Journal of Motor Behavior最新文献

Historically, research aimed at improving motor performance has largely focused on the neural processes involved in motor execution due to their role in muscle activation. However, accompanying somatosensory and proprioceptive sensory information is also vitally involved in performing motor skills. Here we review research from interdisciplinary fields to provide a description for how somatosensation informs the successful performance of motor skills as well as emphasize the need for careful selection of study methods to isolate the neural processes involved in somatosensory perception. We also discuss upcoming strategies of intervention that have been used to improve performance via somatosensory targets. We believe that a greater appreciation for somatosensation's role in motor learning and control will enable researchers and practitioners to develop and apply methods for the enhancement of human performance that will benefit clinical, healthy, and elite populations alike.

The postural system requires the sensory systems to maintain postural control (PC). Blind subjects use the somatosensory system to keep PC whereas sighted subjects use the visual system. So what happens to PC when challenging the sensory systems? We analyzed the center of pressure (COP) in ten blind and 10 sighted subjects under conditions: eyes open/closed (interference of visual system) and on firm/foam surfaces (interference of somatosensory system). We found that under the condition of eyes open on a firm surface, the blind subjects relied on the somatosensory system, whereas sighted subjects relied on the visual system. However, when eyes closed and on foam surface, similar behavior was found in both groups for all COP variables. In general blind subjects use their somatosensory system as the main sensory input to maintain PC.

Gross motor development in the preschool phase depends on several factors that remain poorly understood. This study aimed to investigate whether level of habitual physical activity (HPA) and global cognitive function (CF) can be used as predictors of gross motor skills in Brazilian preschoolers and to verify their possible mediators. A cross-sectional study was conducted with 166 children, aged 3-5 years. Gross motor skills, HPA, CF and possible mediators (e.g., sex, prematurity) were evaluated. Preschoolers with little HPA, low CF, and girls were more likely to have gross motor performance below expected, but female gender did not mediate HPA or CF. Therefore, HPA and CF, in addition to females, may be independent predictors of delayed gross motor skills in Brazilian preschoolers.

Descending stairs is an indicator of independence among stroke survivors, but is demanding in terms of both neuromuscular control and cognitive functioning. Previous studies found a compromised performance when stepping down with a concurrent cognitive task among healthy older adults, but whether stroke survivors react similarly is not known. This cross-sectional study thus investigated how stroke survivors responded to a dual-task that involved stepping down and compared their performance with that of control subjects. Thirty-four healthy individuals and 26 stroke survivors reacted to an auditory Stroop test while stepping off a 19-cm high platform. The auditory Stroop test was evaluated with a composite score (dividing accuracy by averaged reaction time). Stepping down performances were quantified with subjects' sway amplitudes in anteroposterior and mediolateral directions after landing and sway velocities of their center of pressure. Stroke survivors demonstrated significantly lower composite scores when dual-tasking (76.4 ± 31.2) than when single-tasking (90.0 ± 25.6), while no significant change in stepping down performance was observed. Stroke survivors also swayed significantly more and with a higher velocity than controls when dual-tasking. The results suggested that stroke survivors adopted a posture-first strategy to deal with this dual-tasking challenge. This study raised the awareness on dual-tasking ability among stroke survivors.

The practice of early sport specialization, defined as intense year-round training in a single sport at the exclusion of others, is increasing in youth athletics. Despite potential benefits, sport specialization may be detrimental to the health of young athletes, as specialization may increase the risk of musculoskeletal injuries-particularly overuse injuries. However, there remains limited knowledge about how sports specialization uniquely alters underlying sports-related motor behavior. The purpose of this study was to compare the variability of movement patterns exhibited by highly sports specialized youth athletes to that of nonspecialized athletes during performance of a sport-specific, virtual reality based cutting task. It was hypothesized that highly specialized athletes would display different patterns of movement coordination compared to nonspecialized athletes during both the run-up phase and cut-and-decelerate phase. In support of the hypothesis, specialized athletes exhibited both intra- and inter-limb coordination that were significantly different than unspecialized athletes. Overall, the results indicate that the highly specialized athletes tended to exhibit greater degrees of coordination but also the ability to break the coordinated patterns of joint angle changes to execute a cutting maneuver, which requires asymmetric demands on the lower extremities while planting on one leg and changing direction.

We investigated the generation of anticipatory (APAs) and compensatory postural adjustments (CPAs) in preparation for a step during support surface perturbation. Changes in anticipatory muscle activation in the trunk segment were predominantly in the co-contraction indices from -600 t₀ -400 ms to foot-off. Reciprocal indices of the shank muscles were pronounced in the APA intervals. During the CPA intervals, larger reciprocal muscle activities were detected compared to the APA intervals. The results showed subjects co-varied the reciprocal and co-contraction activations in postural muscles to counteract the perturbation and generate mechanical effects sufficient for stepping during the APA and CPA intervals. This study enhances our understanding of the interaction between the APAs and CPAs in balance maintenance.

The purpose of this study was to investigate effects of brain excitability by transcranial direct current stimulation (tDCS) on spike performances of professional female volleyball players. Thirteen professional female volleyball players were recruited for participation. We performed a randomized single-blind, SHAM-stimulus controlled, and counter-balanced crossover design with two interventions in this study. An anodal tDCS current was applied over the primary motor cortex (M1) for 20 min at 2 mA. In the SHAM intervention, the current was first applied for 30 s, after which it was terminated. Exercise performance assessment which comprised spike performance (spike ball speed, spiking consistency), two vertical jumps (jump and reach: JaR, countermovement jump: CMJ), bench-press and back-squat one-repetition maximum (1RM) were tested pre- and post-intervention. Results indicated that spike ball speed and spiking consistency following tDCS were significantly higher than those after SHAM intervention (both p < 0.05). However, JaR and CMJ did not show any significant differences between tDCS and SHAM intervention groups (both p > 0.05). There was no significant difference in bench-press and back-squat 1RM between two groups either (both p > 0.05). These findings suggest that tDCS could be effective in enhancing motor coordination performances of professional female volleyball athletes.

Most actions of daily life engage the two upper extremities (UEs) in a highly coordinated manner. While it is recognized that bimanual movements are impaired post-stroke, understanding how the paretic and non-paretic UE contributes to this impairment is important for future interventions. We investigated kinetic and kinematics at the shoulder, elbow, and wrist joints in the paretic and non-paretic UE in 8 individuals with chronic stroke and non-dominant UE in 8 healthy controls during unimanual and bimanual tasks. Kinematic analysis revealed little effect of stroke. However, kinetic analysis revealed that during unimanual movements, joint control was impaired during unimanual and bimanual movements in both UEs, although to a lesser extent in the non-paretic than paretic UE. During bimanual movements, joint control did not change in the paretic UE, and it further deteriorated in the non-paretic UE compared with the unimanual movements. Our findings suggest that a single session of bimanual task performance does not improve joint control of the paretic UE and it impairs control of the non-paretic UE, making it more like that of the paretic UE.

The characterization of callosal white matter is crucial for understanding the relationship between brain structure and bimanual motor function. An earlier literature review established this. With advancements in neuroimaging and data modeling, we aim to provide an update on the existing literature. Firstly, we highlight new CC parcellation approaches, such as functional MRI- and atlas-informed tractography and in vivo histology. Secondly, we elaborate on recent insights into the CC's role in bimanual coordination, drawing evidence from studies on healthy young and older adults, patients and training-related callosal plasticity. We also reflect on progress in the field and propose future perspectives to inspire research on the underlying mechanisms of structural-functional interactions.