Biomedical subjects

L M Burke

Publications and source records attributed to L M Burke.

At least 19 recordsLinked to original sources

PubMed1996

Muscle glycogen storage after prolonged exercise: effect of the frequency of carbohydrate feedings.

We reported previously that intake of carbohydrate foods with a high glycemic index (GI) produced greater glycogen storage and greater postprandial glucose and insulin responses during 24 h of postexercise recovery than did intake of low-GI carbohydrate foods. In the present study we examined the importance of the greater incremental glucose and insulin concentrations on glycogen repletion by comparing intake of large carbohydrate meals ("gorging") with a pattern of frequent, small, carbohydrate snacks ("nibbling"), which simulates the flattened glucose and insulin responses after low-GI carbohydrate meals. Eight well-trained triathletes [x +/- SEM: 25.6 +/- 1.5 y of age, weighing 70.2 +/- 1.9 kg, and with a maximal oxygen uptake (VO2max) of 4.2 +/- 0.2 L/min] undertook an exercise trial (2 h at 75% VO2max followed by four 30-s sprints) to deplete muscle glycogen on two occasions, 1 wk apart For 24 h after each trial, subjects rested and consumed the same diet composed exclusively of high-GI carbohydrate foods, providing 10 g carbohydrate/kg body mass. The "gorging" trial provided the food as four large meals of equal carbohydrate content eaten at 0, 4, 8, and 20 h of recovery, whereas in the "nibbling" trial each of the meals was divided into four snacks and fed at hourly intervals (0-11, 20-23 h). However, there was no significant difference in muscle glycogen storage between the two groups over the 24 h (gorging: 74.1 +/- 8.0 mmol/kg wet wt; nibbling: 94.5 +/- 14.6 mmol/kg wet wt). The results of this study suggest that there is no difference in postexercise glycogen storage over 24 h when a high-carbohydrate diet is fed as small frequent snacks or as large meals, and that a mechanism other than lowered blood glucose and insulin concentrations needs to be sought to explain the reduced rate of glycogen storage after consumption of low-GI carbohydrate foods.

Adult↗

PubMed1996

Effect of oral creatine supplementation on single-effort sprint performance in elite swimmers.

Oral supplementation with creatine monohydrate (Cr.H2O) has been reported to increase muscle creatine phosphate levels. The aim of the present study was to determine the effect of such supplementation on performance of a single-effort sprint by elite swimmers. Thirty-two elite swimmers (M = 18, F = 14; age = 17-25 years) from the Australian Institute of Sport were tested on two occasions, 1 week apart. Tests performed were 25-m, 50-m, and 100-m maximal effort sprints (electronically timed with dive start, swimmers performing their best stroke), each with approximately 10 min active recovery. A 10-s maximal leg ergometry test was also undertaken. Swimmers were divided into two groups matched for sex, stroke/event, and sprint time over 50 m, and groups were randomly assigned to 5 days of Cr.H2O supplementation (4 . day-1 x 5 g Cr.H2O + 2 g sucrose, n = 16) or placebo (4 . day-1 x 5 g Polycose + 2 g sucrose, n = 16) prior to the second trial. Results revealed no significant differences between the group means for sprint times or between 10-s maximal leg ergometry power and work. This study does not support the hypothesis that creatine supplementation enhances single-effort sprint ability of elite swimmers.

Adolescent↗

PubMed1996

Body weight changes and voluntary fluid intakes during training and competition sessions in team sports.

Fluid losses (measured by body weight changes) and voluntary fluid intakes were measured in elite basketball, netball, and soccer teams during typical summer and winter exercise sessions to determine fluid requirements and the degree of fluid replacement. Each subject was weighed in minimal clothing before and immediately after training, weights, and competition sessions; fluid intake, duration of exercise, temperature and humidity, and opportunity to drink were recorded. Sweat rates were greatest during competition sessions and significantly lower during weights sessions for all sports. Seasonal variation in dehydration (%DH) was not as great as may have been expected, particularly in sports played indoors. Factors influencing fluid replacement during exercise included provision of an individual water bottle, proximity to water bottles during sessions, encouragement to drink, rules of the game, duration and number of breaks or substitutions, and awareness of personal sweat rates. Guidelines for optimizing fluid intakes in these three sports are provided.

Adolescent↗

PubMed1995

Political principles in action: a critical analysis of Education and Training: Working Paper 10 and its implications for nurse education.

Education and Training: Working Paper Ten (WP10) (Department of Health 1989a) was published in October 1989. It was an integral part of Working for Patients (Department of Health 1989b) and as such was alleged to embrace the same fundamental principles. WP10 may result in the most significant change to nurse education in the UK since the 1949 Nurses Act, with variations in its funding, structure and organisation. Surprisingly, there has been relatively little discussion about this important development within the nursing press. The aim, therefore, of this paper is to evaluate WP10 within the context of the ideology which has underpinned social policy in the last 14 years. Firstly, Conservative Party policy will be explored, the WP10 itself will then be examined in order to assess how far such principles have been applied to nurse education through its implementation. It is intended that by this process of analysis further understanding will be gained about this policy and its potential consequences for the future of nursing.

Education, Nursing↗

PubMed1995

Effect of coingestion of fat and protein with carbohydrate feedings on muscle glycogen storage.

Dietary guidelines for achieving optimal muscle glycogen storage after prolonged exercise have been given in terms of absolute carbohydrate (CHO) intake (8-10 g.kg-1.day-1). However, it is of further interest to determine whether the addition of fat and protein to carbohydrate feedings affects muscle glycogen storage. Eight well-trained triathletes [23.1 +/- 2.0 (SE) yr; 74.0 +/- 3.4 kg; peak O2 consumption = 4.7 +/- 0.4 l/min] undertook an exercise trial (2 h at 75% peak O2 consumption, followed by four 30-s sprints) on three occasions, each 1 wk apart. For 24 h after each trial, the subjects rested and were assigned to the following diets in randomized order: control (C) diet (high glycemic index CHO foods; CHO = 7 g.kg-1.day-1), added fat and protein (FP) diet (C diet + 1.6 g.kg-1.day-1 fat + 1.2 g.kg-1.day-1 protein), and matched-energy diet [C diet + 4.8 g.kg-1.day-1 additional CHO (Polycose) to match the additional energy in the FP diet]. Meals were eaten at t = 0, 4, 8, and 21 h of recovery. The total postprandial incremental plasma glucose area was significantly reduced after the FP diet (P < 0.05). Serum free fatty acid and plasma triglyceride responses were significantly elevated during the FP trial (P < 0.05). There were no differences between trials in muscle glycogen storage over 24 h (C, 85.8 +/- 2.7 mmol/kg wet wt; FP, 80.5 +/- 8.2 mmol/kg wet wt; matched-energy, 87.9 +/- 7.0 mmol/kg wet wt).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Preceptorship and post-registration nurse education.

The Report of the Post-Registration Education and Practice Project (UKCC 1990) and the Framework for Continuing Professional Education for Nurses, Midwives and Health Visitors (ENB 1991) have led to an unprecedented period of formalised supervision and support for registered practitioners in the UK. The preceptor has been identified as having a pivotal part to play in providing this support. There is however, a need for further clarification regarding the exact nature of the preceptor's role in post-registration education and practice, and the full extent of the responsibilities involved. This paper explores the issues involved in preceptorship for qualified nurses and some of the related literature. The following key questions are addressed: Who will be designated as preceptors? How will they be selected? What preparation and support will such preceptors be offered? What is the role of the preceptor and what is the conceptual and empirical difference between the preceptor and the mentor? It is proposed that strategies must be identified for clarification of the preceptor's role and responsibilities, identification of selection criteria, and the establishment of preceptor preparation programmes and support networks.

Education, Nursing, Continuing↗

PubMed1994

Teacher self-evaluation: an assessment using Delamont's 'beyond Flanders' fields' technique.

Teacher appraisal is an issue which is becoming increasingly important in nurse education today. One potential system of evaluation which is currently under-valued and under-utilised within nurse education is self-assessment. This paper explores the issues involved through the application of Delamont's 'beyond Flanders' fields' assessment tool to an excerpt of teaching recorded on video tape. It concludes that self-assessment has significant value in developing the reflection skills of the teacher and thereby improving the quality of education delivered. It should therefore form a significant part of any appraisal event.

Faculty, Nursing↗

PubMed1993

The future of the specialist nurse teacher: two different models explored.

The demand for more specialised nurse educators is increasing, yet the nature and direction of this specialisation remains unclear. In this paper the strengths and limitations of two different models are evaluated focusing on the organisation and management of education, integration of theory with practice, the skill of teaching itself and the implications for clinical practice.

Faculty, Nursing↗

PubMed1993

Muscle glycogen storage after prolonged exercise: effect of the glycemic index of carbohydrate feedings.

The effect of the glycemic index (GI) of postexercise carbohydrate intake on muscle glycogen storage was investigated. Five well-trained cyclists undertook an exercise trial to deplete muscle glycogen (2 h at 75% of maximal O2 uptake followed by four 30-s sprints) on two occasions, 1 wk apart. For 24 h after each trial, subjects rested and consumed a diet composed exclusively of high-carbohydrate foods, with one trial providing foods with a high GI (HI GI) and the other providing foods with a low GI (LO GI). Total carbohydrate intake over the 24 h was 10 g/kg of body mass, evenly distributed between meals eaten 0, 4, 8, and 21 h postexercise. Blood samples were drawn before exercise, immediately after exercise, immediately before each meal, and 30, 60, and 90 min post-prandially. Muscle biopsies were taken from the vastus lateralis immediately after exercise and after 24 h. When the effects of the immediate postexercise meal were excluded, the totals of the incremental glucose and insulin areas after each meal were greater (P < or = 0.05) for the HI GI meals than for the LO GI meals. The increase in muscle glycogen content after 24 h of recovery was greater (P = 0.02) with the HI GI diet (106 +/- 11.7 mmol/kg wet wt) than with the LO GI diet (71.5 +/- 6.5 mmol/kg). The results suggest that the most rapid increase in muscle glycogen content during the first 24 h of recovery is achieved by consuming foods with a high GI.

Adolescent↗

PubMed1993

Dietary supplements in sport.

Studies of the dietary practices of athletes report that nutritional supplements are commonly used. Supplementation practices vary between sports and individual athletes; however, there is evidence that at least some athletes use a large number of supplements concurrently, often in doses that are very high in comparison with normal dietary intakes. In exploring supplementation practices we propose a classification system separating the supplements into dietary supplements and nutritional erogogenic aids. The dietary supplement is characterised as a product which can be used to address physiological or nutritional issues arising in sport. It may provide a convenient or practical means of consuming special nutrient requirements for exercise, or it may be used to prevent/reverse nutritional deficiencies that commonly occur among athletes. The basis of the dietary supplement is an understanding of nutritional requirements and physiological effects of exercise. When the supplement is used to successfully meet a physiological/nutritional goal arising in sport it may be demonstrated to improve sports performance. While there is some interest in refining the composition or formulation of some dietary supplements, the real interest belongs to the use or application of the supplement; i.e. educating athletes to understand and achieve their nutritional needs in a specific sports situation. The sports drink (carbohydrate-electrolyte replacement drink) is a well known example of a dietary supplement. Scientific attitudes towards the sports drink have changed over the past 20 years. Initial caution that carbohydrate-electrolyte fluids compromise gastric emptying during exercise has now been shown to be unjustified. Numerous studies have shown that 5 to 10% solutions of glucose, glucose polymers (maltodextrins) and other simple sugars all have suitable gastric emptying characteristics for the delivery of fluid and moderate amounts of carbohydrate substrate. The optimal concentration of electrolytes, particularly sodium, remains unknown. Most currently available sports drinks provide a low level of sodium (10 to 25 mmol/L) in recognition that sodium intake may promote intestinal absorption of fluid as well as assist in rehydration. The sodium level of commercial oral rehydration fluids (used in the clinical treatment of diarrhoea and dehydration) is higher than that of the present range of sports drinks. However, even if research indicates that intestinal glucose transport is optimally stimulated at higher sodium concentrations, concern for the palatability of sports drinks may impose a lower ceiling for sodium levels. Commercial viability of a sports drink requires that it provide a refreshing and palatable fluid replacement across a wide variety of sports and exercise situations.(ABSTRACT TRUNCATED AT 400 WORDS)

Calcium, Dietary↗

PubMed1991

Dietary intakes and food use of groups of elite Australian male athletes.

The present study conducted dietary surveys of four groups of Australian male athletes: triathletes, marathon runners, Australian Rules football players, and Olympic weightlifters. Their training diets were assessed via a 7-day food record from which mean daily intakes of energy, macronutrients, and key micronutrients were estimated. The data were compared between groups as well as to recommendations in the literature for athlete nutrition. Results showed major differences between groups. The contribution of carbohydrate to total energy intake was greater for triathletes and marathon runners than for the other two groups. There was no difference between all four groups in the total amount of fat consumed, yet its contribution to total energy intake was significantly lower for triathletes and marathon runners. The football players and weightlifters consumed a similar fat:energy ratio as the typical Australian diet. Furthermore, the micronutrient density of the football players' diets was significantly lower than that of the other groups.

Attitude to Health↗

PubMed1990

Comparison of mitogen responses of lymphocyte subpopulations separated using coated metal beads and by traditional methods.

In this paper we compare the effects on lymphocyte function of separating peripheral blood mononuclear cells into T and B lymphocytes using monoclonal antibodies and coated metal beads (Dynabeads), with traditional plastic adherence and sheep erythrocyte binding techniques. We demonstrate that B cell function is unaffected using the new Dynabead method but that T cell function is impaired. We ascribe these observations to modulations of the cell surface molecule(s) expressing the lineage specific determinant used in the selection procedure, rather than to inherent difficulties with using the Dynabeads.

Cell Separation↗

PubMed1989

Comparison of three methods of estimating energy expenditure: caltrac, heart rate, and video analysis.

This study examined the accuracy of a new device (Caltrac) in estimating energy expenditure via acceleration measurements. Energy expenditure of 20 high school students during basketball class activity (average length = 37 min) was estimated using the Caltrac, heart rate recording, and video analysis. Heart rate recording and video analysis estimates of energy expenditure were determined from heart rate, caloric expenditure curves, and an activity rating scale, respectively. The following estimates of caloric expenditure (M +/- SD) were found: heart rate recording = 196 +/- 73 greater than Caltrac = 163 +/- 49 greater than film analysis = 123 +/- 30 kcal (p less than .05). Laboratory simulations of the basketball activity revealed that the Caltrac energy expenditure was not significantly different from the actual energy expenditure (p greater than .05). The heart rate recording and video analysis estimates of energy expenditure were significantly (p less than .05) higher and lower, respectively, than the actual energy expenditure. The Caltrac is a lightweight, low-cost device that provides a relatively accurate estimate of energy expenditure in free-ranging activities, such as basketball.

Adolescent↗

PubMed1989

Sports nutrition. Approaching the nineties.

A sophisticated appreciation of the role of nutrition in athletic performance has been made possible by increasing knowledge of the physiology of exercise. The nutritional issues of training are of primary importance, since this occupies most of the athlete's effort. The nutritional support of an intense daily training programme includes an appropriately high energy intake, predominantly in the form of carbohydrate in order to continually replenish muscle glycogen stores. Recent review of the protein needs of athletes indicates that requirements may be substantially above those of sedentary subjects, to account for the oxidation of amino acids during exercise as well as the retention of nitrogen during periods of muscle building. However, these increased requirements are likely to be met by the generous protein intakes anticipated in a high energy diet. The same would seem to hold true for micronutrient considerations, although there is no evidence that vitamin requirements are considerably increased by exercise. Nevertheless, a high energy diet chosen from a sufficiently varied range of foods should allow micronutrient intakes well in excess of population recommended dietary intake levels. Current interest is focused on the mineral status of athletes, particularly that of iron and calcium. In the case of iron, there is a possibility that the increased level of loss by some endurance athletes will not be met by their usual dietary patterns. Screening for early signs of iron deficiency, and appropriate supplementation and dietary counselling seem warranted in high risk groups. Competition poses the challenge of identifying possible factors limiting performance, and taking steps to delay or reduce these. Of paramount importance is body temperature regulation through the maintenance of hydration levels. This issue has long been recognised, but recent studies of gastric emptying and the benefits of carbohydrate supplementation during exercise have caused an update of the advice to athletes regarding fluid intake during exercise. It now seems possible to simultaneously achieve fluid and carbohydrate requirements for endurance exercise within a wide range of choice of beverages containing up to 10% carbohydrate. Concern about the adequacy of carbohydrate fuel stores in endurance exercise situations is also well known. The recognition that training achieves various physiological adaptations to enhance the lifespan of fuel stores has taken away some of the attention previously focussed on carbohydrate-loading techniques.(ABSTRACT TRUNCATED AT 400 WORDS)

Humans↗

PubMed1988

A study of dietary patterns of elite Australian football players.

This report describes the dietary patterns of 56 elite Australian Rules football players. Data collected included an anthropometric profile, training information, and measurements of haemoglobin and blood lipids. Information on dietary practices, for training and game preparation, was collected by interview and food diary. Analysis of training diets showed a mean energy intake of 14.2 MJ/day (0.17 MJ/kg/day). Mean protein intake was 126 g/day (1.5 g/kg/day). The proportions of dietary energy contributed by the macronutrients were carbohydrate, 44%; fat, 37%; protein, 15%; and alcohol, 4%. Mean daily intake of selected vitamins and minerals from food sources was: retinol activity, 1439 mg; thiamin, 1.7 mg; riboflavin, 2.8 mg; niacin equivalents, 45.1 mg; vitamin C, 139 mg; iron, 19.6 mg; and calcium, 1016 mg. Carbohydrate intake was considered low, but overall intake of nutrients studied was adequate.

Adult↗

PubMed1987

A study of carbohydrate loading techniques used by marathon runners.

Carbohydrate loading techniques were studied in a survey of 76 marathon runners. It was found that these runners practised a variety of methods that they believed would achieve carbohydrate loading. Analysis of records of food use showed that the diets actually used by runners did not reach the level of carbohydrate specified in the high carbohydrate phase of the glycogen loading regimens reported in the literature. It is suggested that in a free-living situation, without specific instructions or a knowledge of nutrition and food composition, runners are limited in their ability to achieve the dietary requirements of carbohydrate loading.

Adult↗

PubMed1986

Seasonal changes in body composition in Australian Rules footballers.

Anthropometric measurements were collected from a group of Australian Rules footballers at the start and end of the competitive season. Eighty-nine players were studied, drawn from a top level professional league team, a second level association team and an A-grade amateur association team. Changes in the physical profile of these players during the season were observed. A small but significant gain in fat-free body mass in the top level players was observed (0.9 kg, p less than 0.01), but no change in body fat. The intermediate level players showed no significant change in body mass and a tendency toward a slight loss in body fat, while the lower level players showed a significant loss in body fat during the season (1.8 kg, p less than 0.001) without significant change in fat-free body mass.

Adipose Tissue↗

PubMed1985

Australian Rules football: an anthropometric study of participants.

Anthropometric measurements and personal data were collected from 119 Australian Rules footballers from Victoria. A top level professional league team, a second level association team, and an A-grade amateur association team were observed, representing three levels of ability. The profile of physical features of these athletes at the beginning of the season is presented. A gradation of body size was observed between teams. The players in the top level team were slightly taller and heavier than those in the other teams. They had less body fat, as shown by lesser skinfold thicknesses, a smaller percentage body fat as determined by prediction equations, and a greater fat-free mass. The intermediate level team showed an intermediate level of body fat and the lower level team had the highest proportion of fat.

Anthropometry↗