Motor Control最新文献

Attentional focus strategies, especially external focus, are associated with improvements in mechanisms of postural control. This can be important in reducing sports injuries in practices such as running, which has seen an increase in adherence. However, the impacts of these strategies on postural control in runners are unclear. This study aimed to investigate the effects of internal and external focus strategies on postural control performance with different bases of support tasks in runners. A total of 19 young adults (18-38 years old) were divided into a running group (n = 9) and a control group (n = 10). Posturography tests were performed on stable and unstable surfaces, under control, and internal and external focus conditions. The distance, mean velocity, and total velocity of the center of pressure were analyzed (p ≤ .05). There was a reduction in oscillation under external focus compared to internal and control conditions, as well as under internal focus compared to the control condition. A Group × Surface × Focus interaction for the variables distance and mean velocity in the mediolateral direction was found only for the control group. However, no significant effects were found between groups for postural control performance. Attentional focus strategies were able to reduce postural sway, with external focus condition being the most effective. Practitioners can benefit from these strategies to increase postural control performance to help reduce the number of injuries and improve sports performance. It is speculated that the effects of attentional control strategies on postural control may differ depending on the specific adaptations of each sport.

Movement disorders, such as stroke and amyotrophic lateral sclerosis, result in loss of upper limb function and, hence, severe impairments of bimanual coordination. Although motor imagery is increasingly used to enhance neurorehabilitation, cognitive and neurophysiological parameters that inform effective strategies remain elusive. The aim of the present study is to elucidate the neural dynamics that underlie learning during real and imagined movement using both unimanual and bimanual coordination patterns. The post movement beta rebound (PMBR) has been implicated as a biomarker of motor control and therefore was the focus of this study. Healthy adults (n = 21) learned a visuomotor tracking task in a single session using either one or both hands while brainwaves were captured using electroencephalography. Postmovement beta rebound was evident in the sensorimotor cortex for both unimanual and bimanual conditions. Task-related power of the beta band demonstrated that actual unimanual movement requires greater contralateral activity compared with both actual bimanual movement and imagined movement of either condition. Notably, the PMBR was evident even in imagined movement, although to a lesser extent than real movement. Neurophysiological results support a functional role for beta band in movement. Results of these data may inform neurorehabilitation strategies for patients recovering from movement disorders of the upper limbs.

Aim: To assess the adaptive response of older adults with a history of falls in a single Perturbation-Based Balance Training (PBT) session by examining the margin of stability (MoS) and the number of falls.

Methods: Thirty-two older adults with a history of falls underwent a treadmill walking session lasting 20-25 min. During the PBT protocol, participants experienced 24 unexpected perturbations delivered in two ways: acceleration or deceleration of the treadmill belt, with 12 perturbations in each direction. The MoS in the anteroposterior direction was assessed for the first and last perturbations of the session, during the perturbation step (N) and the recovery step (REC), along with the number of falls during the training session.

Results: There was no statistically significant difference in MoS between the first and last perturbations (acceleration and deceleration) for steps N and REC. Regarding the number of falls, a significant reduction was found when comparing the first half with the second half of the training session (p = .033). There were 13 falls in the first half and only three in the second half of the PBT session.

Conclusion: Older adults with a history of falls exhibited an adaptive response with a reduction in the number of falls during a single session of PBT despite not showing changes in the MoS.

This study aimed to evaluate the effect of age and intellectual disability (ID) on postural balance parameters, dual-task cost (DTC), and choice reaction time (CRT). Fifty-eight individuals with ID and 55 peers without ID performed a postural stance balance task under two conditions: a single task with eyes open and dual task involving an additional cognitive task (light sequence). Four postural balance parameters (total displacement, total sway area, mediolateral, and anteroposterior dispersion), cost of the dual task ([DTC%] = [(single-task performance - dual-task performance)/single-task performance] × 100), and CRT were recorded, calculated, and analyzed. All postural control parameters reflected poorerperformance during the dual-task condition, nevertheless, DTC was significantly higher only in individuals with ID and only for the total sway area, F(1, 111) = 5.039, p = .027, and mediolateral dispersion, F(1, 111) = 6.576, p = .012. CRT was longer in individuals with ID compared with the individuals without ID, F(1, 111) = 94.979, p ≤ .001, while age did not have a significant effect on the DTC nor on the CRT, F(1, 111) = 0.074, p = .786. In conclusion, an additional cognitive task during the postural balance task had a detrimental effect on various postural balance parameters, leading to increased DTC in terms of total sway area, mediolateral dispersion, and prolonged CRT in individuals with ID.

Much of the current research on sprint start has attempted to analyze the biomechanical characteristics of elite athletes to provide guidance on the training of sprint technique, with less attention paid to the effects of motor experience gained from long-term training on neuromuscular control characteristics. The present study attempted to investigate the effect of motor experience on the modular organization of the neuromuscular system during starting, based on he clarification of the characteristics of muscle synergies during starting. It was found that exercise experience did not promote an increase in the number of synergies but rather a more focused timing of the activation of each synergy, allowing athletes to quickly complete the postural transition from crouching to running during the starting.

The aim of this study was to examine the effect of attentional focus instructions on the biomechanical variables associated with the risk of anterior cruciate ligament injury of the knee joint during a drop landing task using a time series analysis. Ten female volleyball players (age: 20.4 ± 0.8 years, height: 169.7 ± 7.1 cm, mass: 57.6 ± 3.1 kg, experience: 6.3 ± 0.8 years) performed landings from a 50 cm height under three different attentional focus conditions: (1) external focus (focus on landing as soft as possible), (2) internal focus (focus on bending your knees when you land), and (3) control (no-focus instruction). Statistical parameter mapping in the sagittal plane during the crucial first 30% of landing time showed a significant effect of attentional focus instructions. Despite the similarity in landing performance across foci instructions, adopting an external focus instruction promoted reduced vertical ground reaction force and lower sagittal flexion moment during the first 30% of execution time compared to internal focus, suggesting reduced knee loading. Therefore, adopting an external focus of attention was suggested to reduce most biomechanical risk variables in the sagittal plane associated with anterior cruciate ligament injuries, compared to internal focus and control condition. No significant differences were found in the frontal and horizontal planes between the conditions during this crucial interval.

The purpose of this study was to assess the immediate effect of video feedback on the regulation and control of the standing back tuck somersault in the absence of vision. Two groups of male parkour athletes performed the standing back tuck somersault under both open and closed eyes conditions. The first group received video feedback, while the second group received verbal feedback. Concurrent analysis, including kinetic data from a force plate (Kistler Quattro-Jump) and kinematic data in two-dimensional by Kinovea freeware, was employed for motion and technical performance analysis. The results indicate that the loss of vision during the standing back tuck somersault affected only the take-off and ungrouping angle, as well as the vertical velocity and displacement. These effects were consistent regardless of the type of feedback provided (i.e., video feedback or verbal feedback). Furthermore, a significant Vision × Feedback interaction was observed at the level of technical performance. This suggests that the use of video feedback enabled the parkour athletes to maintain a high level of technical performance both with and without vision (i.e., 13.56 vs. 13.00 points, respectively, p > .05 and d = 2.233). However, the verbal feedback group technical performance declined significantly under the no-vision condition compared with the vision condition (13.14 vs. 10.25 points, respectively, with and without vision, p < .001 and d = 2.382). We concluded that when the movement is proprioceptively controlled (i.e., without vision), the video feedback enables the athletes to globally assess the technical deficiencies arising from the lack of vision and to correct them. These findings are discussed based on parkour athletes' ability to evaluate the kinematic parameters of the movement.