bluuebunny/crossref_metadata_2025 huggingface dataset:
Values Development through Physical Activity: Promoting Sportsmanlike Behaviors, Perceptions, and Moral Reasoning
Authors: Wandzilak Thomas , Carroll Tim , Ansorge Charles J.
Published: August 2016

This study was conducted to determine the effectiveness of a values-related model in producing changes in the moral reasoning, sportsmanship perceptions, and behaviors of male junior high school basketball players. The Defining Issues Test (DIT) and the Action-Choice Test for Competitive Sports Situations (ACT) were administered during the first and last weeks of a 9-week basketball season. In addition, behaviors of three players from the experiment (n=10) and control (n=10) groups were systematically observed throughout the season. Analysis of covariance was used to determine the effects of the model on the responses to both the DIT and ACT variables. Results revealed no difference (p>.05) between the groups for either dependent variable. However, comparison of pre- and postseason mean scores from each of the instruments and analysis of the behavior patterns of the players observed suggest that, for the experiment group, a sportsmanlike pattern was emerging.
Curriculum and Program Research in Physical Education: Selected Approaches
Authors: Anderson William G.
Published: August 2016

This article reports on a group of eight recent studies that focus on physical education curriculums and programs. The investigations were completed in connection with the doctoral research program at Teachers College, Columbia University. The intent of this review is to provoke interest in curriculum and program research by using selected studies to illustrate a variety of approaches that might be pursued in the areas of curriculum development, collaborative program development, program description, describing the development process, and program evaluation. Essential features of the research strategies employed in each study are presented and related issues are discussed. A limited taxonomy for these types of curriculum and program studies is proposed to facilitate the conceptualization of future studies.
Movement Education in Physical Education—A Definitional Effort
Authors: Radford Keith W.
Published: August 2016

A philosophical approach was taken to the development of a framework for understanding the nature of movement observation as an aspect of teaching performance in physical education. The concepts and relationships that were revealed through a rigorous review of the literature on movement observation resulted in the conception of a theoretical framework. The framework conceived of movement observation as three independent subprocesses: attention, template formation, and motivation. The functional operation of these three subprocesses was proposed in terms of two developmental principles that operate in reciprocal fashion: that of simplicity and that of economy.
Model/Practice versus Verbal/Rehearsal Introductions of Systems Skills Within an Individually Prescribed Instructional System
Authors: Sharpe Thomas L. , Hawkins Andrew , Wiegand Robert
Published: August 2016

This study examined one component of an individualized instructional setting specific to physical education in order to operationally define more clearly one instructional system. A comparison of model/practice and verbal/rehearsal teacher instruction of the systems skills (i.e., pupil non-subject-matter tasks) necessary to two individualized physical education classes was conducted, quantified in terms of academic learning time specific to physical education (ALT-PE). Concomitant variables of student on-task and student off-task were similarly analyzed. The study focused upon visual inspection of pupil graphic behavioral representations in determining significant level differences between and within classes. Analyses showed model/practice instruction of systems skills to produce marked reductions in student on-task and off-task behavior, allowing larger portions of classroom time to be devoted to academic content learning activities. ALT-PE was subsequently enhanced via the model/practice intervention. The verbal/rehearsal condition evidenced negligible changes across dependent measures from baseline to intervention stages.
Relationships between Teacher Expectations and Academic Learning Time in Sixth Grade Physical Education Basketball Classes
Authors: Cousineau William J. , Luke Moira D.
Published: August 2016

This study examined the relationship between teachers’ expectations of performance and the academic learning time (ALT) of elementary students in physical education classes. Six teachers from different schools were asked to rank-order their students according to expected levels of performance in physical education. Thirty-six students, one boy and one girl from the high, middle, and low expectancy groups of each class, were chosen for observation in three basketball lessons to determine ALT–PE. Using ANOVA, a significant difference was found between level of teacher expectation and academic learning time of students. High expectancy students had significantly higher ALT–PE measures than middle expectancy students, who in turn had higher ALT–PE measures than low expectancy students. Significant differences in ALT–PE were also evident across the three basketball lessons observed. No significant difference was found between student gender and ALT–PE. These results suggest that a relationship does exist between teacher expectations and academic learning time in physical education.
Kinesiology and Mental Health: The Promise of Exercise Neuroscience Research for Diseases and Disorders of the Brain
Authors: Hatfield Bradley D.
Published: August 2016

The relevance of kinesiology to the major issues of public health facing the nation is increasing with time. Of great importance is the area of exercise neuroscience in which remarkable developments have occurred in the past 35 years. The primary investigative efforts to date have been devoted to the impact of exercise on normal brain aging and recent efforts have also focused on the neurocognitive benefit to brain development in children. However, little work has been conducted in those with neurological disorders. The literature includes a number of animal studies that offer biological plausibility for the positive influence of exercise observed on brain structure and cognition in normal human subjects and, collectively, these studies provide a foundation on which to examine the role of exercise treatment in some of the major brain disorders that afflict adults and children today. These include the dementias, stroke, traumatic brain disorder (TBI), post-traumatic stress disorder (PTSD), and attentional deficit and hyperactivity disorder (ADHD). A role for exercise in building resilience to such disorders is discussed here that may assist in reducing the financial and emotional burden of these affictions.
Promoting the Dance: Should We Resuscitate Play?
Authors: Kretchmar Scott
Published: August 2016

Douglas Anderson's article about the demise of play in American culture challenges us at both personal and professional levels. It raises the possibility that play is on the wane for us personally, our own children, and our students. It suggests that we have turned our professional backs on play and allowed our play curricula to languish or disappear altogether. In this reaction paper, I affirm Anderson's thesis about the current status of play. I discuss play metaphorically as a dance between the player (the dancer) and the playground (the dancer's partner). I describe this as a fragile relationship, one that needs to be cultivated if it is to endure. I suggest that we kinesiologists have not been good supporters of the dance because of tacit or explicit commitments we have made about knowledge, value, and culture. I claim that unless and until we resolve these issues, we will continue to push physical play off the pedagogical stages at our colleges and universities.
Realizing the Promise to Young People: Kinesiology and New Institutional Designs for School and Community Programs
Authors: Lawson Hal A.
Published: August 2016

As new designs are advanced for industrial age schools and universities, including cradle-to-career systems that connect them, needs and opportunities grow for kinesiology, school physical education programs, and community exercise and sport programs for young people to be redesigned in accordance with 21st century realities. While augmenting its technical problem solving capacities, kinesiology must wrestle with two new problem types. They compel new designs for kinesiology, including new relations among the subdisciplines, outcomes-focused interdisciplinary work, and expanded knowledge systems. This work entails different speci-fcations for school and community programs, and it also necessitates policy and systems changes. Design-oriented language, knowledge frameworks, and planning templates are needed, and so is intervention science. Disciplinary stewards, guided by Francis Bacon's ideals for science, can help realize America's promise to young people by developing synchronized designs for university, school, and community programs, leading to improved outcomes.
Encouraging Physical Activity and Health Through Active Transportation
Authors: Bassett David R.
Published: August 2016

The built environment has profound effects on physical activity and health. Many communities in the US are built around the automobile, with little consideration given to pedestrians, cyclists, and transit users. These places tend to have higher rates of physical inactivity (defined as “no leisure time physical activity”) and higher rates of obesity, diabetes, heart disease, and stroke. However, in some European countries and selected US cities, communities have been constructed in ways that encourage active modes of transportation. In these places, a large segment of the population meets physical activity guidelines, due in part to the activity they acquire in performing daily tasks. In addition to promoting active transportation, these environments promote recreational walking, jogging, and cycling. Kinesiologists can and should work with urban planners, transportation officials, developers, public health practitioners, and the general public to design cities in ways that enhance physical activity and health.
Scope, Impact, and Methods of National Institutes of Health Funded Research in Kinesiology
Authors: Giacobbi Peter R. , Buman Matthew P. , Romney Kimberly J. , Klatt Monica R. , Stoddard Mari J.
Published: August 2016

The purpose of this review was to evaluate the scope, impact, and methods of research funded by the National Institutes of Health (NIH) in kinesiology departments. Information was obtained from university websites, the Research Portfolio Online Reporting Tool (RePORT), PubMed, Google Scholar, and Journal Citation Reports (JCR) from the Institute of Scientific Information (ISI) Web of Knowledge. Abstracts from 2,227 published studies funded by the NIH were reviewed. The National Institute on Aging funded the largest portion of grants. Metabolic functioning, the nervous system, pathology, and cardiovascular diseases were the major foci. Human and animal studies were predominantly discovery-oriented (e.g., comparative studies, clinical research) with a large percentage of translational approaches. Recommendations for interdisciplinary research are provided.
Tensions, Integrations, Messiness, and Hope for the Future
Authors: Kretchmar R. Scott
Published: August 2016

The 2012 Academy meeting focused on research related to increasing levels of physical activity and promoting persistence. Speakers agreed that answers would be hard to come by but that progress was possible. Emphases for potential solutions ranged from the cellular to the cultural, from neural mechanisms to symbolic processes, from particle physics to philosophy. Strategies for intervention were diverse and refected a series of dynamical tensions—behavioral and nonbehavioral, cognitive and noncognitive, traditional and nontra-ditional, environmental and motivational, and finally medical in contrast to educational. It is likely, given the complexities inherent in increasing movement behaviors and assuring persistence, that various blends of solutions emerging from multiple points on the disciplinary landscape and honoring truths that run across these strategic tensions will be needed.
School-Based Physical Activity and Health Behaviors Among Adolescents
Authors: Kulinna Pamela Hodges
Published: August 2016

This paper on school-based physical activity and health behaviors among adolescent students is grounded in the public health literature, various psychosocial theories, and the coordinated school health ecology model. I address three areas: 1) psychosocial influences on youth physical activity patterns, 2) youth physical activity patterns, and 3) comprehensive school health programming (healthy and active schools). I provide an overview and illustrative examples for each section from my own work.
Considerations for Neuropsychological Testing in the Adolescent Athlete: Implications for the Playing Field and Classroom
Authors: Guskiewicz Kevin M.
Published: August 2016

“Concussion” is all over the news, and—yes—it has implications for combating chronic diseases such as obesity and diabetes. Many parents are pushing their children away from collision sports such as football, hockey, and lacrosse because they fear the risk of chronic neurodegenerative problems later in life. However, there is good logic in emphasizing the importance of physical activities such as collision type sports, during the developmental years. Physical educators, researchers, policy makers, and coaches must work together to encourage safe play and rules changes that can keep youth and adolescents active in sports that build character, discipline, and teach teamwork. Understanding the complexity of the highly adaptable adolescent brain both prior to and following sport-related concussion is critically important in accomplishing this goal.
The Effect of Nonspecific Task Constraints on Quadrupedal Locomotion: II. Joint Kinematics
Authors: Forrester Larry , Whitall Jill
Published: August 2016

The effects of directional and postural constraints on preferred speed quadrupedal gait patterns were studied by comparing responses to four hand-foot crawling tasks: forward and backward prone (FP and BP) and forward and backward supine (FS and BS). A central question was whether the task dynamics evident at the end-effector level also appear at the joint effector system level. Timing of reversals in each limb's proximal effector system joints was shown to be related to the functional role (propulsion or reaching) of the limb. Within joints, task constraint changes strongly tended to affect reversal times, and time-reversed directional comparisons tended to show “mirroring” responses. Peak reaching positions were also closely associated with forelimb touchdowns and interlimb coordination. Discussion centers on task function, task dynamics, and their influence on effector system behavior.
Recognizing Propriospinal and Reticulospinal Systems of initiation of Stepping
Authors: Shik Mark L.
Published: August 2016

The population of reticulospinal neurons of the hindbrain receives input from several brain regions and activates spinal interneurons that assemble stepping. Axons of these reticulospinal neurons descend in the ventral part of the lateral funiculus. Axons of certain spinal neurons form the “stepping strip” in the dorsal part of the lateral funiculus. Stimulation of this strip elicits stepping via particular spinal neurons that send their axons to the ventral part of the lateral funiculus. Neurons of these two types form the propriospinal system capable of activating spinal interneurons that assemble stepping.
Performing Saccadic Eye Movements or Blinking Improves Postural Control
Authors: Rougier Patrice , Garin Mélanie
Published: August 2016

To determine the relationship between eye movement and postural control on an undisturbed upright stance maintenance protocol, 15 young, healthy individuals were tested in various conditions. These conditions included imposed blinking patterns and horizontal and vertical saccadic eye movements. The directions taken by the center of pressure (CP) were recorded via a force platform on which the participants remained in an upright position. The CP trajectories were used to estimate, via a low-pass filter, the vertically projected movements of the center of gravity (CGv) and consequently the difference CP-CGv. An analysis of the frequency shows that regular bilateral blinking does not produce a significant change in postural control. In contrast, performing saccadic eye movements induces some reduced amplitude for both basic CGv and CP-CGv movements principally along the antero-posterior axis. The present result supports the theory that some ocular movements may modify postural control in the maintenance of the upright standing position in human participants.
The Temporal Locus of the One-Target Advantage in Rapid Aimed Movements
Authors: van Doorn Robert R.A.
Published: August 2016

The execution of a fast aimed movement takes less time when it is performed in isolation than when it is followed by a movement to a second target. The most recent explanation of this so-called one-target advantage (OTA) is the movement integration hypothesis. The first movement is slowed down to enable a neuromuscular integration of the first and second movements so that a presumably smooth transition between the two movements can take place. The present study shows that the time increase underlying the OTA does not happen just before the transition takes place, but is located in the initial part of the first movement element of the two-tap sequence. It is discussed how such a temporal occurrence relates to the transition of the first movement to the second.
Do Synergies Improve Accuracy? A Study of Speed-Accuracy Trade-Offs during Finger Force Production
Authors: Gorniak Stacey L. , Duarte Marcos , Latash Mark L.
Published: August 2016

We explored possible effects of negative covariation among finger forces in multifinger accurate force production tasks on the classical Fitts’s speed-accuracy trade-off. Healthy subjects performed cyclic force changes between pairs of targets “as quickly and accurately as possible.” Tasks with two force amplitudes and six ratios of force amplitude to target size were performed by each of the four fingers of the right hand and four finger combinations. There was a close to linear relation between movement time and the log-transformed ratio of target amplitude to target size across all finger combinations. There was a close to linear relation between standard deviation of force amplitude and movement time. There were no differences between the performance of either of the two “radial” fingers (index and middle) and the multifinger tasks. The “ulnar” fingers (little and ring) showed higher indices of variability and longer movement times as compared with both “radial” fingers and multifinger combinations. We conclude that potential effects of the negative covariation and also of the task-sharing across a set of fingers are counterbalanced by an increase in individual finger force variability in multifinger tasks as compared with single-finger tasks. The results speak in favor of a feed-forward model of multifinger synergies. They corroborate a hypothesis that multifinger synergies are created not to improve overall accuracy, but to allow the system larger flexibility, for example to deal with unexpected perturbations and concomitant tasks.
Quantifying the Variability of Three-Dimensional Aiming Movements Using Ellipsoids
Authors: Hansen Steve , Elliott Digby , Khan Michael A.
Published: August 2016

The utility of ellipsoids for quantifying central tendency and variability throughout the trajectory of goal-directed movements is described. Aiming movements were measured over 2 days of practice and under full-vision and no-vision conditions. A three-dimensional optoelectronic system measured the movements. Individual ellipsoid locations, dimensions, and volumes were derived from the average location and the spatial variability of the effector’s trajectory at proportional temporal periods throughout the movement. Changes in ellipsoid volume over time illustrate the evolution in motor control that occurred with practice and the processes associated with visual control. This technique has the potential to extend our understanding of limb control and can be applied to practical problems such as equipment design and evaluation of movement rehabilitation.
Fitts’s Law in a Selective Reaching Task: The Proximity-to-Hand Effect of Action-Centered Attention Revisited
Authors: Welsh Timothy N. , Zbinden Michele
Published: August 2016

The “proximity-to-hand” effect refers to the finding that distractors between the home position and the target cause more interference in a selective reaching movement than distractors farther from the home position. Based largely on the proximity-to-hand effect, Tipper, Lortie, and Baylis (1992) proposed that attention is distributed in an action-centered framework such that the interference caused by a specific stimulus depends on the action. The current experiments sought to determine if there is an attentional preference for stimuli closer to home or for stimuli that activate more efficiently executed actions regardless of the location. Results supported the latter hypothesis in that the greatest interference was observed when the distractor activated an action with a lower index of difficulty than the target, even though that distractor was farther from home than the target. These findings indicate that the action context mediates the influence that nontarget stimuli have on the processing of target responses.
Adaptation of Joint Flexibility during a Reach-to-Grasp Movement
Authors: Jacquier-Bret Julien , Rezzoug Nasser , Gorce Philippe
Published: August 2016

In the presence of motor redundancy, recent studies have shown that goal equivalent configurations of the body segments might be used by the central nervous system (CNS) instead of stereotypical movement patterns. In particular, some authors have shown that the CNS might choose a subset of joint configurations (termed the uncontrolled manifold or UCM) such that variability (goal equivalent variance or GEV) in this subset does not affect the value of a particular performance variable while variability in the orthogonal subset ORT (non-goal equivalent variance or NGEV) does. This hypothesis has been used successfully to test whether specific performance variables such as endpoint trajectory or segment global orientation are stabilized by the CNS or to study the influence of constraints on the organization of the movement. Few studies have examined the redundancy problem when considering obstacle avoidance during a grasping task. Indeed, the majority of the works on this topic considers non redundant arm models or do not take into account the movement variability. In the present work, we sought to study the coordination of the trunk and the arm during a reaching task involving an obstacle and to test whether such a spatial constraint in extrinsic space may induce particular adaptations in term of joint flexibility when considering the shoulder, elbow, and wrist joint center positions. In this framework, the upper limb three-dimensional kinematics was recorded. From the calculated joint angles, the variability in joint space related to the three joint center positions was computed and decomposed into GEV and NGEV. In agreement with the UCM hypothesis, results showed higher values of GEV than NGEV for all the experimental conditions. The main finding of the study is that joints’ synergy is strengthened for the stabilization of the elbow joint center position during the late phases of the movement. This strengthening seems to be due mainly to an increase of GEV. Therefore, our results suggest that an increase of joint flexibility may be a mechanism by which the CNS takes into account a spatial constraint in extrinsic space represented by an obstacle.
Modulation of Arm Stiffness in Relation to Instability at the Beginning or the End of Goal-Directed Movements
Authors: Milner Theodore E. , Lai Emily J. , Hodgson Antony J.
Published: August 2016

In reaching to a target, stability near the target may be more critical for success than stability far from the target. Consequently, we postulated that high instability near the start would evoke less compensation than high instability near the target. Three stability conditions were implemented using a robot manipulandum: neutral stability everywhere (null field); high instability along the first half of the trajectory decreasing as the target was approached (start unstable); and instability increasing along the first half of the trajectory and remaining high as the target was approached (end unstable). Under the start unstable condition, the stiffness of the arm in the region of highest instability was significantly less than under the end unstable condition. Furthermore, the stability of the system (manipulandum plus arm) was much lower under the start unstable condition than under the null field condition whereas it was similar under the end unstable and null field conditions.
Interpersonal Postural Coordination on Rigid and Non-Rigid Surfaces
Authors: Stoffregen Thomas A. , Giveans M. Russell , Villard Sebastien , Yank Jane Redfield , Shockley Kevin
Published: August 2016

When two standing people converse with each other there is an increase in their shared postural activity, relative to conversation with different partners. We asked pairs of participants to converse with each other or with experimental confederates while standing on rigid and nonrigid surfaces. On the rigid surface, shared postural activity was greater when participants conversed with each other than when they conversed with confederates. In addition, the strength of interpersonal coupling increased across trials, but only when members of a dyad conversed with each other. On the nonrigid surface, postural sway variability increased, but we found no evidence that shared postural activity was different when participants conversed with each other, as opposed to conversing with confederates. We consider several possible interpretations of these results.
On the Content of Sensorimotor Representations After Actual and Motor Imagery Practice
Authors: Toussaint Lucette , Robin Nicolas , Blandin Yannick
Published: August 2016

We examined the similarities between actual and motor imagery practice with regard to the development of sensorimotor representations. Participants had to reproduce knee joint positions (15 or 150 trials) in visuo-proprioceptive or proprioceptive conditions (Experiment 1) or in visual, proprioceptive or visuo-proprioceptive imagery conditions (Experiment 2), before being transferred in a proprioceptive condition. A familiarization session in a proprioceptive condition was performed before imagery practice only (Experiment 2). Results showed that the effect of vision withdrawal varied according to actual or motor imagery practice: performance accuracy in transfer decreased after actual visuo-proprioceptive practice while it increased after visuo-proprioceptive imagery practice. These results suggest that different movement representations can be developed following actual or imagery practice. They also suggest that information from previous experience could be stored in a sensori-motor memory and could be fundamental for the efficiency of motor imagery practice.
Coarticulation as an Indicator of Speech Motor Control Development in Children: An Ultrasound Study
Authors: Zharkova Natalia , Hewlett Nigel , Hardcastle William J.
Published: August 2016

There are still crucial gaps in our knowledge about developmental paths taken by children to adult-like speech motor control. Mature control of articulators during speaking is manifested in the appropriate extent of coarticulation (the articulatory overlap of speech sounds). This study compared lingual coarticulatory properties of child and adult speech, using ultrasound tongue imaging. The participants were speakers of Standard Scottish English, ten adults and ten children aged 6–9 years. Consonant-vowel syllables were presented in a carrier phrase. Distances between tongue curves were used to quantify coarticulation. In both adults and children, vowel pairs /a/-/i/ and /a/-/u/ significantly affected the consonant, and the vowel pair /i/-/u/ did not. Extent of coarticulation was significantly greater in the children than in the adults, providing support for the notion that children’s speech production operates with larger units than adults’. More within-speaker variability was found in the children than in the adults.
Limb versus Speech Motor Control: A Conceptual Review
Authors: Grimme Britta , Fuchs Susanne , Perrier Pascal , Schöner Gregor
Published: August 2016

This paper presents a comparative conceptual review of speech and limb motor control. Speech is essentially cognitive in nature and constrained by the rules of language, while limb movement is often oriented to physical objects. We discuss the issue of intrinsic vs. extrinsic variables underlying the representations of motor goals as well as whether motor goals specify terminal postures or entire trajectories. Timing and coordination is recognized as an area of strong interchange between the two domains. Although coordination among different motor acts within a sequence and coarticulation are central to speech motor control, they have received only limited attention in manipulatory movements. The biomechanics of speech production is characterized by the presence of soft tissue, a variable number of degrees of freedom, and the challenges of high rates of production, while limb movements deal more typically with inertial constraints from manipulated objects. This comparative review thus leads us to identify many strands of thinking that are shared across the two domains, but also points us to issues on which approaches in the two domains differ. We conclude that conceptual interchange between the fields of limb and speech motor control has been useful in the past and promises continued benefit.
Masked Auditory Feedback Affects Speech Motor Learning of a Plosive Duration Contrast
Authors: Lipski Silvia C. , Unger Stefanie , Grice Martine , Meister Ingo G.
Published: August 2016

Adult speakers have developed precise forward models of articulation for their native language and seem to rely less on auditory sensory feedback. However, for learning of the production of new speech sounds, auditory perception provides a corrective signal for motor control. We assessed adult German speakers’ speech motor learning capacity in the absence of auditory feedback but with clear somatosensory information. Learners were presented with a nonnative singleton-geminate duration contrast of voiceless, unaspirated bilabial plosives /p/ vs. /pp/ which is present in Italian. We found that the lack of auditory feedback had no immediate effect but that deviating productions emerged during the course of learning. By the end of training, speakers with masked feedback produced strong lengthening of segments and showed more variation on their production than speakers with normal auditory feedback. Our findings indicate that auditory feedback is necessary for the learning of precise coordination of articulation even if somatosensory feedback is salient.
Articulatory Kinematics in the Dysarthria Associated with Friedreich’s Ataxia
Authors: Folker Joanne E. , Murdoch Bruce E. , Cahill Louise M. , Rosen Kristin M. , Delatycki Martin B. , Corben Louise A. , Vogel Adam P.
Published: August 2016

Electromagnetic articulography (EMA) was used to investigate the tongue kinematics in the dysarthria associated with Friedreich’s ataxia (FRDA). The subject group consisted of four individuals diagnosed with FRDA. Five nonneurologically impaired individuals, matched for age and gender, served as controls. Each participant was assessed using the AG-200 EMA system during six repetitions of the tongue tip sentence Tess told Dan to stay fit and the tongue back sentence Karl got a croaking frog. Results revealed reduced speed measures (i.e., maximum acceleration / deceleration / velocity), greater movement durations and increased articulatory distances for the approach phases of consonant productions. The approach phase, involving movement up to the palate, was more affected than the release phase. It is suggested that deviant lingual kinematics could be the outcome of disturbances to cerebellar function, or possibly in combination with disturbances to upper motor neuron systems.
Effect of Head Orientation on Postural Control during Upright Stance and Forward Lean
Authors: Johnson Molly B. , Van Emmerik Richard E.A.
Published: August 2016

Sensory feedback from the vestibular system and neck muscle stretch receptors is critical for the regulation of postural control. The postural relationship of the head to the trunk is a major factor determining the integration of sensory feedback and can be interfered with by varying head orientation. This study assessed how 60-s of standing with the head neutral, flexed, or extended impacted postural stability during upright stance and during forward lean in 13 healthy participants (26 ±5 years old). During both quiet upright stance and maximal forward lean, head extension increased postural center of pressure (COP) velocity and decreased the COP time-to-contact the anterior stability boundary compared with the head neutral condition. Head flexion did not differ from head neutral for either of the stance conditions. This study demonstrates that interfering with the head-trunk relationship by adopting extended, but not flexed, head orientations interferes with postural control that may impact postural stability during both quiet upright stance and maximal forward lean conditions.
The Effect of Movement Rate and Complexity on Functional Magnetic Resonance Signal Change During Pedaling
Authors: Mehta Jay P. , Verber Matthew D. , Wieser Jon A. , Schmit Brian D. , Schindler-Ivens Sheila M.
Published: August 2016

We used functional magnetic resonance imaging (fMRI) to record human brain activity during slow (30 RPM), fast (60 RPM), passive (30 RPM), and variable rate pedaling. Ten healthy adults participated. After identifying regions of interest, the intensity and volume of brain activation in each region was calculated and compared across conditions (p < .05). Results showed that the primary sensory and motor cortices (S1, M1), supplementary motor area (SMA), and cerebellum (Cb) were active during pedaling. The intensity of activity in these areas increased with increasing pedaling rate and complexity. The Cb was the only brain region that showed significantly lower activity during passive as compared with active pedaling. We conclude that M1, S1, SMA, and Cb have a role in modifying continuous, bilateral, multijoint lower extremity movements. Much of this brain activity may be driven by sensory signals from the moving limbs.
Assessing Hopping Developmental Level in Childhood Using Wearable Inertial Sensor Devices
Authors: Masci Ilaria , Vannozzi Giuseppe , Getchell Nancy , Cappozzo Aurelio
Published: August 2016

Assessing movement skills is a fundamental issue in motor development. Current process-oriented assessments, such as developmental sequences, are based on subjective judgments; if paired with quantitative assessments, a better understanding of movement performance and developmental change could be obtained. Our purpose was to examine the use of inertial sensors to evaluate developmental differences in hopping over distance. Forty children executed the task wearing the inertial sensor and relevant time durations and 3D accelerations were obtained. Subjects were also categorized in different developmental levels according to the hopping developmental sequence. Results indicated that some time and kinematic parameters changed with some developmental levels, possibly as a function of anthropometry and previous motor experience. We concluded that, since inertial sensors were suitable in describing hopping performance and sensitive to developmental changes, this technology is promising as an in-field and user-independent motor development assessment tool.
Effect of Gait Speed on Muscle Activity Patterns and Magnitude During Stance
Authors: Sousa Andreia S. P. , Tavares João Manuel R. S.
Published: August 2016

This study aims to assess the influence of gait speed (manipulated through cadence) on muscle activity patterns and activation degree during stance.

Methods:

Thirtyfive healthy individuals participated in this study. Surface electromyographic activity from the gastrocnemius medialis (GM), gluteus maximus (GMax), biceps femoris (BF) and rectus femoris (RF) was acquired with subjects walking at three different speeds.

Results:

Speed influenced: (1) relative motor activity patterns at heel strike, midstance-propulsion transition and propulsion; (2) the activity level of RF, GMax, GM and BF, in decreasing order, with higher activity at the fastest and slowest speeds.

Conclusions:

In general, muscle activity was higher at the fastest and slowest speeds than at the self-selected speed and only the activity of the main actions in each subphase remained stable. These findings suggest that gait speeds different from the self-selected speed influence not only activity levels but also relative muscle activity patterns. As a result, caution is advised when choosing standard speeds in gait studies, as this can lead to increased variability in relative muscle activity patterns.
Subthreshold Vestibular Reflex Effects in Seated Humans Can Contribute to Soleus Activation When Combined With Cutaneous Inputs
Authors: Thomas Kristen E. , Bent Leah R.
Published: August 2016

The integration of vestibular and somatosensory information for the control of lower limb musculature remains elusive. To determine whether a subthreshold vestibular input influences the cutaneous evoked response, the isometric EMG activity in the posturally inactive soleus muscles of 13 healthy, seated subjects was collected. Vestibular afferents were activated using galvanic vestibular stimulation (GVS; 1.8–2.5mA, 500ms), while percutaneous electrical stimulation was delivered to the distal tibial nerve (11ms train of 3 × 1.0 ms pulses, 200Hz) to activate foot sole skin afferents. GVS elicited responses in soleus both independently and when combined with cutaneous stimulation. The responses to the combined sensory input showed an interaction between the two sensory modalities to influence muscle activation. Of note is the presence of significant muscle modulation in the combined condition, where subthreshold vestibular inputs altered the outcome of the cutaneous reflex response. This finding has implications for individuals with sensory deficiency. In the case of an absent or deficient sensory modality, balance protective reflexes to maintain postural equilibrium may be enhanced with targeted sensory augmentation.
Standard Assumptions About the Trial-by-Trial Distribution of Averaged Electromyography Data Could Produce Erroneous Results
Authors: Pedersen Asger R. , Stubbs Peter W. , Nielsen Jørgen F.
Published: August 2016

The aim was to challenge the assumptions of standard statistical analyses of average surface electromyography (sEMG) data as a measurement of response magnitudes following the generation of a reflex. The ipsilateral tibial nerve was stimulated at three stimulation intensities and the response sEMG was measured in the contralateral soleus (cSOL) muscle. The magnitude of the cSOL response was measured at a set time window following ipsilateral tibial nerve stimulation. The averaged and trial-by-trial response magnitudes were assessed and compared. The analysis of the averaged and trial-by-trial response revealed significantly different results as the trial-by trial response magnitudes were log-normally distributed with between subject variance heterogeneity violating assumptions of standard statistical analyses. A statistical model has been suggested for the analysis of the responses. By ignoring trial-by-trial response variability and distribution, erroneous results may occur. This may change the interpretation of the results in some studies.
Anchoring in Rhythmic In-Phase and Antiphase Visuomotor Tracking
Authors: Roerdink Melvyn , Bank Paulina J. M. , Peper C. (Lieke) E. , Beek Peter J.
Published: August 2016

Rhythmic limb movements are often anchored at particular points in the movement cycle. Anchoring may reveal essential task-specific information for motor control. We examined the effect of tracking mode (in-phase, antiphase) and gaze direction (left, right) on anchoring in visuomotor tracking with and without concurrent visual feedback of the hand movement. For in-phase tracking, anchoring was observed at the foveated reversal point whereas for antiphase tracking anchoring was observed at both reversals, suggesting the presence of two reference points instead of one. Anchoring at the foveated reversal reflected gaze anchoring (i.e., coalignment of hand and gaze) while anchoring at the nonfoveated reversal reflected visuomotor synchronization (i.e., the hand was steered to the nonfoveated reversal coincident with a target reversal at the point of gaze). We propose that the number and location of anchor points play a crucial role in the underlying control by providing reference values for error correction processes.
Age-Related Differences in the Stabilization of Important Task Variables in Reaching Movements
Authors: Krüger Melanie , Eggert Thomas , Straube Andreas
Published: August 2016

Empirical evidence suggests that the ability to stabilize important task variables of everyday movements by synergistically coordinating redundant degrees of freedom decreases with aging. The aim of the current study was to investigate whether this decrease may be regarded as a characteristic that also applies for the control of multiple task variables. We asked younger and older subjects to repeatedly reach towards and grasp a handle, while joint angle movement of the arm was recorded. The handle constrained final hand position and final hand orientation. Movement variability was analyzed during movement execution by using the uncontrolled manifold method. Results showed that hand orientation was less stabilized in younger than in older subjects. We conclude that aging changes the stability of important task variables. These changes may lead to decreased stability in some task variables, as reported in the literature, but also to increased stability in other task variables.
Perceived Hole Size, Performance, and Body Movement During Putting in Children With and Without Probable Developmental Coordination Disorder
Authors: Chen Fu-Chen , Wu Sheng-Kuang
Published: August 2016

The purpose of this study was to examine the relationships between perceived hole size (perception), performance, and body movement (action) in golf putting for children with probable developmental coordination disorder (DCD) and typically developing children (TDC). Forty-eight children (24 probable DCD, 24 TDC) performed putting in easy and hard conditions. Body movement was measured during putting, performance was measured as the distance between ball and hole, and perceived hole size was recorded using a Microsoft Paint drawing exercise 1 m away from the hole. The present results revealed that perceived hole size was positively related to putting performance, body movement was negatively associated with putting performance, and that there were negative correlations between body movement and perceived hole size. While children with probable DCD tended to perceive the hole as smaller, perform worse, and show more body movement, TDC exhibited the opposite. These findings help characterize the relationships between perception, performance, and action in children with probable DCD and TDC during golf putting.
Considering Handedness in Studies involving Manual Control
Authors: Gabbard Carl
Published: August 2016

With studies of motor behavior that feature manual control, it is suggested that the methodology used to select subjects in reference to handedness be reviewed. This suggestion is in view of the recommendation that simply asking subjects to identify their writing hand is inadequate to define handedness. Complementing this are recent findings in neuroscience indicating differences, at times significant, in information-processing behavior based on handedness classification. A brief review of recently published studies in two prominent outlets for motor behavior research confirms that most reports provide minimal (and sometimes no) information regarding handedness and the method used for assessment. Recommendations for addressing the problem include using an acceptable preference inventory, selecting only those subjects with strong lateral characteristics, and briefly describing the methodology used for the reviewing audience.
Foreperiod Length, but Not Memory, Affects Human Reaction Time in a Precued, Delayed Response
Authors: Mohagheghi Amir A. , Anson J. Greg , Hyland Brian I. , Parr-Brownlie Louise , Wickens Jeffrey R.
Published: August 2016

The effect of foreperiod length on reaction time in memorized (MM) and nonmemorized (NM), precued, delayed responses was investigated. Six subjects participated in one long and one short foreperiod schedule testing session. An aiming task, using elbow supination/pronation, in response to a visual stimulus was employed. In the MM condition, target spatial information was available for a fraction of the foreperiod duration. In the NM condition, target information was available continuously until the subject attained the target position. Subjects responded with a significantly longer latency in the long foreperiod schedule. Within each foreperiod schedule, the shortest foreperiod resulted in significantly longer reaction time. However, the absolute value of foreperiod did not have a major effect on reaction time latency. Memorization and nonmemorization conditions did not affect reaction time.
Reflex Activation Patterns in Relation to Multidirectional Ankle Torque in Decerebrate Cats
Authors: Siegel Sondra G. , Nichols T. Richard , Cope Timothy C.
Published: August 2016

Cutaneous reflexes have been described primarily according to their actions in the flexion/extension plane. It is shown here, by measuring electromyography and isometric force in decerebrate cats, that ankle muscles are activated in relation to their actions in the abduction/adduction plane during sural nerve (SNR) and crossed-extension (XER) reflexes. Ankle adductors (tibialis posterior, extensor digitorum longus, and flexors digitorum and hallucis longus) were active in XER, but not in SNR. Muscles producing ankle abduction (medial and lateral gastrocnemii and peroneus longus and brevis) were often activated in both reflexes, and medial gastrocnemius and peroneus longus were consistently more strongly activated in SNR than in XER. This differential pattern of muscle activation results in greater abduction torque at the ankle in SNR than in XER. These data demonstrate reflex organization in relation to the multidirectional torque generated by individual muscles.