Journal of Motor Behavior最新文献

This study aimed to examine the effects of the presence or absence of visual information (eyes open or eyes closed), leg dominance (dominant leg or nondominant leg), and gait speed (normal gait or maximum gait) on gait performance. The participants (30 young adults 21.3 ± 0.8 years) performed 10-m walking tests with a small triaxial accelerometer attached to their waist. They performed normal and maximum gait tests under two conditions: eyes open and eyes closed. The gait performance evaluation parameters were gait speed, stride, step length, cadence, stance phase, swing phase, double support phase and single support phase. The results of Bayesian mixed-effects model analysis showed that visual condition (eyes open) had a positive effect on many parameters during normal gait speed; however, this effect tended to decrease during maximum gait speed. There were no clear effects for leg dominance or its interaction with visual information. These results suggest that visual information plays an important role in gait control and that its effect depends on the gait speed. Therefore, gait evaluation based on differences in gait speed and sensory integration modalities might be useful in understanding the diversity of gait control mechanisms.

This study examined the effects of self-controlled versus instructor-controlled demonstration on learning basketball free throws in children with different motor imagery abilities. Forty boys aged 9-12 were randomly assigned to four groups based on imagery ability (high/low) and demonstration type (self/instructor-controlled). In self-controlled conditions, participants could choose when to receive the skill demonstration from the instructor. Performance was evaluated using the basketball free throw test, and motor imagery ability was measured using the Motor Imagery Questionnaire for Children (MIQ-C). Following a pretest, participants trained for ten sessions every other day, with each session consisting of twenty throwing trials. Assessments included a post-test (after the last session) and retention and transfer tests (one week later). The results indicated that self-controlled groups performed better than instructor-controlled groups across all phases (p = .001). Additionally, skill learning was not significantly impacted by motor imagery ability (p > .05). These findings suggest that regardless of children's motor imagery skills, the self-controlled demonstration method enhances basketball free throw learning. The superiority of the self-controlled condition, regardless of imagery ability, emphasizes how crucial it is to give learners control over their training when it comes to learning basketball skills.

Thirty-one children (48% female, 55% White, 4-12 years) and twelve adults (67% female, 67% White, 18-50 years) participated in feasibility and validity testing of the Spatial Movement Sense tests. The Spatial Movement Sense tests assess the participant's ability to identify shape patterns based on how their hand moves (actively or passively) through a movement pattern without vision. All participants were able to complete the assessment. Results of our assessment are significantly correlated with endpoint position sense and support these tests as a valid proprioception assessment. There were also developmental trends and strong correlations with motor performance. The Spatial Movement Sense tests appear to be a promising tool for assessing proprioception in children.

Optimality in motor behavior is both task- and person-specific. Despite progress in theoretical models, clinical perspectives on optimal movement most commonly invoke between-subjects research findings studying imprecise constructs, and the implications for practice are far-reaching. Clarifying the theory and evidence concerning optimality in movement is essential for informed application of these nuanced concepts. We studied motor performance effects of optimality in bipedal sagittal configuration, a behavior of disputed significance in disease explanatory frameworks. Sixteen healthy young adults performed bipedal standing tasks under 2 non-optimal stance configurations (toes up, toes down) intended to induce a range of initial displacement from our surrogate for optimal (flat). Goal-equivalent variance (GEV) in joint angle displacement was quantified using an uncontrolled manifold approach. Bipedal standing was periodically interrupted by "mini-squats", around which we quantified the effects of proximity to optimal configuration on 1) motor equivalent (ME) deviation pre-to-post squat, and 2) anticipatory GEV constriction. Toes-up stance was associated with greater pre-to-post squat ME deviation and greater anticipatory GEV constriction, both consistent with greater initial displacement from optimality. These observations partially support our hypothesis that bipedal sagittal configuration is subject to optimality, which informs ongoing debates concerning the role of movement optimality in health and disease.

Reaching and grasping require a combination of visual and somatosensory feedback, both of which can be impaired in neurologic conditions. We examined the effect of removing vision on individuals' ability to perform the Box and Block Test, and compared the effect between younger and older adults and in a small pilot sample of individuals with chronic hemiparetic stroke. Thirty young adults, 16 older adults, and 4 individuals with chronic stroke completed the Box and Block Test with each hand with vision and then with vision occluded. Both younger and older adults had reductions in performance when vision was removed of approximately 27%, with no differences found between age groups or hands. Preliminary data from adults with stroke demonstrated variable performance with the reduction in performance for the less affected hand ranging from 22%-44.4% and for the more affected hand from 42.9%-73.2%. We did not detect any age-related differences in the reliance on vision in our sample. We found that it is feasible to use a modified Box and Block test to assess visual reliance versus somatosensory feedback, and it may be used as a clinically feasible tool for clinical populations, including stroke.

Transfer between limbs in younger adults is typically asymmetrical, with greater changes observed in one limb following practice with the other limb, depending on the controlling hemisphere (Pan & van Gemmert). This asymmetry is linked to lateralized hemispheric control of movement (Sainburg), irrespective of high (HPA) or low (LPA) levels of physical activity (McGregor et al.). Acute exercise affects motor skill transfer (Neva et al.). The purpose of this study was to examine the effects of reported chronic physical activity level on bilateral transfer in young adults. Fifty young right-handed participants (18-30) were grouped by physical activity level and randomly assigned a training limb. Individuals performed a 30° visual rotation drawing task. Pretest established baseline performance of each limb, followed by 40 practice trials on the assigned limb. Post-tests mirrored pretests assessing changes. HPA improved movement time (MT), normalized jerk (NJ), trajectory length (TL), and initial direction error (IDE) in the dominant limb following non-dominant practice (p < .05). LPA showed symmetrical transfer for IDE (p < .05), with improvements in either limb following training. HPA elicited asymmetric transfer of motor planning parameters. LPA elicited symmetric transfer, indicating compensatory ipsilateral hemispheric control, like older adults (Cabeza et al.).

Bilateral movements are important for daily function and are impaired in children with unilateral cerebral palsy (UCP). Prior work has established that coordination is dependent on symmetry demands between the limbs. We examined how symmetry impacted bilateral coordination, and as an exploratory aim, compared age-related differences in upper-limb (UL) coordination in children with UCP to children with typical development (TD). Using an instrumented cycling device, participants performed bilateral UL cycling in symmetric or asymmetric patterns. Metrics of inter-limb (phase error) coordination were compared between groups (TD or UCP) and with respect to age (young: 7-9 years; older: 13-15 years). Children with UCP had poorer inter-limb coordination in both symmetric (50.88°) and asymmetric (93.22°) bilateral tasks compared to TD children. Younger children, regardless of group, had poorer inter-limb coordination for the asymmetric (32.54°) bilateral task only. Regression modeling revealed UCP, age, and unilateral coordination ability were significantly associated with asymmetric bilateral coordination. The results indicate that bilateral coordination skills reflect atypical processes related to UCP and typical age-related motor development, particularly for more complex asymmetric tasks. Altogether, this research confirms children with UCP have impaired bilateral coordination and highlights potential for future work to study developmental changes in this population.

Intact ankle proprioception is essential for the control of balance and gait. This study determined ankle position sense acuity for plantarflexion and dorsiflexion. In two separate assessments, the right ankle of 30 healthy young adults was passively rotated from neutral joint position to a 15° reference position and a smaller comparison position in either plantar- or dorsiflexion. Subsequently, participants verbally indicated which position felt more flexed. After 25 trials, a psychometric function was fitted to the respective response-stimulus size difference data for each participant. Two outcome measures were derived: a Just-Noticeable-Difference (JND) threshold as a measure of systematic error and an Uncertainty Area (UA) indicating random error. Analysis showed that 70% (21/30) of participants exhibited lower JND thresholds for plantarflexion. Mean JND threshold and median UA were both significantly lower in plantarflexion when compared to dorsiflexion (p = 0.008, d = 0.52; p = 0.001, $r_b$ = 0.58) indicating that ankle proprioceptive acuity was not uniform for sagittal plane ankle motion. We discuss differences in plantar and dorsiflexor muscle mechanoreceptor density and central proprioceptive signal processing as possible reasons for the observed differences in acuity and highlight the importance of understanding movement-specific proprioceptive acuity for designing effective rehabilitation protocols.

One of the most important targets after stroke, which is a major cause of disability worldwide, is to improve gait ability. Although many different parameters required for gait improvement are known, determining the key parameters is of great importance. This study aims to identify key parameters that predict gait speed in individuals with stroke, with a particular focus on motor and sensory components. A total of 41 individuals with stroke participated in the study. Gait speed, balance, muscle strength, motor functions, spasticity, proprioception, and plantar cutaneous sensation were assessed by 2-min walk test, Berg Balance Scale, hand-held dynamometer, Fugl Meyer assessment-lower extremity, Modified Modified Ashworth Scale, repositioning error, and Semmes-Weinstein Monofilament Test, respectively. In this study, gait speed was correlated with all parameters except for plantar cutaneous sensation. Balance and lower extremity muscle strength were found to be the main parameters predicting gait speed (Adj. R² = 0.656, p < 0.001). Furthermore, hip flexor muscle strength emerged as an important predictor of gait speed among the lower extremity muscle groups (Adj. R² = 0.618, p < 0.001). The findings indicate that balance and lower extremity muscle strength, particularly hip flexor muscle strength, may serve as potential targets for interventions to increase gait speed, although the statistical results do not imply causality.

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 (p < .05). However, the PL-AOT group demonstrated significantly greater gains in upper extremity function, ADLs, and muscle activation compared to the traditional AOT group (p < .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.