The study investigates the association between dynamic balance performance assessed by the modified hop balance test and cortical hemodynamics in young skiers during single-leg stance (SLS) and dual-leg stance (DLS), utilizing functional near-infrared spectroscopy (fNIRS). The study hypothesizes that SLS will enhance cortical activation than DLS due to challenging postural balance, and imbalances between right- and left-leg stances (RLS vs. LLS) will produce distinct activation patterns. The SLS and DLS were performed to understand cortical activity linked to postural control, brain areas, and lateralization's role. Differences in the hemodynamic response across experimental conditions were formally tested under the statistical framework called the functional mixed effects model, which simultaneously captures common patterns across subjects and accounts for variations in brain functional responses across subjects. Results unveiled a notable contrast (p≤0.0001) in cortical activation between SLS and DLS, with higher cortical activation during SLS, suggesting distinct neural control mechanisms. Intriguingly, distinct cortical activation patterns were observed during both stances, including various regions in the motor cortex and associated areas. No significant differences were found in cortical hemodynamics and balance performance when comparing the left-leg stance (LLS) and right-leg stance (RLS), suggesting equal stimulation of the motor cortex. Future studies comparing skiers with non-skiers might reveal different brain activity patterns between RLS and LLS, warranting further investigation into the functional role of these activations for balance improvement and targeted interventions.

Virtual reality (VR) technology has emerged as a valuable tool for gait rehabilitation, offering controlled and immersive environments that simulate real-world scenarios. Although little is known about how immersive VR affects gait biomechanics in older adults, we specifically investigate how walking in VR influences lower-limb kinematics compared to walking in a non-VR environment. Healthy older adults walked at their self-selected speed on an instrumented treadmill. VR participants experienced a fully immersive virtual industrial environment using the Computer Assisted Rehabilitation Environment (CAREN) system, while non-VR participants walked without a virtual environment. Kinematics were analyzed using one-dimensional Statistical Parametric Mapping to compare the VR and non-VR conditions across the gait cycle. Dimensionless gait speed was also assessed to ensure consistency in walking pace between groups. No significant differences were found between the VR and non-VR groups in dimensionless gait speed. However, phase-specific differences were observed in pelvic tilt, hip adduction/abduction, and ankle dorsiflexion/plantarflexion. These differences were small in magnitude (largest ≈4°) and within ranges often reported for measurement error or minimal detectable change in kinematics; therefore, they should be interpreted cautiously and as associations observed under differing acquisition/processing pipelines rather than as definitive effects attributable to VR. While overall speed was preserved, older adults made localized joint-level adjustments during specific gait phases, suggesting that immersive visual conditions interact with sensorimotor control.

This study investigated the asymmetry of interlimb transfer in motor skill learning and explored a method to eliminate it. Two experiments were conducted using a laser pistol shooting task. In Experiment 1, we examined whether interlimb transfer asymmetry occurs in pistol shooting. Right-handed participants trained with either their dominant or nondominant hand. Pre- and post-tests were conducted with both hands. Results showed that shooting performance transferred from the dominant to the nondominant hand immediately after training, but not in the reverse direction. Experiment 2 tested whether the training-plus-exposure (TPE) paradigm could eliminate this asymmetry. Three groups trained with their nondominant hand. Following training, two exposure groups engaged the dominant hand in either a mouse-tracking or keyboard-typing task, while a third group rested. Only the tracking exposure group exhibited complete transfer of shooting skill to the dominant hand. A control group that performed only the tracking task without prior training showed no performance gain. These findings suggest that interlimb transfer in shooting is asymmetric not because of unequal learning, but due to execution-level inhibition that prevents expression of acquired skill. Exposure to a task with similar control demands reactivates access to shared motor representations. This challenges existing models of interlimb transfer focused on learning or storage limitations and supports a new framework that dissociates acquisition from expression. The results also parallel findings from perceptual learning and may inform interventions in sports training and motor rehabilitation.

Walking requires precise central nervous system control. Although gait adaptation and learning have been extensively investigated, the specific conditions that elicit delayed adaptation and aftereffects remain unclear.

Falls are the leading cause of injury among older adults, often occurring during walking. Effective training programs are essential for reducing falls, and the distribution of practice may influence motor skill learning. This randomized clinical trial investigated the effects of different perturbation-based balance training (PBT) session distributions on postural stability and fall risk in older adults with a history of falls. Thirty participants were randomly allocated to either a massed practice group (2 sessions/day; n = 15) or a distributed practice group (1 session/day; n = 15). Both groups underwent four PBT sessions involving acceleration and deceleration perturbations, followed by a retention test one week later. We assessed the margin of stability (MoS), the number of falls during sessions, and dynamic balance using the Mini-BESTest before and after training. Assessments were performed by evaluators blinded to group allocation. Groups did not differ in any of the variables investigated. Significant improvements were observed in MoS during the deceleration perturbation sessions (p < 0.05), with an increase between sessions 1 and 4, and between session 1 and the retention test (p < 0.05). The number of falls was reduced over the sessions (p < 0.001), and there was an improvement in dynamic balance in the Mini-BESTest after PBT, particularly in reactive control and gait dynamics (p < 0.001). The distribution of PBT sessions, whether massed or distributed, did not affect fall-related outcomes in fall-prone older adults. These findings support the use of flexible PBT schedules for fall prevention. This trial was registered in the Brazilian Clinical Trials Registry (RBR-9dhx6kj; UTN: U1111-1276-4396).

We studied the catching accuracy during the skill acquisition of juggling using a probabilistic model, which was justified by the Bayesian brain hypothesis that the internal model constantly updates its parameters based on prior experiences and new practice. We wondered how practice can increase the probability of catching a ball (θ) in juggling by changing the shape of the posterior distribution of θ.

Virtual reality in artistic gymnastics has hardly been researched yet, but could have positive effects on learning movements, particularly on the balance beam, whose width and height demand significant effort. This study aimed to identify suitable gymnastics elements for the execution with a head-mounted display (HMD), considering potential performance impacts related to its size, weight, and limited field of view. Twelve basic elements covering the characteristics of the balance beam were performed by 36 competitive gymnasts (16.5 ± 6.6 years) on a low beam (10 cm) with and without the HTC VIVE Pro Eye HMD, which displayed the real environment through its cameras instead of a virtual one. A helmet with similar dimensions and weight to the HMD was used as a third condition to isolate vision effects. Licensed judges evaluated all trials for recognition and execution based on international scoring rules. Both analyses show that the performance was more impacted by restricted vision than by additional weight. Execution quality varied significantly between the condition with and without HMD for all movement characteristics, although the differences were smaller for jumps, holds/acrobatic non-flight elements and leaps than for elements with turns. Consistent with this, no significant differences in jumps and holds/acrobatic non-flight were found between the original and helmet conditions. In summary, elements without longitudinal axis rotations are well-suited for HMD execution, and results can be improved with better hardware and longer familiarization. Future studies should prioritize good optical resolution, a large field of view, and compact design over low weight when selecting HMDs.

People with a lower-limb amputation must undergo a process of co-adaptation with a prosthesis to achieve optimal walking performance. Human-in-the-loop optimization could identify optimal prosthetic settings, while also providing insight into the process of motor learning during prosthetic tuning. The aim of the study was to investigate the time course of motor learning of people with transtibial amputation during the human-in-the-loop optimization process of a prosthetic foot, in which the stiffness and alignment were optimized to minimize metabolic cost.

Understanding propulsive and braking mechanisms during gait acceleration and deceleration is essential for ensuring gait stability in daily life.

Alexander technique (AT) is a method of behavior modification that seeks to improve coordination by modifying habitual reactions to the stimuli that incite action. Previous studies have shown that a single session of AT-based postural instructions (Lighten Up) can improve axial stiffness, postural control during quiet stance, and step initiation in older adults with Parkinson's disease, as well as balance and postural control in healthy older and younger adults relative to instructions that encourage muscular effort or relaxation. In the present study, we investigated the effects of AT-based postural instructions on steady state gait in young adult participants with no prior experience with Alexander Technique. Forty-four participants (29 female, 15 male; 23.4 ± 4.2 years old) utilized three sets of instructions while walking: Lighten Up, Pull Up, and Relax and also completed a Control condition in which they walked normally without any additional instructions. We found minimal differences between Lighten Up, Pull Up, and the Control conditions, with a significantly smaller Coefficient of Variation in the Lighten Up and Pull Up conditions compared to the Control condition for Stride Velocity. We found the most notable differences in the Relax condition, where participants walked significantly slower, took significantly shorter Stride Lengths, and spent significantly more time in Double Support compared to the other three conditions. Participants also had significantly higher gait variability in the Relax condition compared to the Lighten Up, Pull Up and Control conditions. Instructions to Relax clearly compromised steady state gait.

Theoretical and empirical evidence suggests a link between motor skills and executive functioning, yet the nature of this relation remains relatively unexplored in children with intellectual disabilities. This study focuses on exploring the developmental relationships between motor skills and executive functioning in this population. We utilized a longitudinal approach to follow 101 children with intellectual disabilities, ranging in age from 7 to 17, across three measurement points with one-year intervals. At each measurement point, participants completed tasks evaluating gross motor skills, fine motor skills, and executive functioning. Random intercept cross-lagged panel modeling revealed distinctive motor-executive function relationship patterns. Specifically, fine motor skills and executive functioning reciprocally predicted each other between Time 1 and Time 2. Additionally, fine motor skills at Time 2 significantly predicted executive functioning at Time 3, whereas the reverse pattern was not observed. In contrast, no significant longitudinal relationship was found between gross motor skills and executive functioning. These findings suggest that interventions integrating fine motor skills and executive functioning could be essential for children with intellectual disabilities, providing an important avenue to support their skills development.

This study explores handedness through a multidisciplinary approach, integrating biomechanical analysis and electroencephalography (EEG) to uncover differences in motor strategies and brain lateralization among right-handed, left-handed, and ambidextrous individuals. Seventy participants were assessed using motion capture and EEG during writing and drawing tasks performed with both dominant and non-dominant hands. Biomechanical data were analyzed through the lens of motion optimization, using the Movement Element Decomposition (MED) method, while EEG data focused on event-related synchronization/desynchronization (ERD/S) patterns. Results highlight that right-handers demonstrate stronger lateralization for fine motor tasks, with optimized neural and biomechanical adaptations favoring the right hand. In contrast, left-handers exhibit specialization for impedance control with their right hand, suggesting distinct motor planning strategies. EEG findings corroborate these behaviors, showing that right-handers require less cognitive effort when using their dominant hand for writing, whereas left-handers show heightened parietal activity associated with sensorimotor integration during similar tasks. The study reveals an asymmetry in motor skill acquisition, possibly related to left-handed adaptations to right-hand-dominated environments. These insights contribute to understanding handedness's role in motor control and brain organization, with implications for neurorehabilitation.

Spinal movement variability is a normal feature of repetitive motions and has been hypothesized to differ between people with and without low back pain. However, normative values for intra-individual variability are currently lacking, making it difficult to judge when the variability becomes abnormal. This study used a combination of principal components analysis, single component reconstruction, and coefficient of variation to assess intra-individual variability of 3 blocks of 10 repeated spinal flexion movements in a group of 15 healthy individuals. Spinal flexion movements were assessed using motion capture cameras and a 19 × 3 matrix of retroreflective stickers on the spinous processes and bilateral paraspinal muscle bellies of S1-C7 spinal levels. All participants showed lower range of motion coefficients of variation in the lumbar spine (1.9-25.3 %) compared to the thoracic spine (7.9-30.1 %). To explain ≥80 % of the total variance within movements, 2-5 principal components were needed for each participant. Single component reconstruction revealed magnitude changes, waveform differences, and phase shifts as common sources of variability. These changes were usually observed when the coefficient of variation exceeded 10 % for that region of the spine. In conclusion, healthy individuals display varying levels of intra-individual spinal movement variability. The sources of variability can be interpreted using a combination of principal components analysis and single component reconstruction.

Auditory-motor synchronization refers to the coupling of motor responses to rhythmic auditory stimuli. This study examined finger-tapping dynamics under three conditions: self-paced tapping, tapping to metronomic stimuli, and tapping to fractal auditory stimuli. Using Detrended Fluctuation Analysis (DFA) to estimate Hurst exponents, H, and Diffusion Entropy Analysis (DEA) to estimate scaling exponents, d, in each condition, we found that self-paced tapping exhibited persistent or super-diffusive inter-tap intervals (H=0.63±0.145, d=0.64±0.097), while tapping to metronomic stimuli showed a trend toward random noise (H=0.55±0.101, d=0.58±0.126). Complexity matching, that is, systematic adjustment of intertap intervals to match persistence levels of fractal stimuli, was observed between the Hurst exponents of auditory stimuli (H=0.25 to H=1.5) and complexity measures of tapping (H=0.54 to H=0.81; d=0.51 to d=0.72). A Gaussian linear mixed model confirmed significant associations between the Hurst exponents of auditory stimuli and H of the corresponding intertap interval time series. In contrast, the associations between the Hurst exponents of auditory stimuli and d of the corresponding intertap interval time series were mixed. To understand these empirical observations, we utilized the neural hopping model to represent the intrinsic mechanism underlying self-paced tapping and incorporated the Van der Pol oscillator to account for auditory stimuli as a driving force. Metronomic stimuli were modeled as harmonic forcing, resulting in simulated tapping with H=0.50±0.175 or d=0.53±0.115. Complexity matching to fractal stimuli was achieved through phase resetting. We evaluated four coupling variants of phase-resetting, i.e., with or without continuous harmonic drive and including or excluding reset jitter. We performed precision-weighted root-mean-square error (WRMSE) model selection across six fractal conditions with a two-stage bootstrap. The Drive+Jitter variant best reproduced the empirical scaling for both H (pointwise WRMSE = 0.05; win probability = 0.79) and d (pointwise WRMSE = 0.09; win probability = 0.70). The Drive+Jitter phase resetting model simulated tapping persistence values ranging from H=0.57 to H=0.78 or d=0.44 to d=0.85, closely aligning with the experimental data. These results indicate that fractal auditory stimuli can elicit fractal motor outputs comparable to those in healthy states, suggesting potential therapeutic benefits for motor recovery and rehabilitation. The modeling approach provides a framework for understanding the mechanisms underlying auditory-motor synchronization across different tapping conditions.

An abundance of research supports an external focus enhancing motor performance relative to an internal focus. However, this blanket recommendation loses some nuance of what types of external cues might be most effective. Some studies have compared a proximal and distal external focus, but this comparison is often confounded by differences in both spatial and temporal distance. In the present study, we aimed to determine how internal and external focus cues that direct attention to either the process or outcome of the movement (i.e., differing in temporal distance, but not spatial distance) impacted hex bar deadlift performance. Twenty-four participants (16 females) experienced in strength training performed hex bar deadlifts with 60 % of their self-reported 1RM. Familiarization trials were followed by conditions using an internal-process (IP), internal-outcome (IO), external-process (EP), and external-outcome (EO) focus presented in a counterbalanced order. Peak velocity, average velocity, and vertical bar displacement were subjected to repeated measures ANOVAs to test for differences due to focus. Peak velocity was impacted by focus with an EP leading to higher values than IO and IP. For average velocity EP had higher values than IO, and approached higher values than IP. For vertical bar displacement, EO led to greater displacement than IO and IP, but did not differ from EP. The present findings suggest EP was most effective for enhancing velocity (primary goal), but EO maximized displacement. These differing findings suggest that the best external focus cues are those which most closely align with important task goals.

Despite growing interest in motion-controlled video games for rehabilitation, the mechanisms that facilitate transfer of motor learning in such situations remain poorly understood. This study examined the transfer of motor learning in a video game task controlled either via center of pressure (CoP) displacement or through torso rotations. For this purpose, during the game, participants controlled an aircraft in vertical and horizontal axes and had to fly through 100 ring-shaped targets. Twenty-one participants were randomly divided into two experimental groups. The first group (CoP-Tor) played first the game controlling the aircraft with CoP displacements and then the one with torso rotations. The second group (Tor-CoP) played the games in reverse order. Spatial errors were calculated between the player's position and the targets to quantify game performance. Sample entropy of the CoP displacement was calculated to quantify repeatability in postural sway variability. Our results showed that spatial errors were significantly lower in the CoP-controlled game for the Tor-CoP group compared to the CoP-Tor group. The Tor-CoP group also exhibited lower repeatability values in the CoP-controlled game compared to the CoP-Tor group. Our results suggested a directional transfer of motor learning from the Tor-controlled game to the CoP-controlled game, because performance improved in the CoP-controlled game when it was played after a Tor-controlled game. The entropy results suggested that the improved CoP-controlled game performance was also followed by a more repeatable pattern of movement variability. Overall, our findings suggest that torso-related training can improve CoP control possibly by increasing the repeatability of movement variability.

This study aimed to investigate bimanual force coordination in 36 healthy young adults employing a vector coding method. The participants performed bimanual force control at two targeted force levels (i.e., 10 % and 40 % of maximum voluntary contraction [MVC]) and the Purdue Pegboard Test. Force accuracy was used to assess bimanual force control performance. Vector coding analysis was conducted to estimate the quantity and quality of bimanual force coordination. Further, the correlation between bimanual force coordination and bimanual dexterity was investigated. Lower force accuracy was observed at 40 % of MVC. The coordination quantity analysis revealed that left- and right-hand phases were more frequently observed at 10 % of MVC, whereas the greatest quantity of in-phase coordination was observed at 40 % of MVC. Notably, anti-phase coordination demonstrated higher quality in error correction despite its lower quantity. Moreover, a greater quantity of anti-phase coordination at 40 % of MVC was associated with superior bimanual dexterity. These results indicated that quantifying the quantity and quality of coordination using the vector coding method provides a novel framework for identifying specific motor control strategies during bimanual tasks.

Previous studies have demonstrated that the cerebral cortex is involved in the postural responses to static standing and disturbances. However, the role of the cortex in postural stabilization remains unclear. This study aimed to clarify cortical activity during postural stabilization.

The self-talk matching hypothesis predicts that instructional self-talk is more effective for tasks involving precision and accuracy, and that motivational self-talk is more effective for tasks involving endurance, strength, and power (Theodorakis et al., 2000). Around 60 % of self-talk interventions support these differential effects predictions (Hardy et al., 2018). Attentional focus research may strengthen the matching hypothesis, where an external focus has been shown to improve performance and facilitate learning for a variety of motor tasks (Chua et al., 2021). It has been postulated that instructional self-talk impacts performance though attentional mechanisms (Galanis & Hatzigeorgiadis, 2020). Infusing internal and external attentional focus into instructional self-talk may allow more consistent performance differences to emerge between instructional and motivational self-talk. The purpose of the present study was to compare instructional self-talk with internal and external foci to motivational self-talk. 36 participants (Male = 10, Female = 26; M = 20.65 years) completed 60 dart throws in a counter-balanced order, with 15 occurring under each of four conditions: control (CON), internal-instructional self-talk (IIST), external-instructional self-talk (EIST), and motivational self-talk (MST). Performance was measured through mean radial error (MRE) for accuracy and bivariate variable error (BVE) for consistency. For a within-subjects design, data were analyzed with separate one-way repeated measures ANOVAs with four levels (i.e., CON, IIST, EIST, and MST) for each dependent variable. EIST and MST had significantly less MRE than IIST (p < .05). Results suggest that incorporating external focus into instructional self-talk may benefit discrete motor task performance.

The purpose of this study was to investigate metabolic cost, muscle activity, and perceptual responses during lateral and forward locomotion at different BWS levels at individual's preferred speed. Twelve participants performed lateral and forward locomotion on a lower body positive pressure treadmill at 0 %BWS, 20 %BWS, and 50 %BWS conditions at mode-specific preferred speed. Oxygen uptake, muscle activity, stride frequency, rating of perceived exertion (RPE), and feeling scale were measured during the tests. Oxygen uptake was influenced by the interaction of BWS and direction (P < 0.001). Muscle activity (rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius), stride frequency, and RPE during locomotion at 50 %BWS were averages of 23.7 %, 6.8 %, and 0.8 rankings lower than that of locomotion at 20 %BWS, respectively, regardless of direction (P < 0.05). Feeling scale value during locomotion at 50 %BWS was significantly higher than that of locomotion at 20 %BWS, regardless of direction (P < 0.01). During lateral locomotion, rectus femoris muscle activity was an average of 27.2 % lower and stride frequency was an average of 23.7 % greater than that of forward locomotion, regardless of BWS (P < 0.01). Furthermore, preferred speed during lateral locomotion was an average of 49.9 % lower than that of forward locomotion, regardless of BWS (P < 0.001). However, muscle activity (biceps femoris, tibialis anterior, and gastrocnemius), RPE, and feeling scale were similar between directions, regardless of BWS (P > 0.05). Our observations suggest that individuals self-selected their locomotion speed and stride frequency and induced similar magnitude of muscle activity from the lower extremity and perceptual responses during lateral locomotion and forward locomotion, regardless of BWS.