Participants Stood Research Articles

The Physiologic Complexity of Prefrontal Oxygenation Dynamics Is Associated With Age and Executive Function: An Exploratory Study.

The hemodynamics of prefrontal cortex (PFC) oxygenation are regulated by numerous processes operating over multiple temporal scales, producing complex patterns in its output fluctuations. Age may alter this multiscale regulation of PFC oxygenation, leading to diminished physiologic complexity of this important regulatory process. We aimed to characterize the effects of age on such complexity and its relationship to performance of an executive n-back task. Twenty-four younger (aged 28 ± 3 years) and 27 older (aged 78 ± 6 years) adults completed this study. Continuous oxygenation (HbO2) and deoxygenation (HHb) signals of PFC were recorded using functional near-infrared spectroscopy (fNIRS) while participants stood and watched a blank screen (blank), clicked a mouse when an X appeared (IdX), or when a letter was repeated from "2-back" in a sequence shown on a screen (2-back). We used multiscale entropy to quantify the HbO2 and HHb complexity of fNIRS signals. Older adults exhibited lower HbO2 and HHb complexity compared to younger adults, regardless of task (p = .0005-.002). Both groups exhibited greater complexity during the IdX and 2-back than blank task (p = .02-.04). Across all participants, those with greater HbO2 and/or HHb complexity during the blank task exhibited faster IdX and 2-back reaction time (β = -0.56 to -0.6, p = .009-.02). Those demonstrating greater increase in HbO2 and/or HHb complexity from IdX to 2-back task had lower percent increase in reaction time from IdX to 2-back task (β = -0.41 to -0.37, p = .005-.01). The complexity of fNIRS-measured PFC oxygenation fluctuations may capture the influence of aging on the regulation of prefrontal hemodynamics involved in executive-function-based task performance.

The influence of smoothness and speed of stand-to-sit movement on joint kinematics, kinetics, and muscle activation patterns.

Stand-to-sit (StandTS) is an important daily activity widely used in rehabilitation settings to improve strength, postural stability, and mobility. Modifications in movement smoothness and speed significantly influence the kinematics, kinetics, and muscle activation patterns of the movement. Understanding the impact of StandTS speed and smoothness on movement control can provide valuable insights for designing effective and personalized rehabilitation training programs. How do the smoothness and speed of StandTS movement affect joint kinematics, kinetics, muscle activation patterns, and postural stability during StandTS? Twelve healthy younger adults participated in this study. There were two StandTS conditions. In the reference condition, participants stood in an upright position with their feet positioned shoulder-width apart on the force plate. Upon receiving a visual cue, participants performed StandTS at their preferred speed. In the smooth condition, participants were instructed to perform StandTS as smoothly as possible, aiming to minimize contact pressure on the seat. Lower leg kinetics, kinematics, and coordination patterns of muscle activation during StandTS were measured: (1) angular displacement of the trunk, knee, and hip flexion; (2) knee and hip extensor eccentric work; (3) muscle synergy pattern derived from electromyography (EMG) activity of the leg muscles; and (4) postural sway in the anterior-posterior (A-P), medio-lateral (M-L), and vertical directions. Compared to the reference condition, the smooth condition demonstrated greater eccentric knee extensor flexion and increased joint work in both the knee and hip joints. Analysis of specific muscle synergy from EMG activity revealed a significant increase in the relative contribution of hip joint muscles during the smooth condition. Additionally, a negative correlation was observed between knee extensor and vertical postural sway, as well as hip extensor work and M-L postural sway. Smooth StandTS facilitates enhanced knee eccentric control and increased joint work at both the hip and knee joints, along with increased involvement of hip joint muscles to effectively manage falling momentum during StandTS. Furthermore, the increased contributions of knee and hip joint work reduced postural sway in the vertical and M-L directions, respectively. These findings provide valuable insights for the development of targeted StandTS rehabilitation training.

Four hours of normobaric hypoxia reduces Achilles tendon reflex inhibition.

Acute exposure to hypoxia increases postural sway, but the underlying neurophysiological factors are unclear. Golgi tendon organs (GTOs), located within the musculotendinous junction (MTJ), provide inhibitory signals to plantar flexor muscles that are important for balance control; however, it is uncertain if GTO function is influenced by hypoxia. The aim of this study was to determine how normobaric hypoxia influences lower limb tendon-evoked inhibitory reflexes during upright stance. We hypothesized that tendon-evoked reflex area and duration would decrease during hypoxia, indicating less inhibition of postural muscles compared with normoxia. At baseline (BL; 0.21 fraction of inspired oxygen, FIO2) and at ∼2 (H2) and 4 (H4) h of normobaric hypoxia (0.11 FIO2) in a normobaric hypoxic chamber, 16 healthy participants received electrical musculotendinous stimulation (MTstim) to the MTJ of the left Achilles tendon. The MTstim was delivered as two sets of 50 stimuli while the participant stood on a force plate with their feet together. Tendon-evoked inhibitory reflexes were recorded from the surface electromyogram of the ipsilateral medial gastrocnemius, and center of pressure (CoP) variables were recorded from the force plate. Normobaric hypoxia increased CoP velocity (P ≤ 0.002) but not CoP standard deviation (P ≥ 0.12). Compared with BL, normobaric hypoxia reduced tendon-evoked inhibitory reflex area by 45% at H2 and 53% at H4 (P ≤ 0.002). In contrast, reflex duration was unchanged during hypoxia. The reduced inhibitory feedback from the GTO pathway could likely play a role in the increased postural sway observed during acute exposure to hypoxia.NEW & NOTEWORTHY The Ib pathway arising from the Golgi tendon organ provides inhibitory signals onto motor neuron pools that modifies force and, hence, postural control. Although hypoxia influences standing balance (increases sway), the underlying mechanisms have yet to be unraveled. Our study identified that tendon-evoked inhibition onto a plantar flexor motoneuron pool is reduced by acute exposure to normobaric hypoxia. This reduction of inhibition may contribute to the hypoxia-related increase in postural sway.

Intersession reliability of center of pressure measurement during bipedal standing with different foot placement angles

IntroductionThe foot placement is a determinant of the base of support and influences standing balance. The reliability of postural stability tests with different foot placement angles is unclear. Research questionTo determine and compare the intra- and inter-day reliability of the center of pressure-based postural stability while standing with different foot placement angles. MethodTwenty-five healthy adults (16 females and 9 males; age: 29 ± 6 years) completed 70 s trials of eyes open and eyes closed stability tests with 0°, 15°, 30°, and 45° angles between the feet while standing on a forceplate in three sessions: two sessions were in the same day, and the third session was one-week apart. The repeatability of measurements was tested using analysis of variance, interclass correlation, and standard error of measurements. ResultThroughout the three study sessions, there was no difference in postural stability while participants stood with different foot placement angles. The interclass correlation scores ranged from 0.71 to 0.96, the standard error of measurements ranged from 2.1% to 12.9%, and no significant systematic changes (p < 0.05) occurred between the testing sessions for any foot placements. Standing with a 45° angle between the feet with closed eyes showed higher reliability values than other conditions. The intra-day reliability scores were greater than inter-day reliability. DiscussionThe relative reliability of postural stability could be impacted by foot placement angles, which might alter ankle mobility and base of support dimensions. The advantages of larger foot placement angles on improving the relative reliability of postural stability could be better demonstrated in healthy people under challenging conditions such as standing with closed eyes. ConclusionStanding with foot placement angles between 0° and 45° are reliable and a quantitative assessment of the center of pressure could be used to monitor the changes in postural stability between sessions.

Benefits of a Light-Painting Technique for Learning to Write New Characters: A Proof of Concept With Adults.

Learning to write relies on the effective integration of sensory feedback and a transition from motor control based on written tracings to motor control based on expert writing movements. This study aimed to test whether the photographic technique of light painting (LP) would facilitate this transition. To achieve this, we conducted two experiments using different LP setups. LP involves moving a light source in a dark environment while taking a long-exposure photograph. LP entails both a real-time reduction of product-related visual information and a post-trial addition of process-related visual information. In the first experiment, we conducted a pre-test, training, and post-test in which 16 adults wrote four new characters with the non-dominant hand. During the training sessions, participants stood and wrote in a vertical frame (1 × 1.2m) two characters in the control condition (with a marker on the vertical support) and two characters in the LP condition (with a flashlight in the air). In the test phases, participants were seated at a table and copied the four characters into a square (4cm * 4cm) on a fixed sheet of graphics paper. As in-air writing strongly differs from classical handwriting situations, we performed a second LP experiment. The aim was to implement LP training in a condition closer to writing. Sixteen new participants followed the same protocol but sat at a table and wrote in a horizontal square (20cm * 20cm). In both experiments, participants who trained with the LP method wrote faster and with less pressure than those trained in the control condition. We also observed an improvement in spatial accuracy in Experiment 2, whatever the training condition. LP seemed to have led participants to focus on the writing process, probably because it modified the nature and timing of the visual information used for writing. LP may be a promising technique for remediating writing difficulties.

Clinical significance of dynamical network indices of surface electromyography for reticular neuromuscular control assessment

BackgroundThere is currently no objective and accurate clinical assessment of reticular neuromuscular control in healthy subjects or patients with upper motor neuron injury. As a result, clinical dysfunctions of neuromuscular control could just be semi-quantified, efficacies and mechanisms of various therapies for neuromuscular control improving are difficult to verify.MethodsFourteen healthy participants were required to maintain standing balance in the kinetostatics model of Gusu Constraint Standing Training (GCST). A backward and upward constraint force was applied to their trunk at 0°, 20° and 25°, respectively. The multiplex recurrence network (MRN) was applied to analyze the surface electromyography signals of 16 muscles of bilateral lower limbs during the tests. Different levels of MRN network indices were utilized to assess reticular neuromuscular control.ResultsCompared with the 0° test, the MRN indices related to muscle coordination of bilateral lower limbs, of unilateral lower limb and of inter limbs showed significant increase when participants stood in 20° and 25° tests (P < 0.05). The indices related to muscle contribution of gluteal, anterior thigh and calf muscles significantly increased when participants stood in 20° and 25° tests (P < 0.05).ConclusionsThis study applied the dynamical network indices of MRN to analyze the changes of neuromuscular control of lower limbs of healthy participants in the kinetostatics model of GCST. Results showed that the overall coordination of lower limb muscles would be significantly enhanced during performing GCST, partly by the enhancement of neuromuscular control of single lower limb, and partly by the enhancement of joint control across lower limbs. In particular, the muscles in buttocks, anterior thighs and calves played a more important role in the overall coordination, and their involvement was significantly increased. The MRN could provide details of control at the bilateral lower limbs, unilateral lower limb, inter limbs, and single muscle levels, and has the potential to be a new tool for assessing the reticular neuromuscular control.Trial registration ChiCTR2100055090

Assessing the effects of sway-back posture on global and regional spinal sagittal angles using inertial measurement units.

Sway-back posture in the sagittal profile is a commonly adopted poor standing posture. Although the terms, definitions, and adverse health problems of sway-back posture are widely used clinically, few studies have quantified sway-back posture. To investigate spinal sagittal alignment in sway-back posture while standing based on global and regional angles using inertial measurement units (IMUs). This cross-sectional study recruited 30 asymptomatic young adults. After measuring the sway angle while standing, the participants were divided into sway-back and non-sway-back groups (normal thoracic group). Each participant stood in a comfortable posture for 5 seconds with IMUs at the T1, T7, T12, L3, and S2 levels. Then, we measured the global and regional lumbar and thoracic angles and sacral inclination in the standing position. Although there was no difference in the global lumbar angle, there was a difference in regional lumbar angles between the two groups. The normal thoracic group had balanced lumbar lordosis between the upper and lower lordotic arcs, whereas the sway back group tended to have a flat upper lumbar angle and increased lower lumbar angle. It is useful to assess the global and regional angles in the spinal sagittal assessment of individuals with sway-back posture.

LIFE JOURNEY WITH SOMEBODY SPECIAL: THE HIGHS AND LOWS OF PARENTS OF CHILDREN WITH DISABILITY

Central to this study is the lived experiences of parents of children with physical disability. This study was conducted at Barangay Poblacion 8, Midsayap, Cotabato. It included as participants purposively chosen parents of children with physical disability. Their ages ranged from 31 to 53 years old, and were all mothers. The physical disabilities of their children were either musculoskeletal (orthopaedic) or visual. This study made use of the phenomenological research design. Findings bared that despite the apparent conditions of their children, the participants joyfully and with gratitude accepted their children as blessings from God. They spent bonding moments with them, and at times appreciative of their learning of new things, and were busy taking good care of the total well-being of their children. They were aware of their children’s limitations, but they do not consider them as different. Nevertheless, they sought acceptance, respect, and understanding from others. The participants were concerned about the health issues of their children, anxious about the mistreatment they received from others, and pondered on their possible rejection in the future. The participants stood by their children and draw strength from God. They look at the bright side of life and hope that their children finish studying. The participants as mothers were longing for help for their children’s sake.&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/soc/0028/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

Creativity and gaze behaviour in football

Performing creative actions is considered a decisive element in football. Recent studies have suggested that football players’ creativity is underpinned by a specific visual search strategy (e.g., Roca et al., 2021). Specifically, studies showed that players who scored high in a football-specific creativity task used more fixations of shorter durations than players who scored low. In the creativity task, players were asked to name as many solution ideas as possible. From an applied perspective, the questions arise: is this gaze strategy generally beneficial to perform creative actions? Should this gaze pattern be trained to improve creativity?&#x0D; In contrast to the idea of one single creativity-related gaze pattern, eye-tracking research in sports suggests that optimal gaze behaviour is highly dependent on situational task demands (Vater et al., 2020). Moreover, generally increasing the number of short fixations is expected to be dysfunctional to both motor accuracy and to the perception of task-relevant opportunities due to saccade-related costs. Accordingly, we hypothesized that many fixations of short duration are positively associated with players’ ability to generate many ideas in the specific creativity task but not with performing creative actions.&#x0D; Fifteen footballers participated in an experiment with two conditions. In one condition (DT-condition), we replicated Roca et al.’s studies: participants stood in front of a large screen and with a ball in front of them. They were asked to view 20 videos of attacking situations and imagine themselves as the player in ball possession. At key moments of the situation, the videos were occluded. At this point, players’ task was to physically play the ball and verbally confirm their decision. Subsequently, the last frame of the video reappeared, and their task was to name as many solution ideas as possible within 45 s. Moreover, a second condition was added (action-condition). While the first part of the task remained identical, the last frame did not reappear after playing the ball. In the action condition, the task-instruction was—as in a real game—to perform the most promising solution. In both conditions, eye tracking data were recorded.&#x0D; Results indicate that many fixations of short durations were linked to generating more ideas in the DT-condition—replicating Roca et al.’s (2021) finding—, however, not with performing creative solutions in the action-condition. As predicted, in the action-condition, the pattern was reversed: Players that performed more functional and creative actions used less fixations per second. For practice the results challenge the idea of training a specific creativity-related gaze pattern to improve creativity. Rather, our findings suggest that training should provide learning opportunities to acquire functional gaze strategies that are optimally adapted to situational task demands.&#x0D; References&#x0D; Roca, A., Ford, P. R., &amp; Memmert, D. (2021). Perceptual-cognitive processes underlying creative expert performance in soccer. Psychological Research, 85(3), 1146–1155. https://doi.org/10.1007/s00426-020-01320-5&#x0D; Vater, C., Williams, A. M., &amp; Hossner, E.-J. (2020). What do we see out of the corner of our eye? The role of visual pivots and gaze anchors in sport. International Review of Sport and Exercise Psychology, 13(1), 81–103. https://doi.org/10.1080/1750984X.2019.1582082

Beyond physiology: Acute effects of side-alternating whole-body vibration on well-being, flexibility, balance, and cognition using a light and portable platform A randomized controlled trial.

A good body-balance helps to prevent slips, trips and falls. New body-balance interventions must be explored, because effective methods to implement daily training are sparse. The purpose of the current study was to investigate acute effects of side-alternating whole-body vibration (SS-WBV) training on musculoskeletal well-being, flexibility, body balance, and cognition. In this randomized controlled trial, participants were randomly allocated into a verum (8.5 Hz, SS-WBV, N = 28) or sham (6 Hz, SS-WBV, N = 27) condition. The training consisted of three SS-WBV series that lasted one-minute each with two one-minute breaks in between. During the SS-WBV series, participants stood in the middle of the platform with slightly bent knees. During the breaks in between, participants could loosen up. Flexibility (modified fingertip-to-floor method), balance (modified Star Excursion Balance Test), and cognitive interference (Stroop Color Word Test) were tested before and after the exercise. Also, musculoskeletal well-being, muscle relaxation, sense of flexibility, sense of balance, and surefootedness were assessed in a questionnaire before and after the exercise. Musculoskeletal well-being was significantly increased only after verum. Also, muscle relaxation was significantly higher only after verum. The Flexibility-Test showed significant improvement after both conditions. Accordingly, sense of flexibility was significantly increased after both conditions. The Balance-Test showed significant improvement after verum, and after sham. Accordingly, increased sense of balance was significant after both conditions. However, surefootedness was significantly higher only after verum. The Stroop-Test showed significant improvement only after verum. The current study shows that one SS-WBV training session increases musculoskeletal well-being, flexibility, body balance and cognition. The abundance of improvements on a light and portable platform has great influence on the practicability of training in daily life, aiming to prevent slip trips and falls at work.

Effects of a body manipulation of Japanese martial arts on interpersonal correlation of postural sway.

This study aimed to investigate the nature of a specific body manipulation named Suichoku-Ririku (SR) in Japanese martial arts. SR is regarded as a method to change the way of stance and to distort the balance control of the opponent, but its nature and mechanism are unknown. In the present study, we attempted to determine the effect of SR in the cases that a person stood alone (Expt. 1) and that two persons stood in contact (Expt. 2). We compared several center of pressure (COP) measures between the normal stance and SR stance conditions. When participants stood independently (Expt. 1), the COP path length, standard deviation of COP velocity and permutation entropy of the COP increased with the SR stance, which suggested that the SR maneuver destabilized a quiet stance. When two participants stood (with normal stance) in contact by wrist-holding or by a light touch (Expt. 2), their COP motions were correlated with each other, as previously reported. When one of the participants took the SR maneuver, their correlation and mutual information were maintained, denying the view that SR would diminish the interpersonal correlation of body sway. On the other hand, a fluctuation in the COP increased only for the participant taking the SR maneuver, and not for the other participant. This asymmetric effect of the SR maneuver between two participants, irrespective of maintained mutual correlation, suggest that the relationship between balance controls of two participants was partly disrupted. We discuss possible mechanisms for the present results.

Postural Balance in Young Tennis Players of Varied Competition Levels.

The aim of this study was to investigate the effect of young tennis players' expertise on their postural balance (PB) under sensorial conditions with eyes open (EO) and with eyes closed (EC). Our participants were 75 healthy adolescents aged 15-18 years, divided into three groups based on their skill levels: (a) national tennis players (NAT; n = 25), regional tennis players (REG; n =25), and a control group of non-sport practitioners (CG; n = 25). We recorded center of pressure area and mean velocity on a force platform while participants stood in bipedal and unipedal stances in EO and EC conditions for all three groups. Statistical analyses showed that NAT participants swayed less than CG participants in all conditions and less than REG participants in the bipedal stance with EC and in the unipedal stance, both with EO and EC. Thus, tennis practice/experience may have improved PB in this sample, as high-level tennis players had better PB compared to novices, especially in challenging conditions.

The Effect of Sex, Sport Participation, and Concussion History on Baseline Concussion Balance Test Performance in Division-I Collegiate Athletes

Explore the effect of baseline characteristics such as sex, sport, and concussion history on the Concussion Balance Test (COBALT) performance in collegiate athletes. The COBALT is a recently developed clinical balance assessment specifically for athletic populations following concussion. The task conditions of the COBALT are designed to challenge sensory integration and reweighting processing underlying postural control. It has been documented that balance performance is influenced by factors such as sex and sport in collegiate athletes. One-hundred twenty seven collegiate athletes (77 male, 50 female; age: 19.81 ± 1.39; height: 68.77 ± 5.57 in; mass: 80.98 ± 26.15 kg), who participated in Division-I football, soccer, or cheerleading were included. Participants completed the 4 baseline conditions (Condition 3, 4, 7, 8) of the COBALT. Condition 3 (C3) included a side-to-side headshake with eyes closed. For Condition 4 (C4) the participant stood with hands clasped, elbows extended, and thumbs up while rotating their trunk side-to-side, visually focusing on their thumbs. Conditions 7 (C7) and 8 (C8) repeated C3 and C4 on a foam surface. Two 20-second trials of each condition were completed on a forceplate and the mean angular sway velocity (°/s) were calculated and number of errors were counted. ANOVAs and ANCOVAs were used to assess the potential effects on COBALT performance. There were no significant differences in postural sway for any COBALT condition based on sex (p > 0.05). Females demonstrated more errors than males on C7 (p < 0.001). Cheerleaders had more balance errors compared to football athletes for C3 and C7 (p < 0.05) and soccer athletes for C7 (p < 0.05). Concussion history did not have an effect on COBALT performance (p > 0.05). Understanding factors that may influence COBALT performance at baseline may enhance concussion evaluation in collegiate athletes with suspected balance deficits following concussion. While concussion history had no effect, sex and sports participation may influence performance and should be considered when interpreting COBALT results post-concussion.

People with persistent postural-perceptual dizziness demonstrate altered postural strategies in complex visual and cognitive environments.

People with PPPD report imbalance, increase in symptoms and impaired function within complex visual environments, but understanding of the mechanism for these behaviors is still lacking. To investigate postural control in PPPD we compared changes in center of pressure (COP) and head kinematics of people with PPPD (N = 22) and healthy controls (N = 20) in response to different combinations of visual and cognitive perturbations during a challenging balance task. Participants stood in a tandem position. Static or moving stars (0.2 Hz, 5 mm or 32 mm amplitude, anterior-posterior direction) were displayed through a head-mounted display (HTC Vive). On half the trials, participants performed a serial-3 subtraction task. We measured medio-lateral and anterior-posterior path and acceleration of COP and head. Controls significantly increased all COP and head parameters with the cognitive task whereas PPPD increased only COP ML path and acceleration. Only controls significantly increased head anterior-posterior & medio-lateral acceleration with moving visual load. Cognitive task performance was similar between groups. We observed altered postural strategies in people with PPPD, in the form of reduced movement with challenge, particularly around the head segment. The potential of this simple and portable head-mounted display setup for differential diagnosis of vestibular disorders should be further explored.

The effect of visual field manipulations on standing balance control in people with multiple sclerosis.

Multiple sclerosis (MS) is associated with an increased risk of falls, degeneration of sensory organization, and possible increased reliance on vision for balance control. The aim of this study was to assess differences in standing postural control between people with MS and age and sex matched controls during medial-lateral (ML) oscillations of the visual field, with and without blinders to the lower periphery. Ten persons with MS (mean age 54.0 ± 5.3 years) and ten age and sex matched controls (mean age: 56.3 ± 6.0 years) participated in this study. Balance control was assessed while participants stood in a Christie Cave system while wearing stereoscopic glasses that projected an immersive forest scene. Visual conditions consisted of 2 m ML visual oscillations of the scene at five frequencies (0.0, 0.3, 0.6, 0.7 and 0.8 Hz) with and without blinders to block the lower periphery. The results demonstrated that, in comparison to controls, participants with MS had a significantly larger center of pressure sway in both the ML and AP direction to ML visual oscillations. Additionally, participants with MS and controls both increased center of pressure frequency content to the visual oscillation frequency, while participants with MS also increased relative power at the visual oscillation frequency in the AP direction. Blinders of lower periphery reduced the percent power at the visual oscillation frequency in both groups and reduced overall sway in participants with MS during visual oscillations. Overall, results indicate that postural balance is sensitive to visual feedback in people with MS. The elicited AP sway to ML visual oscillation could reflect errors in visual processing for the control of balance, and decreased sway in response to blocking vision of the lower peripheral field could indicate an increased reliance on visual cues to maintain balance.

Effects of Dry Needling on Spinal Reciprocal Inhibition

<h3>Research Objectives</h3> Spinal reciprocal inhibition is an important spinal mechanism of motor control. It is often impaired in persons after stroke, negatively impacting locomotion; at the same time, it changes in response to therapeutic interventions (e.g., FES). An increasing number of physical therapists worldwide have been administering trigger point deep dry needling (DDN) to treat post-stroke spasticity. Yet, currently, effects of DDN on spinal somatosensory processing are not well understood. Thus, to understand neurophysiological mechanisms of DDN, we are investigating the effects of DDN on spinal pathways in persons with and without stroke. <h3>Design</h3> Before and 0, 90 minutes, and 72 hours after DDN of the medial gastrocnemius (MG) at myofascial trigger points, reciprocal inhibition of the soleus, MG and lateral gastrocnemius (LG) was examined while the participant stood and maintained his/her standing posture and triceps muscle activity. Passive ankle range of motion (ROM) was also measured before and after DDN. <h3>Setting</h3> University. <h3>Participants</h3> 11 adults 22-57 years old (median 37.5) without known neurological conditions. <h3>Interventions</h3> Trigger point dry needling to medial gastrocnemius <h3>Main Outcome Measures</h3> Reciprocal inhibition of ongoing muscle activity elicited by common peroneal nerve (CPN) stimulation. ROM. <h3>Results</h3> In the MG and LG, there was no systematic changes in the amount of inhibition across participants or measurement times. Soleus inhibition elicited by suprathreshold CPN stimulation was increased significantly at 0 minute and 72 hours post DDN (p>0.05). Ankle dorsiflexion ROM was increased by 4 deg at 0 minutes and 72 hours post DDN. <h3>Conclusions</h3> DDN alters soleus inhibition, which may partially explain increased ankle ROM post DDN. In order to understand how DDN affects reciprocal inhibition in the stroke-impaired CNS, studies of individuals after stroke are currently underway. <h3>Author(s) Disclosures</h3> The authors have no conflicts of interest to declare.

Effects Of Dual Task And Repetition On Five-times Sit-to-Stand Task In Healthy Young Adults

The Sit-to-Stand (STS) task is an essential activity of independent daily living. It is commonly transferred into the clinic as five-times STS task (FTSTS) for assessment and prognosis of balance and muscle efficiency in the lower extremities of various populations. Research has shown that for activities such as the STS task, a certain level of attentional demand is required to perform the multiple components of a transitional movement. However, to our knowledge, the changes that occur in body mechanics with greater repetitions and the effects of dual tasking while performing FTSTS are currently unknown. PURPOSE: To determine the effects of dual tasking and multiple repetitions on the FTSTS task in healthy, young adults. METHODS: 10 healthy adults (mean age 24 (4.1) years) participated. Each participant stood up and sat down five times as fast as possible as part of FTSTS assessment. Three trials were completed without a cognitive task (SingleTask) and then with a concurrent cognitive task of counting backwards by 3 starting from a random number (DualTask). Time to complete FTSTS was measured. Impulse (Ns/BW), peak force (N/BW), and power (Nm/BW.s) variables were calculated using ground reaction force measurements. A 2-way ANOVA and paired samples t-test were conducted. RESULTS: Participants took significantly longer to complete FTSTS while dual tasking (8.16 [1.77]s) compared to SingleTask (7.38 [1.08]; p = .05). Concentric impulse significantly increased from 0.55 (0.02) during SingleTask to 0.59 (0.03) during DualTask (p = .022), however, power significantly decreased from 0.99 (0.04) during SingleTask to 0.92 (0.05) during DualTask (p = .017). FTSTS concentric, eccentric, and total impulse significantly increased from 1st to 5th repetition respectively: 0.56 (0.03) to 0.59 (0.03; p = .005), 0.49 (0.03) to 0.56 (0.04; p = .013), 1.05 (0.05) to 1.15 (0.06; p = .006). Also, standing peak force significantly decreased from 1st repetition (1.39 [0.03]) to 5th repetition (1.34 [0.03]; p = .004). The mean peak force standing decreased more from 1st to 5th repetition under SingleTask (1.39 [0.04] to 1.32 [0.03]) compared to DualTask (1.39 [0.03] to 1.35 [0.03]; p = .044). CONCLUSION: The force characteristics are altered by both dual tasking and number of repetitions during the FTSTS task in healthy, young adults.

Examining feedback mechanisms of postural control in Chiari Malformation by average wavelet coefficient decomposition and the Hurst exponent.

Chiari Malformation (CM) is a congenital disorder occurring when the cerebellar tonsils descend into the foramen magnum, inhibiting cerebrospinal fluid (CSF) flow, causing headaches, dizziness, difficulty swallowing, muscle weakness, and loss of neuromuscular coordination. While there is no cure, surgical decompression of the hindbrain is used to alleviate symptoms. Loss of postural control is a main symptom reported by these patients; however, no study has examined postural stability in this cohort of patients. Do patients with CM exhibit impaired postural stability compared to healthy controls?. Twelve female participants diagnosed with CM performed a postural stability test where six participants had undergone decompression (CM-D) surgery while six had not (CM-ND). Participants stood in Romberg fashion on an AMTI force plate according to an IRB-approved protocol. Postural stability measures were quantified by computing Hurst exponents. These values were determined from the Average Wavelet Coefficient method using a level 12 Symlet-2 wavelet to analyze anterior-posterior (AP) center-ofpressure (COP) trajectories in MATLAB. Identical procedures and analyses were performed on healthy control participants with no known neuromuscular disorders. CM participants displayed significantly impaired postural stability compared to healthy controls (p = 0.0002). CM-D participants displayed significantly impaired postural stability compared to CM-ND (p = 0.002). CM-D and CM-ND both displayed significantly impaired postural stability compared to controls (p < 0.0001 and p < 0.003, respectively). Loss of postural stability is considered a main symptom of CM, however no study has previously quantified human postural control in this cohort of patients. Quantifying this relationship can provide further insight to neurologists studying the disorder and to therapists planning rehabilitation and pain relief methods.

Postural stability is a valid and meaningful disability metric in progressive MS with potential for use in neuroprotective therapy trials

BackgroundBalance impairment is observed in up to 70% of people with MS (pwMS) and worsens with disease progression. Posturography using a force platform is the current gold standard in the measurement of balance. However, posturography has not been adequately studied or widely accepted for use as a disability outcome measure for pwMS. Importantly, the recent emergence of both successful and failed neuroprotective therapy trials in progressive MS has emphasised the need for new disability outcome measures for people with progressive MS. The main objectives of this study were to evaluate the clinical validity, reliability and feasibility of posturography as a disability metric in progressive MS. MethodsThis was a prospective cross-sectional study. We recruited 73 people with progressive MS (age 18–65 years, EDSS 3.5–6.0). Participants stood in the centre of a force platform, feet comfortably apart, under various conditions: (i) eyes open (EO), (ii) eyes closed (EC) – a single task, each lasting ninety seconds; and simultaneous EO with a cognitive test: (iii) N-Back, a three-minute test whereby participants were instructed to click the mouse when two identical letters were displayed consecutively on a screen, (iv) Sustained Attention Response Task, a five-minute test whereby participants were instructed to click the mouse for every number “1″ to “9″ except “3″ – i.e., dual-tasks. Additionally, we performed a battery of validated physical and cognitive outcome measures. Posturographic data was processed using Matlab. Statistical analysis was performed using SPSS version 26. We used multiple linear regression modelling to determine whether significant univariate correlations between posturography and clinical metrics were independent of covariates that may influence the associations seen. A two-tailed significance level of 0.05 was used. ResultsOf 73 participants, mean age 52.4 (8.5) years, mean MS disease duration 13.8 (10.3) years, median EDSS 5.0 (IQR 4.0–6.0), 44 (60.4%) were female. EO-Path-Length independently predicted upper extremity function (9-Hole-Peg-Test) with a larger effect size (adjusted R2=20.0%, p = 0.001) than that for walking measures (Timed 25-Foot Walk, adjusted R2=1.6%, p = 0.01; Two-Minute Walk Test, adjusted R2=7.2%, p = 0.002), while controlling for age, disease duration, height, weight, and sex. The addition of EO-Mediolateral-Displacement to the MS Functional Composite (MSFC) created a four-component z-score that increased the variance explained for quality of life (QOL) by 62.1%. Postural stability was significantly lower with mediolateral vs anteroposterior direction of sway, removal of vision, increased body weight, male sex, and fampridine use. Postural stability improved during dual-tasks compared to EO single task. Posturography detected significant worsening of balance over a single prolonged stance. ConclusionPostural stability independently predicted a wide range of clinical metrics including upper extremity function, walking ability, cognition and QOL, therefore establishing construct and concurrent validity as a disability outcome measure for people with progressive MS. Additionally, posturography is a quantitative, non-invasive, quick-and-easy-to-administer, and highly sensitive device, demonstrating its high feasibility for use as a time- and resource-efficient disability metric in neuroprotective therapy trials for progressive MS.

Characterizing inter-limb synchronization after incomplete spinal cord injury: A cross-sectional study

BackgroundIndividuals with incomplete spinal cord injury (iSCI) demonstrate greater postural sway and increased dependency on vision to maintain balance compared to able-bodied individuals. Research on standing balance after iSCI has focused on the joint contribution of the lower limbs; however, inter-limb synchrony in quiet standing is a sensitive measure of individual limb contributions to standing balance control in other neurological populations. It is unknown if and how reduced inter-limb synchrony contributes to the poor standing balance of individuals with iSCI. Research questionHow does an iSCI affect inter-limb synchrony and weight-bearing symmetry in standing? MethodsEighteen individuals with non-progressive motor iSCI and 15 age- and sex-matched able-bodied individuals (M-AB) were included in the study. Participants stood in a standardized position on two adjacent force plates in eyes open and closed conditions for 70 s per condition. Net centre-of-pressure (COP) root mean square (RMS), net COP velocity, COP inter-limb synchrony (i.e. cross-correlation between left and right COP), and weight-bearing asymmetry (i.e. vertical force from each limb over total vertical force) were calculated. Muscle strength of the lower limbs was assessed with manual muscle testing. ResultsIndividuals with iSCI demonstrated reduced inter-limb synchrony when standing with eyes open and eyes closed, but did not differ to M-AB with respect to weight-bearing asymmetry. They also produced greater net COP RMS and velocity when compared to M-AB. Muscle strength of the two lower limbs demonstrated an overall asymmetry in individuals with iSCI. SignificanceIndividuals with iSCI demonstrated impaired balance control as evidenced by reduced inter-limb synchrony and greater COP RMS and velocity compared to M-AB individuals. This increased understanding of how balance control is impaired following iSCI may inform balance assessment and intervention for this population. Future work examining the association between inter-limb synchrony and the occurrence of falls in iSCI is warranted.