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Annual Congress, BASM 1999

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Elevation of brain natriuretic peptide levels in athletic left ventricular hypertrophy


Department of Medicine and Therapeutics, University of Glasgow

Background—Athletic left ventricular hypertrophy (LVH) occurs in response to long term high intensity exercise, and is characterised by increased left ventricular mass. Brain natriuretic peptide (BNP) is a peptide hormone mainly produced in ventricular myocardium. It is increased in hypertensive LVH, which is associated with adverse prognosis.

Aim—To determine BNP levels in athletes with LVH compared with those without LVH and sedentary controls.

Methods—A total of 108 professional footballers and 24 healthy sedentary controls were studied. LVH was defined as left ventricular mass index >134 g/m2 on echocardiography. BNP was measured using standard techniques. Statistical analysis was performed by analysis of variance.

Results—Twenty eight footballers and no controls had LVH. BNP was higher in the footballers as a whole compared with controls (11.1 v 6.9 pg/ml; p<0.01). It was also higher in the footballers with LVH than in those without (18.9 v 8.3 pg/ml; p<0.0001; 95% confidence interval 6.9 to 14.2) and controls (18.9 v 6.9 pg/ml; p<0.0001; 95% confidence interval 7.3 to 16.7). There was no significant difference in BNP concentration between the footballers without LVH and the controls.

Conclusions—Athletic LVH is associated with elevated BNP levels, possibly resulting from increased left ventricular wall stress. This emphasises the similarity between athletic LVH and other forms of LVH.

Sumatriptan reduces exercise capacity in healthy men: evidence for a peripheral effect of serotonin metabolism?

G P MCCANN, H CAHILL, S KNIPE, D F MUIR, P D MACINTYRE, W S HILLISCentre for Exercise Science and Medicine, University of Glasgow

Aim—Serotonin (5-hydroxytryptamine; 5-HT) has been implicated in the genesis of central fatigue. Sumatriptan is a selective 5-HT1B/D receptor agonist which does not cross the blood-brain barrier. The aim of this study was to determine the effect of sumatriptan on exercise capacity.

Methods—Ten healthy men (mean (SD) age 28.4 (10.8) years) performed a maximal treadmill exercise test according to the Bruce protocol, with expired gas analysis on two occasions. Either 6 mg sumatriptan or placebo was administered subcutaneously in a randomised double blind placebo controlled cross over design.

Results—Exercise time was greater after placebo administration than after sumatriptan administration (15.23 v 14.65 minutes, 95% confidence interval 12.1 to 59.1 seconds; p = 0.008). There was no significant effect on Vo2max (50.6 (6.3) v 51.7 (7.6) ml/kg/min). Mean heart rate and respiratory exchange ratio at peak exercise were reduced after sumatriptan administration: 196 (12.2) v 188 (13.7) beats/min (p = 0.007) and 1.26 (0.07) to 1.23 (0.06) (p = 0.01) respectively. There were no significant differences in blood pressure, heart rate, or submaximal Vo2 after administration of sumatriptan and placebo at any stage of exercise.

Conclusions—Sumatriptan reduces maximal exercise capacity in normal men. The failure to show any haemodynamic or cardiorespiratory effect suggests that sumatriptan enhances perception of fatigue by a peripheral mechanism affecting serotonin modulation.

Effects of creatine supplementation on male and female athletes during high intensity intermittent exercise

P C WILSON, A MAILE, S COLEMANMoray House Faculty of Education, University of Edinburgh, Cramond Road North, Edinburgh

Aim—To examine the effect of oral creatine supplementation on male and female athletes during high intensity intermittent exercise. Previous research has illustrated that uptake of creatine during supplementation may be higher in male athletes than in female athletes,1 and that female skeletal muscle can contain higher initial concentrations of creatine than that of men.2

Methods—Twelve physically active students in various states of training (six men and six women), with a mean (SD) age and body mass of 23.17 (2.37) years and 67.17 (14.04) kg respectively, participated in an exercise protocol consisting of 10 periods of maximal voluntary cycle ergometry exercise, each lasting for six seconds. A 30 second recovery period was allowed between each sprint. Each subject performed two exercise test sessions, after both a placebo and a creatine supplement period. The supplements were administered single blind, and were consumed for three days before each test session (20 g a day).

Results—Mean maximum power output was increased from 795.58 (128.48) W to 889.68 (108.11) W (p<0.01) after the creatine supplement period in the men. This increase (10.6%) was greater (p<0.01) than that seen in the women (2.2%). No significant differences were found in the fatigue rate after supplementation in either men or women.

Conclusions—Creatine monohydrate can increase power output during high intensity intermittent exercise. Creatine supplementation is more effective in improving performance in men than in women.

1 Rossiter HB, Cannell ER, Jakeman PM. The effect of oral creatine supplementation on the 1000 m performance of competitive rowers. J Sports Sci 1996;14:175–9.

2 Forsberg AM, Nilsson E, Werneman J, et al. Muscle composition in relation to age and sex. Clin Sci 1991;81:249–56.

Exercise consultation: an intervention to improve adherence to phase IV exercise based cardiac rehabilitation?

F C GILLIES, A R HUGHES, A F KIRK, N MUTRIE, G P MCCANN, W S HILLIS, P D MACINTYREDivision of Sports Medicine, University of Glasgow

Aim—Evidence suggests that long term adherence to exercise based cardiac rehabilitation is poor, with up to 50% of patients dropping out at one year. This randomised controlled study was designed to evaluate the effectiveness of an exercise consultation in increasing and/or maintaining physical activity levels of cardiac patients over 30 days after successful completion of phase III hospital based cardiac exercise rehabilitation, and thus facilitating progression to phase IV community based cardiac exercise rehabilitation.

Methods—After completion of phase III exercise based cardiac rehabilitation at the Royal Alexandra Hospital, Paisley, 16 cardiac patients were randomised to either an experimental or control group. The experimental group received an exercise consultation, and standard exercise information was issued to both groups. The exercise consultation is a one to one counselling approach, which incorporates cognitive behavioural techniques to assist patients during adoption and maintenance of exercise behaviour by providing them with an individualised exercise prescription. Physical activity levels at baseline and 30 days later were measured using a self report seven day recall questionnaire.

Results—Results are expressed as medians and confidence intervals. Patients in the experimental and control groups were well matched for age and gender. Baseline physical activity levels were similar between the experimental and control groups (210 v 362 min/week; 94.1% confidence interval −325 to 135; p>0.05). At 30 days, physical activity levels increased from baseline in the experimental group (124 min/week; 94.1% confidence interval 8 to 360; p = 0.05), and remained unchanged in the control group (−40 min/week; 94.1% confidence interval −140 to 83; p>0.05). The change in physical activity from baseline was significantly different between the experimental and control groups (124 v −40 min/week; 95.9% confidence interval 25 to 390; p = 0.018). Table 1 shows physical activity levels at baseline and 30 days later.

Table 1

Physical activity (min/week) at baseline and 30 days later

Conclusions—The results indicate that the exercise consultation increased short term physical activity levels of cardiac patients after completion of phase III hospital based cardiac exercise rehabilitation. Physical activity levels of the control patients were maintained at 30 days, therefore short term adherence to phase IV cardiac exercise rehabilitation is satisfactory. The key issue is to study the effectiveness of the exercise consultation on long term adherence to phase IV community based cardiac exercise rehabilitation.

The combination of stretch and submaximal exercise on torque production in the hamstring muscle group

L MITCHELL, D BALLDepartment of Exercise and Sport Science, The Manchester Metropolitan University, Alsager, Cheshire ST7 2HL

Aim—To investigate the effects of individual and combined elements of warm up on torque production in the hamstring muscle group.

Methods—Warm up interventions of static stretches and/or submaximal treadmill running were applied in eight healthy subjects using a repeated measures design. Isokinetic torque production was measured at angular velocities of 3.141 rad/s (180°/s) and 4.188 rad/s (240°/s). In addition, assessment of the resistance to stretch was made using a passive torque (constant angle) protocol.

Results—Concentric torque production at 3.141 rad/s was found to improve after submaximal running with and without the application of static stretches (p = 0.003). At 4.188 rad/s, torque production was not affected by warm up intervention (p = 0.056). After a 20 minute rest period, concentric torque performance at 240°/s was reduced, except after the combined application of stretch and submaximal running (p = 0.008). There was no effect of 20 minutes rest on performance at 3.141 rad/s (p>0.05). Warm up intervention had no significant effect on eccentric torque production, nor on passive torque production (p>0.05).

Conclusion—The combination of stretch and submaximal exercise significantly improves isokinetic concentric peak torque production in the hamstring muscle group. This performance enhancement may be retained after a 20 minute rest period.

Factors influencing uptake and adherence to phase IV community based cardiac exercise rehabilitation (Living Plus)

H WESLEY, A R HUGHES, A F KIRK, S CATTO, G P MCCANN, W S HILLIS, P D MACINTYREDivision of Sports Medicine, University of Glasgow

Aim—To evaluate uptake and adherence to phase IV community based cardiac rehabilitation exercise programmes (Living Plus) after completion of phase III hospital based cardiac exercise rehabilitation, and to assess barriers to participation and factors determining adherence and drop out from phase IV programmes.

Methods—Questionnaires were sent to 65 cardiac patients who were referred to phase IV community based exercise programmes (10 weeks) over a two year period after successful completion of phase III exercise based cardiac rehabilitation at the Royal Alexandra Hospital, Paisley. Drop outs and adherers were defined as patients completing less than seven weeks and those completing seven weeks or more of the 10 week phase IV programmes respectively. Patients' postcodes were used to calculate Carstairs deprivation scores.

Results—Fifty (77%) of the 65 patients referred to phase IV programmes responded to the questionnaire. Twelve (24%) patients did not participate in the phase IV programmes. Barriers to participation included lack of communication (58%) between patients and phase IV programme staff, family commitments (25%), lack of transportation (17%), and other medical reasons (17%). Of the 38 (76%) patients who attended phase IV, 10 (20%) dropped out and 28 (56%) adhered to the programme. Factors influencing drop out from the programme included unsuitable intensity of exercise (40%) and medical reasons (20%). Carstairs deprivation scores were similar between non-participants and participants (p = 0.30), and drop outs compared with adherers (p = 0.22).

Conclusions—The results indicate good uptake and adherence rates of patients referred to phase IV community based exercise programmes after completion of phase III hospital based exercise rehabilitation. However, improving communication between patients and phase IV programme staff may enhance uptake and adherence, and also by tailoring exercise prescription to the individual. Social deprivation was not associated with uptake or adherence to phase IV programmes.

Effects of open versus closed kinetic chain training on knee laxity in the early period after anterior cruciate ligament reconstruction

M C MORRISSEY, Z L HUDSON, W I DRECHSLER, F J COUTTS, P R KNIGHT, J B KINGDepartment of Health Sciences, University of East London

Aim—To compare the effects of open (OKC) and closed kinetic chain (CKC) training of the knee extensors on knee laxity in the early period after anterior cruciate ligament reconstruction surgery.

Methods—Thirty six patients recovering from surgery (29 men and seven women; mean age 30) were tested for knee laxity (anterior tibial displacement with a 178 N force on the tibia) using a knee ligament arthrometer by a physiotherapist blinded to treatment assignment. Testing occurred at two and six weeks after surgery, with training of the knee extensors occurring in the intervening period using either unilateral OKC or CKC exercise which was randomly assigned to subjects. Subjects trained their knee extensors three times a week using three sets of 20 repetition maximum contractions on either a leg extension (OKC) or a leg press (CKC) machine.

Results—There were no significant (p<0.05) differences between the groups for uninjured knee laxity before training and after training. The mean (SD) injured knee anterior tibial displacement at the test before training for the OKC and CKC groups was 9.8 (2.5) mm and 10.4 (3.4) mm respectively, and for the test after training they were 10.6 (3.6) mm and 10.4 (2.8) mm respectively.

Conclusion—The results indicate that the great concern of physiotherapists and orthopaedic surgeons about the safety of OKC knee extensor training in the early period after anterior cruciate ligament reconstruction surgery may not be well founded and requires further analysis.

Angiotensin converting enzyme gene polymorphism does not predict the presence of athletic left ventricular hypertrophy

S W MURRAY, D F MUIR, M DEWAR, G P MCCANN, W S HILLISDepartment of Medicine and Therapeutics, University of Glasgow

Background—Long term high intensity athletic training causes cardiac enlargement and a subsequent increase in left ventricular mass index. Myocardial growth may be regulated by renin-angiotensin systems, which are influenced by polymorphism of the angiotensin converting enzyme (ACE) genotype.

Aim—To assess the influence of ACE genotype polymorphism on the presence of athletic left ventricular hypertrophy.

Methods—A total of 110 full time elite professional footballers (mean (SD) age 20 (4.9) years) were evaluated by full echo echocardiography and analysed by the same operator according to ASE guidelines. ACE genotype was assessed by a two primer system, cross checked with a three primer system and classified according to insertion (I) or deletion (D) allelles.

Results—Twenty five subjects were homozygous for the insertion genotype (II), 31 were homozygous for the deletion genotype (DD), and 54 were heterozygous (ID). There were no differences in left ventricular mass index between any of the three groups (119 (24) g/m2 for II, 115 (27) g/m2 for DD, and 115 (22) g/m2 for ID; means (SEM)).

Conclusions—The presence of athletic left ventricular hypertrophy is not influenced by ACE genotype polymorphism.

Wedged tibial bone plug for anterior cruciate ligament fixation: a biomechanical study of a more economical and biologically sound alternative

G MACKAY*, M TAYLOR*, J COSTI†, T HEARN†, G KEENE**Sportsmed SA, 32 Payneham Road, Stepney 5069, South Australia and †The Repatriation Hospital and Flinders University of South Australia

Background—Elaborate and often expensive options to secure BPB grafts in the tibia have been explored. Complications associated with the use of metallic and biodegradable interference screws have been widely reported.

Aim—To compare reliable biomechanical data for impacted tibial bone plug fixation with data for the conventional cannulated titanium screw (9 × 20 mm) in a standardised model.

Methods—Thirty knees (fifteen matched pairs) from an eight week old calf model were reconstructed and tested biomechanically in a physiological environment to assess ultimate failure loads and mode of failure. Five normal calf knees were failed to provide a reference range, and bone density studies confirmed the suitability of this model. Bone blocks were contoured into tapered three dimensional wedges from the patella with a 10 mm apex in continuity with the middle third of the patellar tendon. The base of the wedge measured either 11 or 13 mm.

Results—Paired t tests found no statistically significant difference in failure loads for 11 mm (p = 0.32) or 13 mm (p = 0.055) wedges compared with interference screw fixation. The wedge was on average 65 N stronger. There was no significant difference in strength between wedge sizes. Analysis of the mode of failure suggests that wedge fixation strength may have been underestimated.

Conclusions—Tibial plug fixation using a tapered wedge offers an alternative to screw fixation with comparable strength. An 11 mm wedge is recommended to minimise donor site morbidity. Clinical trials are recommended.

Poster abstracts

The DXA morphotype: a new approach to body compositionBr J Sports Med 2000;34:149–153

A D STEWART*, W J HANNAN†*Fitness Assessment and Sports Injury Centre, University of Edinburgh and †Department of Medical Physics, University of Edinburgh

Background—Traditional physique determinants1 fail to discriminate the bone mineral content of athletes, which can differ in groups whose physiques are outwardly identical (fig 1).

Aim—To provide a theoretical structure for body composition using dual x ray absorptiometry (DXA) which provides fat, lean and bone content.

Methods—Distance runners (n = 12) and cyclists (n = 16) underwent 42 anthropometric measurements and a DXA scan (Hologic QDR 1000W; Hologic Inc, Waltham, Massachusetts, USA) as part of a cohort of 106 male athletes and 15 controls. Z scores (standard deviations from the mean value) were derived from DXA data to designate coordinates on soft tissue and bone axes of a “DXA morphotype” (fig 1B).

Results—No differences between the groups were found in age, training hours, and anthropometric estimates of % fat, % muscle, endomorphy, mesomorphy, or ectomorphy (p>0.05). DXA morphotype showed cyclists and runners to be similar with respect to soft tissue (p>0.05) but different with respect to bone (p<0.001). Cyclists were found to have similar DXA morphotype coordinates to strength athletes, with a similarly low proportion of bone.

Conclusion—The DXA morphotype is able to distinguish athletic groups by departure from adequate reference data and is an appropriate adjunct to traditional physique descriptors.

1 Heath BH, Carter JEL. A modified somatotype method. Am J Phys Anthropol 1967;27:57–74.

Athletic left ventricular hypertrophy does not confer a performance advantage

D F MUIR, G P MCCANN, K MCMILLAN, S GRANT, J WILSON, W S HILLISCentre for Exercise Science and Medicine, University of Glasgow

Aims—To determine the effect of athletic left ventricular hypertrophy on aerobic fitness.

Methods—Sixty nine professional footballers were studied. Subjects underwent echocardiographic examinations, followed by incremental treadmill exercise tests measuring either Vo2max (n = 25) or lactate threshold (n = 44). Univariate and multivariate regression analyses were performed to determine whether echocardiographic or demographic variables were related to exercise capacity.

Results—There were significant negative relations between age (range 16–34 years) and Vo2max (range 49.3–64.8 ml/kg/min) (R2 = 0.37, p<0.01) and body surface area and Vo2max (R2 = 0.224, p<0.05), and a weakly positive relation between E/A ratio and Vo2max of borderline statistical significance (R2 = 0.14, p = 0.07). After multivariate analysis, only age showed a significant negative correlation with Vo2max (p<0.05). There were significant negative relations between lactate threshold and the following: body surface area (R2 = 0.30, p<0.001), IVSd (range 7.7–14.2 mm) (R2 = 0.10, p<0.05), and LVEDD (range 41.6–60 mm) (R2 = 0.13, p<0.05). Left ventricular mass index (range 63–175 g/m2) correlated negatively with lactate threshold, with borderline statistical significance (R2 = 0.08, p = 0.07). On multivariate analysis body surface area, IVSd, and LVEDD showed independent negative correlations with lactate threshold (p = 0.01, p<0.01, and p<0.05 respectively).

Conclusion—Athletic cardiac enlargement does not confer a performance advantage as measured by Vo2max or lactate threshold.

Effect of hypertensive left ventricular hypertrophy on aerobic exercise capacity

N CATON, D COTTER, D F MUIR, G P MCCANN, W S HILLISCentre for Exercise Science and Medicine, University of Glasgow

Aim—To investigate the relation between left ventricular mass index (LVMI) and aerobic exercise capacity in essential hypertension.

Methods—Thirty two hypertensive patients (18 women, 14 men; mean (SD) age 55.4 (10.2) years) and 11 normotensive controls (eight men, three women; age 47.8 years) underwent echocardiography and an incremental treadmill exercise test with expired gas analysis to determine Vo2max. Echocardiograms were analysed by a blinded observer, and the presence of left ventricular hypertrophy (LVH) determined by the Penn convention according to sex specific cut off values for LVMI of 134 g/m2 for men and 110 g/m2 for women.

Results—The three groups (hypertensive patients with LVH, those without LVH (no LVH), and normotensive controls) were well matched for height and weight. The LVH group were older (61.2 (8.6) v 49.6 (11.4) no LVH v 47.8 (9.0) controls; p = 0.003), with higher body mass index (BMI) (31.3 (7.8) v 28.7 (4.7) no LVH v 25.0 (3.0) controls; p<0.001) and LVMI (140.8 (22.2) v 101.2 (18.1) no LVH v 92.6 (16.2) controls; p<0.001). The controls achieved higher Vo2max than both hypertensive groups (32.2 (9.5) v 25.2 (4.7) no LVH v 21.9 (5.5) LVH; p<0.001). Age and BMI were independent predictors of Vo2max in hypertensive patients on multivariate analysis.

Conclusions—Hypertensive patients with LVH had reduced aerobic exercise capacity compared with those without LVH. This difference was largely accounted for by the greater age and BMI of the LVH group.

A comparison of the multistage fitness test with ergometer derived peak Vo2 in paraplegic athletes

T K CUNNINGHAM*, G P MCCANN*, M A NIMMO†, W S HILLIS*Centre for Exercise Science and Medicine, University of Glasgow and †Scottish School of Sport Studies, University of Strathclyde

Aim—To investigate whether the standard multistage fitness test (MSFT) can accurately predict peak oxygen consumption (peak Vo2) in wheelchair athletes.

Methods—Seven athletes aged between 23 and 46 (six men and one woman) undertook a progressive wheelchair ergometry test with simultaneous direct measurement of peak Vo2. Before testing, each subject undertook familiarisation on the wheelchair ergometer. In addition, the subjects performed the standard MSFT on a hard synthetic surface, using their own wheelchairs. Both tests were conducted within 10 days of each other so that no training effect was observed, and the order of testing was randomised.

Results—The mean (SEM) peak power output and peak Vo2 on the ergometer test were 89.3 (15.5) W and 33.1 (4.0) ml/kg/min respectively for the male athletes and 48 W and 25.7 ml/kg/min for the female athlete. The mean predicted peak Vo2 for the male athletes was 25.1 ml/kg/min and for the female athlete 15.7 ml/kg/min. A non-parametric Wilcoxon signed rank test gave a p<0.05 indicating a significant difference between the two tests.

Conclusion—The findings suggest that on this sample the use of the MSFT is not justified as an estimate of peak Vo2.

Athletes' knowledge of banned substances in “over the counter” preparations

S MCGIBBON, J WHITE, K BENNETTCentre for Sports Medicine, Department of Orthopaedic and Accident Surgery, University of Nottingham, Queens Medical Centre

Aim—To examine the current level of knowledge of elite athletes with regard to “over the counter” preparations that could potentially cause an athlete to fail a drugs test through inadvertent ingestion of a prohibited substance.

Method—The elite athlete's knowledge of banned substances in over the counter preparations was tested using a self completed questionnaire. Athletes competing in Olympic sports were accessed by governing body medical officers.

Results—Nearly one third (31%) of the athletes tested (n = 113) would be prepared to take at least one preparation containing prohibited substances. Athletes competing in individual sports are significantly better at identifying preparations than those competing in team sports (p = 0.004). Athletes in sports with a younger average age have a significantly lower level of knowledge than those in sports with an older average age (p = 0.002).

Conclusions—Despite the implementation of comprehensive drugs education programmes, there remains a lack of knowledge about the potential to ingest inadvertently a prohibited substance in an over the counter preparation. As more than half of the failed drugs tests involving the use of stimulants are through inadvertent ingestion of banned substances1 in over the counter preparations, this is a cause for concern and needs to be addressed.

1 Sports Council. Ethics and anti-doping directorate. Annual report 1996/97.

Creatine supplementation: an experimental study of its effect on causal attributions made for exercise performance

j mckay, n mutrie, p anderson, y moulds, y pitsiladisCentre for Exercise Science and Medicine, University of Glasgow

Background—The effect of creatine supplementation on exercise performance has been extensively studied.1 However, psychological issues relating to creatine supplementation have not been investigated.

Aim—To consider the effect of creatine supplementation on causal attributions made for exercise performance.

Method—Eighteen physically active women were randomly assigned on a double blind basis to either a creatine supplementation or a placebo group. Before supplementation, baseline measurements were established for causal attributions, as measured by the causal dimension scale II (CDSII),2 after high intensity cycle ergometry work. These were compared with measurements after supplementation.

Results—Significant differences were found between the two groups for the locus of causality (95% confidence interval 0.96 to 4.59) and personal control (95% confidence interval 0.00 to 2.89) dimensions of the CDSII, indicating that attributions of those in the creatinine supplementation group had become significantly more external and less controllable.

Conclusion—Creatine supplementation may be associated with undesirable changes in causal attributions. Potentially these may alter athletes' perceptions of their abilities to control athletic performances and to perform optimally without the use of creatine.

1 Greenhaf PL. Creatine and its application as an ergogenic aid. Int J Sports Nutr 1995;18(suppl):S100–10.

2 McAuley E, Duncan TE, Russel DW. Measuring causal attributions: the revised causal dimension scale (CDSII). Personality and Social Psychology Bulletin 1992;18:566–73.

Exercise during pregnancy: are we giving good advice? A questionnaire survey of health professionals

M D STILLWELL, M E BATTCentre for Sports Medicine, Queens Medical Centre, Nottingham

Aim—To assess the views of health professionals on the advice they give and their need for more evidence based information on exercise during pregnancy.

Method—A cross sectional postal questionnaire survey of all North Derbyshire general practitioners and midwives, and all of the Mid-Trent Region hospital obstetricians and gynaecologists.

Results—This topic is discussed less than smoking, diet, or alcohol during pregnancy. Patients ask for advice about this subject infrequently. Although health professionals feel confident about the generic exercise advice they provide, they are much less confident about advising women who exercise regularly. Some 18% of health professionals incorrectly believe that regular exercise during pregnancy could cause spontaneous abortion and 8% incorrectly believe that it would not help women to maintain their fitness. Nearly all (97%) thought that an evidence based consensus statement on this subject would be useful, and 64% were interested in further training about the subject.

Conclusions—There have been few recent publications about exercising during pregnancy, and information for health professionals is difficult to obtain. The benefits of regular exercise during pregnancy have been proven and offer the opportunity to give positive recommendations. It is recommended that information and education on this subject should be made more widely available to health professionals.

The management of rugby injuries

Y KATHIRAVEL, L THOMSON, M GARRAWAY*, D A D MACLEOD††Department of Surgery, St John's Hospital, Livingston, West Lothian and *Department of Public Health Sciences, Medical School, Edinburgh

Background—Rugby is a collision sport with the highest risk per player hour of injury.1

Aim—To determine the level of treatment received by injured players and the relation between severity of injury and level of treatment received.

Method—This study is based on a prospective cohort study involving 1169 (96%) of 1200 rugby players, from 26 senior clubs conducted in the Scottish Borders during the 1993–1994 season. The nature of injury, level of treatment received, and duration of absence from play was recorded by a club link person using standard closed questionnaires validated by chartered physiotherapists.

Results—A total of 361 players experienced 512 injury episodes, 429 in matches and 83 in training. Some 19.3% of injury episodes received no treatment, and 27.1% were treated on the field of play. General practitioners treated 12.5% of injury episodes, and 41.1% were treated at hospital, 21.3% in the accident and emergency department.

Conclusion—Garraway and Macleod2 showed that, in 28% of injury episodes, players were absent from education and employment for an average of 18 days. Comprehensive documentation of rugby injuries and the level of treatment received by players is essential in planning the best management to minimise cost to the NHS, loss of playing days, and absence from work.

1 Bedford PJ, Macauley DC. Attendances at a casualty department for sports related injuries. Br J Sports Med 1984;18:116–21.

2 Garraway M, Macleod D. Epidemiology of rugby football injuries. Lancet 1995;345:1485–7.

The effectiveness of laboratory trials in simulating true 10 km running performance

S C THEAKSTON, R C R DAVISON, S R BIRDDepartment of Sport and Exercise Science, Canterbury Christ Church University College

Aim—To determine whether 10 km laboratory time trials are a valid simulation of 10 km races.

Method—Seven good club standard runners (age 34–62 years; mean (SD) Vo2max 55.5 (6.7) ml/kg/min; mean (SD) height 1.77 (0.08) m; mean (SD) body mass 70.8 (10.8) kg) performed a discontinuous incremental velocity treadmill test to volitional exhaustion, from which Vo2max and lactate threshold were determined. On separate occasions they then completed two 10 km performance trials at a 1% gradient (as recommended by Jones and Doust1). In the first trial, (T1) only heart rate was recorded, while during the second trial (T2), heart rate, oxygen uptake, and lactate accumulation were recorded (at five and 30 second, and 3, 6, 9, and 10 km intervals). These data were then compared with the subjects' best 10 km road race times from the previous three months.

Results—Table 1 gives the results. The %Vo2max and %lactate threshold data for T2 (82.1 (7.65) and 100.5 (6.83) respectively; mean (SD)) indicate that the subjects were exercising at a high intensity. However, despite this, they were running at about 90% of their best recent competitive race pace in both, and slower than the normal variation in road race times, with the gas and lactate collection in T2 further exacerbating this (p<0.05).

Table 1

Results of laboratory trials simulating a 10 km road race

Conclusion—It is surmised that this type of protocol may underestimate the true performance of the athlete, and therefore questions the validity of laboratory trials when assessing performance.

1 Jones AM, Doust JH. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. J Sports Sci 1996;14:321–7.

Effects of neuromuscular stimulation and “Ab worker” and supervised exercise on static strength and dynamic endurance of the abdominal musculature

N MAHONY, B DONNE, E BALLANTYNE, G ROBINSONTrinity College, Dublin 2, Ireland

Aim—To compare the effects of training supervised by a physiotherapist (SE), unsupervised training with an “Ab worker” (AB), and neuromuscular stimulation (NMES) on static strength and dynamic endurance of the abdominal musculature.

Method—Forty healthy men were randomised to the following groups: controls (n = 14) no training; SE (n = 8) and AB (n = 8), both three times a week (four exercises/three sets/10 repetitions); or NMES (n = 10), 30 minutes a day (15 seconds on/off, pulse width 250 microseconds; frequency 50 Hz) using a neuromuscular stimulator. Static isometric strength was measured in N using a load cell and strain gauge (mean of five trials with 60 seconds rest, 0° hip angle). The abdominal curl conditioning test assessed dynamic endurance as time to volitional exhaustion in seconds. Data were collected on day 0 and 42 days after randomisation. Before-after within group changes were analysed using two tailed paired t tests. Improvements across groups were compared with controls using analysis of variance.

Results—There were significant within group improvements (p<0.05) for all interventions except for static isometric strength in the control and AB groups (p>0.05). Across group comparisons with controls showed significant improvement in static isometric strength for the SE and NMES groups (p<0.001) but not for the AB group (p>0.05). For dynamic endurance, significant increases were noted for all interventions.

Conclusion—Neuromuscular stimulation and supervised training were of equal benefit in terms of static isometric strength and dynamic endurance. Unsupervised training with an “Ab worker” improved dynamic endurance but not static isometric strength.

Effect of the Q angle on the onset timing of electromyographic activity in the vastus medialis oblique and vastus lateralis muscles

A C RENNIE*, K ARBUTHNOTT†*Department of Physiotherapy, Podiatry and Radiography and †City Campus, Glasgow Caledonian University

Aim—To investigate the relation between the Q angle and the timing of initial electromyographic (EMG) activity in the vastus medialus oblique (VMO) and vastus lateralis (VL).

Method—Twenty randomly selected subjects with no history of patellofemoral joint pathology participated. The resting Q angle was measured, and then EMG data were recorded from the VMO and VL under concentric, eccentric, and isometric conditions. Contraction onset times were determined, and the onset timing difference between the VMO and VL calculated.

Results—Statistical analysis (Pearson product-moment correlation coefficient) identified a significant (p<0.005) negative correlation between Q angle and the VMO and VL onset timing difference—that is, as the Q angle increases the onset timing difference decreases. In addition, a one way analysis of variance showed a significant (p<0.05) difference in the onset timing difference between subjects with high Q angles and those with low Q angles for each gender with regard to the concentric and isometric contractions. There was no such alteration with respect to the eccentric contraction.

Conclusion—The findings indicate that there was a reversal in the activation pattern of the VMO and VL in subjects with high Q angles, suggesting that a neuromuscular imbalance between these muscles may be associated with a high Q angle. In addition, the non-significant findings for the eccentric contraction may have major implications for the rehabilitation of such patients.

Clinical audit of acute sporting knee injuries presenting to Glasgow accident and emergency departments

E MCKILLOP*, N BREMNER*, F DALLAS*, K HERD*, J A MACLEAN*, R KNILL-JONES†, G P MCCANN*, P D MACINTYRE*, W S HILLIS**Division of Cardiovascular and Exercise Medicine, Department of Medicine and Therapeutics and †Public Health, University of Glasgow

Aim—To provide descriptive data on patients attending Glasgow accident and emergency departments with acute knee injuries, and on their management.

Method—The records of all patients attending the five Glasgow accident and emergency departments with acute sporting knee injuries over an eight week period were reviewed retrospectively.

Results—A total of 233 patients attended; 81.1% were men (mean age 22 years). Some 44% of injuries and 39% of attendances occurred at the weekend. Football (54%) was the most common sporting cause. Just over half (51%) were radiographed. The most common diagnoses were soft tissue injury (42%), ligamentous injury (26%), meniscal injury (10%), and fracture (2%). Patients were seen by senior house officers in 72% of cases. There were no significant differences between hospitals except for their in hospital clinic follow up rates. Only 3% of patients were referred to physiotherapy. Case notes often failed to document important clinical signs including meniscal stability (84%), ligamentous stability (20%), weight bearing ability (28%), and mechanism of injury (20%).

Conclusion—As senior house officers deal with most of the acute sporting knee injuries, the implementation of x ray decision rules and an algorithm is suggested to improve management by inexperienced staff. More use of hospital clinic initial follow up and physiotherapy referral would be appropriate. Further studies could address the problem of immediate follow up.

The use of a cycle ergometer compared with a treadmill for determining symptom limited exercise tolerance in patients with chronic obstructive pulmonary disease and healthy subjects

O GEORGIADOU*, K PATEL†, J A MACLEAN*, G MCCANN*, W S HILLIS**Division of Cardiovascular and Exercise Medicine, University Department of Medicine and Therapeutics and †Department of Respiratory Medicine, University of Glasgow

Aim—To examine the difference in maximal physiological and ventilatory responses between two modes of exercise (treadmill and cycle ergometer) in healthy subjects and subjects with chronic obstructive pulmonary disease.

Method—Seven subjects with mild to moderate chronic obstructive pulmonary disease and four subjects with no previous respiratory problems underwent random maximal exercise testing on treadmill and cycle. Ventilation (Ve) and gas exchange (Vo2, Vco2, respiratory exchange ratio) were measured by breath by breath analyser. Heart rate was measured throughout, and spirometry (forced expiratory volume in one second (FEV1) and forced vital capacity) before and after the exercise test. Peak exercise duration and perceived rate of exertion were assessed (Borg scale).

Results—In the control group, there was no statistical significance in any of the variables measured. In the patient group, maximum heart rate, peak respiratory exchange ratio, rate of perceived exertion at peak exercise, and peak exercise duration were not significantly different between treadmill and cycle ergometer. Symptom limited maximal minute ventilation (Ve), oxygen consumption (Vo2), and carbon dioxide production (Vco2) were significantly higher on the treadmill than on the cycle ergometer. %FEV1 was significantly reduced only after cycle ergometry in the patient group. A positive correlation was found between Ve/Vo2 and Ve/Vco2.

Conclusion—In this group of patients with mild to moderate chronic obstructive pulmonary disease, higher symptom limited peak Ve, Vo2, and Vco2 were achieved with treadmill testing despite muscle fatigue limitation. These findings support the use of the treadmill rather than the cycle ergometer for determining symptom limited exercise tolerance.

Effect of exercise training on blood flow to the lower limb in patients with non-insulin-dependent diabetes mellitus and intermittent claudication

M L PACEY, J A MACLEAN, W S HILLISDivision of Cardiovascular and Exercise Medicine, Department of Medicine and Therapeutics, University of Glasgow

Aim—To determine whether an exercise training programme improves onset of intermittent claudication (IC), maximal walking times, and foot transcutaneous oxygen tension (TcPo2) in patients with non-insulin-dependent diabetes mellitus (NIDDM) and IC, and whether a relation exists between walking times and TcPo2.

Methods—Ten patients with NIDDM and IC were randomised to eight weeks of unsupervised exercise training (30 minutes a day, five times a week) or a non-exercising control group. Graded treadmill testing was performed to determine onset and maximal walking times, and TcPo2 measurements were obtained at the start and end of the programme. The physical activity level of each patient was assessed with a general physical activity questionnaire, at the start and end of the programme and during the trial.

Results—Of the 10 patients, 80% completed the trial (four intervention and four control). No significant increases in walking times and TcPo2 measurements were documented in the intervention group. However, an overall trend in walking times and TcPo2 measurements was observed, with relative gains of 34.7% and 13.7% in onset and maximal walking times, and TcPo2 measurements improved by 13.7%. No correlation was noted between onset and maximal walking times and TcPo2.

Conclusion—Eight weeks of unsupervised exercise training did not result in significantly improved walking times and TcPo2 measurements in patients with NIDDM and IC. Furthermore no physiological correlate was identified between walking times and TcPo2.

We thank Lindsay Thomson of FASIC, the University of Edinburgh, Centre for Sport and Exercise, for collecting together the abstracts and posters for publication in the journal.

Figure 1

Morphology of runners, cyclists, and strength athletes. (A) Traditional somatotype; (B) DXA morphotype.

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