Showing papers in "British Journal of Sports Medicine in 2003"

Limits to the measurement of habitual physical activity by questionnaires

Abstract: Despite extensive use over 40 years, physical activity questionnaires still show limited reliability and validity. Measurements have value in indicating conditions where an increase in physical activity would be beneficial and in monitoring changes in population activity. However, attempts at detailed interpretation in terms of exercise dosage and the extent of resulting health benefits seem premature. Such usage may become possible through the development of standardised instruments that will record the low intensity activities typical of sedentary societies, and will ascribe consistent biological meaning to terms such as light, moderate, and heavy exercise.

Risk factors for sports injuries--a methodological approach.

Abstract: The methodology for studies designed to investigate potential risk factors for sports injury is reviewed, using the case of hamstring strains as an example. Injuries result from a complex interaction of multiple risk factors and events. Therefore, a multivariate statistical approach should be used. In addition, the sample size of the study needs to be considered carefully. Sample size mainly depends on the expected effect of the risk factor on injury risk, and to detect moderate to strong associations 20-50 injury cases are needed, whereas small to moderate associations would need about 200 injured subjects. Studies published to date on the risk factors for hamstring strains have methodological limitations, and are too small to detect small to moderate associations.

Risk factors for lower extremity injury: a review of the literature

Abstract: Prospective studies on risk factors for lower extremity injury are reviewed. Many intrinsic and extrinsic risk factors have been implicated; however, there is little agreement with respect to the findings. Future prospective studies are needed using sufficient sample sizes of males and females, including collection of exposure data, and using established methods for identifying and classifying injury severity to conclusively determine addtional risk factors for lower extremity injury.

Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period

Abstract: New guidelines for exercise in pregnancy and postpartum have been published by the American College of Obstetricians and Gynecologists In January 2002 the American College of Obstetricians and Gynecologists (ACOG) published new recommendations and guidelines for exercise during pregnancy and the postpartum period.1 Regular exercise is promoted for its overall health benefits. Pregnancy is recognised as a unique time for behaviour modification and is no longer considered a condition for confinement. It is currently recognised that habits adopted during pregnancy could affect a woman's health for the rest of her life. For the first time the recommendation suggests a possible role for exercise in the prevention and management of gestational diabetes. The recommendations also promote exercise for sedentary women and those with medical or obstetric complications, but only after medical evaluation and clearance. Box 1 lists the absolute contraindications to aerobic exercise during pregnancy, and box 2 the relative contraindications. As with any form of exercise prescription, these recommendations also include the warning signs to terminate exercise while pregnant (box 3). The recommendations also offer guidelines for sports and recreational activities. It cautions against participation in contact sports and recommends avoidance of scuba diving. As for postpartum resumption of activities, the recommendations note that rapid resumption has no adverse effects, but gradual return to former activities is advised. This review includes background and comments to the above recommendations. The health benefits of physical activity are well recognised, and conversely sedentary habits and low levels of cardiorespiratory fitness are leading risk factors for subsequent development of cardiovascular disease.2,3 The Centers for Disease Control and Prevention and the American College of Sports Medicine (CDC-ACSM) have recommended the accumulation of 30 minutes or more of moderate intensity physical activity on most, and preferably all, days of the week.4 Moderate …

A prospective study of running injuries: the Vancouver Sun Run “In Training” clinics

Abstract: dictor variables: age, body mass index (BMI), previous aerobic activity, running frequency, predomi- nant running surface, arch height, running shoe age, and concurrent cross training. Results: Age played an important part in injury in women: being over 50 years old was a risk factor for overall injury, and being less than 31 years was protective against new injury. Running only one day a week showed a non-significant trend for injury risk in men and was a significant risk factor in women and overall injury. A BMI of > 26 kg/m 2 was reported as protective for men. Running shoe age also significantly contributed to the injury model. Half of the participants who reported an injury had had a previous injury; 42% of these reported that they were not completely rehabilitated on starting the 13 week training programme. An injury rate of 29.5% was recorded across all training clinics surveyed. The knee was the most commonly injured site. Conclusions: Although age, BMI, running frequency (days a week), and running shoe age were asso- ciated with injury, these results do not take into account an adequate measure of exposure time to injury, running experience, or previous injury and should thus be viewed accordingly. In addition, the reason for the discrepancy in injury rate between these 17 clinics requires further study.

How valid is a self reported 12 month sports injury history

Abstract: Objective: To assess the accuracy of a 12 month injury history recall in a population of 70 community level Australian football players. Methods: The retrospective, self reported injury histories of 70 community level Australian football players were compared with prospective injury surveillance records for the same 12 month period. The accuracy of the players' recall of the number of injuries, injured body regions, and injury diagnosis was assessed. Results: Recall accuracy declined as the level of detail requested increased. All players could recall whether or not they were injured during the previous year. Almost 80% were able to accurately recall the number of injuries and body regions injured, but not the diagnoses, whereas only 61% were able to record the exact number, body region, and diagnosis of each injury sustained. Discussion: The findings of this study highlight the difficulty of using retrospectively collected injury data for research purposes. Any injury research relying on self reported injury history data to establish the relation between injury history and injury risk should consider the validity of the self report injury histories.

Are ultrasound and magnetic resonance imaging of value in assessment of Achilles tendon disorders? A two year prospective study

Abstract: Objectives: To (a) compare ultrasound (US; including grey scale and colour and power Doppler) and magnetic resonance imaging (MRI; with high resolution and fat saturation sequences) with a clinical yardstick in the evaluation of chronic Achilles tendinopathy, and (b) examine whether either imaging method predicted 12 and 24 month clinical outcome. Methods: Forty five patients with symptoms in 57 Achilles tendons were diagnosed with tendinopathy by an experienced sports medicine doctor. All patients underwent US examination (12 MHz probe) with colour and power Doppler, and 25 consecutive patients also underwent MRI with high resolution T1 weighted and STIR sequences. Results: US identified abnormal morphology in 37 of the 57 symptomatic tendons (65%) and normal morphology in 19 of 28 asymptomatic tendons (68%). Baseline US findings did not predict 12 month clinical outcome. The addition of colour and power Doppler did not improve the diagnostic performance of US. MRI identified abnormal morphology in 19 of 34 symptomatic tendons (56%) and normal morphology in 15 of 16 asymptomatic tendons (94%). Lesser grades of MR signal abnormality at baseline were associated with better clinical status at 12 month follow up. Conclusions: US and MRI show only moderate correlation with clinical assessment of chronic Achilles tendinopathy. Graded MRI appearance was associated with clinical outcome but US was not.

The Football Association Medical Research Programme: an audit of injuries in professional football: an analysis of ankle sprains

Abstract: Aim: To conduct a detailed analysis of ankle sprains sustained in English professional football over two competitive seasons. Methods: Club medical staff at 91 professional football clubs annotated player injuries. A specific injury audit questionnaire was used together with a weekly form that documented each club's current injury status. Results: Completed injury records for the two competitive seasons were obtained from 87% and 76% of the participating clubs. Ankle ligament sprains accounted for 11% of the total injuries over the two seasons, with over three quarters (77%) of sprains involving the lateral ligament complex. A total of 12 138 days and 2033 matches were missed because of ankle sprains. More sprains were caused by contact mechanisms than non-contact mechanisms (59% v 39%) except in goalkeepers who sustained more non-contact sprains (21% v 79%, p<0.01). Ankle sprains were most often observed during tackles (54%). More ankle sprains were sustained in matches than in training (66% v 33%), with nearly half (48%) observed during the last third of each half of matches. A total of 44% of sprains occurred during the first three months of the season. A high number of players (32%) who sustained ankle sprains were wearing some form of external support. The recurrence rate for ankle sprains was 9% (see methodology for definition of reinjury). Conclusion: Ankle ligament sprains are common in football usually involving the lateral ligament complex. The high rate of occurrence and recurrence indicates that prevention is of paramount importance.

Analysis of the characteristics of competitive badminton

Abstract: Objective: To describe the characteristics of badminton in order to determine the energy requirements, temporal structure, and movements in the game that indicate performance level. To use the findings to plan training with greater precision. Methods: Eleven badminton players (mean (SD) age 21.8 (3.26) years) with international experience from four different countries (France, Italy, Spain, and Portugal) were studied. Two of the Spanish players were monitored in several matches, giving a total of 14 samples, all during the 1999 Spanish International Tournament. Blood lactate concentration was measured with a reflective photometer. Maximum and average heart rates were recorded with a heart rate monitor. Temporal structure and actions during the matches were determined from video recordings. All variables were measured during and after the game and later analysed using a descriptive study. Results: The results confirmed the high demands of the sport, with a maximum heart rate of 190.5 beats/min and an average of 173.5 beats/min during matches over 28 minutes long and performance intervals of 6.4 seconds and rest time of 12.9 seconds between exchanges. Conclusions: The results suggest that badminton is characterised by repetitive efforts of alactic nature and great intensity which are continuously performed throughout the match. An awareness of these characteristics, together with data on the correlations between certain actions such as unforced errors and winning shots and the final result of the match, will aid in more appropriate planning and monitoring of specific training.

Are activity promotion interventions based on the transtheoretical model effective? A critical review

Abstract: The health benefits of physical activity are well documented yet 70% of adults remain sedentary. It has been suggested that inverventions based on the transtheoretical model of behaviour change (TTM) may be useful in promoting physical activity. Published work on the effectiveness of such inteventions is therefore critically reviewed. Although there is evidence that TTM based activity promotion interventions are effective in promoting activity adoption, initial results on longer term adherence are disappointing.

Comparison of three different sit and reach tests for measurement of hamstring flexibility in female university students

Abstract: Background: The sit and reach test is the most common flexibility test used in health related fitness test batteries. Objective: To examine and compare three different sit and reach tests as a measure of hamstring flexibility in 102 female students. Method: The traditional sit and reach test, the chair sit and reach test, the back saver sit and reach test, and passive straight leg raise were administered in three trials to all 102 students (mean (SD) age 22 (1) years) on the same day. Results: A Pearson correlation coefficient analysis was significant (p<0.01) for the traditional sit and reach test with back saver sit and reach test and flexibility of hamstrings (r = 0.45 and 0.65 for left and right legs, and 0.63 and 0.53 for left and right legs respectively). Also, the back saver sit and reach test for the left (p<0.01) and right (p<0.05) leg was significantly associated with hamstring flexibility (r = 0.37 and 0.25 for the left leg and 0.50 and 0.44 for the right leg respectively). Conclusion: The results indicate that the back saver sit and reach test produces reasonably accurate and stable measures of hamstring flexibility. Moreover, it appears that this test is a safe and acceptable alternative to the traditional and chair sit and reach tests as a measure of hamstring flexibility in young women.

Evaluation of muscle damage after a rugby match with special reference to tackle plays

Abstract: Objective: To investigate blood indices of muscle damage after a competitive rugby match. Methods: Fifteen elite amateur rugby players volunteered to participate (mean (SE) age 26.6 (0.7) years, height 179.8 (1.0) cm, weight 87.4 (2.2) kg, and VO2MAX 58.5 (1.2) ml/kg/min). The study was conducted after two competitive matches during the 1999–2000 season. Plasma concentrations of lactate, potassium (K+), sodium (Na+), and myoglobin, and the activity of creatine kinase were measured before and after the matches. In addition, the number of tackles by and on each subject and the average duration of the work and rest periods were analysed using video recordings of the matches. Results: Myoglobin concentration and creatine kinase activity showed appreciable transient increases after the match. Peak values for myoglobin concentration (980 (166) µg/l) and creatine kinase activity (1081 (159) U/l) were observed 45 minutes and 24 hours after the match respectively. Positive and significant correlations were observed between the number of tackles and both peak myoglobin concentration (r = 0.85, p<0.01; n = 14) and peak creatine kinase activity (r = 0.92, p<0.01; n = 14). Plasma lactate and K+ concentrations also showed appreciable increases after the match, whereas plasma Na+ concentration showed a gradual decrease. The mean duration of the work and rest periods were 21.5 (2.2) and 24.3 (3.1) seconds respectively. Conclusions: The rugby matches resulted in serious structural damage to the muscles, the extent of which was highly dependent on the number of tackles.

Sex differences in whole body skeletal muscle mass measured by magnetic resonance imaging and its distribution in young Japanese adults

Abstract: Objectives: To determine sex differences in the distribution of regional and total skeletal muscle (SM) using contiguous whole body magnetic resonance imaging (MRI) data, and to examine the relations between fat free mass (FFM) and total and regional SM masses. Methods: A total of 20 Japanese college students (10 women and 10 men) volunteered for the study. FFM was measured by two compartment densitometry. Whole body MRI images were prepared using a 1.5 T scanner. Contiguous transverse images with 1.0 cm slice thickness were obtained from the first cervical vertebra to the ankle joints. All MRI scans were segmented into four components (SM, subcutaneous adipose tissue, bone, and residual tissues). In each slice, the SM tissue cross sectional areas (CSAs) were digitised, and the muscle tissue volume per slice was calculated by multiplying muscle CSA by slice thickness. SM volume units (litres) were converted into mass units (kg) by multiplying the volumes by the assumed constant density (1.041 mg/ml) for SM. Results: The SM distribution pattern (shape of curve) from the contiguous whole body slices was essentially similar for the two sexes, with two large peaks and three smaller peaks (arms excluded). However, the largest peak was observed at the upper portion of the thigh for women and at the level of the shoulder for men. Men had larger (p<0.01) total and regional SM mass than women. All regional SM masses correlated highly (r = 0.90‐0.99, p<0.01) with total SM mass. A strong positive correlation was observed between FFM and total and regional SM masses in both sexes (women, r = 0.95; men, r = 0.90; all p<0.01). As FFM increased, there was a corresponding increase in SM/FFM ratio for all subjects (r = 0.86, p<0.01). Conclusions: Sex differences in total SM/FFM ratio and regional SM distributions are associated with the degree of absolute FFM accumulation in men and women.

Energy demands during a judo match and recovery

Abstract: Objective: To assess energy demand during a judo match and the kinetics of recovery by measuring the metabolites of the oxypurine cascade, lipolytic activity, and glycolytic pathway. Methods: Venous blood samples were taken from 16 national judoists (mean (SEM) age 18.4 (1.6) years), before (T1) and three minutes (T2), one hour (T3), and 24 hours (T4) after a match. A seven day diet record was used to evaluate nutrient intake. Results: Nutrient analysis indicated that these athletes followed a low carbohydrate diet. Plasma lactate concentration had increased to 12.3 (1.8) mmol/l at the end of the match. An increase in the levels of extracellular markers of muscle adenine nucleotide catabolism, urea, and creatinine was observed at T2, while uric acid levels remained unchanged. High concentrations of urea persisted for 24 hours during the recovery period. Ammonia, hypoxanthine, xanthine, and creatinine returned to control levels within the 24 hour recovery period. Uric acid concentrations rose from T3 and had not returned to baseline 24 hours after the match. The levels of triglycerides, glycerol, and free fatty acids had increased significantly (p<0.05) after the match (T2) but returned to baseline values within 24 hours. Concentrations of high density lipoprotein cholesterol and total cholesterol were significantly increased after the match. Conclusions: These results show that a judo match induces both protein and lipid metabolism. Carbohydrate availability, training adaptation, and metabolic stress may explain the requirement for these types of metabolism.

Effects of physical activity on exercise tests and respiratory function

Abstract: Background: Exercise is an important component of pulmonary rehabilitation for patients with chronic lung disease. Objective: To explore the role of physical activity in maintaining cardiac and respiratory function in healthy people. Methods: Cardiorespiratory fitness was measured by a maximal treadmill test (MTT), and respiratory function was tested by spirometry. The cross sectional study included data from 24 536 healthy persons who were examined at the Cooper Clinic between 1971 and 1995; the longitudinal study included data from 5707 healthy persons who had an initial visit between 1971 and 1995 and a subsequent visit during the next five years. All participants were aged 25–55 years and completed a cardiorespiratory test and a medical questionnaire. Results: In the cross sectional study, after controlling for covariates, being active and not being a recent smoker were associated with better cardiorespiratory fitness and respiratory function in both men and women. In the follow up study, persons who remained or became active had better MTT than persons who remained or became sedentary. Men who remained active had higher forced expiratory volume in one second (FEV 1 ) and forced vital capacity (FVC) than the other groups. Smoking was related to lower cardiorespiratory fitness and respiratory function. Conclusions: Physical activity and non-smoking or smoking cessation is associated with maintenance of cardiorespiratory fitness. Change in physical activity habits is associated with change in cardiorespiratory fitness, but respiratory function contributed little to this association during a five year follow up.

The inflammatory response: friend or enemy for muscle injury?

Abstract: Limiting certain aspects of inflammation may be a useful new treatment for sport related muscle injury.

Reckoning with risk: learning to live with uncertainty.

Abstract: Gerd Gigerenzer has a passion for improving statistical numeracy which is rarely encountered in the normally dry statistics texts. He has researched and published extensively on how doctors and other professionals interpret risks and convey that information to their patients. He has also shown how clinicians' understanding of …

The effects of massage on delayed onset muscle soreness

Abstract: Objectives: The purpose of this study was to investigate the physiological and psychological effects of massage on delayed onset muscle soreness (DOMS). Methods: Eighteen volunteers were randomly assigned to either a massage or control group. DOMS was induced with six sets of eight maximal eccentric contractions of the right hamstring, which were followed 2 h later by 20 min of massage or sham massage (control). Peak torque and mood were assessed at 2, 6, 24, and 48 h postexercise. Range of motion (ROM) and intensity and unpleasantness of soreness were assessed at 6, 24, and 48 h postexercise. Neutrophil count was assessed at 6 and 24 h postexercise. Results: A two factor ANOVA (treatment v time) with repeated measures on the second factor showed no significant treatment differences for peak torque, ROM, neutrophils, unpleasantness of soreness, and mood (p > 0.05). The intensity of soreness, however, was significantly lower in the massage group relative to the control group at 48 h postexercise (p < 0.05). Conclusions: Massage administered 2 h after exercise induced muscle injury did not improve hamstring function but did reduce the intensity of soreness 48 h after muscle insult.

Effect of strength and proprioception training on eversion to inversion strength ratios in subjects with unilateral functional ankle instability

Abstract: Objectives: To examine the effect of six weeks of strength and proprioception training on eversion to inversion isokinetic strength ratios (E/I ratios) in subjects with unilateral functional ankle instability. Methods: Thirty eight subjects were randomly assigned to one of four treatment groups: strength training (S); proprioception training (P); strength + proprioception training (B); control (C). Isokinetic strength was tested before and after training using a Kin Com 125 automatic positioning isokinetic dynamometer. Subtalar joint eversion and inversion motions were tested both concentrically and eccentrically through a range of motion involving 40°. All peak torque and average torque values were normalised for body mass. E/I ratios were calculated from average torque and peak torque measures by taking the concentric eversion value and combining it with the eccentric inversion value. Data were analysed using a mixed model analysis of variance with repeated measures on the test factor. Average torque and peak torque E/I ratios at 30 and 120°/s were analysed separately. Results: There were no significant differences in average torque and peak torque E/I ratios of the functionally unstable ankle for any of the groups after training compared with before. Conclusions: Six weeks of strength and proprioception training (either alone or combined) had no effect on isokinetic measures of strength in subjects with self reported unilateral functional instability. Further studies examining this agonist (concentric) to antagonist (eccentric) muscle group strength ratio are needed.

Incidence of injury in semi-professional rugby league players

Abstract: Objectives: To investigate the site, nature, cause, and severity of injuries in semi-professional rugby league players. Methods: The incidence of injury was prospectively studied in one hundred and fifty six semi-professional rugby league players over two competitive seasons. All injuries sustained during matches and training sessions were recorded. Injury data were collected from a total of 137 matches and 148 training sessions. Information recorded included the date and time of injury, site, nature, cause, and severity of injury. Results: During the two seasons, 1694 playing injuries and 559 training injuries were sustained. The match injury incidence was 824.7 per 1000 player-position game hours and training injury incidence was 45.3 per 1000 training hours. Over 20% of the total training (17.4 per 1000) and playing (168.0 per 1000) injuries sustained were to the thigh and calf. Muscular injuries (haematomas and strains) were the most common type of injury sustained during training (22.0 per 1000, 48.7%) and matches (271.7 per 1000, 32.9%). Playing injuries were most commonly sustained in tackles (382.2 per 1000, 46.3%), while overexertion was the most common cause of training injuries (15.5 per 1000, 34.4%). The majority of playing injuries were sustained in the first half of matches (1013.6 per 1000, 61.5% v 635.8 per 1000, 38.5%), whereas training injuries occurred more frequently in the latter stages of the training session (50.0 per 1000, 55.3% v 40.5 per 1000, 44.7%). Significantly more training injuries were sustained in the early half of the season, however, playing injuries occurred more frequently in the latter stages of the season. Conclusions: These results suggest that changes in training and playing intensity impact significantly upon injury rates in semi-professional rugby league players. Further studies investigating the influence of training and playing intensity on injuries in rugby league are warranted.

Musculoskeletal manifestations of diabetes mellitus

Abstract: Rheumatic complaints are common in patients with diabetes. Maintaining good glycaemic control by exercise, diet, and medication improves or prevents the development of rheumatic conditions.

Anthropometry of young competitive sport rock climbers

Abstract: Background: Adult elite competitive rock climbers are small in stature with low body mass and very low body fat percentage. These characteristics have generated concern that young climbers may attempt body mass reduction to extreme levels with adverse consequences for health and performance. No published anthropometry data for young competitive climbers exist. Objective: To describe the general anthropometric characteristics of junior US competitive rock climbers. Methods: Ninety subjects (mean (SD) age 13.5 (3.0) years) volunteered to participate. All competed at the Junior Competition Climbers Association US National Championship. Anthropometric variables, including height, mass, body mass index (BMI), arm span, biiliocristal and biacromial breadths, skinfold thickness at nine anatomical sites, forearm and hand volumes, and handgrip strength, were measured. Selected variables were expressed as ratio values and as normative age and sex matched centile scores where appropriate. A control group (n = 45) of non-climbing children and youths who participated in a variety of sports activities, including basketball, cross country running, cross country skiing, soccer, and swimming, underwent the same testing procedures in the Exercise Science Laboratory of Northern Michigan University. Results: Mean (SD) self reported climbing ability was 11.80 (1.20), or about 5.11d on the Yosemite decimal system scale. The mean (SD) experience level was 3.2 (1.9) years, and subjects competed in 10 (5) organised competitions over a 12 month period. Despite similarity in age, there were significant differences (p<0.01) between climbers and control subjects for height, mass, centile scores for height and mass, ratio of arm span to height ("ape index"), biiliocristal/biacromial ratio, sum of seven and sum of nine skinfolds, estimated body fat percentage, and handgrip/mass ratio. Despite significantly lower skinfold sums and estimated body fat percentage, no differences were found between climbers and controls for absolute BMI or BMI expressed as a centile score. Conclusions: Young competitive climbers have similar general anthropometric characteristics to elite adult climbers. These include relatively small stature, low body mass, low sums of skinfolds, and high handgrip to mass ratio. Relative to age matched athletic non-climbers, climbers appear to be more linear in body type with narrow shoulders relative to hips. Differences in body composition exist between climbers and non-climbing athletes despite similar BMI values.

Effects of 12 months of exercise training on salivary secretory IgA levels in elderly subjects.

Abstract: Background: The immune system declines in efficiency with advancing age, making the elderly less resistant to pathogenic microorganisms. Upper respiratory tract infection (URTI) is a common illness. Recent studies have shown that suppression of secretory immunoglobulin A (SIgA) is associated with increased incidence of URTI. Objective: To assess the effect of exercise on salivary SIgA in elderly subjects. Methods: Forty five elderly subjects (18 men, 27 women; mean (SD) age 64.9 (8.4) years) performed both 60 minute resistance and 60 minute moderate endurance training a week for 12 months. Saliva samples were obtained before training, and at four and 12 months during the training period. Salivary SIgA concentrations were measured by enzyme linked immunosorbent assay, and the SIgA secretion rate was calculated. Results: SIgA concentrations before training, and at four and 12 months during training were 24.7 (14.4), 27.2 (14.2), and 33.8 (18.5) μg/ml respectively. SIgA secretion rates were 29.5 (26.0), 33.8 (27.2) and 46.5 (35.1) μg/min respectively. The results indicate that both the concentration and secretion rate of SIgA significantly (p Conclusion: Regular moderate exercise seems to enhance mucosal immune function in elderly subjects.

A pilot study of the prevalence of lumbar disc degeneration in elite athletes with lower back pain at the Sydney 2000 Olympic Games

Abstract: Objectives: To observe the prevalence of lumbar intervertebral disc degeneration in elite athletes as compared with published literature of changes seen in non-athletes—that is, normal population. Methods: The lumbar spines of 31 Olympic athletes who presented to the Olympic Polyclinic with low back pain and/or sciatica were examined using magnetic resonance imaging. Three criteria were looked at: ( a ) the loss of disc signal intensity; ( b ) the loss of disc height; ( c ) the presence of disc displacement. The results were then recorded and correlated with the lumbar levels. Results: The disc signal intensity was progressively reduced the more caudal the disc space. It was most common at the L5/S1 level, and, of the abnormal group, 36% (n = 11) showed the most degenerative change. Disc height reduction was also found to be most common at the L5/S1 level. However, the most common height reduction was only mild. A similar trend of increased prevalence of disc herniation was noted with more caudal levels. At the L5/S1 level, 58% were found to have an element of disc displacement, most of which were disc bulges. Compared with changes seen in the normal population (non-athletes) as described in the literature, disc degeneration defined by the above criteria was found to be significantly more severe in these Olympic athletes. Conclusions: Although the study was limited, the results suggest that elite athletes have a greater prevalence and greater degree of lumbar disc degeneration than the normal population. A more detailed follow up study should be considered to investigate which particular training activities have the most impact on the lumbar spine, and how to modify training methods so as to avoid the long term sequelae of degenerative disc disease of the lumbar spine.

Cricket injuries: a longitudinal study of the nature of injuries to South African cricketers

Abstract: Objective: To determine the incidence and nature of injuries sustained by elite cricketers during a three season period in order to identify possible injury patterns. Methods: Thirty six physiotherapists and 13 doctors working with 11 provincial and the South African national teams completed a questionnaire for each cricketer who presented with an injury during each season to determine anatomical site of injury, month of injury during the season, diagnosis, mechanism of injury, whether it was a recurrence of a previous injury, whether the injury had recurred again during the season, and biographical data. Results: A total of 436 cricketers sustained 812 injuries. Bowling (41.3%), fielding and wicketkeeping (28.6%), and batting (17.1%) accounted for most of the injuries. The lower limbs (49.8%), upper limbs (23.3%), and back and trunk (22.8%) were most commonly injured. The injuries occurred primarily during first class matches (27.0%), limited overs matches (26.9%), and practices (26.8%) during the early part of the season. Acute injuries made up 64.8% of the injuries. The younger players (up to 24 years) sustained 57% of the first time injuries, and the players over 24 years of age sustained 58.7% of the injuries that recurred from a previous season. The injuries were mainly soft tissue injuries predominantly to muscle (41.0%), joint (22.2%), tendon (13.2%), and ligament (6.2%). The primary mechanism of injury was the delivery and follow through of the fast bowler (25.6%), overuse (18.3%), and fielding (21.4%). Conclusion: The results indicate a pattern of cause of injury, with the young fast bowler most likely to sustain an acute injury to the soft tissues of the lower limb while participating in matches and practices during the early part of the season.

A 16 year study of injuries to professional boxers in the state of Victoria, Australia

Abstract: Objectives: To determine the rate and type of injuries occurring to registered professional kickboxers in Victoria, Australia over a 16 year period. Methods: Data describing all fight outcomes and injuries sustained during competition for the period August 1985 to August 2001 were obtained from the Victorian Professional Boxing and Combat Sports Board. Results: A total of 382 injuries were recorded from 3481 fight participations, at an injury rate of 109.7 injuries per 1000 fight participations. The most common body region injured was the head/neck/face (52.5%), followed by the lower extremities (39.8%). Specifically, injuries to the lower leg (23.3%), the face (19.4%), and intracranial injury (17.2%) were the most common. Over 64% of the injuries were superficial bruising or lacerations. Conclusion: The nature of kickboxing, whereby kicking the opponent is the prime movement and the head a prime target, is reflected in the distributions of body regions most commonly injured by participants. Further research into injury patterns in different styles of kickboxing and the mechanism of injury occurrence is required. Exposure adjusted prospective studies are needed to monitor injury rates over time.

Diagnostic criteria for exercise dependence in women

Abstract: Objective: To formulate diagnostic criteria for exercise dependence. Method: Fifty six adult female exercisers were interviewed about their exercise behaviour and attitudes. The eating disorders examination, a semistructured clinical interview, was used to diagnose eating disorders. Interviews were taped, transcribed verbatim, and analysed from a social constructionist perspective using QSR NUD*IST. Participants also completed the exercise dependence questionnaire. Results: Two diagnostic criteria emerged from analysis of the interview data: impaired functioning and withdrawal. Impaired functioning was manifest in four areas: psychological, social and occupational, physical, and behavioural. Impairment in at least two areas was considered necessary for diagnosis. Withdrawal was evident as either an adverse reaction to the interruption of exercise or unsuccessful attempts at exercise control. Either sufficed for diagnosis. The absence or presence of an eating disorder was used to distinguish between primary and secondary exercise dependence. Ten women met these criteria for exercise dependence. All 10 also exhibited eating disorders and, accordingly, should be regarded as showing secondary, rather than primary, exercise dependence. Exercise dependent women had significantly higher scores on the exercise dependence questionnaire than non-dependent women. Conclusion: These new diagnostic criteria should now be adopted and explored further, particularly among men and individuals with possible primary exercise dependence.

Football incident analysis: a new video based method to describe injury mechanisms in professional football

Abstract: Objectives: To develop and test a new video based method for match analysis that combines football specific and medical information to achieve a better understanding of the injury mechanisms and events leading up to high risk situations. Methods: Football incident analysis (FIA) is a video based method describing incidents that may result in an injury using 19 variables and categories modified from match analysis. Videos from 35 of 76 (46%) official Norwegian under 21 matches played from 1994 to 1998 were analysed. Two football experts classified each incident on the basis of predetermined criteria, and their results were compared using interobserver and intraobserver reliability tests. Results: κ correlation coefficients for interobserver and intraobserver agreement were very good for 63% and 95% and good for 37% and 5% of the variables respectively. Fifty two incidents were recorded (1.6 incidents per team per match or 94 per 1000 player hours), and 16 (31%) led to injuries (0.5 injuries per match or 29 injuries per 1000 player hours). FIA results showed that 28 incidents occurred while attacking in midfield zone 2 or the attacking zone, and 24 took place while defending in the defensive zone or midfield zone 1. Midfielders were exposed in 67% of the incidents, mainly in breakdown attacks or during long attacks by the opposing team. Of the 28 incidents during offence, only one was classified as having great potential to score a goal. Most incidents (70%) were the result of tackling duels both in the offensive and defensive playing phases. Of the 21 offensive incidents resulting from tackling duels, in 19 cases the exposed player was unaware of the tackling (passive duellist). Conclusions: This study shows that football incident analysis is a potentially valuable tool for understanding the events leading up to injuries in football.

Claims for the anabolic effects of growth hormone: a case of the Emperor’s new clothes?

Abstract: This review examines the evidence that growth hormone has metabolic effects in adult human beings. The conclusion is that growth hormone does indeed have powerful effects on fat and carbohydrate metabolism, and in particular promotes the metabolic use of adipose tissue triacylglycerol. However, there is no proof that net protein retention is promoted in adults, except possibly of connective tissue. The overexaggeration of the effects of growth hormone in muscle building is effectively promoting its abuse and thereby encouraging athletes and elderly men to expose themselves to increased risk of disease for little benefit.

Effect of wearing an ice cooling jacket on repeat sprint performance in warm/humid conditions

Abstract: Objective: To examine the effect of cooling the skin with an ice jacket before and between exercise bouts (to simulate quarter and half time breaks) on prolonged repeat sprint exercise performance in warm/humid conditions. Methods: After an initial familiarisation session, seven trained male hockey players performed two testing sessions (seven days apart), comprising an 80 minute intermittent, repeat sprint cycling exercise protocol inside a climate chamber set at 30°C and 60% relative humidity. On one occasion a skin cooling procedure was implemented (in random counterbalanced order), with subjects wearing an ice cooling jacket both before (for five minutes) and in the recovery periods (2 x 5 min and 1 x 10 min) during the test. Measures of performance (work done and power output on each sprint), heart rates, blood lactate concentrations, core (rectal) and skin temperatures, sweat loss, perceived exertion, and ratings of thirst, thermal discomfort, and fatigue were obtained in both trials. Results: In the cooling condition, chest (torso) skin temperature, thermal discomfort, and rating of thirst were all significantly lower (p 0.05) was observed between conditions for measures of work done, power output, heart rate, blood lactate concentration, core or mean skin temperature, perceived exertion, sweat loss, or ratings of fatigue. However, high effect sizes indicated trends to lowered lactate concentrations, sweat loss, and mean skin temperatures in the cooling condition. Conclusions: The intermittent use of an ice cooling jacket, both before and during a repeat sprint cycling protocol in warm/humid conditions, did not improve physical performance, although the perception of thermal load was reduced. Longer periods of cooling both before and during exercise (to lower mean skin temperature by a greater degree than observed here) may be necessary to produce such a change.