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Journal of Clinical Epidemiology Jul 2023Exercise is beneficial for fall prevention. Targeting interventions to people who fall more may lead to greater population impacts. As trials have used varying methods... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND AND OBJECTIVES
Exercise is beneficial for fall prevention. Targeting interventions to people who fall more may lead to greater population impacts. As trials have used varying methods to assess participant risk level, prospectively-measured control group fall rates may provide a more accurate and poolable way to understand intervention effects in different subpopulations. We aimed to explore differences in effectiveness of fall prevention exercise according to prospectively-measured fall rate.
METHODS
Secondary analysis of a Cochrane review investigating exercise for fall prevention in peopled aged ≥60 years. Meta-analysis assessed the impact of exercise on fall rate. Studies were dichotomized according to the median control group fall rate (0.87, IQR 0.54-1.37 falls/person-year). Meta-regression explored the effects on falls in trials with higher and lower control group fall rates.
RESULTS
Exercise reduced the rate of falls in trials with higher (rate ratio 0.68, 95% CI 0.61-0.76, 31 studies) and lower control group fall rates (rate ratio 0.88, 95% CI 0.79-0.97, 31 studies, P = 0.006 for difference in effects).
CONCLUSION
Exercise prevents falls, moreso in trials with higher control group fall rates. As past falls strongly predict future falls, targeting interventions to those with more past falls may be more efficient than other falls risk screening methods.
Topics: Humans; Accidental Falls; Independent Living; Control Groups; Exercise; Exercise Therapy
PubMed: 37156341
DOI: 10.1016/j.jclinepi.2023.05.003 -
ELife Sep 2021Many spinal circuits dedicated to locomotor control have been identified in the developing zebrafish. How these circuits operate together to generate the various...
Many spinal circuits dedicated to locomotor control have been identified in the developing zebrafish. How these circuits operate together to generate the various swimming movements during development remains to be clarified. In this study, we iteratively built models of developing zebrafish spinal circuits coupled to simplified musculoskeletal models that reproduce coiling and swimming movements. The neurons of the models were based upon morphologically or genetically identified populations in the developing zebrafish spinal cord. We simulated intact spinal circuits as well as circuits with silenced neurons or altered synaptic transmission to better understand the role of specific spinal neurons. Analysis of firing patterns and phase relationships helped to identify possible mechanisms underlying the locomotor movements of developing zebrafish. Notably, our simulations demonstrated how the site and the operation of rhythm generation could transition between coiling and swimming. The simulations also underlined the importance of contralateral excitation to multiple tail beats. They allowed us to estimate the sensitivity of spinal locomotor networks to motor command amplitude, synaptic weights, length of ascending and descending axons, and firing behavior. These models will serve as valuable tools to test and further understand the operation of spinal circuits for locomotion.
Topics: Animals; Locomotion; Models, Biological; Motor Activity; Motor Neurons; Nerve Net; Neurons; Spinal Cord; Swimming; Zebrafish
PubMed: 34473059
DOI: 10.7554/eLife.67453 -
Journal of Neuroengineering and... Feb 2022In the last two decades, lower-limb exoskeletons have been developed to assist human standing and locomotion. One of the ongoing challenges is the cooperation between...
BACKGROUND
In the last two decades, lower-limb exoskeletons have been developed to assist human standing and locomotion. One of the ongoing challenges is the cooperation between the exoskeleton balance support and the wearer control. Here we present a cooperative ankle-exoskeleton control strategy to assist in balance recovery after unexpected disturbances during walking, which is inspired on human balance responses.
METHODS
We evaluated the novel controller in ten able-bodied participants wearing the ankle modules of the Symbitron exoskeleton. During walking, participants received unexpected forward pushes with different timing and magnitude at the pelvis level, while being supported (Exo-Assistance) or not (Exo-NoAssistance) by the robotic assistance provided by the controller. The effectiveness of the assistive strategy was assessed in terms of (1) controller performance (Detection Delay, Joint Angles, and Exerted Ankle Torques), (2) analysis of effort (integral of normalized Muscle Activity after perturbation onset); and (3) Analysis of center of mass COM kinematics (relative maximum COM Motion, Recovery Time and Margin of Stability) and spatio-temporal parameters (Step Length and Swing Time).
RESULTS
In general, the results show that when the controller was active, it was able to reduce participants' effort while keeping similar ability to counteract and withstand the balance disturbances. Significant reductions were found for soleus and gastrocnemius medialis activity of the stance leg when comparing Exo-Assistance and Exo-NoAssistance walking conditions.
CONCLUSIONS
The proposed controller was able to cooperate with the able-bodied participants in counteracting perturbations, contributing to the state-of-the-art of bio-inspired cooperative ankle exoskeleton controllers for supporting dynamic balance. In the future, this control strategy may be used in exoskeletons to support and improve balance control in users with motor disabilities.
Topics: Ankle; Ankle Joint; Biomechanical Phenomena; Exoskeleton Device; Gait; Humans; Walking
PubMed: 35172846
DOI: 10.1186/s12984-022-01000-y -
Trials Feb 2023Procrastination or "postponing until later" is a common phenomenon defined as the intentional delay in partaking in and finishing important activities despite negative...
BACKGROUND
Procrastination or "postponing until later" is a common phenomenon defined as the intentional delay in partaking in and finishing important activities despite negative outcomes potentially outweighing the positive. Procrastination adversely affects mental health, academic performance, and career achievement. Although studies on procrastination intervention methods and effectiveness exist, utility and cost-effectiveness are limited by various factors, including practitioner availability and skills, barriers to participant participation, and the time investment required by participants. Thus, internet-based interventions could increase the availability of evidence-based treatments for adult procrastination.
METHODS
This study explored the efficacy of an online-based self-help intervention in the context of voluntary procrastination among undergraduate psychology students. The study design is a randomized controlled trial. Participants who self-reported procrastination-related problems and behaviours were included in the trial consisting of two groups; specifically, one group undergoing a self-directed internet-based intervention for coping with procrastination (N=160) and (2) another group with delayed access to the intervention programmes (waitlist control group; N=160). Follow-up assessments were scheduled 6 and 12 weeks after baseline, and the control group received the intervention after 12 weeks. Procrastination, measured by the Irrational Procrastination Scale and the Simple Procrastination Scale, was examined as the primary outcome. Meanwhile, secondary outcomes included susceptibility, stress, depression, anxiety, well-being, self-efficacy, time management strategies, self-control, cognition, and emotion regulation. Other measures comprised acceptability (e.g., intervention satisfaction, potential side effects, and expectations) and learning behaviour analysis to reflect adherence.
DISCUSSION
This randomized controlled trial will provide data on the effectiveness of online interventions for adult procrastination. If deemed effective, this low-cost, high-coverage internet-based intervention could aid more people who seek to address their procrastination.
TRIAL REGISTRATION
Chinese Clinical Trial Registry. https://www.chictr.org.cn/showproj.aspx?proj=171246 .
Topics: Adult; Humans; Internet-Based Intervention; Control Groups; Procrastination; Mental Health; Anxiety; Internet; Randomized Controlled Trials as Topic
PubMed: 36747265
DOI: 10.1186/s13063-023-07112-7 -
Frontiers of Neurology and Neuroscience 2021Hypothalamic hypocretin/orexin neurons have been initially conceptualized as slow, modulatory controllers of behavior. Furthermore, their behavioral effects have been... (Review)
Review
Hypothalamic hypocretin/orexin neurons have been initially conceptualized as slow, modulatory controllers of behavior. Furthermore, their behavioral effects have been assumed to be a secondary consequence of their impact on arousal. However, cellular-resolution calcium imaging and optogenetic studies show that orexin neurons regulate self-generated and sensory-evoked movement on rapid, subsecond timescales. Orexin cell activity rapidly and transiently peaks before and during movements. Optogenetic prevention of this activation reduces the probability of locomotion initiation, and optogenetic mimicry of orexin cell activation rapidly causes locomotion. Neural ensemble calcium imaging experiments reveal that the same orexin cells whose activity underlies movement initiation display subsecond-latency responses to diverse sensory stimuli. These findings establish orexin neurons as rapid and strong sensorimotor controllers that are in many ways operationally similar to classic subcortical movement controllers, such as midbrain dopamine neurons. While a scientific definition of "arousal" is still lacking, the subsecond-scale sensorimotor control by orexin neurons could be viewed as reminiscent of a motor rather than an arousal system.
Topics: Animals; Humans; Hypothalamus; Locomotion; Motor Activity; Neurons; Orexins; Sensation
PubMed: 34052808
DOI: 10.1159/000514957 -
Consciousness and Cognition Aug 2019Sense of agency refers to the subjective feeling of controlling one's own action, and through it, external events. Action-effect delay is widely used to disrupt this... (Review)
Review
Sense of agency refers to the subjective feeling of controlling one's own action, and through it, external events. Action-effect delay is widely used to disrupt this subjective feeling. Numerous studies have shown that self-reported sense of agency decreases along with the increase in delay. I discussed the distinction between body and external agency, and the possible different effects of delay on them. Furthermore, I reviewed literature that examined the influence of delay on self-reported sense of agency, implicit measures of sense of agency, and control-based action selection, and discussed possible reasons of the reported effects. Delay influences the measures of agency via multiple possible processes, such as graded response, task performance, sensory pre-activation, and temporal perceptual sensitivity. However, the causal relation between action and effect at higher-level of judgment may remain intact even for super-second delays. I conclude that the effects of delay on the sense of agency significantly differ between different levels, and researchers willing to use delay to disturb the sense of agency should carefully clarify which process it may affect.
Topics: Feedback, Sensory; Humans; Motor Activity; Psychomotor Performance; Sensation; Time Perception
PubMed: 31173998
DOI: 10.1016/j.concog.2019.05.007 -
Journal of Neurophysiology Mar 2020Generalizing newly learned movement patterns beyond the training context is challenging for most motor learning situations. Here we tested whether learning of a new...
Generalizing newly learned movement patterns beyond the training context is challenging for most motor learning situations. Here we tested whether learning of a new physical property of the arm during self-initiated reaching generalizes to new arm configurations. Human participants performed a single-joint elbow reaching task and/or countered mechanical perturbations that created pure elbow motion with the shoulder joint free to rotate or locked by the manipulandum. With the shoulder free, we found activation of shoulder extensor muscles for pure elbow extension trials, appropriate for countering torques that arise at the shoulder due to forearm rotation. After locking the shoulder joint, we found a partial reduction in shoulder muscle activity, appropriate because locking the shoulder joint cancels the torques that arise at the shoulder due to forearm rotation. In our first three experiments, we tested whether and to what extent this partial reduction in shoulder muscle activity generalizes when reaching in different situations: ) different initial shoulder orientation, ) different initial elbow orientation, and ) different reach distance/speed. We found generalization for the different shoulder orientation and reach distance/speed as measured by a reliable reduction in shoulder activity in these situations but no generalization for the different elbow orientation. In our fourth experiment, we found that generalization is also transferred to feedback control by applying mechanical perturbations and observing reflex responses in a distinct shoulder orientation. These results indicate that partial learning of new intersegmental dynamics is not sufficient for modifying a general internal model of arm dynamics. Here we show that partially learning to reduce shoulder muscle activity following shoulder fixation generalizes to other movement conditions, but it does not generalize globally. These findings suggest that the partial learning of new intersegmental dynamics is not sufficient for modifying a general internal model of the arm's dynamics.
Topics: Adolescent; Adult; Biomechanical Phenomena; Elbow; Female; Generalization, Psychological; Humans; Learning; Male; Middle Aged; Motor Activity; Muscle, Skeletal; Shoulder; Young Adult
PubMed: 32101490
DOI: 10.1152/jn.00696.2019 -
Sports Health 2022Female athletes are more predisposed to anterior cruciate ligament (ACL) injuries in comparison with their male counterparts. Research on ACL injury prevention...
BACKGROUND
Female athletes are more predisposed to anterior cruciate ligament (ACL) injuries in comparison with their male counterparts. Research on ACL injury prevention strategies has demonstrated beneficial effects of plyometric exercises and feedback (FB) during the exercises. FB has resulted in reductions in vertical ground-reaction force and kinematic risk factors associated with ACL injury. Furthermore, taping (TP) may draw attention to the restriction created by the tape and serve as real-time biofeedback. The additional influence of FB and TP on plyometric exercises has not been determined.
HYPOTHESIS
FB and TP interventions delivered during plyometric exercises would result in positive changes in biomechanics and muscle onset in female athletes displaying dynamic knee valgus.
DESIGN
Controlled trial.
SETTING
University research laboratory.
LEVEL OF EVIDENCE
Level 2.
METHODS
Forty-eight active female athletes were divided into 3 groups: control (n = 16), plyometric training with FB (n = 16), and plyometric training with TP (n = 16). The 2 experimental groups performed a 6-week exercise program with either FB or TP. The control group continued its regular team schedule. Knee joint position sense, landing error scoring system (LESS), and the onset of muscle activation (the point at which muscle activation exceeds 3 standard deviations over baseline and continued above this threshold for at least 25 ms) before landing for the rectus femoris, vastus medialis, vastus lateralis, gluteus medius, semitendinosus, and biceps femoris during pre- and posttests were measured.
RESULTS
The vastus lateralis onset later in the TP group compared with the FB group ( [95% CI] = 0.64 [0.35-0.82], = 0.01). Joint position sense accuracy improved only in the TP group ( = -0.63, = 0.001). Both the FB ( = -0.85, = 0.001), and TP ( = -0.82, = 0.001) groups improved in LESS scores.
CONCLUSION
The results of the present study showed that plyometric exercises with FB or TP affect LESS and the onset of the vastus lateralis in active uninjured women with dynamic knee valgus, while TP improves joint position sense. Therefore, when more accurate joint position sense is desired, practitioners may use plyometric with TP. If an improved LESS score is desired, plyometrics with either TP or FB are acceptable.
CLINICAL RELEVANCE
Our findings indicate that female athletes may benefit more when completing a plyometric training program with a TP versus an FB. Trainers, coaches, and clinicians should consider utilizing instructions that promote an external focus when implementing plyometric training programs with male athletes.
Topics: Anterior Cruciate Ligament Injuries; Biomechanical Phenomena; Feedback; Female; Humans; Knee; Knee Joint; Male; Plyometric Exercise
PubMed: 34651505
DOI: 10.1177/19417381211049805 -
PloS One 2020Recent literature has indicated altered motor control in individuals with non-specific low back pain (NSLBP). These individuals present variations in back muscular...
Recent literature has indicated altered motor control in individuals with non-specific low back pain (NSLBP). These individuals present variations in back muscular activity and center of mass (CoM) oscillations. The aim of this study is to explore the possibility of quantitatively measuring these differences using standard parameters with electronic devices. Twenty individuals with NSLBP and 20 healthy controls, matched by sex and age, performed a total of three trials under three different conditions for 90 seconds each. These conditions were standing on firm ground with eyes open, with eyes closed and standing on unstable foam with eyes open. Balance data was acquired via a Kistler force platform and muscular activity was measured by electromyography derived bilaterally from the erector spinae. Afterwards, participants were asked to complete a questionnaire on their current mood, pain rating, well-being, disability and physical activity. Descriptive data from the questionnaire showed an average acute pain score of 2.6 and an average pain score of 5.1 for the prior six weeks in the NSLBP group, while the control group reported an acute pain of 0.1 and an average pain of 0.5. For wellbeing, differences were found only for the physical scale. Average disability was low for the NSLBP group. No differences in physical activity were found among groups. A repeated measures ANOVA did not show significant differences between groups for any parameter. There was also no main effect for the standing conditions and no interaction between group and condition. Simultaneously measuring biomechanical and neuromuscular parameters, allowed for a fine grain approach to understanding motor control in individuals with NSLBP. This study did not find differences as described in the literature, and suggests further examination of factors involved in pain and control processes to better understand implications of NSLBP and possible avenues for support.
Topics: Adult; Back Muscles; Back Pain; Case-Control Studies; Female; Humans; Low Back Pain; Male; Motor Activity; Postural Balance; Standing Position
PubMed: 32628670
DOI: 10.1371/journal.pone.0234858 -
Journal of Neurophysiology Nov 2021Motor skill learning involves improvement in feedforward control, the ability to execute a motor plan more reliably, and feedback control, the ability to adjust the...
Motor skill learning involves improvement in feedforward control, the ability to execute a motor plan more reliably, and feedback control, the ability to adjust the motor plan on the fly. The dependence between these control components and the association between training conditions and their improvement have not been directly examined. This study characterizes the contribution of feedforward and feedback control components to motor skill learning using the arc-pointing task (APT), a drawing task that requires high motor acuity. In , the performance of three groups of subjects was tested before and after training with online visual feedback (OF group), with knowledge of performance feedback that was presented after movement completion (KP group), and with both online and KP feedback (KP + OF group). Although the improvement of the OF group was not different from the improvement of the KP + OF group, comparison of the KP and KP + OF groups revealed an advantage to the KP group in the fast test speed, suggesting that training without online feedback leads to a greater improvement in feedforward control. In , subject's improvement was examined using test probes for estimating feedback and feedforward control. Both KP + OF and KP groups showed improvement in feedforward and feedback conditions with a trend toward a greater improvement of the KP group. Our results suggest that online visual feedback suppresses improvement in feedforward control during motor skill learning. Becoming a skillful player requires both executing reliable movements and being able to efficiently control them online. We study here how training with and without online visual feedback affects feedforward and feedback control improvement in a drawing task that requires high precision. We show that training with online feedback suppresses improvement in feedforward control and leads to inferior performance in fast movements.
Topics: Adult; Executive Function; Feedback, Sensory; Female; Humans; Male; Motor Activity; Motor Skills; Practice, Psychological; Visual Perception; Young Adult
PubMed: 34525324
DOI: 10.1152/jn.00145.2021