Perceived leg extension and flexion forces of young adult men and women: comparison to previous findings.
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Adult↗
Biomedical subjects
Rod K Dishman
Publications and source records attributed to Rod K Dishman.
The effects of exercise on children with attention-deficit hyperactivity disorder.
PURPOSE: The effects of exercise on children with attention-deficit hyperactivity disorder (ADHD) were evaluated by studying the rate of spontaneous eye blinks, the acoustic startle eye blink response (ASER), and motor impersistence among 8- to 12-yr-old children (10 boys and 8 girls) meeting DSM-III-R criteria for ADHD. METHODS: Children ceased methylphenidate medication 24 h before and during each of three daily conditions separated by 24-48 h. After a maximal treadmill walking test to determine cardiorespiratory fitness (VO(2peak)), each child was randomly assigned to counterbalanced conditions of treadmill walking at an intensity of 65-75% VO(2peak) or quiet rest. Responses were compared with a group of control participants (11 boys and 14 girls) equated with the ADHD group on several key variables. RESULTS: Boys with ADHD had increased spontaneous blink rate, decreased ASER latency, and decreased motor impersistence after maximal exercise. Girls with ADHD had increased ASER amplitude and decreased ASER latency after submaximal exercise. CONCLUSIONS: The findings suggest an interaction between sex and exercise intensity that is not explained by physical fitness, activity history, or selected personality attributes. The clinical meaning of the eye blink results is not clear, as improvements in motor impersistence occurred only for boys after maximal exercise. Nonetheless, these preliminary findings are sufficiently positive to encourage additional study to determine whether a session of vigorous exercise has efficacy as a dopaminergic adjuvant in the management of behavioral features of ADHD.
Acoustic Stimulation↗
Hemodynamic responses to stress among black women: fitness and parental hypertension.
PURPOSE: We compared hemodynamic aspects of the relationship between cardiorespiratory fitness and blood pressure changes during and after laboratory stress in young black women with or without parental history of hypertension. METHODS: Participants were 30 normotensive, black American women having low to moderate fitness levels (i.e., VO2peak) assessed by cycle ergometry who performed standard active and passive coping laboratory stressors. Blood pressure, heart rate, stroke volume, cardiac output, total peripheral resistance (TPR), calf blood flow (CBF), and calf vascular resistance (CVR) were assessed during exposure to forehead and hand cold pressors, and mental arithmetic, as well as during recovery after the tasks. RESULTS: Fitness was positively related to increases in either TPR or CVR during each stressor. In contrast, fitness was positively related to blunted blood pressure during or after passive stress (i.e., hand or forehead cold) and enhanced recovery of blood pressure and TPR after the active stressor (i.e., mental arithmetic); effects of fitness on the vascular responses during and after mental arithmetic were stronger among women having a negative history of parental hypertension. CONCLUSION: The findings confirm our previous report that fitness blunts systolic blood pressure response during the hand cold pressor in young women. They also suggest that future studies of fitness and blood pressure reactivity during stress should focus on the regulation of vascular responses and their recovery after stress. Weaker effects of VO2peak after mental arithmetic in the positive history group indicate that the level of fitness required to modify recovery from mental stress among black American women may differ according to parental history of hypertension.
Adolescent↗
Emotional responsiveness after low- and moderate-intensity exercise and seated rest.
PURPOSE: Few experiments have been conducted regarding the effects of exercise on emotional responsiveness. The aim of this experiment was to determine whether anxiety-reducing conditions of low- and moderate-intensity cycling exercise lead to changes in emotional responsiveness to pictures designed to elicit pleasant, neutral, and unpleasant emotions. METHODS: 24 healthy college women completed counterbalanced conditions of 25 min of low- and moderate-intensity cycling exercise and seated rest. Indices of emotional responsiveness, including the acoustic startle eyeblink and corrugator supercilii responses, as well as baseline corrugator supercilii electromyographic (EMG) activity, were measured immediately before and 20 min after each condition while participants viewed pleasant, neutral, and unpleasant pictures from the International Affective Picture System. RESULTS: State anxiety was significantly reduced 20 min after each condition. Startle response magnitude was modulated by the affective content of the pictures and was reduced after each condition in response to each type of picture. Baseline corrugator EMG activity did not change after seated rest but decreased in an exercise intensity-dependent fashion after cycling. Corrugator EMG responses during the pictures were not different between conditions or from pre- to post-conditions. CONCLUSION: The findings suggest that cycling exercise results in decreased baseline activity of facial muscles involved in the expression of emotion but does not lead to changes in appetitive or defensive responses to emotional stimuli. Furthermore, anxiolytic conditions of low- and moderate-intensity cycling exercise and seated rest are related to decreased startle magnitude in healthy college women.
Adult↗
Differences in physical activity between black and white girls living in rural and urban areas.
This study examined the relationship of race and rural/urban setting to physical, behavioral, psychosocial, and environmental factors associated with physical activity. Subjects included 1,668 eighth-grade girls from 31 middle schools: 933 from urban settings, and 735 from rural settings. Forty-six percent of urban girls and 59% of rural girls were Black. One-way and two-way ANOVAs with school as a covariate were used to analyze the data. Results indicated that most differences were associated with race rather than setting. Black girls were less active than White girls, reporting significantly fewer 30-minute blocks of both vigorous and moderate-to-vigorous physical activity. Black girls also spent more time watching television, and had higher BMIs and greater prevalence of overweight than White girls. However, enjoyment of physical education and family involvement in physical activity were greater among Black girls than White girls. Rural White girls and urban Black girls had more favorable attitudes toward physical activity. Access to sports equipment, perceived safety of neighborhood, and physical activity self-efficacy were higher in White girls than Black girls.
Adolescent↗
Examining social-cognitive determinants of intention and physical activity among black and white adolescent girls using structural equation modeling.
Structural equation modeling was used to evaluate components within the theories of reasoned action (TRA), planned behavior (TPB), and self-efficacy (SET) for understanding moderate and vigorous physical activity among 1,797 Black and White adolescent girls. Modest to strong support was provided for components of TPB and SET; weak support was provided for components of TRA. Perceived behavioral control was related to vigorous physical activity. Self-efficacy was related to moderate and vigorous physical activity, and it accounted for the effect of intention on physical activity. The observed relationships were similar between Black and White girls. Self-efficacy and perceived behavioral control are independent influences on physical activity among Black and White adolescent girls and warrant study as potential mediators in physical activity interventions.
Adolescent↗
Naturally occurring changes in physical activity are inversely related to depressive symptoms during early adolescence.
OBJECTIVE: We examined the relationship between naturally occurring changes in physical activity and depressive symptoms across a 2-year period among adolescent boys and girls. METHODS: Participants (N = 4594) reported their frequency of physical activity outside of school and completed the Center for Epidemiological Studies Depression scale in the Fall of 1998 (beginning of 7th grade; baseline data), Spring of 1999 (end of 7th grade; interim data), and Spring of 2000 (end of 8th grade; follow-up data). RESULTS: Latent growth modeling indicated that a 1 SD unit change in the frequency of leisure-time physical activity was inversely related to a.25 SD unit change in depressive symptoms. This relationship was attenuated but remained statistically significant when simultaneously controlling for the confounding variables of sex, socioeconomic status, smoking, alcohol consumption, and the value participants placed on their health, appearance, and achievement. CONCLUSIONS: Naturally occurring changes in physical activity were negatively related with changes in depressive symptoms. The results encourage randomized controlled trials to experimentally determine whether an increase in physical activity reduces depression risk among adolescent boys and girls.
Achievement↗
Comparison of social variables for understanding physical activity in adolescent girls.
OBJECTIVE: To evaluate social support and theory of planned behavior (TPB) constructs in explaining physical activity in adolescent girls. METHODS: One thousand seven hundred ninety-seven 8th-grade girls completed a survey measuring social provisions, family support, TPB constructs, moderate-to-vigorous physical activity (MVPA), and team sport involvement (TSI). RESULTS: Structural equation modeling (SEM) indicated statistically significant direct effects from TPB constructs and social provisions to intention; social provisions, family support, and intention to MVPA; and social provisions and family support to TSI. CONCLUSIONS: Social variables play a greater role in explaining TSI than in explaining MVPA in this sample.
Adolescent↗
Scale development for perceived school climate for girls' physical activity.
OBJECTIVES: To test an original scale assessing perceived school climate for girls' physical activity in middle school girls. METHODS: Confirmatory factor analysis (CFA) and structural equation modeling (SEM). RESULTS: CFA retained 5 of 14 original items. A model with 2 correlated factors, perceptions about teachers' and boys' behaviors, respectively, fit the data well in both sixth and eighth graders. SEM detected a positive, significant direct association of the teacher factor, but not the boy factor, with girls' self-reported physical activity. CONCLUSIONS: School climate for girls' physical activity is a measurable construct, and preliminary evidence suggests a relationship with physical activity.
Adolescent↗