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Biomedical subjects

N Armstrong

Publications and source records attributed to N Armstrong.

At least 73 records · Page 4Linked to original sources
PubMed1992

Daily physical activity and blood lactate indices of aerobic fitness in children.

This study examined the relationship between daily physical activity and aerobic fitness in 11-16-year-olds. Habitual physical activity was assessed in 28 boys (mean(s.d.) age 13.6(1.3) years) and 45 girls (mean(s.d) age 13.7(1.3) years) from minute-by-minute heart rate monitoring during 3 school days. Aerobic fitness was assessed by determining the percentage peak VO2 at blood lactate reference values of 2.5 and 4.0 mmol l-1 during incremental treadmill running. The 4.0 mmol l-1 level occurred at a mean(s.d.) value of 89(7)% peak VO2 in both boys and girls and mean(s.d.) values at the 2.5 mmol l-1 level were 82(9)% peak VO2 in girls. Mean(s.d.) percentage time with heart rates at or above 140 beats min-1 was 6(3)% in boys and 5(3)% in girls. Corresponding values for percentage time at or above 160 beats min-1 were 3(2) for boys and 2(1) for girls. The number of 10- and 20-min periods of activity with the heart rate sustained above the 140 and 160 beats min-1 thresholds were also totalled over the 3 days. No significant relationships were identified between percentage peak VO2 at the 2.5 or 4.0 mmol l-1 blood lactate reference levels and either percentage time or number of 10- or 20-min periods above 140 or 160 beats min-1 (P > 0.05). These results support the hypothesis that daily physical activity levels in 11-16-year-old children do not stress aerobic metabolism sufficiently to influence aerobic fitness.

Adolescent↗
PubMed1991

The peak oxygen uptake of British children with reference to age, sex and sexual maturity.

The purposes of this study were to provide baseline data on the peak oxygen consumption (VO2) of British children, aged 11-16 years and to examine the peak VO2 of children in relation to their pubertal stage of development. The peak VO2 of 226 boys and 194 girls was determined during either treadmill running or cycle ergometry. The sexual maturity of 320 of the children was estimated using Tanner's indices. Peak VO2 increased with chronological age in both sexes and from about the age of 12 years boys exhibited significantly higher (P less than 0.05) values than girls. Boys' peak VO2 in relation to body mass was consistent over the age range studied and was superior (P less than 0.05) to girls' values at all ages. It appears that mass-related peak VO2 is independent of sexual maturity in both sexes. The more mature boys demonstrated a significantly higher (P less than 0.05) peak VO2 (1.min-1) than the less mature boys on both ergometers. The more mature girls demonstrated significantly higher (P less than 0.05) peak VO2 (1.min-1) than the less mature girls only on the cycle ergometer. On both ergometers the differences between the peak VO2 of the girls and boys were more pronounced in the mature children whether expressed in relation to body mass or not. Comparison of the results with earlier data drawn from smaller samples failed to provide evidence to suggest that British children's peak VO2 has declined in recent years. No study with which to compare our maturity peak VO2 data appears to be available.

Age Factors↗
PubMed1991

Physical activity patterns defined by continuous heart rate monitoring.

To investigate the physical activity patterns of British primary schoolchildren (mean (SD) 10.7 (0.3) years) the minute by minute heart rates of 67 boys and 65 girls were monitored continuously for three 12 hour periods during normal schooldays. In addition 39 children had their heart rates monitored during a 12 hour period on a Saturday. Few children experienced the volume (frequency, intensity, and duration) of physical activity associated with an improvement in cardiopulmonary fitness. Shorter (five minute) periods of the required intensity were, however, quite common. No difference between moderate amounts of activity was detected between boys and girls, but the boys had more five minute sessions of intense activity than the girls. These findings suggest that more research into the effects of short periods of intense physical activity on the cardiopulmonary systems of young children is required and that the determinants of habitual physical activity require further investigation especially in the context of sex differences at such an early age.

Child↗
PubMed1991

Nutritional status, pressure sores, and mortality in elderly patients with cancer.

This prospective study aimed to determine differences in nutritional status, incidence of pressure sores, and incidence of mortality between two groups, one composed of 33 elderly, institutionalized patients with cancer and the other a matched group of 33 patients without cancer. Subjects with cancer were paired with subjects without cancer based on age (mean = 78), sex, and pressure sore risk. Skin breakdown, dietary intake, and blood and serum indices of nutritional status were studied for 12 weeks. Of the subjects with cancer, 85% developed pressure sores, compared to 70% of the subjects without cancer. Hemoglobin (Hgb) (female), serum total protein, total lymphocyte count, serum albumin, serum total iron binding capacity, and serum transferrin were significantly lower in subjects with cancer with pressure sores than in subjects without cancer with pressure sores. Total lymphocyte count and serum total protein were significantly lower in subjects with cancer with pressure sores than in subjects with cancer without pressure sores. Kwashiorkor was found in 70% of the subjects with cancer, compared to 21% of the subjects without cancer. During the study, 39% of the subjects with cancer and 15% of the subjects without cancer died. All 13 of the subjects with cancer who died had kwashiorkor and pressure sores and had died an average of three weeks after developing pressure sores. These results implicate that elderly patients with cancer who have protein deficiencies should be considered to be at risk of pressure sore development. Frequent repositioning and mattress overlays that reduce pressure and increase comfort may delay development of pressure sores.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Patterns of physical activity among 11 to 16 year old British children.

OBJECTIVE: To examine the patterns of physical activity among British schoolchildren aged 11 to 16 and to assess whether the children experience the intensity and duration of physical activity that are believed to stress the cardiopulmonary system appropriately. DESIGN: Cross sectional study of a sample of children drawn from a larger survey of coronary risk factors in children. Continuous monitoring of heart rate for 12 hour periods on three school days and one Saturday. SETTING: Two communities in Devon. SUBJECTS: 266 Children (163 girls, 103 boys) aged 11 to 16 randomly selected from a sample of 707 children. MAIN OUTCOME MEASURES: Percentage of time and number of sustained periods in which heart rate was greater than 139 beats/min. Anthropometric measures and external assessment of sexual maturity with Tanner's indices. RESULTS: The boys had heart rates greater than 139 beats/min for a significantly higher percentage of time than the girls (p less than 0.01) during the weekday (6.2% v 4.3%) and the Saturday (5.6% v 2.6%). The boys had significantly more five and 10 minute periods with heart rates greater than 139 beats/min than the girls during the Saturday and weekdays and more 20 minute periods during the weekdays. 84 Girls and 37 boys had no 10 minute period with a heart rate greater than 139 beats/min during the three weekdays and 112 girls and 65 boys had no such 10 minute period during the Saturday. No significant relation was detected in either sex between the amount or habitual physical activity (heart rate) and skinfold thickness or maturity group. CONCLUSIONS: British children have surprisingly low levels of habitual physical activity, and many children seldom undertake the volume of physical activity believed to benefit the cardiopulmonary system. Boys are more active than girls. The pubertal stage of development or body fatness, or both, do not seem to be sensitive indicators of physical activity in either girls or boys.

Adolescent↗
PubMed1990

The 4 mM blood lactate level as an index of exercise performance in 11-13 year old children.

The aim of this study was to assess the use of the 4 mM blood lactate level measured during incremental treadmill exercise as an indicator of exercise performance in 11-13 year old children. Fifty girls and 53 boys (means age 12.2 +/- 0.6 years) gave informed consent to participate in the study. The children completed a discontinuous, incremental running test on a motorized treadmill. A 1 min pause separated the 3 min exercise stages during which time duplicate capillary blood samples were taken for immediate assay of whole blood lactate concentration. Cardiorespiratory variables were measured continuously during exercise using a computerized on-line system. Mean values for peak oxygen uptake were 48 +/- 7 ml kg-1 min-1 and 42 +/- 7 ml kg-1 min-1 in boys and girls respectively. The exercise intensity corresponding to a blood lactate concentration of 4 mM was interpolated from plots of % peak oxygen uptake vs blood lactate and was reached at 91 +/- 7% peak oxygen uptake in both boys and girls. The results indicate that children can exercise at intensities close to their peak oxygen uptake without accumulating high levels of blood lactate and the use of the 4 mM blood lactate level to assess and monitor exercise performance in children of this age may therefore be inappropriate.

Adolescent↗
PubMed1990

Estimation of coronary risk factors in British schoolchildren: a preliminary report.

Surveys from several countries have identified the presence of risk factors known to be associated with coronary heart disease in children. Data on the distribution of coronary risk factor variables in British children are scarce. This study was therefore designed to test the feasibility of collecting coronary risk factor data from British children and to conduct a preliminary examination of the problem. One hundred and seven children (mean age 12.8 yr) had their height, weight, triceps skinfold and blood pressure checked. Blood samples for cholesterol and HDL-cholesterol analysis were obtained from 93 children. Peak VO2 was determined on 48 children, 76 children had their daily activity monitored and 59 children's stage of sexual maturity was assessed. The boys' peak VO2 was significantly higher than the girls, whether expressed in l.min-1 (p less than 0.05) or ml.kg.-1min-1 (p less than 0.01). No other significant differences (p greater than 0.05) between the sexes were detected. The results indicate that children have relatively high serum cholesterol levels (boys 4.58 +/- 0.79; girls 4.72 +/- 0.80 mmol.l-1). The willingness and enthusiasm of the children, parents and schools to take part in the study clearly demonstrated the feasibility of a large scale study being successfully pursued in the United Kingdom.

Adolescent↗
PubMed1987

Coping with diabetes mellitus. A full-time job.

The coping demands of diabetes may be insurmountable to the unprepared and unwary. The psychosocial, self-management, and knowledge/skill demands of diabetes can affect every aspect of a person's life. Planning ways to cope with this unique circumstance may help a diabetic person adjust to a complex and difficult lifelong problem. Viewing the client, family and friends, nurse, physician, dietitian, and relevant other team members as a full corporate partnership, with individual and shared responsibility, also lays the groundwork for realistic problem-solving and coping by all concerned.

Adaptation, Psychological↗
PubMed1987

Setting up an effective records management program.

The records management program at Kingston General Hospital is by no means complete, though considerable progress has been made. Users are gaining confidence in the records centre and more departments are becoming involved. To date, 12 departments are participating fully in the program. In the future, we may consider computerization--for faster retrieval of records--staffing requirements and storage of paperless abstracts to maintain an efficient and effective records management program.

Archives↗
PubMed1985

Absence of branched chain acyl-transferase as a cause of maple syrup urine disease.

Decreased function of human mitochondrial branched chain alpha-ketoacid dehydrogenase complex results in branched chain ketoacidemia or maple syrup urine disease. Activity of this multienzyme complex varies from 0 to approximately 15% of wild type branched chain alpha-ketoacid dehydrogenase complex activity within the population of homozygous affected individuals. We used the technique of Western Blotting with antibodies against purified bovine liver branched chain alpha-ketoacid dehydrogenase complex to screen mitochondrial proteins from cultured human fibroblasts for immunocrossreactive proteins. This method probes the physical structure of the proteins forming this multienzyme complex. One patient with branched chain ketoacidemia lacked an immunoreactive transacylase protein. This protein catalyzes the transfer of the branched chain acyl group from the decarboxylase to reduced coenzyme A. Kinetic analysis of the enzyme activity in cell lysates from this patient confirmed that the complex would not utilize coenzyme A. Thus, we have defined a structural basis for an impaired multienzyme complex of mitochondria in man.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1983

The specificity of energy utilisation by trained and untrained adolescent boys.

This study examined the relationship between estimates of alactacid anaerobic power, lactacid anaerobic power and aerobic power in a sample of trained swimmers (age 14.4 yr., n = 8) and a sample of untrained boys (age 13.7 yr., n = 13). The anaerobic power outputs were estimated using a modification of the Wingate Anaerobic Test and aerobic power was estimated using a continuous, incremental cycle ergometer test. In addition to leg power outputs the swimmers' arm power using each energy system was estimated and compared with the corresponding leg value. There was no relationship between the estimates of the power of the three energy systems with either the trained or untrained boys. Furthermore with the trained boys there was no relationship between estimates of the power of the same energy system utilised by different limbs. The data support a specificity hypothesis of energy utilisation during exercise with both trained and untrained adolescent boys.

Adolescent↗
PubMed1981

An ergometric analysis of age group swimmers.

Thirteen male competitive swimmers (mean age 14.7 years) were studied during maximal exercise on a treadmill, cycle ergometer and biokinetic swim bench. The mean maximal oxygen uptake values elicited (treadmill = 66.5 ml.kg-1 min.-1; cycle ergometer = 61.0 ml.kg.-1 min.-1; biokinetic swimbench = 44.5 ml.kg.-1 min.-1) were higher than those reported elsewhere for children not engaged in intensive training and even when compared with other groups of similarly aged swimmers the values exhibited were some of the highest recorded. The results were directionally similar to those of other studies comparing treadmill and cycle ergometer exercise with the mean maximal oxygen uptake on the cycle ergometer 9% lower than that on the treadmill. There is no other study with which to compare swim bench values but the majority of maximal values were consistently and significantly lower than those achieved on the other ergometers. The swimmers rank within the group was minimally affected by the type of ergometer on which the measurement was made.

Adolescent↗