Human Movement Science最新文献

Previous studies have suggested an association between conscious movement investment and inhibiting motor actions. However, no within-designs were used in which conscious movement investment was manipulated. The current study compared changes in inhibition after instruction interventions that aimed to expand and limit conscious investment in the execution of a golf putting task. During a baseline and post-intervention test, participants were asked to putt balls in a hole. Randomly, an auditory stop-signal appeared 50 ms after reaching the end of backswing on some trials, signalling them to stop the downswing as quickly as possible. Between the two tests, the participants practiced under different instructions, without the stop-signal. One group (i.e., expanded conscious investment, ECIG) received multiple explicit movement-related instructions along with the internal focus of attention instructions, while the second group (i.e., limited conscious investment, LCIG) received a single analogy instruction paired with external focus of attention instructions. The results did not reveal significant differences in stopping rate and stopping time between the baseline and post-intervention tests and the two groups. However, a mediation analysis highlighted that the ECIG exhibited a greater change in downswing time compared to the LCIG. This change was correlated with a larger increase in stopping rate and stopping time. We conclude that conscious movement investment did not directly influence inhibition. Instead, we discuss how conscious movement investment may indirectly influence inhibition dependent on the putting kinematics.

Transcranial direct current stimulation (tDCS) and high-intensity interval training (HIIT) have been demonstrated to enhance inhibitory control and working memory (WM) performance in healthy adults. However, the potential benefits of combining these two interventions have been rarely explored and remain largely speculative. This study aimed to explore the effects of acute HIIT combined with dual-site tDCS over the dorsolateral prefrontal cortex (DLPFC, F3 and F4) on inhibitory control and WM in healthy young adults. Twenty-five healthy college students (20.5 ± 1.3 years; 11 females) were recruited to complete HIIT + tDCS, HIIT + sham-tDCS, rest + tDCS, and rest + sham-tDCS (CON) sessions in a randomized crossover design. tDCS or sham-tDCS was conducted after completing HIIT or a rest condition of the same duration. The Stroop and 2-back tasks were used to evaluate the influence of this combined intervention on cognitive tasks involving inhibitory control and WM performance in post-trials, respectively. Response times (RTs) of the Stroop task significantly improved in the HIIT + tDCS session compared to the CON session across all conditions (all p values <0.05), in the HIIT + tDCS session compared to the rest + tDCS session in the congruent and neutral conditions (all p values <0.05), in the HIIT + sham-tDCS session compared to the CON session in the congruent and neutral conditions (all p values <0.05), in the HIIT + sham-tDCS session compared to the rest + tDCS session in the congruent condition (p = 0.015). No differences were found between sessions in composite score of RT and accuracy in the Stroop task (all p values >0.05) and in the 2-back task reaction time and accuracy (all p values >0.05). We conclude that acute HIIT combined with tDCS effectively improved inhibitory control but it failed to yield cumulative benefits on inhibitory control and WM in healthy adults. These preliminary findings help to identify beneficial effects of combined interventions on cognitive performance and might guide future research with clinical populations.

Mediolateral gait stability can be maintained by coordinating our foot placement with respect to the center-of-mass (CoM) kinematic state. Neurological impairments can reduce the degree of foot placement control. For individuals with such impairments, interventions that could improve foot placement control could thus contribute to improved gait stability. In this study we aimed to better understand two potential interventions, by investigating their effect in neurologically intact individuals. The degree of foot placement control can be quantified based on a foot placement model, in which the CoM position and velocity during swing predict subsequent foot placement. Previously, perturbing foot placement with a force-field resulted in an enhanced degree of foot placement control as an after-effect. Moreover, timed muscle vibration enhanced the degree of foot placement control whilst the vibration was applied. Here, we replicated these two findings and further investigated whether Q1) timed muscle vibration leads to an after-effect and Q2) whether combining timed muscle vibration with force-field perturbations leads to a larger after-effect, as compared to force-field perturbations only. In addition, we evaluated several potential contributors to the degree of foot placement control, by considering foot placement errors, CoM variability and the CoM position gain (β_pos) of the foot placement model, next to the R² measure as the degree of foot placement control. Timed muscle vibration led to a higher degree of foot placement control as an after-effect (Q1). However, combining timed muscle vibration and force-field perturbations did not lead to a larger after-effect, as compared to following force-field perturbations only (Q2). Furthermore, we showed that the improved degree of foot placement control following force-field perturbations and during/following muscle vibration, did not reflect diminished foot placement errors. Rather, participants demonstrated a stronger active response (higher β_pos) as well as higher CoM variability.

Background

At present, Chinese children aged 3–6 years old are facing challenges such as insufficient physical activity, declining physical health, and obesity, and China has yet to issue curriculum standards or physical activity guidelines for this age group. At the same time, the present kindergarten physical activity curriculum is insufficient. To address this issue, this study focused on designing and executing a planned active play intervention program for the kindergarten setting to analyze its efficacy in enhancing children's fundamental movement skills (FMS). This study aims to provide a reference for the theoretical and practical exploration of children's acquisition of fundamental movement skills in the Chinese context.

Methods

Fifty-two preschoolers participated in this study and were either part of an intervention group (n = 30) or a control group (n = 24). Children's FMS were assessed before and after the intervention using the Test of Gross Motor Development-3 (TGMD-3) and the balance ability of the The Movement Assessment Battery for Children-2 (MABC-2). Physical activity (PA) during the planned active play intervention and the routine physical activity curriculum were assessed using the SOFIT throughout the intervention.

Results

All the children significantly improved their locomotor skills, ball skills, and TGMD from baseline to the late assessment (p < 0.05). Children in the planned active play intervention group demonstrated greater rates of change (p < 0.001) and scored higher on ball skills and TGMD in the late assessment than those in the control group (p < 0.001). The children in the intervention group, but not those in the control group, significantly improved their balance over time (p < 0.05), and the former had greater rates of change (p < 0.001). Similarly, planned active play was found to provide children with more physical activity than the routine physical activity curriculum.

Conclusions

The eight-week planned active play intervention was effective in improving FMS in preschool children, with higher rates of FMS change in children who completed the intervention than children in the control group.

Introduction

Parkinson's disease (PD) causes gait abnormalities that may be associated with an arm swing reduction. Medication and freezing of gait (FoG) may influence gait characteristics. However, these comparisons do not consider differences in gait speed and clinical characteristics in individuals with PD.

Objective

This study aims to analyze the effect of FoG and medication on the biomechanics of the trunk and upper limbs during gait in PD, controlling for gait speed and clinical differences between groups.

Methods

Twenty-two people with a clinical diagnosis of idiopathic PD in ON and OFF medication (11 FoG), and 35 healthy participants (control) were selected from two open data sets. All participants walked on the floor on a 10-m-long walkway. The joint and linear kinematic variables of gait were compared: (1) Freezers and nonfreezers in the ON condition and control; (2) Freezers and nonfreezers in the OFF condition and control; (3) Group (freezers and nonfreezers) and medication.

Results

The disease affects the upper limbs more strongly but not the trunk. The medication does not significantly influence the joint characteristics but rather the linear wrist displacement. The FoG does not affect trunk movement and partially influences the upper limbs. The interaction between medications and FoG suggests that the medication causes more substantial improvement in freezers than in nonfreezers.

Conclusion

The study shows differences in the biomechanics of the upper limbs of people with PD, FoG, and the absence of medication. The future rehabilitation protocol should consider this aspect.

Individuals with untreated, mild-to-moderate recurrent neck pain or stiffness (subclinical neck pain (SCNP)) have been shown to have impairments in upper limb proprioception, and altered cerebellar processing. It is probable that aiming trajectories will be impacted since individuals with SCNP cannot rely on accurate proprioceptive feedback or feedforward processing (body schema) for movement planning and execution, due to altered afferent input from the neck. SCNP participants may thus rely more on visual feedback, to accommodate for impaired cerebellar processing. This quasi-experimental study sought to determine whether upper limb kinematics and oculomotor processes were impacted in those with SCNP. 25 SCNP and 25 control participants who were right-hand dominant performed bidirectional aiming movements using two different weighted styli (light or heavy) while wearing an eye-tracking device. Those with SCNP had a greater time to and time after peak velocity, which corresponded with a longer upper limb movement and reaction time, seen as greater constant error, less undershoot in the upwards direction and greater undershoot in the downwards direction compared to controls. SCNP participants also showed a trend towards a quicker ocular reaction and movement time compared to controls, while the movement distance was fairly similar between groups. This study indicates that SCNP alters aiming performances, with greater reliance on visual feedback, likely due to altered proprioceptive input leading to altered cerebellar processing.

Mirror therapy has become an effective and recommended intervention for a range of conditions affecting the upper limb (e.g. hemiparesis following stroke). However, little is known about how mirror feedback affects the control of bimanual movements (as performed during mirror therapy). In this study, in preparation for future clinical investigations, we examined the kinematics of bimanual circle drawing in unimpaired participants both with (Experiment 1) and without (Experiment 2) a visual template to guide movement. In both experiments, 15 unimpaired right-handed participants performed self-paced continuous bimanual circle-drawing movements with a mirror/symmetrical coordination pattern. For the mirror condition, vision was directed towards the mirror in order to monitor the reflected limb. In the no mirror condition, the direction of vision was unchanged, but the mirror was replaced with an opaque screen. Movements of both hands were recorded using motion capture apparatus. In both experiments, the most striking feature of movements was that the hand behind the mirror drifted spatially during the course of individual trials. Participants appeared to be largely unaware of this marked positional change of their unseen hand, which was most pronounced when a template to guide movement was visible (Experiment 1). Temporal asynchrony between the limbs was also affected by mirror feedback in both experiments; in the mirror condition, illusory vision of the unseen hand led to a relative phase lead for that limb. Our data highlight the remarkable impact that the introduction of a simple mirror can have on bimanual coordination. Modulation of spatial and temporal features is consistent with the mirror inducing a rapid and powerful visual illusion, the latter appearing to override proprioceptive signals.

Background

This study evaluated psychometric properties of the Intersection Point Height, derived from ground-on-feet force characteristics, as a tool for assessing balance control. We compare this metric with traditional center of pressure (CP) measurements.

Methods

Data from a public dataset of 146 participants, divided into younger (<60 years old) and older (≥60 years old) adults, were analyzed. Clinical tests included the Short Falls Efficacy Scale-International, International Physical Activity Questionnaire-Short Form, Trail Making Tests A and B, and the Mini-Balance Evaluation Systems Test. Reliability and validity were assessed through the intra-class correlation coefficient (ICC[3,1]) for mean Intersection Point Height in each test condition and Spearman's rho between summative Intersection Point Height (the sum of intra-condition mean values across all test conditions within one subject) and other variables of interest, respectively.

Findings

Mean Intersection Point Height showed good to excellent reliability (ICC = 0.712–0.901), similar to that of CP velocity (ICC = 0.733–0.922) and greater than that of variance CPx (0.475–0.768). Summative Intersection Point Height exhibited strong convergent validity with Trail Making Tests A and B (rho = 0.49, p < 0.001) and the Mini-Balance Evaluation Systems Test (rho = −0.47, p < 0.001). At most, a weak to moderate association (rho = 0.39–0.49, p < 0.001) was found between intra-condition mean Intersection Point Height with CP metrics. Intra-condition mean Intersection Point Height demonstrated weak to moderate convergent validity with several clinical measures (rho = 0.32–0.52, p < 0.001). In contrast, at most, a weak to moderate association (rho = 0.39–0.49, p < 0.001) was found between intra-condition mean Intersection Point Height with CP metrics.

Interpretation

The Intersection Point Height is a reliable and valid balance measure. Further, we believe that it is a more comprehensive evaluation than CP metrics.

Postural control may encounter acute challenges when individuals are immersed in a virtual reality (VR) environment, making VR a potential pertinent tool for enhancing balance capacity. Nonetheless, the effects of repeated exposure to VR on balance control remain to be fully elucidated. Fifty-five healthy participants stood upright for six bouts of 90 s each in an immersive virtual reality (VR) environment using a head-mounted display (repeated VR exposure). During these bouts, participants experienced simulated forward and backward displacements. Before and after the repeated VR exposure, the center of pressure mean velocity (VEL_COP) was measured in response to simulated forward and backward displacement in VR, as well as during quiet upright standing with eyes open (EO) and closed (EC) in the real environment. The results revealed a significant decrease in VEL_COP for forward and backward simulated displacements in both antero-posterior and medio-lateral directions (p < 0.01) after compared to before repeated VR exposure. Furthermore, VEL_COP significantly decreased when participants stood upright in EC (−5%; p = 0.004), but not EO (+3%; p > 0.05) in the real environment after repeated VR exposure. The Romberg ratio (EC/EO) was reduced in both antero-posterior and medio-lateral directions (p < 0.05) after VR exposure. This study indicates that repeated exposure to VR induces changes in balance control in both virtual and real environments. These changes may be attributed, in part, to a reduction in the weighting of visual inputs in the multisensory integration process occurring during upright standing. Accordingly, these findings highlight VR as a potentially effective tool for balance rehabilitation.

Significance statement

This study indicates that repeated exposure to VR induces changes in balance control in both virtual and real environments that can rely, in part, on a reduction in the weighting of visual inputs in the multisensory integration process occurring during upright standing.

We evaluated the effect of haptic coordination on anxiety and arousal. Participants looked at a stressful or calming image and then repeatedly squeezed a vibrating stress ball for 20 s. Using a pre-post paradigm with a control group, we showed that squeezing the vibrating ball reduced anxiety and arousal, as assessed by the State-Trait Anxiety Inventory and electrodermal activity, respectively. The stability of haptic coordination was manipulated by varying the detuning between the spontaneous squeezing frequency and the intrinsic frequency of ball vibration. Coordination stability affected arousal and stress affected stability. The data were discussed in the light of Kahneman's attentional resource-sharing model.