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Biomedical subjects

T B Gilliam

Publications and source records attributed to T B Gilliam.

17 recordsLinked to original sources
PubMed1983

Activity-induced morphologic changes in rat soleus nerve.

The effects of 8 to 12 weeks of intense running or swimming on the morphology of the soleus nerve of the adult male albino rat were investigated. Nerve fiber diameter and number, axon diameter, and myelin area were determined. Mean fiber diameter (5.50 +/- 0.47) of the trained rats was smaller (P less than 0.05) than for sedentary control rats (6.19 +/- 0.27). The decrease in fiber size in the trained rats appeared to be reflected by a combination of smaller (P greater than 0.05) mean axon diameter and myelin area. Total fiber number was not different in the control (means = 113 +/- 6) and trained (means = 108 +/- 4) rats. These results provide further evidence that a chronic, intense but physiologic exercise can impose a functional demand on peripheral nerves that can alter morphologic features that are closely related to conduction velocity and commonly are associated with neuronal cell size.

Animals↗
PubMed1982

Echocardiographic measures in 6 to 7 year old children after an 8 month exercise program.

The influence of an exercise intervention program on cardiac dimensions was studied in 79 normal children (aged 6 to 7 years) in an experimental (n = 38) and control (n = 41) group. The experimental group participated in an aerobic exercise session that met four days/week for 8 months. Anthropometric measurements and M mode echocardiograms were obtained before and after the intervention program. Comparison of the data between groups revealed no significant (probability [p] greater than 0.05) differences in left ventricular end-diastolic dimension, shortening fraction or resting heart rate. Left ventricular posterior wall thickness exhibited a significant increase (p less than 0.0256) from 3.9 to 4.7 mm in the experimental group compared with an increase from 4.3 to 4.6 mm in the control group after correcting for preintervention differences with an analysis of covariance. Likewise, left ventricular mass increased significantly (p less than 0.0004) from 21.2 to 27.4 g in the experimental group compared with 23.4 to 25.8 g in the control group. These findings indicate that when compared with control subjects, young children involved in an aerobic exercise program showed progressive increases in left ventricular posterior wall thickness and left ventricular mass and no change in left ventricular end-diastolic dimension, shortening fraction or resting heart rate.

Body Height↗
PubMed1982

Daily physical activity patterns of prepubertal children involved in a vigorous exercise program.

The purpose of the present investigation was to examine the effects of a vigorous physical activity program on daily physical activity patterns of 59 7-year-old children divided into experimental (n = 26) and control (n = 33) groups. The experimental group participated in a 25-min vigorous, aerobic exercise session 4 days per week, while the control group maintained their normal daily activities, which included a 1 day per week physical education class, for 8 months. The intensity of each experimental exercise session and each control physical education class was determined by fitting Exersentry heart rate devices to two different children randomly selected from each group without replacement. Daily activity patterns were determined using minute-by-minute heart rates calculated from a 12-h EKG recorded from 8 a.m. to 8 p.m. using an Oxford Instruments ambulatory monitor. Analysis of the Exersentry data demonstrated significantly higher heart rates (P less than 0.05) during the experimental exercise session compared to the control physical education class, except during pre-exercise. Analysis of the 12-h EKG data (n = 720 min) revealed the experimental group spent significantly more time (P less than 0.05) at heart rates greater than 160 bts X min-1 (35 +/- 6 min, experimental; 21 +/- 3 min, control) during the intervention program. No significant group differences (P greater than 0.05) were observed in 12-h heart rate data collected prior to initiation of the intervention program. These data suggest that a vigorous physical activity program resulted in differences in the daily physical activity patterns of 7-year-old children.

Cardiovascular Diseases↗
PubMed1981

Energy expenditure in prepubescent children: influence of sex and age.

The purpose of this investigation was to examine the relationship between energy expenditure and speed for 6-and 7-yr-old children and to compare these data to published data for adults. Eight subjects (n = four boys, four girls) completed three treadmill tests at 67, 94, and 127.5 m . min-1 (k = 12 trials for the boys, 12 trials for the girls). Heart rate was monitored continuously and oxygen uptake (VO2) and carbon dioxide production (VCO2) were determined at each speed in order to estimate caloric expenditure. Sex differences were observed in the metabolic and heart rate responses to exercise. In comparison to the females, the energy expenditure (kcal . min-1) was 16 (p less than 0.05), 11 (p greater than 0.05) and 14 (p less than 0.05) percent higher for the males at the slow, medium, and fast speeds, respectively. Additionally, heart rate was 13 beats . min-1 lower (p less than 0.05) for the males at a speed of 94 m . min-1. Differences in kcal . kg . min-1 between children and adults were observed (children higher). In contrast to adults' linear increase in energy expenditure with increasing speed, a curvilinear pattern was observed for prepubescent children. It was concluded that these sex and age effects must be considered when attempting to quantify children's daily energy expenditure and caloric requirements.

Age Factors↗
PubMed1981

Physical activity patterns determined by heart rate monitoring in 6-7 year-old children.

The purpose of this study was to examine 12-h heart rate patterns during the summer using a holter monitoring system (Oxford Instruments) in prepubescent children. Parental consent was obtained for the 40 volunteers (22 boys, 18 girls) ages 6 to 7 years. Heart rates exceeding 160 bts min-1 occurred 20.9 min and 9.4 min for the boys and girls, respectively, during the 12-h monitoring period (8:00 a.m.-8:00 p.m.). When comparing the heart rate profiles between the sexes, the boys had significantly (P less than 0.05) more heart beats at a level of 140 bts min-1 and above than the girls. Even though the children appear moderately active, they very seldom experience high intensity physical activity. Furthermore, the heart rate patterns show that the boys are more physically active than the girls.

Child↗
PubMed1981

Body shape in prepubescent children.

The present study was designed to investigate changes in body shape during growth in 219 children ages six to ten years. Body shape was determined by a series of bone diameter measurements. Regression analysis was employed as a means of comparing changes in one measure relative to another. Sex differences in body shape were also examined. The results revealed significant (P less than .05) sex differences between biacromial width and extremity diameter composite (EDC) vs. height, biacromial width vs. biiliac width, and EDC vs. trunk diameter composite. These, findings indicate both age and sex influence body shape in six to ten year old children.

Anthropometry↗
PubMed1981

Heart rate response to bicycle ergometer exercise in children ages 6-7 years.

The purpose of the present investigation was to compare the heart rate response of pre-pubertal males and females during rest, steady-rate power output, peak power output, and recovery. Sixty-six children (38 males and 28 females) ages 6-7 years performed a continuous bicycle ergometer exercise test, including 4 min of steady-rate work (males = 15.3 +/- 0.17 W.min-1, females = 15.0 +/- 0.16 W.min-1) followed by a progressive increase in resistance until volitional fatigue, and a 5-min recovery period immediately following termination of exercise. Mean steady-rate heart rate response of 119.0 +/- 1.75 beats.min-1 for males was significantly (P less than 0.05) lower than the females (132.1 +/- 2.92 beats.min-1). Peak heart rate response was similar between the sexes (190.1 +/- 1.21 and 192.1 +/- 1.73 beats.min-1 for males and females, respectively; P greater than 0.05). Sex differences in heart rate recovery from peak values were significant (P less than 0.05) during the first 3 min of the 5-min recovery period, but not thereafter (P greater than 0.05). It was concluded that sex differences in heart rate response were present in these prepubertal children at rest, during steady-rate power output, and during the first 3 min of recovery.

Anthropometry↗
PubMed1981

Comparison of serum lipids between habitually high and low active pre-adolescent males.

Evaluations of 55 pre-adolescent males were made to determine if differences existed in the serum levels of total triglycerides, total cholesterol, HDL-cholesterol, or HDL-cholesterol/total cholesterol ratios between groups with contrasting levels of body fatness and physical activity habits. Underwater weighing revealed a median body fatness of 13.8% and 5-d physical activity records revealed a median of 3.9 h for daily participation in moderate to very high intensity activities. These values were respectively employed to stratify the sample into groups characterized as "lower fatness" or "higher fatness," as well as "lower active" or "higher active." Statistical comparisons between these groups indicated an absence of body fatness effects on any of the serum lipids. However, in contrast to similarities in physical characteristics, body composition, and nutritional intake (except total calories) between the "lower active" and "higher active" groups, physical activity effects were noted for two of the four serum lipid traits. Greater exposure to activities classified as moderate to very highly intense was consistent with lower total triglycerides (52.1 mg/dl vs 68.2 mg/dl) and higher HDL-cholesterol/total cholesterol ratios (0.33 vs 0.29) in these 8- to 11-year-old males.

Body Composition↗
PubMed1979

Isokinetic torque levels for high school football players.

One hundred fifteen high school football players were screened isokinetically for the knee extensor and flexor torque generating capabilities and muscle imbalances. Each player was tested on a Cybex II at speeds of 30 degrees/sec and 180 degrees/sec. The subjects were stratified by age (15, 16, 17) and by position (linemen vs receivers and backs). Significant (p less than 0.05) torque differences were observed at both the slow and fast speeds for the knee extensors and flexors across the 3 age groups. However, the flexion to extension ratios did not differ significantly. On the other hand, when considering the positions, flexor torque and flexion to extension ratio at the slow speed were greater (p less than 0.05) for the linemen than the receivers and backs. Partial correlation analyses showed that body weight had the greatest effect on the knee torque values. It was concluded that basic torque measures differed with age and by position in the sport of football. Also, speed of movement altered the force generating capabilities of the muscle and resultant ratios.

Adolescent↗
PubMed1977

Prevalence of coronary heart disease risk factors in active children, 7 to 12 years of age.

Forty-seven active boys and girls, 7 to 12 years of age, underwent a comprehensive medical and physical evaluation in order to assess their prevalence of single and multiple coronary heart disease risk factors. Each subject received a densiometric determination of body composition, blood lipid analysis, pulmonary function and a physical work capacity test to assess their peak oxygen consumption (Vo2max). Obesity (greater than 25% fat), elevated triglycerides (greater than 100 mg %) and the presence of Type IV hyperlipoproteinemia appear to be the more predominant risk factors. Twenty-nine (62%) of the children had at least one risk factor. Of these, seventeen had two or more risk factors with one subject having as many as five factors.

Blood Gas Analysis↗
PubMedDate not supplied

Effects of a physical activity program on metabolic control and cardiovascular fitness in children with insulin-dependent diabetes mellitus.

The purpose of this investigation was to determine the effects of a regular vigorous physical activity program on children aged 5-11 yr with insulin-dependent diabetes mellitus (IDDM). The experimental group of children (N = 9) took part in a 30-min vigorous exercise program three times a week for 12 wk; the control group (N = 10) did not. Hemoglobin A1 (HbA1) and fasting blood glucose (FBG) were used to determine metabolic control. Oxygen consumption was evaluated by treadmill testing and analyses of expired air. The experimental group significantly (P less than 0.05) decreased their HbA1 and FBG while the control group showed no change. The experimental group significantly (P less than 0.05) increased their peak aerobic capacity (ml/kg . min) when compared with baseline values (47.14 +/- 1.94 versus 50.69 +/- 1.30). It was concluded that a carefully applied program of regular vigorous physical activity can beneficially influence metabolic control and cardiovascular fitness in young children with IDDM.

Blood Glucose↗