Variability of Postural Coordination in Dual-Task Paradigm.

Postural control is influenced by cognition. In most studies, variability of motor output has been considered regardless of variability in patterns of joint coordination. Uncontrolled manifold framework has been applied to decompose the joint's variance in two components. The first component leaves position of the center of mass in anterior-posterior direction (CoMAP) unchanged (VUCM) while the second component is in charge of variations of CoM (VORT). In this study, 30 healthy young volunteers were recruited. The experimental protocol consisted of three random conditions: quiet standing on a narrow wooden block without a cognitive task (NB), quiet standing on a narrow wooden block with an easy cognitive task (NBE), and quiet standing on a narrow wooden block with a difficult cognitive task (NBD). Results showed that CoMAP sway in NB condition was higher than both NBE and NBD conditions (p = .001). VORT in NB condition was higher than NBE and NBD conditions (p = .003). VORT in NB condition was higher than NBE and NBD conditions (p = .003). VUCM was unchanged in all conditions (p = 1.00) and synergy index in NB condition was smaller than NBE and NBD conditions (p = .006). These results showed that postural synergies increased under dual-task conditions.

Focus of Attention During ACL Injury Prevention Exercises Affects Improvements in Jump-Landing Kinematics in Soccer Players: A Randomized Controlled Trial.

ABSTRACT: Dalvandpour, N, Zareei, M, Abbasi, H, Abdoli, B, Mohammadian, MA, Rommers, N, and Rössler, R. Focus of attention during ACL injury prevention exercises affects improvements in jump-landing kinematics in soccer players: a randomized controlled trial. J Strength Cond Res 37(2): 337-342, 2023-Anterior cruciate ligament tears are severe and complex knee injuries that commonly occur in soccer. Prevent injuries enhance performance (PEP) is an exercise-based prevention program to effectively reduce anterior cruciate ligament injuries. It is, however, unclear how the delivery of the program contributes to its effectiveness. Therefore, we aimed to investigate the effect of the focus of attention that was emphasized during the delivery of the PEP program on jump-landing kinematics in male, elite-level, U21 soccer players. Forty-two players participated in this randomized controlled trial and were allocated to (a) the internal focus of attention (IF) group, receiving instructions focusing on the execution of the exercise (b), the external focus of attention (EF) group, receiving instructions focusing on the outcome of the exercise, or (c) the control group. Before and after the 8-week intervention, players performed a jump-landing task during which we measured hip and knee angles at the initial contact, peak knee flexion, and peak vertical ground reaction force using a 3-dimensional motion analyzer. A repeated-measures analysis of variance was used to compare groups over time. Significant time-by-group interaction effects with large effect sizes were found for hip flexion at all moments (p < 0.032; η2 > 0.15) and for the knee flexion angle at initial contact and maximum knee flexion (p < 0.001; η2 > 0.35), all in favor of the EF group. This shows that EF during PEP improves hip and knee joint kinematics in the sagittal plane more than IF. Therefore, EF during PEP instructions is preferred to increase the effectiveness of this injury prevention program.

The Effect of Modeling Methods on Mirror Neuron Activity and a Motor Skill Acquisition and Retention.

Introduction: Mirror neurons have been suggested as a potential neural mechanism of observational learning. This study aims to investigate the effect of self-modeling, skilled model, and learning model on mu rhythm suppression and golf putting acquisition and retention. Methods: The study was conducted on 45 male volunteer students (aged 19.4±0.37 years) in three experimental groups, self-modeling, skilled, and learning models with six sessions of physical and observational training in three periods of pre-test, acquisition, and retention. In the pre-test, after the initial familiarity with the skill, participants performed 10 golf putting actions while scores were recorded. Then, electrical brain waves in C3, C4, and Cz regions were recorded during the observation of 10 golf putting actions by their group-related models. The acquisition period consisted of golf putting training during six sessions, each consisting of six blocks of 10 trials. Before each training block, participants observed golf putting related to their group 10 times in the form of a video. Acquisition and delayed retention tests were also performed by recording scores of 10 golf putting actions, as well as recording electrical brain waves while observing the skill performed by the related model. Results: Mixed analysis of variance (ANOVA) showed that the mu rhythm suppression in the pre-test was more in the self-modeling group compared to the skilled model and learning model groups, but this suppression was not significantly different in all three groups in the acquisition and retention tests. In putting task variables, all three groups that had no significant difference in the pre-test period made considerable progress in learning the desired skill from the pre-test to the acquisition test, and this progress was somewhat stable until the retention test. Also, both in the acquisition and retention periods, the self-modeling group showed better performance than the other two groups; however, no significant difference was observed between these groups. Conclusion: These results suggest that the model-observer similarity is a crucial factor in modeling interventions and can affect the rate of mu rhythm suppression.

Pain-induced Impact on Movement: Motor Coordination Variability and Accuracy-based Skill.

Introduction: Studies on pain are generally conducted for two purposes: first, to study patients with pain who have physical changes due to nerve and muscle lesions, and second, to regain the appropriate kinematic post-pain pattern. The present study aimed to investigate the effect of pain on the coordination variability pattern and throwing accuracy. Methods: The study participants included 30 people aged 18-25 years who volunteered to participate in the study. Participants practiced and acquired skills in 10 blocks of 15 trials. In the test phase associated with pain, Individuals were randomly divided into three groups: local pain, remote pain, and control. In their respective groups, participants were tested in a 15-block trial, 24 hours, and 1 week after acquisition. Results: The results revealed that pain did not affect the throwing accuracy (P=0.456). Besides, in the phase of acceleration in throwing, movement variability in the pain-related groups in the shoulder and elbow joints (P=0.518), elbow and wrist (P=0.399), and the deceleration and dart drop phase movement variability in the pain-related groups in the shoulder and elbow joints (P=0.622), elbow and wrist (P=0.534). Conclusion: Based on the results, the accuracy and coordination variability in pain-related groups were similar. However, to confirm these results, more research is needed on performing motor functions in the presence of pain. Highlights: Pain are generally conducted for two purposes.pain which has physical changes due to nerve and muscle lesions and pain to regain the appropriate kinematic post-pain pattern.People who experience pain show poor motor results.Pain restriction is ordinary in joints and the body compensates by increasing movement. Plain Language Summary: One of the constant concerns of sports science experts is to find ways to improve performance or to know the factors that strengthen or weaken motor learning. After injury, pain has been described as one of the passive symptoms, and the mechanism of how overexertion of joints and muscles increases injury and pain is unknown. Following any injury, pain is one of the most important causes of disability and one of the most important problems in people's general health. Many treated individuals present with pain and impaired movement, and typically changes in movement control are a result of the pain. Research evidence suggests that pain induces changes in cortical excitability and the neuroplasticity model that accompanies practice of a new motor task interferes with the performance improvement that must occur simultaneously. According to the new approaches of motor and biomechanical learning and control, movement variability, especially in movement coordination, is considered as an important and influential factor of a person with different conditions. Novice athletes show high non-functional variability in order to reduce the degrees of freedom and then simplify their motor task, in contrast to skilled people, they display functional variability that allows them to perform a motor task better. in variable conditions. Scientists and researchers have concluded that in the presence of pain, there are changes in the pattern requirements and muscle coordination. Clearly, variability is a main feature of most neurological and musculoskeletal pains, and it is necessary for therapists to diagnose and classify incomplete movements and to effectively manage symptoms by controlling incomplete movements, so conducting such research in this field in order to show muscle and movement changes It is necessary under the influence of pain.

Multigenerational effects of paternal spatial training are lasting in the F1 and F2 male offspring.

Recent studies on intergenerational transmission of learning and memory performances demonstrated that parental spatial training before fertilization could facilitate learning and memory in the offspring, but many questions remain unclarified. Essential issues regarding whether and how long the effects of parental training in a task can last in several generations, and whether learning a task repeated in the successive generations can enhance a load of multigenerational effects. In the present study, the spatial performances of F1 and F2 generations of male offspring of fathers or grandfathers spatially trained in the Morris Water Maze were evaluated and compared with the performance of a control sample matched for age and sex. Further, to investigate the memory process in F1 and F2 male offspring, brain-derived neurotrophic factor (BDNF), p-ERK1/2 and acetylated histone 3 lysine 14 (H3K14) expression levels in the hippocampus were analyzed. The findings showed that paternal training reduced escape latencies and increased time spent in the target quadrant by F1 and F2 male offspring. Besides, paternal spatial training repeated in two generations did not enhance the beneficial effects on offspring's spatial performances. These findings were supported by neurobiologic data showing that paternal training increased BDNF and p-ERK1/2 in the hippocampus of F1 and F2 male offspring. Furthermore, the hippocampal level of acetylated H3K14 increased in the offspring of spatially trained fathers, reinforcing the hypothesis that the augmented histone acetylation might play an essential role in the inheritance of spatial competence.

Assessment of motor skill accuracy and coordination variability after application of local and remote experimental pain.

Motor learning is a relatively permanent change in motor performance. Also, one of the factors that can affect movement acquisition and movement patterns is pain and injury. The present study aims to investigate the effect of the induced local and remote pain during dart-throwing skill acquisition by examining motor skill accuracy and coordination variability. Three groups of 30 participants with a mean age of 18-25 were randomly assigned to local and remote pain or control groups. Capsaicin gel was applied to the pain groups for measuring the severity of pain using the Visual Analogue Scale (VAS). The results revealed that pain had no impact on dart-throwing skill acquisition, and there was no significant difference (p = 0.732) among the three groups at three stages of retention test. The results also showed that there was a significant difference among the three groups in terms of variability in shoulder-elbow (p = 0.025) and elbow-wrist joints (p = 0.000) in the deceleration and dart-throwing phases. The Central Nervous System seems to make adjustments when the task is associated with pain during the acquisition phase. Also, the groups with or without pain have notably various strategies, so differently, to perceive motor skills.

Maternal spatial training before fertilization improves the spatial learning process in female offspring.

Recent results of our team showed that parental spatial training before fertilization improves the offspring's spatial memory. However, the process of spatial learning (short-term/working and long-term memories, mnesic consolidation and procedures) in the offspring has not been fully clarified yet. Therefore, this study aimed at specifically analyzing whether maternal learning of a spatial task before fertilization can impact on the process of spatial learning in the female offspring. In the present study, 8-week-old female Wistar rats that had been spatially trained (or not) in the Morris Water Maze (MWM) were mated with conspecific standard-reared male rats, and their 4-week-old female offspring were spatially tested in the same MWM to evaluate their learning and memory processes. Results showed that the female offspring of trained mothers significantly displayed lower escape latencies, higher swimming speed, shorter total distance swum, longer percentage of time spent in the target quadrant and better localization memory in comparison to the female offspring of not trained mothers. Further, MWM performances of mothers trained and their female offspring significantly correlated. These findings indicate that the maternal spatial training before fertilization improves the spatial learning and memory consolidation process of the female offspring.

Comparison of Visual Search Behavior and Decision-making Accuracy in Expert and Novice Fencing Referees.

SIGNIFICANCE: Perceptual-cognitive skills are the capacity of athletes to identify task-relevant information in the environment and integrate information with the knowledge available for decision making or controlling motor responses. Gaze behavior is one performance-related perceptual skill and a key factor affecting expertise affecting referee performance. PURPOSE: The aim of this study was to compare visual search behavior and decision-making accuracy of expert and novice fencing referees. METHOD: Twenty-eight referees were divided into expert (n = 14) and novice (n = 14) groups. Participants were fitted with mobile eye trackers and participated in tests that consisted of five blocks of 10 video clips. Videos are provided annually by the World Fencing Federation for referee testing. RESULTS: The results showed a significant difference between the two groups in terms of the accuracy of decision making, number, duration, and location of fixations. Expert referees had higher decision-making accuracy compared with novice referees. Expert referees had fewer fixations than did novice referees. Fixations of expert referees were longer than those of novice referees, and the locations of fixations of expert and novice referees were different. CONCLUSIONS: According to the results of this study, it can be concluded that the difference in visual search behavior of expert and novice referees was one of the factors contributing to better decision making of expert referees.

Visual deprivation is met with active changes in ground reaction forces to minimize worsening balance and stability during walking.

Previous studies suggest that visual information is essential for balance and stability of locomotion. We investigated whether visual deprivation is met with active reactions tending to minimize worsening balance and stability during walking in humans. We evaluated effects of vision on kinetic characteristics of walking on a treadmill-ground reaction forces (GRFs) and shifts in the center of mass (COM). Young adults (n = 10) walked on a treadmill at a comfortable speed. We measured three orthogonal components of GRFs and COM shifts during no-vision (NV) and full-vision (FV) conditions. We also computed the dynamic balance index (DN)-the perpendicular distance from the projection of center of mass (pCOM) to the inter-foot line (IFL) normalized to half of the foot length. Locally weighted regression smoothing with alpha-adjusted serial T tests was used to compare GRFs and DN between two conditions during the entire stance phase. Results showed significant differences in GRFs between FV and NV conditions in vertical and ML directions. Variability of peak forces of all three components of GRF increased in NV condition. We also observed significant increase in DN for NV condition in eight out of ten subjects. The pCOM was kept within BOS during walking, in both conditions, suggesting that body stability was actively controlled by adjusting three components of GRFs during NV walking to minimize stability loss and preserve balance.

Intergenerational effect of parental spatial training on offspring learning: Evidence for sex differences in memory function.

On the basis of recent works demonstrating that environmental factors experienced by parents can affect their offspring, the present study was aimed at investigating whether the learning of a spatial memory task by parents before fertilization can facilitate the same learning in their offspring, and the role each parent can play in this transition. In the present study animals spatially trained (or not) in the Morris water maze were mated, and their 4 week-old male and female pups underwent spatial assessment in the same spatial task. Also, ERK1/2, BDNF, SYT1 and H3K14ac levels in the hippocampus of offspring were analyzed. We found that parental spatial training before fertilization facilitated the spatial learning and memory in their offspring. Interestingly, it was found that this transmission happened from fathers to their male offspring, and from mothers to their female offspring. Moreover, father's spatial training increased expression of BDNF and phosphorylated ERK1/2 specifically in the male offspring. We observed that father's spatial training increased acetylated H3K14 in male offspring's hippocampus, suggesting that histone acetylation may upregulate the expression of BDNF and phosphorylated ERK1/2 in the male offspring of father trained and thus contribute to the enhancement of spatial learning and memory.

Using the locus-of-slack logic to determine whether inhibition of return in a cue-target paradigm is delaying early or late stages of processing.

Inhibition of return (IOR) is a phenomenon characterized by slower responses to targets at cued locations relative to those at uncued locations. Based on the results of previous research, it has been suggested that IOR affects a process at the input end of the processing continuum when it is generated while the reflexive oculomotor system is suppressed (cf. Satel, Hilchey, Wang, Story, & Klein, 2013). To test this theory, we employed a modified psychological refractory period paradigm designed to elicit input IOR with visual stimuli, allowing us to use the locus-of-slack logic to determine whether an early or late stage of processing was inhibited by IOR. On each trial a visual cue was presented, followed by an auditory target (T1) and visual target (T2) separated by a target-target onset asynchrony (TTOA) of varying lengths (200 ms, 400 ms, or 800 ms). Participants (31 young adults) were instructed to ignore the cue and respond to the targets as quickly and accurately as possible. Eye tracking was used to ensure that participants actively suppressed eye movements during trials. As predicted, the inhibitory effect of the cue was observed at the longest TTOA but not when TTOAs were short, supporting our hypothesis that, when generated while the reflexive oculomotor system is suppressed, IOR affects processing before response selection. (PsycINFO Database Record