Differences in calf-raise exercise and short-foot exercise on feedforward and feedback activation in healthy young.

Introduction: Balance tasks require cognitive resources to ensure postural stability. Pupillometry has been used to quantify cognitive workload of various cognitive tasks, but has not been studied in postural control. The current investigation utilized pupillometry to quantify the cognitive workload of postural control in healthy young adults. We hypothesized that cognitive workload, indexed by pupil size, will increase with challenging postural control conditions including visual occlusion and cognitive dual tasking.Methods: Twenty-one young healthy adults (mean ± standard error of the mean), (age = 23.2 ± 0.49 years; 12 females) were recruited for this study. Participants completed four tasks: (1) standing with eyes open; (2) standing with eyes occluded (3) standing with eyes open while performing an auditory Stroop task; and (4) standing with eyes occluded while performing an auditory Stroop task. Participants wore eye tracking glasses while standing on a force platform. The eye tracking glasses recorded changes in pupil size that in turn were converted into the Index of Cognitive Activity (ICA). ICA values were averaged for each eye and condition. A two-way Analysis of Variance with post-hoc Sidak correction for pairwise comparisons was run to examine the effect of visual occlusion and dual tasking on ICA values as well on Center of Pressure (CoP) sway velocity in anterior–posterior (AP) and medio-lateral (ML) directions. A Pearson’s correlation coefficient was utilized to determine the relationship between ICA values and CoP sway velocity.Results: Significant within-condition effect was observed with visual occlusion for the right eye ICA values (p = 0.008). Right eye ICA increased from eyes open to eyes occluded conditions (p = 0.008). In addition, a significant inverse correlation was observed between right eye ICA values and CoP sway velocity in the ML direction across all the conditions (r = -0.25, p = 0.02).Conclusion: This study demonstrated support for increased cognitive workload, measured by pupillometry, as a result of changes in postural control in healthy young adults. Further research is warranted to investigate the clinical application of pupillometry in balance assessment.

Effects of transcranial direct current stimulation on foot sensorimotor function and postural control in healthy young adults: A systematic review and meta-analysis based on randomized controlled trials.

Postural control is important to cope with demands of everyday life. It has been shown that both attentional demand (i.e., cognitive processing) and fatigue affect postural control in young adults. However, their combined effect is still unresolved. Therefore, we investigated the effects of fatigue on single- (ST) and dual-task (DT) postural control. Twenty young subjects (age: 23.7 ± 2.7) performed an all-out incremental treadmill protocol. After each completed stage, one-legged-stance performance on a force platform under ST (i.e., one-legged-stance only) and DT conditions (i.e., one-legged-stance while subtracting serial 3s) was registered. On a second test day, subjects conducted the same balance tasks for the control condition (i.e., non-fatigued). Results showed that heart rate, lactate, and ventilation increased following fatigue (all p < 0.001; d = 4.2–21). Postural sway and sway velocity increased during DT compared to ST (all p < 0.001; d = 1.9–2.0) and fatigued compared to non-fatigued condition (all p < 0.001; d = 3.3–4.2). In addition, postural control deteriorated with each completed stage during the treadmill protocol (all p < 0.01; d = 1.9–3.3). The addition of an attention-demanding interference task did not further impede one-legged-stance performance. Although both additional attentional demand and physical fatigue affected postural control in healthy young adults, there was no evidence for an overadditive effect (i.e., fatigue-related performance decrements in postural control were similar under ST and DT conditions). Thus, attentional resources were sufficient to cope with the DT situations in the fatigue condition of this experiment.

Ten hemiplegic subjects completed 20 rapid dorsiflexions of their afflicted and nonafflicted limbs. Electrodes were attached to the tibialis anterior and the gastrocnemius muscles and electromyograms were recorded for their premotor time, motor time, and simple reaction time during ankle dorsiflexion and plantar flexion of their lower limbs. The fractionated components of reaction time, namely, premotor time and motor time, of both legs were statistically compared. It was found that the premotor time of the subject's stroke-affected limb was significantly slower than the premotor time of the nonaffected limb (control), with no differences between their associated mean motor times. These results supported the hypothesis that a stroke has a deleterious affect upon the central, premotor time processing centers and has no disruptive influence upon the peripheral motor time. Comparing the fractionated components of reaction time (premotor time and motor time), with simple reaction time, the former provided a more sensitive and valid method to detect possible injurious side effects of a stroke upon the brain's neuromotor transmission centers and subcenters, and their peripheral, stimulus, response network.

We examined the influence of perceived cognitive fatigue on static balance control in healthy young adults to gain greater clarity about this issue than provided in previous research. Based on the prevailing assumption in pertinent literature, we hypothesized that the influence of cognitive fatigue on balance control depends on the attentional effort required by the balance tasks being performed. To test this hypothesis, 44 young adults (24 women and 20 men) were alternately assigned to either the experimental group that was cognitively fatigued (using the 16-min TloadDback-task with individualized settings) or the control group (who watched a documentary). Before and after the intervention, the participants performed six balance tasks that differed in (attentional) control requirements, while recording the center of pressure (COP). From these time series, sway variability, mean speed, and sample entropy were calculated and analyzed statistically. Additionally, perceived cognitive fatigue was assessed using VAS scales. Statistical analyses confirmed that the balance tasks differed in control characteristics and that cognitive fatigue was elevated in the experimental group, but not in the control group. Nevertheless, no significant main effects of cognitive fatigue were found on any of the COP measures of interest, except for some non-robust interaction effects related primarily tosample entropy. These results suggest that, in young adults, postural control in static balance tasks is largely automatic and unaffected by task-induced state fatigue.

Postural control is an outcome of complex interactions between many systems and structures to control body position in space. Appropriate postural control is necessary for the initiation and continuation of movements in different body parts, such as the upper limbs. Although the importance of maintaining postural control for movement is well recognized, its relationship with upper limb functions is unknown. The present study investigated the factors related to the upper limb in determining postural control in healthy young adults. We included 68 nonsymptomatic individuals in this cross-sectional study. The static and dynamic postural stability and upper limb performance parameters of the participants were evaluated. Multiple Linear Regression analysis was performed to determine the independent determinants of postural control. According to the results of the analysis, Six Minute Peg Board Ring Test (6PBRT) explaining 11% of the variance was the independent determinant of static general stability index (p&lt;0.05). Nine-Hole Peg Test (9HPT) explaining 5.3% of the variance was the independent determinant of static anterior-posterior stability index (p&lt; 0.05). It was concluded that upper limb functions were a determinant of static postural control in non-symptomatic young adults. The 6PBRT and Medicine Ball Chest Launch Test (MBCLT) explaining 16.5% of the variance were found as independent determinants of static medial-lateral stability index (p&lt;0.05). It was concluded that upper limb functions were a determinant of static postural control in non-symptomatic young adults. There was no significant relationship between dynamic stability indices and upper extremity functional parameters (p&gt;0.05). It was concluded that upper limb functions were a determinant of static postural control in non-symptomatic young adults.

ABSTRACTTurning, while walking, is an important component of adaptive locomotion. Current hypotheses regarding the motor control of body segment coordination during turning suggest heavy influence of visual information. The authors aimed to examine whether visual field impairment (central loss or peripheral loss) affects body segment coordination during walking turns in healthy young adults. No significant differences in the onset time of segments or intersegment coordination were observed because of visual field occlusion. These results suggest that healthy young adults can use visual information obtained from central and peripheral visual fields interchangeably, pointing to flexibility of visuomotor control in healthy young adults. Further study in populations with chronic visual impairment and those with turning difficulties are warranted.

Background Fatigue may impair the proprioceptive and kinesthetic properties of joints and has been shown to have a negative effect on neuromuscular control, thus increasing the risk for injury. Purpose This study aimed to determine the effect of induced whole-body fatigue on dynamic balance control in healthy young adults. Participants and methods Thirty healthy young participants of both sexes were included in this study; their ages ranged between 18 and 22 years. All of the participants were tested on the Biodex Stability System (BSS) at a stability level 4, subjected to induced fatigue on a treadmill, and then retested directly on the BSS again to evaluate dynamic postural balance. Results There was a significant decrease in the overall stability index, anteroposterior stability index, and mediolateral stability index of dynamic balance at stability level 4 of BSS in healthy young adults as P -values were 0.0001, 0.0001, and 0.0001, respectively. Conclusion and implication It was concluded that induced whole-body fatigue decreased the dynamic postural balance (overall stability index, anteroposterior stability index, and mediolateral stability index) in healthy young adults. This implies that muscles of a fatigued individual are at increased risk for musculoskeletal injury, and steps should be taken during conditioning and rehabilitation programs to prevent muscle fatigue through balance training and endurance exercises to avoid disturbed balance related to fatigue among young healthy adults.

Recently, there have been several studies that have examined the acute effects of aerobic exercise on cognitive function. Importantly, one precise indicator of cognitive function is response time (RT), which has two main components; premotor time (PMT) and motor time (MT). PMT is the time for perception, decision making and response preparation, while MT is executing the response. Using fractionated response time (FRT) instead of RT provides a more precise estimate of the location of the effect of aerobic exercise on cognitive or motor components of the response. There is emerging evidence that shows an acute bout of exercise may improve FRT. Therefore, the purpose of this systematic review and meta-analysis was to explore the acute effect of aerobic exercise on FRT by considering the effects of various cognitive function tests. Fourteen studies were included investigating FRT during and/or after aerobic exercise. The results indicated that during exercise, PMT increased in simple reaction time and decreased in flanker task; MT decreased in choice reaction time; interestingly, RT decreased when it was assessed by choice reaction time and flanker task, almost similar to PMT and MT. After exercise, PMT decreased specifically in flanker and go/no-go tasks. However, MT and RT did not change significantly. In conclusion, as changes in RT are affected by both PMT and MT, FRT provides a more precise estimate of the locus of the effects of aerobic exercise on response time.

Inter-session reliability and sex-related differences in hamstrings total reaction time, pre-motor time and motor time during eccentric isokinetic contractions in recreational athlete

Objective: In the present study, we investigated the efficacy of transcranial random noise stimulation (tRNS) combined with an exergame training (physical exercise combined with a videogame) chosen as potential techniques to boost brain functioning and to promote plastic effects in healthy young adults. The aim was to improve the motor response speed and the response time when inhibition was required. Method: Forty-nine participants were randomly assigned to four conditions. The protocol consisted of eight sessions of exergame cognitive training (or no training) associated with the active or sham stimulation of the left dorsolateral prefrontal cortex (left-DLPFC). Results: The results indicated faster simple reaction times following the exergame training, and faster reaction times in Go trials (while the ratio of NoGo trials remained unaltered) following tRNS. No interactions were present between the two procedures. Conclusions: These findings reveal better performance in both tasks with independent effects of the two techniques. Using noninvasive brain stimulation and exergame training may be a viable strategy to increase motor response speed and improve executive control. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

This study aimed to provide a basic description of the motor control strategy during bimanual isometric force control in healthy young adults. Thirty healthy young adults (mean age: 27.4 ± 3.7 years) participated in the study. The subjects were instructed to press both hands simultaneously to match the target force level of 5%, 25%, and 50% bimanual maximum voluntary force using continuous visual feedback. Bimanual motor synergy and bimanual coordination, as well as force asymmetry, force accuracy, and force variability were compared. This study identified the specific motor control strategy of healthy young adults during bimanual isometric force control, indicating that they proportionally increased “good” and “bad” variabilities, resulting in comparable bimanual motor synergy as the target force level increased.

Performing everyday tasks requires the use of multiple cognitive, sensory, and emotional systems. The interference of different variables in these multitasking systems affects our motor-balance system. This study was conducted to investigate how acoustic stimuli presented during a cognitive-motor dual task affect postural control in healthy young adults. Fifty-four healthy participants (39 females, 15 males; total age 21.87±1.18, range 19-24) were randomly assigned to control (silent), noise (multi-talker babble), or music (Mozart-Jupiter) groups based on testing environment. During the Stroop test, conducted with acoustic stimuli, postural sway velocity was measured on firm and foam surfaces with eyes open. The dual-task effect was assessed using the Wilcoxon test, and group comparisons employed one-way ANOVA or Kruskal-Wallis tests. Independent t tests and Mann-Whitney U tests were used for two-group comparisons. Statistical significance was set at p<0.05 (Bonferroni-adjusted p<0.017). The silent cognitive-motor dual task increased postural sway on firm (median increased from 0.18 to 0.26deg/s) and foam (median increased from 0.21 to 0.32deg/s) surfaces. Music did not significantly affect cognitive performance or postural sway compared to the control group. However, noise reduced postural sway on firm and foam surfaces compared to the control group but did not affect cognitive performance. There was no significant difference in average Stroop response times between the groups or between the firm and foam surface comparisons. During inhibitory control tasks, cognitive effort prioritized in young people in easy-to-balance situations. Background noise affects motor-cognitive interaction, highlighting its potential for enhancing vestibular rehabilitation strategies in multitasking and guiding future research.

Altered serotonergic and dopaminergic function have been widely implicated in behavioural disorders associated with impulsivity and risk-taking. However, little research has addressed the specific cognitive consequences of changed monoaminergic function that might contribute to the production of impulsive behaviour. We compared the effects of rapid plasma tryptophan depletion, acute doses of the mixed indirect catecholamine agonist, methylphenidate (40 mg), and acute doses of the alpha(1)/alpha(2 )agonist, clonidine (1.5 microg/kg), on aspects of visual discrimination learning involving either acquisition of altered stimulus-reward associations (i.e. updating the affective valence of exteroceptive stimuli) or the control of attention towards relevant as opposed to irrelevant stimulus dimensions. Relative to subjects who received placebo, subjects with reduced tryptophan exhibited a deficit in the ability to learn changed stimulus-reward associations, but were still able to shift an acquired attentional set away from a now-irrelevant stimulus dimension towards a newly relevant dimension. By contrast, subjects who received methylphenidate were able to learn effectively about changing stimulus-reward associations, but showed an enhanced ability to shift an attentional bias, in combination with slowed response times. Subjects who received clonidine showed neither of these changes. These results suggest that reduction in central serotonin leads to altered neuromodulation of the cortical and subcortical regions (e.g. orbitofrontal cortex, striatum and anterior temporal structures) that mediate important aspects of associative learning whereby exteroceptive stimuli acquire altered incentive motivational value. On the other hand, facilitation of catecholamine neurotransmitters may disrupt the allocation of attention between relevant and irrelevant features of the environment, perhaps through altered modulation of the dorsolateral prefrontal cortex. The implications of these results for understanding the differential neuromodulation of cognitive functions are discussed.

To compare the performance of a bioreactance cardiac output (CO) monitor (NICOM) and transcutaneous Doppler (USCOM) during head up tilting (HUT). Healthy young adult subjects, age 22±1years, 7 male and 7 female, were tilted over 3-5s from supine to 70° HUT, 30° HUT and back to supine. Positions were held for 3min. Simultaneous readings of NICOM and USCOM were performed 30s into each new position. Mean blood pressure (MBP), heart rate (HR), CO and stroke volume (SV), and thoracic fluid content (TFC) were recorded. Bland-Altman, percentage changes and analysis of variance for repeated measures were used for statistical analysis. Pre-tilt NICOM CO and SV readings (6.1±1.0L/min and 113±25ml) were higher than those from USCOM (4.1±0.6L/min and 77±9ml) (P<0.001). Bland-Altman limits of agreement for CO were wide with a percentage error of 38%. HUT increased MBP and HR (P<0.001). CO and SV readings decreased with HUT. However, the percentage changes in USCOM and NICOM readings did not concur (P<0.001). Whereas USCOM provided gravitational effect proportional changes in SV readings of 23±15% (30° half tilt) and 44±11% (70° near full tilt), NICOM changes did not being 28±10 and 33±11%. TFC decreased linearly with HUT. The NICOM does not provide linear changes in SV as predicted by physiology when patients are tilted. Furthermore there is a lack of agreement with USCOM measurements at baseline and during tilting.