Motor learning of cue-dependent pull-force changes during an isometric precision grip task

The “raspberry task” represents a precision grip task that requires continuous adjustment of grip and pull forces. During this task subjects grip a specialized grip rod and have to increase the pull force linearly while the rod is locked. The aim of this study was to determine whether an associated, initially neutral cue is able to evoke pull-force changes in the raspberry task. A standard delay paradigm was used to study cued pull-force changes during an ongoing movement resulting in unloading. Pull force and EMG activity of hand and arm muscles were recorded from 13 healthy, young subjects. The cue was associated with a complex change in motor behavior.In this task, cued force changes take place more rapidly than in protective reflex systems (in median after the second presentation of the cueing stimulus). A cued force change was detectable in two-thirds of paired trials. Although the force change is produced by a decrease of the EMG activity in several grip- and pull-force-producing muscles, the most significant effect in the majority of the subjects was an increase of the activity of the flexor carpi ulnaris muscle which antagonises corresponding pull-force-producing muscles. Cued force changes require adequately and precisely controlled activation of the muscle groups involved in the movement.     

The Effects of Attentional Focus Instructions and Task Difficulty in a Paced Fine Motor Skill

Abstract

An external focus of attention is considered superior to an internal focus for learning and performance. However, findings specific to changing the task difficulty are inconsistent. The present study used a reciprocal aiming task to determine the effects of attentional focus on motor performance using speed-accuracy paradigm. We constrained timing to examine how internal and external focus of attention influenced accuracy when task difficulty changes. The results indicated greater accuracy on the right target and greater consistency on both targets for the external focus condition, regardless of task difficulty. Our results uniquely demonstrated how instruction modified a speed-accuracy task.     

Crawling in and out of sleep

The goal of the study was to examine the link between motor attainments and sleep–wake regulation by comparing the sleep characteristics of infants who are crawling with the sleep of same‐age infants who have not yet acquired the locomotion milestone. The participants were 59 healthy 8‐month‐old infants with no developmental delays, who were recruited through well‐baby clinics and childcare centers. The measurements included objective sleep recordings (actigraphy), sleep questionnaire, and motor milestones checklist. The main finding was that the sleep of crawlers was more fragmented in comparison to the sleep of pre‐crawlers. While the findings of this report give support to the hypothesized link between sleep regulation and motor development, more studies are needed to clarify why crawling might provide a marker of nightwaking. In discussing the results, it is proposed that the association between fragmented sleep and crawling could be related to maturational, constitutional, and relational factors. Copyright © 2005 John Wiley & Sons, Ltd.     

Is Segmental Trunk Control Related to Gross Motor Performance in Healthy Preterm and Full-Term Infants?

Abstract

The authors’ aim was to verify the correlation between segmental trunk control and gross motor performance in healthy preterm (PT) and full-term (FT) infants aged 6 and 7?months and to verify if there are differences between groups. All infants were assessed at 6 and 7?months by means of Segmental Assessment of Trunk Control (SATCo) to identify the exact level of segmental trunk control and Alberta Infant Motor Scale (AIMS) to measure gross motor performance. A significant correlation between segmental trunk control and gross motor performance was found in healthy PT infants at 7?months and FT infants at 6?months. PT infants showed a delay on segmental trunk control at 6 and 7?months and in supported standing posture at 6?months compared with FT infants. Segmental trunk control and gross motor performance showed an important relationship in healthy PT and FT infants, mainly in sitting posture.     

Analytical Hierarchy Process Based Assignment Model for Allotting Parking Slots to Different Localities

Because of growing population and a consequent increase in number of vehicles, the problem of parking personal vehicles is becoming explosive. This paper suggests efficient use of surplus space to be utilized as parking slot using analytical hierarchy process and integer programming model. Examples covering a real situation justify the approach. Copyright © 2011 John Wiley & Sons, Ltd.