Biomedical subjects

Christopher M Janelle

Publications and source records attributed to Christopher M Janelle.

8 recordsLinked to original sources

PubMed2006

Near-infrared light and expectancy effects on maximal isokinetic strength performance: a randomized, double-blind, placebo-controlled study.

Infrared-light radiation has recently and effectively been applied to solving a wide range of problems in the sport sciences. However, few investigations have focused on the potential performance-enhancing properties of near-infrared (NIR)-light stimulation, and none have examined its effects on muscle strength. As such, the purpose of this investigation was to determine the extent to which NIR light influenced the maximal isokinetic strength of the quadriceps and hamstrings. Forty-eight college students participated in the study. Four experimental conditions were created: (a) an active group with expectancy instructions, (b) an active group without expectancy instructions, (c) a placebo group with expectancy instructions, and (d) a placebo group without expectancy instructions. Individuals in active conditions were outfitted in NIR light-emitting bandages, T-shirts, and socks, whereas those in placebo conditions were outfitted in the same attire but without active NIR light. Maximal isokinetic torque values of the quadriceps and hamstrings were measured. Results indicated that the active group without expectancy instructions exhibited enhanced isokinetic strength for the hamstrings at a contractile speed of 180 degrees x s(-1) as compared with the placebo groups. With continued replication of our initial exploratory findings, infrared equipment might emerge as a promising means for performance enhancement.

Adolescent↗

PubMed2005

Emotion and movement: activation of defensive circuitry alters the magnitude of a sustained muscle contraction.

Understanding the emotion-movement relationship is crucial to the development of motor theory and movement rehabilitation recommendations for a wide range of diseases and injuries that involve motor impairment. Behaviorally, when movements are executed following exposure to emotional stimuli, evidence suggests that active defensive circuitry results in faster but more variable voluntary movements. However, each of the existing protocols has involved movement execution following the offset of anxiety or emotion eliciting stimuli. The specific aim of this study, therefore, was to determine whether the continued exposure to emotional stimuli would alter the magnitude and variability of a sustained motor contraction. During the presentation of pleasant, unpleasant, neutral, and blank images, participants (N=45) were instructed to respond to the onset of an auditory stimulus by initiating and then sustaining a maximal bimanual isometric contraction of the wrist and finger extensor muscles against two independent load cells (left/right limb). Corroborating previous evidence and supporting hypothesis 1, findings indicated that exposure to unpleasant images lead to an increase in mean force production. Variability of movement, however, did not vary as a function of affective context. These findings indicate that continued exposure to unpleasant stimuli magnifies the force production of a sustained voluntary movement, without sacrificing the variability of that contraction. Mechanism driven open and closed loop explanations are offered for these phenomena, implications are addressed, and future directions are discussed.

Adolescent↗

PubMed2004

Adults with dyslexia: theta power changes during performance of a sequential motor task.

Performance deficits during cerebellar intensive motor tasks maybe reflected by discrepant theta activity in the cerebral cortex. The present experiment examined the relationship between performance on a novel motor task and theta activity in adults with developmental dyslexia (DD) and an age- and IQ-matched control group (CG). Time-locked tonic and phasic lower and upper theta measures were derived and separate event-related theta band power (ERBP) scores were calculated for each of three experimental trials. The DD made significantly more errors than CG during Trials 1 and 2 of the motor task. Tonic theta did not differ between groups; however, the DD group displayed a significant decrease in ERBP across all trials and sites, specifically in central and parietal regions during Trial 3. No significant behavioral or physiological evidence supported the notion of conscious compensation (CC). Rather, deficient task performance in the DD group was associated with a general inability to recruit sufficient working memory processes.

Adolescent↗

PubMed2004

An open-source LabVIEW application toolkit for phasic heart rate analysis in psychophysiological research.

The cardiovascular system has been extensively measured in a variety of research and clinical domains. Despite technological and methodological advances in cardiovascular science, the analysis and evaluation of phasic changes in heart rate persists as a way to assess numerous psychological concomitants. Some researchers, however, have pointed to constraints on data analysis when evaluating cardiac activity indexed by heart rate or heart period. Thus, an off-line application toolkit for heart rate analysis is presented. The program, written with National Instruments' LabVIEW, incorporates a variety of tools for off-line extraction and analysis of heart rate data. Current methods and issues concerning heart rate analysis are highlighted, and how the toolkit provides a flexible environment to ameliorate common problems that typically lead to trial rejection is discussed. Source code for this program may be downloaded from the Psychonomic Society Web archive at www.psychonomic.org/archive/.

Heart Rate↗

PubMed2003

Mechanisms of attentional cueing during observational learning to facilitate motor skill acquisition.

We examined the effectiveness of different cueing conditions during observational learning of a soccer accuracy pass. Sixty participants (30 males, 30 females) were randomly assigned and stratified by sex into one of six groups: discovery learning, verbal instruction, video model with visual cues, video model with verbal cues, video model with visual and verbal cues, and video model only. Each participant completed eight blocks of 10 trials each, with trial blocks 1 and 2 representing the practice phase (no manipulation), trial blocks 3, 4, 5 and 6 the acquisition phase (manipulation administered) and trial blocks 7 and 8 the retention phase (24 h after acquisition, with no manipulation). Absolute error, variable error and kicking form were recorded. The results indicated that those who used video modelling with visual and verbal cues collectively displayed less error and more appropriate form across acquisition and retention trial blocks compared with other groups. Our findings suggest that verbal information in addition to visual cues enhances perceptual representation and retention of modelled activities to improve task reproduction capabilities. Future research directions are proposed with implications for both direct and indirect perception accounts of skill acquisition through observed behaviours.

Adolescent↗

PubMed2003

Affective responses of high and low body satisfied men to viewing physique slides.

The purpose of this study was to examine the acute affective responses of high and low body satisfied (BS) men who viewed physique slides of the male ideal (model-slides), physique slides of themselves (self-slides), and nonphysique slides (control-slides). During three laboratory visits the participants viewed the slides from one of the three conditions, and they completed pre-, in-, and post-task affective measures. It was found that the: (a) high BS group reported less mood disturbance than the low BS group; (b) participants reported an increase in depression, anger, and body dissatisfaction after viewing the self-slides; (c) participants indicated a decrease in body dissatisfaction after viewing the model-slides; and (d) viewing the control-slides did not result in affective changes. Findings suggest that viewing physique slides results in increased mood disturbance, regardless of BS level.

Journal Article↗

PubMed2002

Anxiety, arousal and visual attention: a mechanistic account of performance variability.

Despite extensive research devoted to determining the nature of the relationship between stress and performance, there has been little systematic examination of the mechanisms underlying this relationship. Recently, researchers have begun to empirically address the attentional mechanisms underlying theoretical accounts of how stress, anxiety and arousal influence performance. Given the critical role of visual attention to sport expertise, this paper focuses primarily on literature dealing with how visual cues are differentially identified and processed when performers are anxious. Emerging evidence indicates that gaze behaviour tendencies are reliably altered when performers are anxious, leading to inefficient and often ineffective search strategies. Alterations of these visual search indices are addressed in the context of both self-paced and externally paced sports events. Recommendations concerning the utility of perceptual training programmes and how these training programmes might be used as anxiety regulation interventions are discussed. The theoretical implications and directions for future research are also addressed.

Anxiety↗

PubMed2002

A Nationwide Learning-Style Assessment of Undergraduate Athletic Training Students in CAAHEP-Accredited Athletic Training Programs.

OBJECTIVE: To identify the learning styles and preferred environmental characteristics of undergraduate athletic training students in Commission on Accreditation of Allied Health Education Programs (CAAHEP)-accredited athletic training education programs and to determine if learning-style differences existed among geographic regions of the country. DESIGN AND SETTING: Fifty CAAHEP-accredited athletic training programs were randomly selected in proportion to the number of programs in each geographic region. Ten students from each school were selected to complete the Kolb Learning Style Inventory (LSI) and the Productivity Environmental Preference Survey (PEPS). SUBJECTS: A total of 193 undergraduate athletic training students (84 men, 109 women) with a mean age of 22.3 +/- 2.8 years completed the PEPS, while 188 students completed the LSI. MEASUREMENTS: We used chi-square analyses to determine if differences existed in learning-style type and if these differences were based on geographic location. We calculated analysis of variance to determine if there were any geographic differences in the mean overall combination scores of the LSI. Descriptive statistics were used to evaluate the PEPS. RESULTS: The overall return rate was 38%. The chi-square analyses revealed no significant difference in learning-style type for athletic training students, regardless of the geographic region. The LSI yielded a relatively even distribution of learning styles: 29.3% of the students were accommodators, 19.7% were divergers, 21.8% were convergers, and 29.3% were assimilators. The overall mean combination scores were 4.9 (abstract-concrete) and 4.9 (active-reflective), and analysis of variance indicated no significant difference in the mean combination scores among the geographic regions. The PEPS revealed that undergraduate athletic training students demonstrated a strong preference for learning in the afternoon. CONCLUSIONS: Undergraduate athletic training students demonstrated great diversity in learning style. Educators must strongly consider this diversity and incorporate teaching methods that will benefit all types of learners.

Journal Article↗