Journal of Motor Behavior最新文献

During reaching, arm choice depends on handedness, success, and effort; however, whether these factors influence leg choice for goal-directed stepping is still unknown. We aimed to quantify the kinematics and behavioral patterns of leg choice and to explore whether success and/or effort influence leg choice during goal-directed stepping under two Choice conditions in 20 right-leg dominant neurotypical adults. We adapted the classic center-out target array; participants stepped to pre-cued targets with an emphasis on accuracy without time constraints. The first set of trials was always Free for which either leg could be chosen. The second set of trials was verbally Constrained for which there was no choice as only the left non-dominant leg was to be used. We separately compared success, effort, and subjective difficulty between Free and Constrained trials for left and right target regions. In Free, participants uniformly selected the limb ipsilateral to the target. While success and subjective difficulty were not influenced by Choice, effort varied depending on Choice. Our preliminary findings suggest that during goal-directed stepping, leg choice depends on effort and may be independent of leg dominance and subjective difficulty, while the difficulty of the Constrained Choice condition can improve success independent of leg used.

Walking, often performed automatically, allows for concurrent tasks like carrying objects, but dual-tasks can be challenging for the older adults. As previous search supports the benefits of external focus (EF) over internal focus (IF) of attention in motor tasks, this study investigated attentional effects on dual-task walking performance in young and older adults. A total of 84 healthy participants (42 young adults, 23.02 ± 2.91 years; 42 older adults, 23.02 ± 2.91 years) were instructed to walk while carrying a filled cup without spilling. Walking speed (comfortable, fast) and attentional focus (internal, external, none) were systematically varied. Inertial sensors captured gait speed, cadence, step duration, step length, and pelvis acceleration variability, while spillage was measured in grams. A generalized linear model with bootstrap resampling (α = 0.05) examined the effects of focus, walking speed, and group. Results indicated that young adults walked faster than older adults (p < 0.001), and speed decreased from single-task to dual-task (p = 0.003) and from fast walking to comfortable walking (p < 0.001). No significant effect of attentional focus was found (p ≥ 0.056). The interaction between focus and speed was significant only for spillage (p = 0.041), showing an unimportant difference in spillage between fast walking without focus instructions (398.85 g) and with external focus instructions (399.76 g) (p = 0.030). The interaction between focus and group was not significant (p ≥ 0.531). Overall, this suggests that dual task walking may not be significantly affected by attentional focus instructions.

In sequential joint actions, one co-actor performs the first step of a task (the initiator) before the second co-actor finishes the task (the finisher). Studies of sequential joint actions have revealed the initiator plans their movement to facilitate their finisher's action, consistent with the principle of "pre-crastination". Pre-crastination refers to the finding that actors choose to complete more demanding tasks earlier to decrease cognitive and/or motor load later. The present experiments examined the potential for pre-crastination in a sequential joint action task. Partners performed a task wherein an initiator passed a cube with a 3D-protuberance to a finisher so the protuberance could be inserted into a target slot. The initiator could rotate the cube all, some, or none of the way into the final orientation before passing. The results of Experiment 1 were that initiators completed more rotations when working with a partner than actors completed in the first step when working alone. Experiment 2 revealed that visual information about the finisher's task influenced the amount of rotation completed by the initiator. These findings are consistent with the notion of pre-crastination because co-actors facilitated their partner's achievement of a shared goal by doing more of the work earlier on.

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.

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.

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.

This study aimed to compare the effects of electroacupuncture on traditional acupoints and muscle belly of different target muscles against upper limb dysfunction in stroke patients with hemiplegia. A total of thirty-nine stroke patients with subacute hemiplegia were randomly divided into the control group (n = 19) and observation group (n = 20). The control group was treated with physical therapy and normal electroacupuncture, while the observation group was treated with physical therapy and ultrasound-guided electroacupuncture on the muscle belly. After three weeks' intervention, the scores of Barthel Index, Fugl-Meyer assessment and Action Research Arm Test were compared between the two groups. Before the intervention, there were no significant differences in the scores of Barthel Index, Fugl-Meyer assessment and Action Research Arm Test between these two groups. After three weeks' intervention, there was significant increase in the scores of Barthel Index, Fugl-Meyer assessment, and Action Research Arm Test between the observation and control groups. Electroacupuncture on muscle belly under ultrasound guidance could significantly improve the performance of activities of daily living, motor function and the upper limb function in patients with subacute hemiplegia after stroke, and its effect was superior to electroacupuncture on the acupoints.

This review verified the extent, variety, quality and main findings of studies that have tested the neurophysiological and clinical effects of muscle tendon vibration (VIB) in individuals with sensorimotor impairments. The search was conducted on PubMed, CINAHL, and SportDiscuss up to April 2024. Studies were selected if they included humans with neurological impairments, applied VIB and used at least one measure of corticospinal excitability using transcranial magnetic stimulation (TMS). Two investigators assessed the studies' quality using critical appraisal checklists and extracted relevant data. The 10 articles included were diverse in populations and methods, generally rated as 'average' to 'good' quality. All studies reported an increased corticospinal excitability in the vibrated muscle, but the effects of VIB on non-vibrated muscles remain unclear. Positive clinical changes in response to VIB were reported in a few studies, such as a decreased spasticity and improved sensorimotor function. These changes were sometimes correlated with corticospinal effects, suggesting a link between VIB-induced plasticity and clinical improvements. Despite the limited and heterogeneous literature, this review supports the facilitatory influence of VIB on motor outputs controlling vibrated muscles, even with altered sensorimotor functions. It highlights knowledge gaps and suggests future research directions on VIB mechanisms and clinical implications.

This study explored the effectiveness of combining motor imagery with physical practice in enhancing snare drum performance among trained percussionists. Motor imagery has promoted learning in related contexts such as sport but has yet to be applied in music training. Twenty-eight percussion majors were assigned to either a physical practice group or a combined imagery/physical practice group. Participants performed a novel snare drum excerpt while motion capture measured upper-limb movements prior to and following training. Temporal errors were also computed by comparing note onsets to the ideal timing specified by a metronome. Results revealed that temporal errors were lower in post- vs. pre-training performances, irrespective of group. In both groups, post-test performances were characterized by a higher average position of the mallets above the playing surface and greater hand velocity vs. pre-training performances. Notably, the combined imagery/physical practice group reported less perceived effort associated with training which coincided with an increase in training adherence likelihood. These findings highlight the potential of integrating motor imagery into music education to optimize practice efficiency, particularly when time constraints limit physical rehearsal opportunities.

The literature that investigated the influence of visual feedback properties on the magnitude and temporal structure of variability suggests that increases in the precision of visual information of the torque output (through manipulation of visual gain and its intermittency) lead the neuromuscular system to produce torque in a more steady and complex manner. However, less is known about the influence of the nature of visual feedback on torque variability. The present study aimed to investigate the effect of two different feedback natures, one from the angular position and the other from the torque produced, on the magnitude and temporal structure of torque variability during submaximal hold isometric tasks. Twenty healthy and young participants performed a knee extension isometric task, consisting in sustaining an applied resistance equivalent to 40% of their Maximal Voluntary Isometric Contraction for 30 s with visual feedback from angular position (H_angle) and with visual feedback from torque (H_torque). The magnitude of torque variability was calculated through the coefficient of variation. Sample Entropy was used to analyze the temporal structure of torque fluctuations, i.e., torque complexity. We observed no significant differences between conditions (H_angle vs H_torque) in both magnitude (p = 0.117) and the temporal structure of torque fluctuations (p = 0.940). Our results demonstrated that torque regulation seems not to be affected by the nature of the visual feedback during hold submaximal isometric tasks, suggesting a participation of sensorimotor system due to the nature of the task. Researchers should take this into account to take methodological decisions when using hold submaximal isometric tasks to investigate possible changes in motor control.