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Biochemical Education ELSEVIER

Biochemical Education 26 (1998) 119-120

Exercise biochemistry

as an approach to the study of intermediary metabolism H&-&r Filippusson

Department of Biochemistry, University of Iceland, Faculty of Science, IS-107 Reykjavik, Iceland

Abstract The study of metabolism during exercise addresses all major aspects of metabolic pathways, their distribution between tissues as well as their metabolic control mechanisms. An experiment in teaching metabolism from this point of view, using student-presented seminars, is described. This approach turned out to be a popular and successful alternative to lecture-based teaching. 0 1998 IUBMB. Published by Elsevier Science Ltd. All rights reserved

1. Introduction

The teaching of intermediary metabolism to undergraduate students can be a considerable challenge. The major metabolic pathways covered in most introductory courses constitute a substantial amount of detailed information. Any student of biochemistry must, to a greater or lesser extent, familiarize himself with this body of knowledge. For the student, the quickest way would perhaps be to assimilate all this information parrot fashion before turning to the business of understanding it as a whole. For the teacher this is also the most straightforward approach. Such an approach is, however, not conducive to an enjoyable learning process and other methods should be explored if possible. The metabolism of the human body and its individual organs and tissues cannot be well understood unless viewed as a whole. For the medical student taking an introductory course in biochemistry the object of the study of metabolism is to be able to view the human body as a metabolic machine, with the various organs contributing to the function of this machine. For the student studying biochemistry towards a science degree metabolism is often presented mainly as a series of reactions within E. coli cells but he would be well served by being presented with some whole-body metabolism. And those taking biochemistry as part of a degree in general biology would also benefit from a whole-body view of metabolism, as many aspects of animal physiology and nutrition are better understood with a thorough grounding in metabolism. However, the appreciation of the role of the different tissues and organs frequently seems to pass many students by to a large extent as is often all too 0307-4412/98/$19.00

evident to the teacher marking examination papers on the subject. This is of course but an example of the problems, frequently discussed in articles in Biochemical Education and elsewhere, which face those teaching the basic science courses of a medical curriculum. The basic problem is motivation, or lack of it, on behalf of students who sometimes regard basic biochemistry as a subject with little direct relevance to their future professional requirements. The remedies suggested have typically been centered around approaches such as ‘student centered learning’ and ‘problem-based learning’, approaches which might be characterized as ‘anything but lectures’. In fact, many of the newer biochemistry textbooks have taken to presenting the biochemistry of some individual tissues. This is of course not entirely new, as the biochemistry textbooks used in the sixties were very much that way inclined as far as metabolism was concerned. The revolution in textbook writing starting with those of Mahler and Cordes [l] and Lehninger [2] produced much improved reading material for the student of biochemistry, but tended to leave out the ‘physiological’ aspects of metabolism. The functioning of the whole body during exercise is an example of a metabolic situation of some complexity. The purpose of this communication is to describe briefly an experiment where student seminars with a focus on the biochemistry of exercise proved to be a successful and popular alternative to lectures on metabolic pathways. It transpires that the study of metabolism in exercise is an excellent way of addressing all the major aspects of metabolic pathways, metabolic control and the

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PII: SO307-4412(98)00056-9

H. FilippussonlBiochemical Education 26 (1998) 119-120

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distribution of metabolic functions between the various tissues of the body. 2. Student seminars The organization of the ‘experiment’ was simple. The series of lectures usually given on intermediary metabolism was shortened to make room for the experiment. The class of 36 medical students was given the task of preparing short lectures on various topics related to exercise metabolism and its control. A pair of students was given, jointly, a topic to present, with 15 min being allotted for each presentation including questions and discussion (Table 1). Three double-lecture periods (2 h) during one week were set aside for this. Two weeks prior to the first seminar day topics were distributed along with photocopies of relevant material. All the students were supplied with some general reading on metabolism in exercise [3] and each pair with one or two photocopies on their special topic, mostly drawn from two works on the subject [4,5]. As evident from the list of topics, most major aspects of intermediary metabolism are evoked in the discussion of exercise. This includes the metabolic pathways of the major classes of compounds, carbohydrates, lipids and proteins as well as energy metabolism, the control of metabolic pathways and the transport of fuel throughout the body. Thus, these aspects may be studied and appreciated in a precisely focused context without sacrificing any of the relevant details. 3. Student response and conclusions Attendance at lectures is not compulsory and neither was participation in this exercise. Nevertheless, only one of the 36 students did not attend the sessions or play a Table 1 Titles of student 1. 2. 3. 4. 5. 6. I. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.

seminars

on metabolism

in exercise

The structure and function of muscle Energy provision for muscular contraction Fibre types and composition in skeletal muscle The energy stores of the body Management of fuel stores in the body Basic aspects of metabolic control Metabolic control of energy provision during exercise An overview of carbohydrate metabolism The management of glycogen stores during exercise Adenine nucleotide metabolism during exercise The mobilization of lipids and their utilization in exercise Overall aspects of protein metabolism Protein turnover in exercise Metabolic integration during slow and fast running Can a man run forever? What is fatigue? Diabetes and other metabolic disorders in relation to exercise Nutrition in relation to exercise

part in the seminar. The delivery was in most cases very good, clear and concise, and was supported by carefully prepared and imaginative overhead transparencies. It was evident that the students enjoyed the opportunity to take an active part in the proceedings instead of the usually passive role played as part of a lecture audience. The understanding of metabolic pathways, control mechanisms and the role of the different tissues turned out to be good, quite remarkably so in the opinion of the two teachers present. At the end of the exercise, the students were asked for their opinions of the seminars and their usefulness. An overwhelming majority were of the opinion that there should be more of this kind of teaching, that other subjects could be covered in this fashion, that participation ought to be compulsory and that marks should be given for each student’s performance which should count towards the final marks for the semester. This definitive result came as something of a surprise to all concerned. The experiment was followed up in the end of year examination paper. Half of the paper consisted of essaytype questions with four of five questions being answered. Over 80% of the students sitting the paper opted for writing an essay on a topic of their own choice within the general field of metabolism in exercise. Only one student obtained a mark lower than the pass rate (5 out of 10) for this essay and the average mark for the essay was 7.67 as compared with 6.71 for all the essays in the paper. Two things may be learnt from this experiment. First, the study of exercise biochemistry is a valuable way of getting students interested in intermediary metabolism and metabolic control. Second, students enjoy learning by doing. Exercise metabolism is of course not the only field where fascinating answers to intriguing questions about the workings of living creatures are to be found in metabolic pathways and their control mechanisms. They do not only relate to the human body but also - to name but a few - to the diving mammals, the migrating birds travelling long distances and the fast-moving butterflies. All this and much more can be used to kindle the interest and fire the imagination of students of basic biochemistry, whatever their other interests may be. References H.R. Mahler, E.H. Cordes, Biological Chemistry. Harper, New York, 1966. PI A.L. Lehninger, Biochemistry. Worth, New York, 1970. A.R. Leech, Biochemistry for the Medical 131 E.A. Newsholme, Sciences, Chap. X. John Wiley, Chichester, 1983. [41 J.R. Poortmans (ed.), Principles of Exercise Biochemistry, 2nd edn. Karger, Basel, 1993. 151 E.A. Newsholme, T. Leech, G. Duester, Keep on Running: The Science of Training and Performance. John Wiley, Chichester, 1994.

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