Biomedical subjects

C Gabbard

Publications and source records attributed to C Gabbard.

At least 19 recordsLinked to original sources

PubMed2001

Motor development during the first year: a comparative study.

This investigation of the motor development characteristics of Brazilian infants during the 1st year of postnatal life compared the findings with those of a widely used U.S. sample (N. Bayley, 1993). Analysis of the 12 monthly assessments indicated that Brazilian infants' scores increased with age, with the greatest increase occurring over the first 8 months. As a general comparison, the results are similar to the U.S. patterns of development. However, the Brazilian sample exhibited mean scores significantly lower than the U.S. sample's in the 3rd, 4th, and 5th months. More specific analyses indicated that the difference within these months was on tasks of sitting and grasping. Possible explanations for the differences focus on variations in child-rearing practices and the influence of biological maturation in early movement behaviors.

Age Factors↗

PubMed2001

The need for quality physical education.

Recently, the U.S. Surgeon General described two aspects of national health that require our immediate attention: As a nation, we are becoming increasingly more sedentary and more overweight. Furthermore, he and some of the most prominent health agencies have suggested that one of the primary strategies to overcome what is viewed as a national epidemic is the promotion of quality physical education in our schools. This paper describes in brief the facts associated with this concern, what is meant by quality physical education, and the role of the school nurse in helping to promote physical education in the schools.

Adolescent↗

PubMed2001

Lateralized effects on reaching by children.

This study examined the limb selection profiles of children for a reach-to-grasp task presented in various positions of hemispace. Underlying questions focused on the use of attentional information and lateralized effects in motor programming for reaching movements. As expected, both right- and left-handed groups used their dominant limb more frequently at the midline and in their own ipsilateral hemispace. However, in response to stimuli presented in contralateral (to the dominant limb) hemispace, both groups switched to using their nondominant limbs at significant levels. As a general comparison, right-handers exhibited greater use of their dominant limb, but arguably, motor dominance in this context may have intervened with the participant's ability to use attentional information to produce a more efficient response. Overall, these findings address the phenomenon associated with motor dominance and use of attentional information in programming.

Child↗

PubMed2000

What determines choice of limb for unimanual reaching movements?

Currently, relatively little is known about what drives the choice of limb for goal-oriented reaching. Traditionally, the explanation has been tied predominately to motor dominance as manifested in handedness. This article offers data and an argument suggesting that handedness can be modified by attentional (spatial) information. Although motor dominance may be the controlling factor in the programming and execution of reaching movements at the midline and hemispace ipsilateral (same side) to the dominant limb, attentional information alters the programming of movements in what would be contralateral space. The general trend of behavior is characterized by reaching on the same side as the stimulus, in ipsilateral fashion, a phenomenon explained by kinesthetic efficiency and hemispheric bias.

Attention↗

PubMed2000

Foot preference changes through adulthood.

Developmental observations in foot laterality suggest increasing right-footedness from early childhood to young adult years, with few reports on behaviour beyond this time frame. This investigation confirmed recent suggestions by Porac (1996) of a continuation of this trend into middle and older adulthood, along with significant decreases in mixed-and left-foot preferences. Trends towards increasing right-footedness are linked to hemispheric heterochrony (right hemisphere ageing) and the right-sided world phenomenon.

Journal Article↗

PubMed1999

Attentional effects on reaching in hemispace.

Previous evidence notes that attentional information in the form of visually guided stimuli can override motor dominance when programming reaching-to-grasp movements in contralateral hemispace. The present experiment verified these effects for 135 university students, using an auditory stimulus, and the pattern of behavior in the two modalities was quite similar.

Adult↗

PubMed1998

Considering handedness in studies involving manual control.

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.

Functional Laterality↗

PubMed1998

Examining the mobilizing feature of footedness.

This study examined the mobilizing feature of footedness in a unilateral and a bilateral context. Analysis for 47 right- and 32 left-footed undergraduates indicated a strong relationship between preferred limbs in both conditions, with right footer showing the strongest concordance. Theoretical explanations for the origin of behavior and differences in right versus left concordance are discussed. Based on selected previous reports and present findings, it seems reasonable that for most persons the right foot may be preferred for mobilizing activities regardless of behavioral context.

Foot↗

PubMed1998

Attentional stimuli and programming hand selection: a developmental perspective.

This experiment examined the use of attentional stimuli for reaching in hemispace by strong right-dominant adults and children. Driving the hypothesis was the notion that developmental factors associated with use of attentional information may affect the programming of reaching movements in hemispace. Although the general pattern of responses was similar for both samples, children did not use attentional cues to program reaching movements in contralateral hemispace as effectively as adults. This result suggests that motor dominance and perhaps other factors were pivotal in motor programming for children. One possible explanation for the general behavior observed underlies an attentional hemispheric bias for a tendency to use the hand that is on the same side as the stimulus.

Adult↗

PubMed1997

A lateralized comparison of handedness and object proximity.

This study was motivated by the emerging hypothesis that right-handers are more strongly lateralized and perform better on various aspects of functional asymmetry than do left-handers. Right- and left-handers were observed for hand selection responses to a unimanual task of reaching for a small cube in positions of right- and left hemispace, prompting hemispheric decision-making related to hand dominance and attentional (visuospatial) stimuli. As predicted, left-handers did not respond with their preferred limb as consistently across positions as did right-handers. Additional inspection of the task suggests that being lateralized may not be a disadvantage in this context, and that environmental influence may play a significant role in hand selection for a particular motor event.

Adult↗

PubMed1997

Examining the stabilising characteristics of footedness.

The stabilising characteristics of footedness within the contexts of unilateral and bilateral preference and performance were examined. Predictions from Previc's (1991) theory of prenatal determination of functional asymmetry suggest a reliance on the left side of the body for stabilisation regardless of context. To test the hypothesis, right- and left-footers (as assessed bilaterally) were examined for preference and performance using a one-leg static balance task on a force plate in simple and complex conditions. Results indicated that preference for stabilisation in the bilateral context was independent of limb choice in the unilateral context. That is, the majority of individuals switched limbs for stabilisation in the unilateral context (most favoured the right side). These findings lead to the conclusion that foot preference may be dependent in part on the context of the task and not bound exclusively to neurodevelopmental origins.

Journal Article↗

PubMed1996

A question of foot dominance.

It is suggested that the popular definition of foot dominance (i.e., the limb preferred to execute a manipulative or mobilizing action while the other [nondominant] foot provides stabilizing support, e.g., kicking a ball) be reconsidered in light of understanding the functional characteristics of footedness and selected theoretical explanations. Relevance to future research designs and assessment methodology is discussed.

Foot↗

PubMed1996

Foot laterality in children, adolescents, and adults.

This investigation reviewed 14 studies describing the trichotomous distribution of foot preference behaviour spanning early childhood to adult years. Findings suggest that a substantially greater percentage of children are mixed-footed in comparison to older individuals. A significant shift towards right-sidedness appears to occur sometime during late childhood, after which, behaviour remains relatively stable. The incidence of left-footedness is similar across the lifespan. In comparison to handedness, substantially more (about twice as many) young children are mixed-footed compared to mixed-handed. A similar pattern is noted during adolescence and adulthood, but the differences are smaller. Values for leftsidedness (upper and lower limbs) are comparable across the lifespan. Of the existing theoretical models, Annett's Right-shift hypothesis with additional propositions related to environmental influences (Collins, 1977; Porac, 1993; Provins, 1992) provides partial explanation for the findings.

Journal Article↗

PubMed1996

Laterality patterns and visual-motor coordination of children.

This study examined the association between laterality patterns of eye-hand and eye-foot described as congruent or cross-lateral, and visual-motor coordination skill (target throwing and kicking) by 606 4- to 6-yr.-olds. Speculation derived from contemporary reports of hand preference and motor coordination provided the hypothesis that persons exhibiting congruent patterns of eye and limb laterality such as right-eye and hand or right-eye and foot pattern would perform better than peers who exhibited other laterality patterns. To the contrary, this study yielded no significant differences in motor performance between groups with different patterns of preference. In view of past studies and present results, additional inquiry seems warranted before any consensus regarding the association between laterality and motor coordination can be established.

Child↗

PubMed1996

Brief communication: bilateral footedness and task complexity.

The primary intent of this investigation was to determine if stabilizing complexity (postural control) influenced lower limb selection while performing a bilateral footedness task. Right- and left-footed subjects (as determined by a bilateral preference inventory) were asked to stand on one foot and tap a telegraph key with the opposite foot repeatedly. The bilateral task was conducted in two conditions of stabilizing complexity, with the intent to augment focus of attention between stabilizing and mobilizing limb: simple (lights on) and complex (limitation of visual cues). Results indicated that in both simple and complex conditions, 50% or more of subjects switched stabilizing limbs or showed no preference when comparing preference inventory behavior to experimental conditions, suggesting, in general, that foot preference may be in part dependent on the context of the task and not tied predominantly to biological theory.

Female↗

PubMed1995

Foot-preference behavior: a developmental perspective.

The developmental course of foot-preference behavior was examined in participants spanning early childhood to young adulthood. Results indicated significant age-group differences, with no effect for gender. Evidence suggests that footedness adheres to some variant developmental features characterized primarily by a significant shift toward greater right-footedness between 8 and 11 years, after which preferences remain relatively stable. Complementing this shift is a substantial decrease in mixed-footedness across the same time line. Of the existing models of hemispheric specialization, Annett's (1978, 1985) right-shift hypothesis, which considers cultural and environmental effects, provides a partial explanation for the findings. Hand-preference data were also collected and are contrasted with foot-preference data.

Adolescent↗

PubMed1995

Patterns of limb laterality and gross-motor agility in children.

This study examined the association of nine patterns of limb preference (combination hand/foot), described as congruent or cross-lateral, with gross-motor agility of 302 4- to 6-yr-old boys. Based on contemporary reports of handedness and motor coordination, it was hypothesized that persons exhibiting a right-hand/foot congruent pattern would outperform their peers in other groups. However, analyses indicated no significant differences on total motor performance between groups with different limb patterns. Further nonsupport of the hypothesis was evident since the best performance was exhibited by the mixed-hand/left-foot group. In view of past studies and these results, it appears that additional inquiry is warranted before any consensus regarding the association between limb laterality and motor coordination can be established.

Child↗

PubMed1995

Foot performance of right- and left-handers: a question of environmental influence.

Prior research has shown that right-handed adults perform better on a speed-tapping task with the right hand and right foot, while left-handers execute more rapidly with the left hand and right foot. Speculation is that environmental influence, most likely driving experience, may account for the right-foot bias. To examine this hypothesis further, 48 young right- and left-handed children were tested on a similar protocol. Analyses indicated no significant differences in foot performance within hand-preference groups. Since these findings do not complement reports for adults, factors such as experience or maturation might contribute to the difference. Were patterns similar, the effect of environmental influence would be assumed to be small. However, much more evidence is needed before an adequate explanation can be developed. The issue of possible environmental influence is discussed from various theoretical perspectives.

Child↗