Background: Obstacle avoidance during walking is a critical aspect of locomotion that relies on visual information to ensure safe navigation. Implicitly perceived cues in the environment may aid in visuomotor control by subtly guiding decisions without explicit instructions. Aim: Therefore, we investigated the relationship between the availability of implicit cues and young adults’ visuomotor behavior during walking with obstacle circumvention. Methods: Twelve participants performed 30 trials of obstacle avoidance during walking under two experimental protocols: i) aperture-based protocol – manipulating the available width (aperture) on either side of the obstacle; and ii) light-based protocol – projecting a brief (1 s) green light spot on one side of the obstacle as a visual cue to guide the participant towards the side where they should circumvent the obstacle. Medial-lateral and horizontal center of mass distance to the obstacle, as well as gaze behavior, were recorded. Results: Our results showed that implicit visual cues, whether aperture-based or light-based, were not consistently related to the side chosen for obstacle circumvention, nor did were they related to the medial-lateral or horizontal distances. However, participants exhibited a higher number of fixations on the obstacle in the right visual cue condition (p = 0.047), with no differences in mean fixation duration or in the total percentage of fixations. Interpretation: These findings suggest that, under the present task constraints, implicit visual cues were not related to young adults’ visuomotor behavior during walking with obstacle circumvention, perhaps due to participants prioritizing obstacle-related visual information over environmental cues.
BACKGROUND: The structure of variability in postural sway reflects the adaptability and health of the postural control system. Entropy quantifies this structure by measuring the regularity of repeated fluctuations over time. Although entropy has been used to examine sway in neurological populations, little is known about how sway complexity changes following anterior cruciate ligament reconstruction (ACLR). Attentional focus may also influence postural control, with external focus typically promoting more efficient and automatic regulation than internal focus. AIM: To examine how attentional focus (internal vs. external) influences the structure of postural sway in individuals with and without ACLR. METHODS: Forty-three participants (20 ACLR, 23 controls) completed quiet standing trials on a force plate under three attentional focus conditions: internal focus on the injured or non-injured limb, and external focus. Sample entropy was calculated to assess sway complexity, and traditional linear sway variables (mean velocity, path length) were also examined. RESULTS: Participants with ACLR exhibited lower sample entropy than controls, indicating more regular and less adaptable sway patterns. In the ACLR group, external focus instructions significantly increased sample entropy relative to internal focus conditions. Linear sway measures also reflected improved control under external focus, with lower mean sway velocity and reduced path length. INTERPRETATION: Individuals with ACLR demonstrate reduced complexity in postural control, but external focus instructions can enhance adaptability. These findings suggest that attentional focus modulates sway dynamics after ACLR. Incorporating external focus into rehabilitation may facilitate more automatic and flexible postural control strategies.
BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disorder that compromises motor control, leading to reduced functional independence and quality of life. Dance-based interventions have emerged as a complementary intervention to mitigate PD-related motor symptoms. As aging naturally reduces joint range of motion (ROM), these limitations are further exacerbated in PD, emphasizing the need for targeted movement-based interventions. AIM: To investigate changes in joint range of motion following a structured dance-based intervention in individuals with PD, in comparison with age-matched healthy controls exposed to a different dance practice. METHODS: Participants included individuals with PD in Hoehn and Yahr stages I-III (n = 16) and age-matched controls (n = 16). Participants with PD engaged in a six-month dance-based intervention program based on the Baila Parkinson Method, while aged-matched controls participated in regular ballroom dance classes. Joint ROM of the shoulder, elbow, and hip was assessed using Kinovea (R) software during standardized movements. Multiple t-tests were used to examine inter-and intra-group differences (p < 0.05). RESULTS: Dance-based intervention significantly increased ROM in the right shoulder (p = 0.002), right elbow (p = 0.01), and right hip flexion (p < 0.0001) during uncompensated movements. Improvements were also observed in compensated movements, particularly elbow flexion (p = 0.005). Post-intervention, PD participants achieved ROM levels comparable to the control group. INTERPRETATION: The findings indicate that participation in a structured dance-based program was associated with improvements in ROM for individuals with PD, beyond compensatory movement adaptations. Dance-based interventions may thus represent an effective, accessible strategy to enhance motor performance and functional mobility in PD.
BACKGROUND: The level of difficulty of the goal is one factor that can influence the learning of motor skills. The effect of goals of greater or lesser difficulty depends on the leamer's characteristics, such as self-efficacy beliefs AIM: This study examined the effects of goal difficulty on the learning of volleyball serves and self-efficacy beliefs 1 METHODS: Twenty-five male university students (mean age = 21.68 +/- 2.69 years) were divided into two groups a higher difficulty goal group and a lower difficulty goal group. The quasi-experimental design consisted of pretest, acquisition phase (180 trials), and a retention test. RESULTS: Both groups showed Improvement in serve accuracy, however, only the lower difficulty group showed a significant increment in movement consistency (p<.001) from the pretest to the retention test. Goal difficulty did not affect self-efficacy beliefs. Furthermore, self-efficacy beliefs Bid not mediate the effect of goal difficulty level on leaming the volleyball serve. INTERPRETATION: These results suggest that lower-difficulty goals facilitate motor leaming by reducing performance Variability without affecting self-efficacy in beginners.
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BACKGROUND: Wearable devices integrate sensors and computational systems into daily life, supporting health, sports, and rehabilitation. Modularity, defined as the division of functions into interoperable subsystems, has emerged as a strategy to enhance personalization, usability, and lifecycle management. AIM: This systematic review examined how modular design strategies have been applied to wearable devices and evaluated their impacts on development, user experience, and maintenance. METHOD: A structured search in PubMed, IEEE Xplore, ScienceDirect, and Wiley (2019–2025) identified 15,208 records. Following PRISMA guidelines, 25 studies met eligibility criteria, including modular hardware wearables with functional implementation. Study quality was assessed using a custom 12-item checklist. RESULTS: Results: All studies (25/25; 100%) described attachment strategies such as snaps, hook-and-loop fasteners, magnetic couplers, or customized geometries. Modularity improved development in 80% of studies, supporting distributed architectures, wireless integration, and scalable workflows, though conversion of monolithic systems remained a challenge. Positive impacts on user experience were reported in 64% of studies, particularly through ergonomic adaptability, comfort, and configurability. Maintenance benefits were highlighted in 36% of studies, with modular systems enabling quick repairs, upgrades, and reuse of electronic and textile components. Importantly, modularity facilitated integration of neurophysiological tools (sEMG, fNIRS, EEG), enhancing sensor placement flexibility and artifact reduction in applied contexts. INTERPRETATION: Evidence consistently supports modularity as a foundational strategy to improve adaptability, usability, and sustainability of wearable devices. While its potential for portable neurophysiological assessment is promising, further validation in sports, rehabilitation, and everyday environments is urgently needed.
BACKGROUND:Affordance is one of the main pillars of direct perception theory. It refers to the possibilities offered by the environment to an animal with reference to its action capabilities. This paper presents recent findings from a set of empirical research on team sport of futsal developed under an ecological dynamic perspective. AIM:Because in team sports the players' interactions are inherently variable, we described the affordances from the variability of interpersonal coordination in futsal based on the research findings. METHODS:A set of empirical research on futsal was developed under an ecological dynamic perspective, examining players’ interpersonal coordination and the affordances emerging from the variability of these interactions. INTERPRETATION:(1) affordance for dribbling emerges from variability in the interpersonal distance and relative angles of passing and shooting; these variabilities mean uncertainty regarding the performance of these last two, as well as the risk of the ball being recovered; (2)affordance for passing emerges from (i) consistency in the velocity of emergence of great and specific relative angles; it signifies the possibility of a pass being successfully completed; and, (ii) intradyadic variability in passer and receiver dyads; it means the possibility of the attacking players to break the coupling to their respective marking defenders; (3)affordance for shooting emerges from (i) consistency in the velocity of emergence of specific interpersonal angle; it signifies optimal angular interpersonal relationship for shooting; and (ii) consistency in the defensive area during goalkeeper-as-an-outfield player situation; such consistency means the defensive team's low flexibility to adapt to the attacking team's numerical superiority.
BACKGROUND: The concepts of body-scaling, specifically pi ratios, have been developed to establish systematic guidelines for adapting junior sports. AIM: To investigate the impact of modifying court size and game rules using a body-scaling approach on badminton performance during match-play among children.. METHODS: In a seven-week crossover training program, thirty boys (mean age = 13.17 +/- 0.83 years) were exposed to both standard court and rules (SCR) and modified court and rules (MCR) conditions. Three evaluation points-the pre-test, the intermediate test, and the post-test-were used to measure performance indicators such as winning strokes, successful strokes, and unforced errors. RESULTS: Successful strokes (F(2, 58) = 10.412, p <.05, eta 2 =.488), winning strokes (F(2, 58) = 12.865, p < .001, eta 2 = .556), and unforced errors (F(2, 58) = 8.231, p < .05, eta 2 = .487) all showed significant interaction effects, according to a two-way repeated measures ANOVA. Under the MCR condition, the following main effects also improved more: winning strokes (F(1, 29) = 42.947, p < .005, eta 2 = .748), successful strokes (F(1, 29) = 71.583, p < .001, eta 2 = .902), and less unforced errors (F(1, 29) = 33.114, p < .001, eta 2 = .695). INTERPRETATION: These findings imply that task constraints based on children's physical attributes greatly improve technical skills and overall game performance in badminton performance. The body-scaling strategy provides a practical way to promote more effective performance and stroke execution in junior badminton by increasing stroke effectiveness and reducing unforced errors during match play.
BACKGROUND: Parkinson's disease (PD) can impair postural control and reduce functional limits of stability (LOS), which may constrain exploration and learning in whole-body motor tasks. AIM: This study investigated whether practicing whole-body virtual motor tasks changes LOS and whether LOS is associated with motor learning outcomes in adults with PD and age-matched healthy controls. METHODS: Twenty-five adults aged >= 50 years participated: 12 with PD and 13 healthy controls. Participants with PD were assessed in the medication ON state. Participants practiced four Kinect Adventures! games across 12 sessions. Game performance was assessed at pre-test, post-test, and one-month retention. LOS was assessed at pre-test and post-test using a center-of-pressure targeting task. LOS changes were examined with a mixed repeated-measures ANOVA. Structural equation modeling tested whether baseline LOS and practice-related individual variability in LOS (Delta LOS) predicted retained in-game scores. RESULTS: The Group & times; Moment interaction for LOS was significant, but Bonferroni-adjusted post hoc comparisons did not identify significant pairwise differences. There were no main effects of Group or Moment. Baseline LOS did not significantly predict retention performance. In contrast, Delta LOS significantly predicted retention performance, explaining 15.4% of the variance in the latent retention outcome. INTERPRETATION: Whole-body virtual task practice did not produce a uniform group-level increase in LOS. However, Delta LOS significantly predicts retention performance, suggesting that individual variability during acquisition is associated with long-term motor learning outcomes in adults with PD and healthy older adults.
BACKGROUND: According to the Dynamic Dominance Model (DDM), the dominant (preferred) and non-dominant (non-preferred) upper limbs are specialized for different control mechanisms, which may influence postural regulation during goal-directed manual actions. AIM: To compare postural control during a reaching and grasping task performed in an upright posture with the preferred and non-preferred upper limbs across different movement directions. METHODS: Thirty right-handed participants performed a reaching and grasping task in multiple directions and movement conditions using both upper limbs. Postural control was assessed using a force platform by analyzing the center of pressure (CoP) area, orientation (major elliptical axis), mean velocity, antero-posterior and medial-lateral excursion, and their lateral symmetry indices (LSIs). LSI values were compared to zero using t-tests, and task conditions were analyzed using repeated-measures ANOVA. RESULTS: Traditional CoP measures (area, velocity, and antero-posterior and medial-lateral excursion) did not differ across limbs or task conditions (all P-values > 0.065). However, the elliptical major angle revealed significant task- and limb-dependent effects, indicating changes in the directional organization of postural sway. INTERPRETATION: Although upper limb preference did not influence the magnitude of postural sway, it modulated the spatial organization of postural control. Within the DDM, these findings suggest that lateralized control mechanisms may affect coordination strategies rather than global stability. Thus, postural adjustments during upright reaching and grasping appear to be shaped by both task demands and limb-specific organization, even when overall stability is preserved.
BACKGROUND: Aging affects multiple body systems, compromising dynamic balance and increasing fall risk. Older adults retain the capacity for motor learning transfer. Therefore, balance training can generalize to different situations and help reduce falls. Balance-beam practice offers a highly challenging stimulus that drives neuromuscular adaptation, potentially benefiting both habitual and AIM: This study will investigate the effect of a walking beam training program on dynamic balance during habitual and adaptive locomotion in older adults with a METHODS: The sample will include 50 older adults with a history of falls, randomly assigned to either the beam or control groups. The training consists of six sessions of walking on a balance beam, with parameters adjusted to challenge participants to maintain dynamic balance (beam group). Simultaneously, the control group will follow a similar protocol of habitual walking without using the balance beam. The primary outcome is whole-body angular momentum during walking in different contexts, while secondary outcome variables include center of mass velocity, step length, and step width. Assessments of these variables will be performed pre-training, during (after 3 training sessions), post-training, and at a four-week follow-up after the end of the protocol. The Mini-BESTest (secondary outcome variable) will also be used to assess the participants' functional balance at the same time points. INTERPRETATION: The beam group is expected to demonstrate greater learning transfer and gains in dynamic balance than the control group during both habitual and adaptive locomotion, which may inform fall-prevention strategies
BACKGROUND: Coherent and ordered movement patterns emerge from the many available degrees-of-freedom and constraints channeling the interactions between them and the environment. AIM: We propose that task constraints have a different ontological status compared to the constraint categories of the environment and organism. METHODS: We argue that environmental and organismic constraints can be characterized as hard constraints as they are alternative descriptions of the dynamics (i.e., they describe the boundaries and characteristics of the system). Task constraints can, instead, be categorized as soft constraints-functions that influence the behavior toward task relevant solutions. Individuals search through the task space (function relating performance and movement parameters) encompassing rules and goal description but, only through learning, do the task constraints become actualized. Thus, in this manuscript, we discuss the ontology of task constraints elaborating how they should be discussed in the literature. CONCLUSION: This modified interpretation leads to an expansion of the concept into two frames (learner-based, experimenter-based) that has a series of consequences to future research on motor behavior.
BACKGROUND: The selection of rotational axes during unconstrained 3D arm movements is influenced by limb dynamics. Previous research suggests a velocity-dependent shift toward the minimum inertia axis (e3), but it remains unclear how changes in gravitational torque, induced by different arm elevation angles, affect this axis selection. AIM: This study aimed to examine whether the previously described velocity-dependent shift toward the e3 axis occurs independently of arm posture and variations in gravitational loading. METHODS: Participants performed cyclic internal-external arm rotations at slow and fast velocities across four shoulder elevation angles (0 degrees, 45 degrees, 90 degrees, and 135 degrees). This experimental paradigm systematically altered gravitational torque while preserving the geometric relationships among three candidate rotational axes: e3, the shoulder-center of mass axis (SH-CM), and the shoulder-elbow axis (SH-EL). Angular variability of the axes' displacement was evaluated. RESULTS: A repeated measures ANOVA revealed a significant main effect of shoulder elevation angle on angular variability (p < 0.001), with significantly higher variability observed at 90 degrees and 135 degrees compared to 0 degrees and 45 degrees. Furthermore, a significant Axis & times; Velocity interaction was observed (F(2,18) = 4.32, p < 0.05). Post-hoc analyses indicated that during the slow condition, the SH-EL axis exhibited significantly lower variability than the SH-e3 axis (p < 0.05). In contrast, during the fast condition, the variability across axes converged and differences between the axes did not reach statistical significance (p = 0.08). The comparison of SH-e3 variability between slow and fast conditions revealed a marginal trend (p = 0.052), but contrary to our hypothesis, no consistent shift toward e3 was observed across all elevation angles. INTERPRETATION: Axis selection is jointly shaped by movement velocity and limb configuration. The findings indicate that the motor system does not uniformly adopt a single rotation axis (such as e3) across conditions but instead exhibits a context-dependent organization where gravitational torque modulates, but does not fully determine, the observed kinematic patterns.
BACKGROUND: Doors are among the most commonly used everyday objects. Like all objects, doors have multiple affordances. While it is up to the user to choose from among the available affordances of a given designed object, it is up to the designer to allow the user to do so easily and safely. Doors with ambiguous affordances may hinder safe egress, especially under emergency conditions. AIM: This study investigated how doors with ambiguous affordances influence egress behavior. METHODS: We recorded and coded 328 egress attempts at three sets of exit doors on a university campus. We expected that the design and layout of two of the three sets of doors would create ambiguities about where to push on a horizontal push bar to open the door. Moreover, we expected that doors with ambiguous affordances would hinder egress relative to those with unambiguous affordances by generating more (initially) unsuccessful egress attempts and leading to longer egress times. RESULTS: Analyses of video coding of egress behaviors supported these hypotheses. Approximately 10-15% of egress attempts on the ambiguous doors were (initially) unsuccessful, but there were no unsuccessful egress attempts on the unambiguous doors. Moreover, unsuccessful egress attempts were nearly 1s longer than successful attempts. INTERPRETATION: This study provides the first empirical evidence that doors with ambiguous affordances hinder safe egress. A well-designed door, like any well-designed object, is one for which affordances can be perceived unambiguously, highlighting the need to design with affordances in mind. Design implications of the findings are also discussed.
BACKGROUND: Levodopa effects on postural sway may vary between motor subtypes Parkinson's disease (PD). AIM: This study investigated the impact of Levodopa on postural sway and identified clinical predictors of postural sway in individuals with PD classified as either postural instability/gait difficulty (PIGD) or tremor dominant (TD). METHODS: Thirty individuals with PD were classified as PIGD (n=12) or TD (n=18) subtypes. A subgroup of TD-participants without freezing of gait (FOG) was also analyzed (n=14) to control for FOG as a confounding factor. Participants stood as still as possible on a force plate for 30 seconds with closed-eyes both On-and Off-medication. Repeated-measures analyses of variance were used to compare groups and assess the effect of medication on postural sway. Backward regression analyses were conducted to identify the clinical predictors of postural sway in both medication states for each subtype. RESULTS: Medication state significantly influenced postural sway in the PIGD group, with increased sway observed in the On-medication condition, while the sway in the TD group remained unchanged across medication states. In the TD group, postural sway under medication was predicted by disease duration and cognition performance. In the PIGD group, sway in the Off-medication state was predicted by motor severity and cognition performance. FOG was confirmed as a confounding factor in postural sway among TD participants. INTERPRETATION: Levodopa affected postural balance only PIGD-subtype. Despite subtype differences in Levodopa effects, cognition emerged as a common predictor of postural sway between groups. Excluding participants with FOG strengthened the relationship between clinical characteristics and postural sway in the TD-subtype.
BACKGROUND: Although hippotherapy is considered an effective rehabilitation method for improving postural balance and mobility in children with cerebral palsy (CP), the evidence defining the dosage is still limited. AIM: To evaluate the effects of 40 hippotherapy sessions on static balance and functional mobility in children with CP. METHODS: A cohort study with 18 children with spastic CP (4-14 years), who completed forty weekly 30-minute sessions. Postural control was assessed using center of pressure (CoP) variables during sitting position with eye closed (EC) on a firm surface (FS) and foam surface (FoS), and standing position with eye open (EO) and EC on FS and FoS. Functional mobility was measured with the Modified Timed Up and Go (mTUG) and One-Minute Walk Test (1MTW). Assessments occurred at baseline (A1) and every eight weeks until post-intervention (A6). Data were analyzed using Generalized Estimating Equations with LSD post hoc. RESULTS: Functional outcomes improved, both mTUG and 1MTW at A6 vs. A1 (p = 0.001). In sitting position (EC/FS), reductions occurred in anteroposterior amplitude (ACoPap) (p = 0.021) and velocity (Vavg) (p = 0.002). In sitting position (EC/FoS), decreases were found in mediolateral amplitude (ACoPml) (p = 0.012), ACoPap (p = 0.007), Vavg (p = 0.011), and area (Area95) (p = 0.027). In standing position (EC/FoS), ACoPml decreased (p = 0.031). INTERPRETATION: Hippotherapy improved functional mobility from 8 and static balance from 16 sessions. These findings support hippotherapy as a long-term intervention to enhance postural control and functional mobility in children with CP.
Background: Somatosensory information (sensitivity of proprioceptive and cutaneous aspects) is crucial for maintaining a stable upright posture, especially in aging and neurodegenerative diseases. Furthermore, studies implement interventions to manipulate somatosensory inputs to understand the role of sensory information on postural control. Aim: In this scoping review we aimed to discuss the relationship between biomechanical parameters of postural control and somatosensory information in three sub-questions regarding aging, neuropathic conditions (mainly diabetes-induced), and sensory interventions. Methods: Literature review. Results: The literature search identified 1,355 potentially relevant articles, of which 49 met the inclusion criteria. We found significant relationships between biomechanical measures such as the center of pressure (CoP) and the availability of somatosensory information. Interpretation: Our review suggests that biomechanical analyses commonly focus on CoP as a key measure of balance, while the methods for assessing somatosensory function vary greatly. This variability could bias participant recruitment and study outcomes. Our review also offers an overview of the most common experimental setups used in recent decades and proposes suggestions for future research. We conclude that a methodological approach that integrates biomechanics with neurophysiological measurements is crucial for a more comprehensive understanding of postural responses and recommends its consideration in future studies. Additionally, future studies should aim to standardize somatosensory assessments to improve the reliability of biomechanical findings in studies addressing postural control.
The untimely death of Professor David Lee is taken as an opportunity to praise his extensive work on actions encompassing different contexts and species. The General Tau Theory is pointed out as the closest call the field of Motor Behavior has for stating a Law of Motion ecologically valid for living beings. The scope of Professor Lee’s works is emphasized from two narratives from one of the last scientific meetings he took part.
Background: Binge eating disorder (BED) is the most prevalent eating disorder in the world and recent findings on neuromodulation suggest potential benefits of Transcranial Direct Current Stimulation (tDCS) on the symptoms of binge eating. Aim: to carry out a systematic review to summarize the effects of tDCS on the symptoms of binge eating. Methods: This systematic review follows the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and was registered in PROSPERO (CRD42020140950). Searches were applied in PubMed (Medline), ScienceDirect (Elsevier), SciELO and LILACS. The included studies should have reported the effects of tDCS on the symptoms of binge eating. Results: 122 articles were found, of these, five were excluded due to duplication and 109 due to lack of framework. After reading the studies in full (n=08), seven studies remained eligible for analysis. A total sample of 195 individuals, aged between 18 and 55 years, with diagnosis or symptoms of binge eating was included. Interpretencion: For the tested protocols, tDCS over dorsolateral prefrontal cortex improved binge eating symptoms, as well as food craving, and can be an option within the treatment strategy.
Using the example of Environmental Enrichment (EE), we argue in this opinion piece that a qualitative interrogation of animal-based experimental paradigms can provide a substantial contribution to advance translational and rehabilitation practices. EE, a well-established paradigm in animal-based experimental biology, has been translated to human rehabilitation using a mechanistic approach, providing limited results. To advance current understanding of the paradigm, we have interrogated EE through a qualitative lens and have identified six principles—complexity, novelty, variety, individualization, integration, and scaffolding—that define EE in animals and can inform more effective, tailored rehabilitation strategies. This approach can be used in future research to create novel resources and teaching didactical methods that can help translate the impact of experimental paradigms, such as EE, seen in animals to human populations.
