Journal of Motor Behavior最新文献

The present study investigated the effect of visual offset (visuo-proprioceptive mismatch) in joint repositioning task in a three-dimensional virtual reality (VR) environment when participants were instructed to ignore vision. Twenty-five physically healthy young individuals performed shoulder joint position sense test. Repositioning accuracy was tested under two visual conditions, accurate and offset visions, and two instructions, no guidance or ignore vision. In accurate vision trials, the virtual hand of the tested limb seen in VR was congruent with where the participant placed their hand. In the offset vision condition, the virtual hand was seen 8° above or below their actual hand in the vertical plane. Repositioning error (i.e. constant error) in offset vision trials was lower when the participants were instructed to ignore vision compared to when no instruction about the visual offset was given (p < 0.001). However, constant error in offset vision trials was larger than accurate vision trials when the participants tried to ignore vision in both visual conditions (p < 0.001). Our results suggest that humans may be able to down-weight vision to some extent by conscious effort, while the influence of vision is difficult to eliminate when vision is present.

We asked whether the quantitative kinematics of standing postural activity might be related to short-term learning of affordances. Standing participants viewed a narrow path for 15 s, and then gave perceptual reports about the distance that they could walk along the path while wearing a weighted vest (novel affordance) or while not wearing the vest (familiar affordance). In a control condition, participants gave perceptual reports about egocentric distance along the path. During the 15 s viewing intervals, we measured the kinematics of head and torso movement as standing participants made a series of 12 perceptual reports. Perceptual reports improved across trials, but only in the condition in which participants were asked to perceive a novel affordance. The dynamical complexity of head movement changed across trials as participants gave perceptual reports about the novel affordance, but did not change systematically when perceiving a familiar affordance, or a non-affordance egocentric distance. We argue that the dynamical complexity of postural activity may have served an exploratory function supporting the learning of a novel affordance. Our results are consistent with the broader hypothesis that affordances are learned through active engagement with the environment, rather than (for example) through abstract cognitive processing.

The aim of the study was to compare the effects of implicit learning using dual task-paradigm, with explicit learning on learning a novel skill, and if the performance is maintained over a prolonged period of time. Twenty-six high school adolescents (n = 26, boys n = 15, girls n = 11, age: 16 ± 0.66 years) performed a four-week front-flip learning program, where participants underwent two hours front flip practice in total between the pre- and post-test session followed by two tests; three and six months after the post-test, in which the front-flip was not practiced. Performance was evaluated by two independent gymnastics judges. Both groups increased performance at the post test, with significantly higher scores in the explicit group compared with the implicit group. Probably benefiting from error correction to select positive action outcomes and avoid negative ones consciously. However, the explicit group was also the only group that significantly decreased performance again at first retention test, suggesting that their reliance on the retrieval of declarative knowledge from working memory was subject to decay. While it seems that performance learned via implicit learning may deteriorate more slowly, but also continuously throughout six months suggesting that the directly accumulated procedural knowledge may need for proper reinforcement and practice.

The aim of the study is to examine the effects of menstrual cycle phases (MCP) on balance and postural control. The study was carried out with 63 volunteer women. Digital ovulation kits and, a Menstrual Cycle Regularity Questionnaire (MCRQ) to detect menstrual cycle regularity and duration, Premenstrual Syndrome Questionnaire (PMSQ) to question the presence of premenstrual syndrome, Menstruation Attitude Questionnaire (MAQ) to assess menstrual attitudes, International Physical Activity Questionnaire Short Form (IPAQ-SF) to question physical activity level was used. Balance and postural oscillation were evaluated with Balance Master balance and performance test device and Tekscan MatScan™ Pressure Mat System, respectively. All evaluations were repeated twice, in the preovulatory period and the postovulatory period. When the evaluations of the preovulatory period and the postovulatory period were compared, there was %3 increase in the percent weight-bearing of the non-dominant extremity (p = 0.01) and %2.5 decrease in the percent weight-bearing of the dominant limb in the postovulatory period (p = 0.01). %8 increase in functional reach distances was detected in the postovulatory period (p < 0.01). It was determined that there was %7.4 decrease in the oscillation rate of the center of gravity in the static stance with eyes open and %9 decrease in the static stance with eyes closed in the postovulatory period (p = 0.35, p = 0.18, respectively). It has been determined that the balance and postural control of young women are negatively affected in the preovulatory period and the function improved from the preovulatory period to the postovulatory period.

The purpose of this study was to clarify the effects of the standing center of gravity sway by providing visual stimulus information as if the subjects were walking in virtual reality (VR) and by monitoring conditions with different corridor widths. We included 25 healthy young individuals in our study. The center of gravity sway was measured during open- and closed-eye static standing using images of walking in corridors of different widths (780 and 1600 mm) presented on a VR and personal computer monitor (Monitor). The parameters measured for the center of gravity sway were swing path length (SPL), height of excursion (HoE), and width of excursion (WoE). The results showed that the SPL and HoE values were significantly greater in the VR group than those in the Monitor group. The greater center of gravity sway in the VR compared with the Monitor group can be attributed to the ability of the head-mounted VR display to cover the entire field of vision and its head-tracking function. There was no change in the center of gravity sway with respect to the corridor width, which may be because the width of the corridor alone did not provide sufficient visual stimulation to affect physical function. This research could lead to further studies which could impact the motivation of patients for rehabilitation therapies.

The Post-Movement Beta Rebound (PMBR) is the increase in beta-band power after voluntary movement ends, but its specific role in cognitive processing is unclear. Current theory links PMBR with updates to internal models, mental frameworks that help anticipate and react to sensory feedback. However, research has not explored how reactivating a preexisting action plan, another source for internal model updates, might affect PMBR intensity. To address this gap, we recruited 20 participants (mean age 18.55 ± 0.51; 12 females) for an experiment involving isolated (single-step) or sequential (two-step) motor tasks based on predetermined cues. We compared PMBR after single-step movements with PMBR after the first movement in two-step tasks to assess the influence of a subsequent action on the PMBR power associated with the first action. The results show a significant increase in PMBR magnitude after the first movement in sequential tasks compared to the second action and the isolated movements. Notably, this increase is more pronounced for right-hand movements, suggesting lateralized brain activity in the left hemisphere. These findings indicate that PMBR is influenced not only by external stimuli but also by internal cognitive processes such as working memory. This insight enhances our understanding of PMBR's role in motor control, emphasizing the integration of both external and internal information.

The benefits of less repetitive practice schedules on motor learning are usually described in terms of greater demand for memory processes. The present study aimed to investigate the interactions between working memory and practice schedule and their effects on motor learning. Forty female participants had their WMC evaluated by the N-back test and were randomly allocated to either the variable random (VP) or the constant practice (CP) groups. In the acquisition phase, participants practiced 120 trials of a sequential key-pressing task with two goals: learning the relative and the absolute timing. Delayed retention and transfer tests occurred 24 h after the acquisition phase. Participants performed 12 trials of the motor task. Results showed that in the CP, learners with a high level of WMC presented better motor performance in the transfer test than learners with a low level of WMC. In the RP, no difference between WMC levels was found. Learners with a high level of WMC in the CP presented the same motor performance as learners in the RP regardless of the WMC level in the transfer test. In conclusion, learners with a high WMC could compensate for the poor working memory stimulation of a more repetitive practice schedule. The high WMC did not seem to exert an additional benefit when learners were well stimulated by a less repetitive practice schedule.

The strategy used by the brain to organize human goal-directed movements is still debated. Here, I argue that without the knowledge of this strategy, teaching movement skills required in complex sports activities and for rehabilitation of motor disorders remains an art and can often result in inefficient techniques and misleading instructions. However, the leading joint hypothesis offers a solution to this problem. It suggests that the control strategy consists in rotation of a single ('leading') joint actively and using the biomechanical effect produced by the leading joint as the primary contributor to motion of the other ('trailing') joints. This "trailing joint control pattern" was found in a large variety of movement types. This pattern is simple even for seemingly complex movements, it can be easily verbalized, and it requires focusing attention during learning only on one or two movement elements at a time. The use of the trailing joint control strategy therefore allows development of better targeted techniques of motor learning and rehabilitation.

Treadmills are important rehabilitation tools used with or without handrails. The handrails could be used to attain balance, prevent falls, and improve the walking biomechanics of stroke survivors, but it is yet unclear how the treadmill handrails impact their stability margins. Here, we investigated how 3 treadmill handrail-use conditions (no-hold, self-selected support, and light touch) impact stroke survivors' margins of stability (MoS). The anteroposterior MoS significantly increased for both legs with self-selected support while the mediolateral MoS of the unaffected leg decreased significantly when the participants walked with self-selected support in comparison to no-hold in both cases. We concluded that the contextual use of the handrail should guide its prescription for fall prevention or balance training in rehabilitation programs.

Consolidation has been associated with performance gains without additional practice (i.e., off-line learning). However, the movement characteristics improving off-line remain poorly understood. To investigate this question, participants were trained to produce a sequence of planar reaching movements toward four different visual targets. The training session with feedback required them to learn the relative time of the movements, the total movement time and aim accurately at each target. The retention test was performed either 10-min or 24-h after. Results revealed that a 24-h consolidation interval did not result in better temporal or spatial accuracy. This finding suggests that off-line learning may be restricted to sequence production tasks in which the different segments must be regrouped ("chunked") together to accelerate their execution.