This study examined the effects of point-light action observation therapy (PL-AOT) on muscle activation, upper extremity function, and activities of daily living (ADL) in stroke patients. Thirty-two participants were randomly assigned to either a PL-AOT group or a traditional AOT group. Both groups received 30-minute sessions, five times a week for four weeks. Assessments included the Fugl-Meyer Assessment for Upper Extremity (FMA-UE), Action Research Arm Test (ARAT), Box and Block Test (BBT), Korean Modified Barthel Index (K-MBI), Motor Activity Log (MAL), and surface electromyography (sEMG). Both groups showed significant improvements in all outcomes after the intervention ( < .05). However, the PL-AOT group demonstrated significantly greater gains in upper extremity function, ADLs, and muscle activation compared to the traditional AOT group ( < .05). Additionally, co-contraction ratios indicated positive changes in shoulder and elbow joint coordination only in the PL-AOT group. These findings suggest that PL-AOT may be more effective than traditional AOT in promoting motor recovery and functional improvements in individuals with stroke.

Complexity and local dynamic stability (LDS) of electromyographic (EMG) signals are valuable indicators for understanding motor control mechanisms and distinguishing skill levels in dynamic sports such as wrestling. This study investigates the relationship between complexity and LDS of EMG signals to understand the neuromuscular mechanisms underlying skill differentiation in wrestling. The complexity [using the Higuchi fractal dimension (FD)] and LDS [using the largest Lyapunov exponent (LLE)] activity of the upper limb muscles were calculated in elite and sub-elite wrestlers ( = 72) during the arm-drag and double-leg attack techniques. The correlation between complexity and LDS was evaluated using Pearson's correlation coefficient, and random forest analysis was used to determine their importance in differentiating skill levels. Elite wrestlers showed higher complexity, LDS, and correlation between complexity and LDS in EMG signals than sub-elite wrestlers. Random forest analysis showed that complexity is more important than LDS in differentiating skill levels. The findings show that training programs should be designed according to athletes' skill levels. Training programs should adopt a phased approach, initially targeting LDS and motor control and integrating complex exercises to promote adaptability and variability in motor responses. This approach can help athletes improve their motor control and achieve higher skill levels.

We investigated the influence of mental fatigue on motor performance and learning. Additionally, we examined whether practicing under mental fatigue induces resilience in future performance under similar fatigue conditions. Ninety-two participants were randomly assigned to a Mental Fatigue group (MENTAL-FATIGUE) or a Control group (CONTROL). The MENTAL-FATIGUE group completed a 30-minute Stroop task before practice, while the CONTROL group watched a movie. All participants practiced a Visuomotor Tracking Task (VTT). The experiment occurred over three days. On Day 1, participants completed a pretest (1 block of 5 trials), followed by their respective fatigue protocols, then practiced the VTT over 10 blocks. A post-test (1 block) followed the practice. On Day 2, participants performed a retention test under non-fatigued conditions. On Day 3, all participants completed the Stroop task and performed a fatigued retention test. Mental fatigue levels were assessed using a Visual Analog Scale before and after the fatigue protocols and at the end of Day 1. Motor performance was evaluated through the mean and variability of coincidence timing in the VTT. Results showed that mental fatigue impaired motor performance during acquisition but did not affect motor learning. Practicing under fatigue did not enhance future performance under similar conditions.

This study investigated the impact of real-time laser-guided visual cues on spatiotemporal gait parameters during initiation and termination in people with Parkinson's (PwP). Fifteen PwP walked a 5-m path under uncued and laser-cued conditions while gait kinematics and center of pressure (CoP) data were collected. Results revealed that laser-guided visual cues significantly increased anterior-posterior CoP displacement during the propelling phase of gait initiation ( = .016) and improved dynamic stability, evidenced by reduced lateral asymmetry ( = .007) and decreased fractal dimension of lateral gait variability ( = .001). Conversely, step time increased ( = .005) and step velocity decreased ( < .001) with cueing, while step length remained unchanged. No significant effects of cueing were observed during gait termination. These findings suggest that laser-guided visual cues enhance gait initiation in PwP by promoting propulsion and stability, likely by facilitating an external focus of attention and improving anticipatory postural adjustments. The lack of effect on gait termination may reflect differing neural control mechanisms. This study contributes to the understanding of laser-guided visual cueing mechanisms in PwP gait and supports its potential as a targeted intervention for improving functional mobility, particularly during the challenging phase of gait initiation.

By stimulating proprioceptive receptors, muscle vibration helps understand the crucial role of proprioception in gait control. From the literature, variability in responses during the stance phase across studies may be due to protocol differences, such as lighting conditions that affect visual information. This study aimed to investigate the interaction between vision and proprioceptive information from ankle and neck muscles over the gait cycle during treadmill walking.

Visual-motor illusion (VMI) is a kinesthetic illusion produced by viewing an image showing joint motion. VMI with enhanced joint movement intensity (power-VMI; P-VMI) is expected to activate a wide range of motor association brain regions, and when combined with electrical stimulation that activates the motor sensory cortex, further activation of brain activity can be expected. This study aimed to verify the effectiveness of VMI using functional near-infrared spectroscopy to confirm brain activity during combined P-VMI and electrical stimulation. Brain activity was measured in 15 healthy adults during three tasks performed on the left ankle joint: P-VMI with electrical stimulation, P-VMI alone, and electrical stimulation alone. The tasks were performed randomly on a single participant. Brain activity was measured during each task using a protocol comprising 15 s of rest, 30 s of task performance, and 30 s of follow-up. Regions of interest included motor-related areas. The results showed that P-VMI alone activated the right superior parietal lobule and left supramarginal gyrus more than P-VMI combined with electrical stimulation. These findings suggest that P-VMI and sensory-threshold electrical stimulation do not necessarily complement each other in enhancing brain activity, as P-VMI alone shows greater activation in specific motor-related brain regions.

Theories of human motor learning commonly assume that movement plans are adjusted in response to the sensory feedback received about their success or failure. The degree to which movement errors drive changes in feedforward motor plans is further assumed to scale inversely with sensory uncertainty. However, support for these assumptions comes primarily from experiments that limit feedback corrections during an ongoing movement. In contrast, we have recently shown that when this restriction is relaxed, a different pattern of behavior emerges. Participants gradually adjust their reaching movements in response to a perturbation from trial-to-trial, following a consistent and incremental envelope of error reduction. Riding on top of this gradual learning envelope, participants also exhibit large and abrupt changes in their initial reach direction that are strongly correlated with the uncertainty level of the sensory feedback experienced on the previous trial, but are insensitive to the size and direction of the movement error made on that trial. A class of models in which sensory uncertainty influences an aiming process best accounted for this pattern. Here, we examine the possibility that uncertainty acts as a contextual cue to shunt motor processes to one of many context-specific internal models.

There is a lack of research on the effects of fatigue and dual-task motor performance in people with Multiple sclerosis (MS), especially in women. Using a group of 20 women with MS and 20 healthy controls, we examined the effects of fatigue and attentional demands on center of pressure (COP) displacements during upright stance. Anterior-posterior (AP), Media-lateral (ML), and total COP displacements, and also ankle plantar flexors' strength were measured. Results indicated that fatigue and dual-task resulted in higher ML COP displacements in both groups, but unlike controls, MS patients had higher ML displacements during the dual-task compared to single-task trials. Additionally, while fatigue resulted in an increased single-task AP and total COP displacements in both groups, it yielded higher dual-task AP and total COP displacements only in MS patients. Moreover, MS patients had weaker ankle plantar flexors compared to healthy controls, but the plantar flexors-mainly soleus-maximum voluntary contraction (MVC) was only associated with fatigued single-task balance performance in MS patients. Our study confirmed the adverse effects of fatigue and dual-task on balance performance, especially in MS patients. Further research is required on whether the modulation of balance performance of ankle plantar flexors' MVC depends on fatigue and attentional task demands.

Standing at elevated heights can elicit postural adjustments often characterized by reduced center of pressure (COP) magnitude, higher frequencies, and increased irregularity. While often attributed to postural stiffening, such changes may also reflect a shift toward more automatic control. However, most height-related studies use a feet-parallel stance, which may not be generalized to more constrained foot positions like semi-tandem, which are often encountered in real-world height situations. This study investigated the effects of acute virtual height exposure on postural control in a semi-tandem stance. Twenty young adults stood on a force platform under three conditions: (1) no VR, (2) VR sidewalk at ground level, and (3) VR elevated plank. Each participant completed six 60-second trials per condition. Repeated-measures ANOVAs revealed that wearing the VR headset alone affected postural control, with further changes under height exposure. Height was associated with increased COP frequency and irregularity, suggesting more automatic control. However, due to biomechanical constraints, the semi-tandem stance may have influenced postural strategies, resulting in increased COP variability. These findings support the use of VR to study postural threat and highlight the role of foot position in postural adaptations.

This study examines the traces of movement trajectories for perception accuracy in expert performance, focusing on table tennis. Twenty participants (10 experts and 10 novices) performed self-generated movements for extended haptic accuracy tasks, and their performance was analyzed for absolute error and movement trajectory. The results reveal that the expert participants exhibited more movement entropy than novices, strategically sacrificing trajectory predictability to enhance haptic perception accuracy. These findings reveal the adaptive strategies used by experts to optimize performance and provide insights into the balance between movement entropy and perception accuracy in skilled motor control.

Human behavior is influenced by the social context and depends on emotional state. This study focuses on the effect of the presence of others and group in interaction with the emotional impact on motor, cognitive and affective performance. Seventy-four subjects participated in the study. Each participant performed a dart shooting action in three conditions: the individual, presence of others, and group presence. Motion kinematics were detected using Adope Premier software and affective states were recorded using a Deep-learning facial expression recognition model. Performance analysis revealed that subjects performed the task with a shorter reaction time and movement duration during the others' presence condition as well as the group presence condition compared to the single case. The results thus demonstrate the effect of emotions on movement kinematics and emotional correspondence and stability. This improvement can be attributed to the social facilitation related to the audience effect and motivational factor.

This study investigates cognitive-motor interference by combining Raven's Progressive Matrices Test (RPMT) with treadmill walking. Two groups of healthy adults-20 young adults (born after 1995) familiar with treadmill walking and 18 older adults (born before 1980) without treadmill experience-completed both single-task and dual-task conditions. Cognitive performance (RPMT score) and gait metrics (stride interval variability and sample entropy) were recorded. Results revealed diverse interference patterns, with a predominance of gait-prioritization strategies under dual-task conditions. Significant differences between groups were found: younger adults showed greater cognitive performance decline, while older adults increased stride interval under dual-task conditions. A negative correlation between gait variability and complexity suggested adaptive motor strategies in some participants. This dual-task paradigm offers a standardized framework to explore both individual and group variability in multitasking performance. These insights may inform the design of safer environments and interventions targeting populations with different cognitive-motor profiles.

This study investigated the effects of Adapted Tango (AT) on dynamic balance, dual-tasking, and leg muscle antagonist activity in individuals with Parkinson's disease (PD), a condition characterized by cognitive and muscular difficulties. A total of 33 participants with mild-to-moderate PD were recruited and assigned to either an AT group ( = 16, 9 M/7F) or a control group ( = 17, 10 M/7F). Participants' dual-task performance was evaluated using Serial 7 walking tasks and the Dynamic Gait Index (DGI) at three different time points: before the intervention, immediately after, and four weeks post-intervention. Additionally, muscle activity modulation (the ability to activate and inhibit muscles appropriately) was quantified using Modulation Indices (MI) derived from EMG data. The results demonstrated an improvement in dual-task performance following the AT intervention; however, these differences between the AT and control groups were not statistically significant ( > 0.05). Notably, significant enhancements in DGI scores were observed in the AT group compared to controls ( < 0.05). Conversely, MI did not significantly change after the intervention ( > 0.05). This research highlights the potential of Adapted Tango in enhancing dynamic balance for individuals with PD, suggesting a need for larger-scale randomized trials to provide further evidence and inform clinical practice.

Sixteen right-handed percussionists performed a musical excerpt under crescendo and decrescendo conditions to explore kinematic and directional motor control strategies in percussion dynamics. Motion capture technology measured mallet and hand movements to analyze peak mallet/hand height and velocity for each stroke, as well as average mallet/hand position and velocity during upstrokes (mallet trajectory from playing surface to peak height) and downstrokes (trajectory from peak height to playing surface). These measures assessed execution and directional control, respectively. Results showed that peak mallet heights increased from notes 1-4 during crescendos and decreased over the same range during decrescendos, coinciding with increased and decreased peak hand velocity. During crescendos, the left mallet and hand were consistently elevated higher above the playing surface than the right. Within the right hand effects were localized to the velocity domain. For upstrokes, hand velocity was lower in crescendos versus decrescendos, while velocity was higher for downstrokes in crescendos. These findings indicate distinct motor control strategies contributing to the directional control and execution of sound-producing movements, emphasizing limb-specific mechanisms that could inform percussion pedagogy.

In the biomechanics of striking tasks, different types of visual feedback for the upper extremities influence motor learning and control in distinct ways. Quantitative feedback (QN), which provides precise numerical data, and qualitative feedback (QL), which offers descriptive or interpretive guidance, may facilitate different aspects of motor skill acquisition. Given that ballistic motor skills, such as the badminton underhand-clear stroke, require not only rapid and coordinated movement execution but also precise control of distal joints for accuracy, the underlying feedback processing mechanisms play a crucial role in optimizing motor control. Therefore, this study aims to determine the most effective type of visual feedback for enhancing motor learning in the badminton underhand-clear stroke by examining its impact on movement efficiency and accuracy. Participants ( = 36, all male; mean age 25.1 ± 1.2 years) were recruited into three groups: QN group, QL group, and the control group. Each participant completed a pretest, post-test, and retention-test of 20 trials each for the badminton underhand-clear stroke, along with three practice sessions consisting of 50 trials each. Performance accuracy and coordination patterns were significantly improved in the QN group compared to the QL and control groups in the retention test [performance accuracy (mean radial error) = QN-control: .01, QN-QL: .01; coordination pattern (discrete relative phase) = QN-control: .001, QN-QL: .01]. Additionally, the kinematics of the wrist joint were significantly improved in the QN group compared to the QL and control group in the retention test (maximum extension angle of wrist joint = QN-control: .001, QN-QL: < .01). These findings suggest that quantitative feedback may be more effective than qualitative feedback in facilitating motor learning in a badminton striking task, particularly in terms of long-term retention of movement accuracy and coordination. By analyzing motor coordination patterns, this study provides insight into the role of different types of visual feedback in motor learning and offers practical implications for instructors aiming to optimize skill acquisition in striking tasks.

When planning reach-to-grasp movements, individuals frequently face a tradeoff between biomechanical comfort (i.e., avoiding effortful actions) and "socio-emotional comfort" (i.e., avoiding decisions with a negative socio-emotional outcome). But what happens when socio-emotional comfort conflicts with biomechanical comfort? This study investigated whether and under what conditions individuals may prioritize socio-emotional over biomechanical comfort during motor planning. In a series of three experiments based on the end-state comfort effect, 88 participants selected one of two mugs which varied in orientation (i.e., upright/inverted) and social meaning (i.e., socially positive, neutral, or negative symbol printed on the mug). The findings confirmed that symbolic meaning may influence motor planning. This effect was however context-dependent, i.e. stronger when participants had a social instead of a functional goal (i.e., choosing a mug to give it as a present vs. to use it). In this condition, participants prioritized socio-emotional comfort over their own biomechanical comfort. The findings suggest that individuals integrate social information (e.g., social norms) into motor plans. Furthermore, this information can sometimes bypass biomechanical constraints: when the social meaning of objects is salient (here, based on contrasts between positive and negative symbols) and context-relevant, biomechanical comfort can be sacrificed in favor of socio-emotional comfort.

This study explores the association between motor competence (MC) and response time (RT) in schoolchildren. 251 participants (mean age 14.58 ± 3.07 years) completed assessments over two sessions using standardized procedures. MC was evaluated through the Motor Competence Assessment, which includes stability, locomotor, and manipulative skills, while RT was measured using a structured reaction task. Pearson correlations and multiple linear regression analyses examined the relationships between variables. Moderate correlation (r = -0.35, < .001), with stability and manipulative skills as significant predictors of RT were found. The model accounted for 24.4% of RT variance, highlighting MC's role in neuromuscular coordination and cognitive processing. These findings emphasize the importance of MC in more efficient responses during youth, with potential applications for physical education and sports.

The current understanding of balance development in middle childhood is predominantly from static postural tasks, in which a typical finding is a linear pattern. A paucity of studies, however, have examined the development of dynamic balance. Thus, we investigated how 354 girls and boys aged 7-10-years-old crossed a river on a wide or narrow plank in virtual reality, while their movement strategies were measured. Sex, height and perceived motor competence were examined as covariates. The results indicated that age did not appear as a significant independent variable for any measures, and that significant differences emerged between boys and girls. These findings suggest that dynamic balance can have a non-linear development in middle childhood, with boys and girls utilizing different task-specific strategies.

The Timed Up-and-Go (TUG) test, a clinical assessment tool of functional mobility and balance scale for fall risk, is potentially helpful for evaluating anticipatory locomotor adjustments (ALA). This study aimed to simplify ALA evaluation in older adults using the TUG test. Thirty-eight older adults (mean ± : 74.97 ± 6.42 years) and 24 younger adults (25.16 ± 4.82 years) participated. Two identical poles replaced the cone-shaped object, creating the "obstacle TUG (Obs-TUG) test." Participants chose between passing between the poles or detouring around them. We examined the quality of ALA in terms of their route selection. Results showed that older adults selected a detour more frequently than younger adults, even if the opening between the two poles was so wide that passing through the opening required less time than taking a detour. Older adults were characterized by shorter step lengths and narrower step widths while turning, indicating prioritization of stability over efficiency. The Obs-TUG test effectively describes ALA characteristics in older adults through consistent behavioral choices in route selection and walking patterns.

Upper extremity Selective Voluntary Motor Control (SVMC) is a key factor influencing upper extremity functions in children with Cerebral Palsy (CP), but differences in SVMC of the upper extremity between unilateral and bilateral CP and its association with trunk control and balance remain unclear. This study aims to examine differences in upper extremity SVMC and its association with trunk control and balance in 58 children (31 unilateral, 27 bilateral) with spastic CP. SVMC, balance, and trunk control were assessed using the Selective Control of Upper Extremity Scale (SCUES). Pediatric Balance Scale (PBS), and the Trunk Control Measurement Scale (TCMS), respectively. No significant difference in SCUES scores was found between unilateral and bilateral CP ( > 0.05). SCUES scores correlated with TCMS in both types ( < 0.05), with a stronger correlation in bilateral CP (unilateral rho = 0.38, bilateral rho = 0.87). PBS correlated with SCUES only in bilateral cases ( < 0.01, rho = 0.88). In conclusion, impaired upper extremity SVMC is common in spastic CP and more linked to trunk control and balance in bilateral than unilateral cases. Addressing this difference may guide the development of tailored interventions for both types.

This study investigated the effects of neck angle on center of mass (CM) stability and joint angle variability in the handstand. Seven experienced female gymnasts performed handstands in extended, neutral, and flexed neck angles. Kinematic data were collected using a 3D motion capture system, and variability was assessed for wrist, elbow, shoulder, hip, and neck angles and, CM position. The findings showed that the extended neck angle posture exhibited the lowest CM variability, aligning with its prevalent use in practice and competition. Regression analyses revealed that joint angle variability was significantly corelated to CM motion, with the typical extended neck angle related to shoulder, wrist, and neck angle variability contributions (33%, 23%, and 21%, respectively). In contrast, the neutral neck angle was moderately corelated to hip variability (32%), while the flexed neck angle showed a dominant reliance on neck angle variability (63%). The results show the strong role of neck angle in the postural variability of the handstand that is mediated by joint angle variability, visual information and tonic reflex support.