconsidered based on the principle of abundance. Abundance of efferent and afferent signals is viewed as the means of stabilizing both salient action characteristics and salient percepts formalized as stable manifolds in high-dimensional spaces of relevant elemental variables. This theoretical scheme has led recently to a number of novel predictions and findings. These include, in particular, lower accuracy in perception of variables produced by elements involved in a multielement task compared with the same elements in single-element tasks, dissociation between motor and perceptual effects of muscle coactivation, force illusions induced by muscle vibration, and errors in perception of unintentional drifts in performance. Taken together, these results suggest that participation of efferent signals in perception frequently involves distorted copies of actual neural commands, particularly those to antagonist muscles. Sense of effort is associated with such distorted efferent signals. Distortions in efference copy happen spontaneously and can also be caused by changes in sensory signals, e.g., those produced by muscle vibration.

Action-dependent processing of self-motion in parietal cortex of macaque monkeys.

Successful interaction with the environment requires the dissociation of self-induced from externally induced sensory stimulation. Temporal proximity of action and effect is hereby often used as an indicator of whether an observed event should be interpreted as a result of own actions or not. We tested how the delay between an action (press of a touch bar) and an effect (onset of simulated self-motion) influences the processing of visually simulated self-motion in the ventral intraparietal area (VIP) of macaque monkeys. We found that a delay between the action and the start of the self-motion stimulus led to a rise of activity above the baseline activity before motion onset in a subpopulation of 21% of the investigated neurons. In the responses to the stimulus, we found a significantly lower sustained activity when the press of a touch bar and the motion onset were contiguous compared to the condition when the motion onset was delayed. We speculate that this weak inhibitory effect might be part of a mechanism that sharpens the tuning of VIP neurons during self-induced motion and thus has the potential to increase the precision of heading information that is required to adjust the orientation of self-motion in everyday navigational tasks.NEW & NOTEWORTHY Neurons in macaque ventral intraparietal area (VIP) are responding to sensory stimulation related to self-motion, e.g. visual optic flow. Here, we found that self-motion induced activation depends on the sense of agency, i.e., it differed when optic flow was perceived as self- or externally induced. This demonstrates that area VIP is well suited for study of the interplay between active behavior and sensory processing during self-motion.

Whole-body procedural learning benefits from targeted memory reactivation in REM sleep and task-related dreaming.

Sleep facilitates memory consolidation through offline reactivations of memory traces. Dreaming may play a role in memory improvement and may reflect these memory reactivations. To experimentally address this question, we used targeted memory reactivation (TMR), i.e., application, during sleep, of a stimulus that was previously associated with learning, to assess whether it influences task-related dream imagery (or task-dream reactivations). Specifically, we asked if TMR or task-dream reactivations in either slow-wave (SWS) or rapid eye movement (REM) sleep benefit whole-body procedural learning. Healthy participants completed a virtual reality (VR) flying task prior to and following a morning nap or rest period during which task-associated tones were readministered in either SWS, REM sleep, wake or not at all. Findings indicate that learning benefits most from TMR when applied in REM sleep compared to a Control-sleep group. REM dreams that reactivated kinesthetic elements of the VR task (e.g., flying, accelerating) were also associated with higher improvement on the task than were dreams that reactivated visual elements (e.g., landscapes) or that had no reactivations. TMR did not itself influence dream content but its effects on performance were greater when coexisting with task-dream reactivations in REM sleep. Findings may help explain the mechanistic relationships between dream and memory reactivations and may contribute to the development of sleep-based methods to optimize complex skill learning.

A different point of view: the evaluation of motor imagery perspectives in patients with sensorimotor impairments in a longitudinal study.

BACKGROUND: Motor imagery (MI) has been successfully applied in neurological rehabilitation. Little is known about the spontaneous selection of the MI perspectives in patients with sensorimotor impairments. What perspective is selected: internal (first-person view), or external (third-person view)? The aim was to evaluate the MI perspective preference in patients with sensorimotor impairments. METHODS: In a longitudinal study including four measurement sessions, 55 patients (25 stroke, 25 multiple sclerosis, 5 Parkinson's disease; 25 females; mean age 58 ± 14 years) were included. MI ability and perspective preference in both visual and kinaesthetic imagery modalities were assessed using the Kinaesthetic and Visual Imagery Questionnaire-20 (KVIQ-20), the body rotation task (BRT), and mental chronometry (MC). Additionally, patients' activity level was assessed. Descriptive analyses were performed regarding different age- (< 45, 45-64, > 64), activity levels (inactive, partially active, active), and KVIQ-20 movement classifications (axial, proximal, distal, upper and lower limb). A mixed-effects model was used to investiage the relationship between the primary outcome (MI perspective: internal, external) with the explanatory variables age, MI modality (visual, kinaesthetic), movement type (axial, proximal, distal), activity levels and the different assessments (KVIQ-20, BRT, MC). RESULTS: Imagery modality was not a significant predictor of perspective preference. Over the four measurement sessions, patients tended to become more consistent in their perspective selection, however, time point was not a significant predictor. Movement type was a significant predictor: imagination of distal vs. axial and proximal vs. axial movements were both associated with preference for external perspective. Patients with increased physical activity level tend to use internal imagery, however, this effect was borderline not statistically significant. Age was neither a significant precictor. Regarding the MI assessments, the KVIQ- 20 score was a significant predictor. The patients with higher test scores tend to use the external perspective. CONCLUSION: It is recommended to evaluate the spontaneous MI perspective selection to design patient-specific MI training interventions. Distal movements (foot, finger) may be an indicator when evaluating the consistency of the MI perspective in patients with sensorimotor impairments.

Effects of visual-motor illusion on functional connectivity during motor imagery.

This study aimed to verify whether visual-motor illusion changes the functional connectivity during kinesthetic motor imagery and the vividness of kinesthetic motor imagery. Twelve right-handed healthy adults participated in this study. All participants randomly performed both the illusion and observation conditions in 20 min, respectively. Illusion condition was induced kinesthetic illusion by viewing own finger movement video. Observation condition was observed own finger movement video. Before and after each condition, the brain activity of kinesthetic motor imagery was measured using functional near-infrared spectroscopy. The measure of brain activity under kinesthetic motor imagery was executed in five sets using block design. Under the kinesthetic motor imagery, participants were asked to imagine the movement of their right finger. Functional connectivity was analyzed during the kinesthetic motor imagery. In addition, after performing the task under kinesthetic motor imagery, the vividness of the kinesthetic motor imagery was measured using a visual analog scale. Furthermore, after each condition, the degree of kinesthetic illusion and sense of body ownership measured based on a seven-point Likert scale. Our results indicated that the functional connectivity during kinesthetic motor imagery was changed in the frontal-parietal network of the right hemisphere. The vividness of the kinesthetic motor imagery was significantly higher with the illusion condition compared with the observation condition. The degree of kinesthetic illusion and sense of body ownership were significantly higher with the illusion condition compared with the observation condition. In conclusion, the visual-motor illusion changes the functional connectivity during kinesthetic motor imagery and influences the vividness of kinesthetic motor imagery. The visual-motor illusion provides evidence that it improves motor imagery ability. VMI may be used in patients with impaired motor imagery.

Imagining handwriting movements in a usual or unusual position: effect of posture congruency on visual and kinesthetic motor imagery.

Motor imagery has been used in training programs to improve the performance of motor skills. Handwriting movement may benefit from motor imagery training. To optimize the efficacy of this kind of training, it is important to identify the factors that facilitate the motor imagery process for handwriting movements. Several studies have shown that motor imagery is more easily achieved when there is maximum compatibility between the actual posture and the imagined movement. We, therefore, examined the effect of posture congruency on visual and kinesthetic motor imagery for handwriting movements. Adult participants had to write and imagine writing a sentence by focusing on the evocation of either the kinesthetic or visual consequences of the motion. Half the participants performed the motor imagery task in a congruent posture (sitting with a hand ready for writing), and half in an incongruent one (standing with arms crossed behind the back and fingers spread wide). The temporal similarity between actual and imagined movement times and the vividness of the motor imagery were evaluated. Results revealed that temporal similarity was stronger in the congruent posture condition than in the incongruent one. Furthermore, in the incongruent posture condition, participants reported greater difficulty forming a precise kinesthetic motor image of themselves writing than a visual image, whereas no difference was observed in the congruent posture condition. Taken together, our results show that postural information is taken into account during the mental simulation of handwriting movements. The implications of these findings for guiding the design of motor imagery training are discussed.

Using visual and/or kinesthetic information to stabilize intrinsic bimanual coordination patterns is a function of movement frequency.

Coordination dynamics suggest that both in-phase and anti-phase movements are intrinsic and can be readily performed without practice. As movement frequency increases, individuals performing anti-phase movement inevitably switch to perform in-phase movement. However, due to different frames of reference used to define intrinsic coordination patterns in visual and kinesthetic domains, the perception of intrinsic coordination patterns could be ambiguous, which leads to the question whether the visually or kinesthetically perceived information is used to maintain the intrinsic coordination patterns. The current study explored how the consistency between visual and kinesthetic information would impact the performance and the associated metabolic energy consumption of intrinsic bimanual coordination patterns as movement frequency increased. Thirty participants were recruited and randomly assigned to one of three groups ("Info + Spatial +", "Info + Spatial -", and "Info-Spatial +") to perform intrinsic bimanual coordination tasks using a computer-joystick system at low, high, and self-selected frequencies. The visual and kinesthetic information were manipulated to be either consistent or inconsistent by changing the spatial mapping between the motion of display and motion of joysticks. The results showed that the kinesthetic information was largely used to maintain the stability of intrinsic coordination patterns at high frequency, which could be an energy-conserving solution. However, spatial mapping alone seemed to be beneficial for keeping the visually perceived in-phase and anti-phase coordination patterns equally stable at low movement frequency, and spatially mapping the visual information to be consistent with kinesthetic information greatly enhanced the stability of anti-phase coordination. The dynamical use of visual and kinesthetic information for control of bimanual coordination is discussed.

Differences in cervical kinesthesia between amateur athletes with and without a history of contact sport participation.

Objective: Identify cervical sensorimotor function differences between amateur athletes with and without a history of contact sport participation. A secondary aim of the study was to explore the association between neck reposition error and previously identified injury risk factors.Design: Cross-sectional.Participants: 27 amateur campus recreation sport athletes with a history of contact sport participation and 20 amateur campus recreation sport athletes with no history of contact sport.Main Outcome Measures: Baseline signs and symptoms (S/S) number and severity, Neck Disability Index, total neck reposition error, maximum reposition error, cervical range of motion, and cervical isometric strength were then compared between independent factor groups (contact vs. non-contact).Results: Amateur sport athletes with a history of contact sport exposure exhibited 25.2% more total neck reposition error and 24.6% more maximum neck reposition error than athletes with no history of contact sport participation. S/S number (r2 = .12, F(2,44) = 6.2, p = .017) and S/S severity (r2 = .14, F(2,44) = 5.6, p = .02) were significantly correlated with total neck reposition error.Conclusions: Athletes with a history of contact sport participation exhibited greater cervical spine reposition error. The degree to which these sensory position-sense deficits increase risk of injury and long-term quality of life is unknown, but should be explored in future studies.