Showing papers in "British Journal of Sports Medicine in 2000"

Effects of exercise on lymphocytes and cytokines

Abstract: Objectives —To review results on exercise induced changes in the immune system following strenuous and moderate exercise. Methods —A literature search over the past 15 years was conducted using Medline and selected papers. Results —After intense long term exercise, the immune system is characterised by concomitant impairment of the cellular immune system and increased inflammation. Thus low concentrations of lymphocytes, suppressed natural immunity, suppressed lymphocyte proliferation, and suppressed levels of secretory IgA in saliva are found simultaneously with high levels of circulating proinflammatory and anti-inflammatory cytokines. The underlying mechanisms are multifactorial and include neuroendocrinological and metabolic factors. The clinical consequences of the exercise induced immune changes have not formally been identified, but the exercise effect on lymphocyte dynamics and immune function may be linked to the exercise effects on resistance to infections and malignancy and the cytokine response may be linked to muscle damage or muscle cell growth. Conclusions —Moderate exercise across the life span seems to increase resistance to upper respiratory tract infections, whereas repeated strenuous exercise suppresses immune function. It is premature to offer advice on nutrition to athletes in order to alter the exercise induced immunosuppression found after exercise.

Balance control, flexibility, and cardiorespiratory fitness among older Tai Chi practitioners

Abstract: Background—Tai Chi Chuan (TTC) exercise has beneficial eVects on the components of physical condition and can produce a substantial reduction in the risk of multiple falls. Previous studies have shown that short term TCC exercise did not improve the scores in the single leg stance test with eyes closed and the sit and reach test. There has apparently been no research into the eVects of TCC on total body rotation flexibility and heart rate responses at rest and after a three minute step test. Methods—In this cross sectional study, 28 male TCC practitioners with an average age of 67.5 years old and 13.2 years of TCC exercise experience were recruited to form the TCC group. Another 30 sedentary men aged 66.2 were selected to serve as the control group. Measurements included resting heart rate, left and right single leg stance with eyes closed, modified sit and reach test, total body rotation test (left and right), and a three minute step test. Results—Compared with the sedentary group, the TCC group had significantly better scores in resting heart rate, three minute step test heart rate, modified sit and reach, total body rotation test on both right and left side (p<0.01), and both right and left leg standing with eyes closed (p<0.05). According to the American Fitness Standards, the TCC group attained the 90th percentile rank for sit and reach and total body rotation test, right and left. Conclusion—Long term regular TCC exercise has favourable eVects on the promotion of balance control, flexibility, and cardiovascular fitness in older adults. (Br J Sports Med 2000;34:29‐34)

Exercise in preventing falls and fall related injuries in older people: a review of randomised controlled trials

Abstract: Objective —To assess the effectiveness of exercise programmes in preventing falls (and/or lowering the risk of falls and fall related injuries) in older people. Design —A review of controlled clinical trials designed with the aim of lowering the risk of falling and/or fall injuries through an exercise only intervention or an intervention that included an exercise component Main outcome measures —Falls, fall related injuries, time between falls, costs, cost effectiveness. Subjects —A total of 4933 men and women aged 60 years and older. Results —Eleven trials meeting the criteria for inclusion were reviewed. Eight of these trials had separate exercise interventions, and three used interventions with an exercise programme component. Five trials showed a significant reduction in the rate of falls or the risk of falling in the intervention group. Conclusions —Exercise is effective in lowering falls risk in selected groups and should form part of falls prevention programmes. Lowering fall related injuries will reduce health care costs but there is little available information on the costs associated with programme replication or the cost effectiveness of exercise programmes aimed at preventing falls in older people.

Spondylolysis: a critical review.

Abstract: Aim —To provide an understanding of the current concepts in the natural history, pathophysiology, diagnosis, and treatment of spondylolysis based on the available medical literature. Methods —Articles were selected for review by the following methods: ( a ) MEDLINE searches with review of abstracts to select relevant articles; ( b ) review of multiple textbooks considered likely to contain information on spondylolysis; ( c ) review of references in articles identified by ( a ) and ( b ). Over 125 articles were ultimately reviewed fully. Publications were selected for inclusion in this article on the basis of perceived scientific and historical merit, particularly as thought to be relevant to achieving the stated purpose of this review. As no controlled clinical trials were identified, this could not be used as an inclusion criterion. Conclusions —Isthmic spondylolysis is considered to represent a fatigue fracture of the pars interarticularis of the neural arch. There is a relatively high incidence of radiographically identified spondylolysis in the general population, but the vast majority of these lesions probably occur without associated symptoms. Symptomatic pars lesions appear to be particularly a clinical problem in adolescents, especially adolescent athletes. The optimal diagnostic and treatment algorithms are not well identified in the current literature. Multiple imaging studies may have a role in the diagnosis of a pars lesion, and treatment seems likely to require at least relative rest and physical rehabilitation with consideration of bracing or, rarely, surgical intervention depending on the clinical context.

Physiological and anthropometric determinants of sport climbing performance

Abstract: Objective—To identify the physiological and anthropometric determinants of sport climbing performance. Methods—Forty four climbers (24 men, 20 women) of various skill levels (self reported rating 5.6‐5.13c on the Yosemite decimal scale) and years of experience (0.10‐44 years) served as subjects.They climbed two routes on separate days to assess climbing performance. The routes (11 and 30 m in distance) were set on two artificial climbing walls and were designed to become progressively more diYcult from start to finish. Performance was scored according to the system used in sport climbing competitions where each successive handhold increases by one in point value. Results from each route were combined for a total climbing performance score. Measured variables for each subject included anthropometric (height, weight, leg length, arm span, % body fat), demographic (self reported climbing rating, years of climbing experience, weekly hours of training), and physiological (knee and shoulder extension, knee flexion, grip, and finger pincer strength, bent arm hang, grip endurance,hip and shoulder flexibility,and upper and lower body anaerobic power). These variables were combined into components using a principal components analysis procedure. These components were then used in a simultaneous multiple regression procedure to determine which components best explain the variance in sport rock climbing performance. Results—The principal components analysis procedure extracted three components. These were labelled training, anthropometric, and flexibility on the basis of the measured variables that were the most influential in forming each component. The results of the multiple regression procedure indicated that the training component uniquely explained 58.9% of the total variance in climbing performance. The anthropometric and flexibility components explained 0.3% and 1.8% of the total variance in climbing performance respectively. Conclusions—The variance in climbing performance can be explained by a component consisting of trainable variables.More importantly, the findings do not support the belief that a climber must necessarily possess specific anthropometric characteristics to excel in sport rock climbing. (Br J Sports Med 2000;34:359‐366)

The menisci: basic science and advances in treatment

Abstract: Once described as a muscle remnant, and therefore treated with disrespect, the meniscus is now known to be a vital structure within the knee. Minimal partial meniscectomy performed arthroscopically, or meniscal repair when practical, have become the standard treatments. In spite of the advancements in understanding meniscal function and its preservation, much remains to be studied. In the future, availability of better repair techniques and the option of meniscal replacement with allograft or prosthetic menisci are expected to improve outcomes.

Effects of one year of resistance training on the relation between muscular strength and bone density in elderly women

Abstract: Objectives —There is a paucity of long term studies on exercise training in elderly women The purpose of this study was to investigate the effects of one year of progressive resistance exercise (PRE) on dynamic muscular strength and the relations to bone mineral density (BMD) in elderly women Methods —Forty four healthy sedentary women (mean age 688 years) volunteered for this study and were randomly assigned to either an exercise group or a control group The exercise group were involved in three one hour sessions a week for 52 weeks of supervised PRE to strengthen the large muscle groups of the body, while the control group were instructed to continue their normal lifestyle The exercise circuit included three sets of eight repetitions at 75% of one repetition maximum focused on the large muscle groups BMD was measured by dual energy x ray absoptiometry (Lunar DPX) at the lumbar spine and at three sites in the proximal femur Other selected parameters of physical fitness were also measured Results —Statistical analyses (analysis of covariance) showed significant strength gains (p 29%), bilateral leg press (>19%), and unilateral biceps curl (>20%) No significant difference between groups was evident in body weight, grip strength, flexibility, waist to hip ratio, or the sum of eight skinfolds Significant relations (p Conclusions —Significant strength changes, after one year of PRE, were evident in elderly women, and the muscle increases may parallel changes in BMD; however, correlation coefficients were moderate

Where is the pain coming from in tendinopathy? It may be biochemical, not only structural, in origin

Abstract: Traditional dogma would have it that pain in tendinopathy arises through one of two mechanisms. Firstly, it may result from inflammation in “tendinitis”. Secondly, it may be due to separation of collagen fibres in more severe forms of tendinopathy. The latter situation parallels the mechanism of pain with collagen separation after an acute grade I or II ligament injury (fig 1). Despite the wide acceptance of these two classical models of pain production, a number of studies provide data inconsistent with either theory. Consider first the inflammation mechanism. Histopathological examination of surgical specimens from patients with chronic tendon pain are devoid of inflammatory cells.1 This applies to tissue from the Achilles, patellar, lateral elbow, medial elbow, and rotator cuff tendons. Furthermore, prostaglandin E2 (a marker of the inflammatory process) is no more abundant in patients with Achilles tendon pain than in normal controls.2 Unfortunately, the collagen separation theory does not hold up under scrutiny either. The following five observations about pain and collagen in the patellar tendon are inexplicable. ( a ) Patients who have patellar tendon allograft anterior cruciate ligament reconstruction have minimal donor site knee pain, yet …

Impact of professionalism on injuries in rugby union

Abstract: Objectives —To measure the frequency and nature of injuries occurring in competitive matches since professionalism was introduced in rugby union. Methods —The cohort study previously conducted in players from senior rugby clubs in the Scottish Borders in 1993–1994 when rugby union was an entirely amateur sport was repeated in 1997–1998. The same injury definition, outcome criteria, and method of calculating playing hours were used. In total, 803 (84%) of 960 eligible players participated, including all 30 adult players who played professionally for the Scottish Rugby Union or Border Reivers District. The 576 injury episodes in 381 of these players in competitive matches were compared with the 373 injuries in 266 players out of 975 (94 %) who were eligible and registered with the same senior rugby clubs in 1993–1994. Outcomes were the occurrence of injury episodes, days away from playing or training for rugby, and time lost to employment or attendance at school/college as a consequence of being injured. Results —The proportion of players who were injured almost doubled from 1993–1994 to 1997–1998, despite an overall reduction of 7% of the playing strength of participating clubs. Period prevalence injury rates rose in all age specific groups, particularly in younger players. This translated into an injury episode every 3.4 matches in 1993–94, rising to one in every 2.0 matches in 1997–1998. An injury episode occurred in a professional team for every 59 minutes of competitive play. Professional players sustained a higher proportion of recurrent injuries, particularly in the early part of the season. Some 56% of all their days lost to the game were caused by injuries to the muscles, ligaments, and joints of the knee, hip, and thigh. Conclusions —The introduction of professionalism in rugby union has coincided with an increase in injuries to both professional and amateur players. To reduce this, attention should be focused on the tackle, where many injuries occur. The International Rugby Board should place a moratorium on the use of protective equipment in competitive matches until its contribution to player morbidity has been fully assessed.

Decreasing landing forces: effect of instruction.

Abstract: Objective —To examine the effects of instructions related to joint kinematics, auditory stimuli, and imagery on lowering the vertical ground reaction forces associated with landing from a jump. Study Design —Randomised controlled trial. Setting —A laboratory in an educational institution. Subjects —Eighty asymptomatic subjects (27 men) with a mean age of 24 years. Intervention —Subjects were randomly assigned to the following groups: (1) instruction (limb position instructions); (2) auditory cue (listen to impact sounds); (3) imagery (metaphorical); (4) control. Subjects were required to jump from a box 300 mm in height and land on a force plate. Measures of the ground reaction force were recorded before and after the intervention. Main Outcome Measure —The peak vertical ground reaction force recorded at footstrike. Results —The peak vertical ground reaction forces in the technical instruction and auditory groups were significantly less than those of the control group. There was no significant difference between the auditory and technical instruction groups. There was no significant difference between the imagery and control groups. Conclusions —When an aim of a rehabilitation programme is to minimise forces on the lower limb during landing type activities, the findings support the use of instructions related to kinematics as well as instructions that draw the patient9s attention to the sound at impact.

Effects of massage on physiological restoration, perceived recovery, and repeated sports performance

Abstract: Background—Despite massage being widely used by athletes, little scientific evidence exists to confirm the eYcacy of massage for promoting both physiological and psychological recovery after exercise and massage eVects on performance. Aim—To investigate the eVect of massage on perceived recovery and blood lactate removal, and also to examine massage eVects on repeated boxing performance. Methods—Eight amateur boxers completed two performances on a boxing ergometer on two occasions in a counterbalanced design. Boxers initially completed performance 1, after which they received a massage or passive rest intervention. Each boxer then gave perceived recovery ratings before completing a second performance, which was a repeated simulation of the first. Heart rates and blood lactate and glucose levels were also assessed before, during, and after all performances. Results—A repeated measures analysis of variance showed no significant group diVerences for either performance, although a main eVect was found showing a decrement in punching force from performance 1 to performance 2 (p<0.05). A Wilcoxon matched pairs test showed that the massage intervention significantly increased perceptions of recovery (p<0.01) compared with the passive rest intervention. A doubly multivariate multiple analysis of variance showed no diVerences in blood lactate or glucose following massage or passive rest interventions, although the blood lactate concentration after the second performance was significantly higher following massage (p<0.05). Conclusions—These findings provide some support for the psychological benefits of massage, but raise questions about the benefit of massage for physiological restoration and repeated sports performance. (Br J Sports Med 2000;34:109‐115)

Incidence, site, and nature of injuries in amateur rugby league over three consecutive seasons

Abstract: Objectives —To report the incidence, site, and nature of injuries in amateur rugby league over three consecutive seasons. Methods —Six hundred players registered with an amateur rugby league organisation were studied over three consecutive seasons. All injuries sustained during the amateur rugby league matches were recorded. Information recorded included the date and time of injury, name of injured player, anatomical site and nature of injury, and position of the player. Results —The incidence of injury was 160.6 per 1000 player-position game hours, with forwards having a significantly higher incidence of injury than backs (182.3 per 1000 v 142.0 per 1000, χ 2 = 14.60, df = 1, p 2 = 21.83, df = 8, p 2 = 17.98, df = 7, p 2 = 22.94, df = 1, p 2 = 162.29, df = 1, p Conclusions —The results show that muscular injuries and injuries to the head and neck are the most commonly sustained injuries in amateur rugby league. Furthermore, injuries are more often sustained in the latter stages of the season and during the second half of matches. These findings suggest that fatigue or accumulative microtrauma, or both, may contribute to injuries in amateur rugby league players.

The pathological status of exercise dependence

Abstract: Objectives—This study was concerned with the concept of exercise dependence. Levels of psychological morbidity, personality profiles, and exercise beliefs were compared among subjects screened for exercise dependence and eating disorders. Method—Adult female exercisers were allocated on the basis of questionnaire screening to one of the following groups: primary exercise dependence (n = 43); secondary exercise dependence, where there was the coincidence of exercise dependence and an eating disorder (n = 27); eating disorder (n =14); control, where there was no evidence of either exercise dependence or eating disorder (n = 110). Questionnaire assessment was undertaken of psychological morbidity, self esteem, weight and body shape dissatisfaction, personality, and exercise beliefs. Results—Aside from a higher incidence of reported menstrual abnormalities, the primary exercise dependence group was largely indistinguishable from the controls. In stark contrast, the secondary exercise dependence group reported higher levels of psychological morbidity, neuroticism, dispositional addictiveness, and impulsiveness, lower self esteem, greater concern with body shape and weight, as well as with the social, psychological, and aesthetic costs of not exercising than the controls, but differed little from the eating disorder group. Conclusions—In the absence of an eating disorder, women identified as being exercise dependent do not exhibit the sorts of personality characteristics and levels of psychological distress that warrant the construction of primary exercise dependence as a widespread pathology. Key Words: exercise dependence; eating disorders; personality; self esteem; neuroticism; psychological morbidity

Epidemiology of knee injuries: diagnosis and triage

Abstract: In the Western world we live in a society obsessed by sport. At recreational level, this allows an escape from the pressures of modern life, and, at the elite level, sport is now an established part of the entertainment industry, with enormous material rewards for the participants. At all levels, injury is a constant threat, and, of all injuries, those of the knee fulfil the athlete's greatest fear of spending a long time out of action. This is confirmed by a study from Sheffield, which showed the knee to have been the most commonly injured joint and soccer and rugby to have the highest risks.1 It has been said of our national game that it is not so much a sport as a knee disease! Not only may a knee injury require surgery followed by months of rehabilitation, but permanent disability from both sport and work may be the outcome. Indeed, a large study from Scandinavia found that the most common cause of permanent disability following a sports injury was injury to the knee.2 There is little work on the pattern of knee injuries in the United Kingdom, although a multicentre study is currently in progress. The work that has been carried out abroad, however, has produced some interesting information. It is not widely appreciated that ligament damage to the knee is more common than any other type of knee injury pathology (fig 1).3 Many medical students, general practitioners, and paramedics may be familiar with the story of a weight bearing, twisting injury producing a meniscal tear; however, there is generally a profound ignorance about the history and signs of the more common (and potentially more devastating) ligament …

Sport, age, and sex specific incidence of sports injuries in Western Australia

Abstract: Objective—To describe the trends in recreational sports injury in Perth, Western Australia. Design—A prospective cohort study of sports injuries during the 1997 winter season (May to September). Setting—Sample of Australian football, field hockey, basketball, and netball players from the Perth metropolitan area, Western Australia. Methods—A cohort of sports participants was followed over the five month winter sports season. Before the season, participants completed a baseline questionnaire and during the season were interviewed every four weeks by telephone. Results—Overall, 92% of participants (n = 1391) who completed a baseline questionnaire completed at least one follow up telephone interview. About half (51%) of the cohort sustained one or more injuries during the winter season accounting for a total of 1034 injuries. Most injuries were of moderate (58%, n = 598) or minor (40%, n = 412) severity, with only 3% (n = 24) requiring emergency department treatment or a hospital stay. The injury incidence rate was greatest for football (20.3/1000 hours of participation), similar for field hockey and basketball (15.2/1000 hours and 15.1/1000 hours respectively), and lowest for netball (12.1/1000 hours). The incidence of injury was greatest in the first four weeks of the season, and participants aged between 26 and 30 years had about a 55% greater risk of injury than those aged less than 18 years. Conclusions—This is one of the first studies to show that recreational sports are safe. Although the likelihood of injury was greatest in the first month of the season, few injuries required admission to hospital or emergency department treatment. A greater emphasis on prevention in the early part of the season should help to reduce the elevated incidence of injury found at this time. Key Words: injury incidence; prospective study; time at risk

Physiological and biomechanical adaptations to the cycle to run transition in Olympic triathlon: review and practical recommendations for training

Abstract: Current knowledge of the physiological, biomechanical, and sensory effects of the cycle to run transition in the Olympic triathlon (1.5 km, 10 km, 40 km) is reviewed and implications for the training of junior and elite triathletes are discussed. Triathlon running elicits hyperventilation, increased heart rate, decreased pulmonary compliance, and exercise induced hypoxaemia. This may be due to exercise intensity, ventilatory muscle fatigue, dehydration, muscle fibre damage, a shift in metabolism towards fat oxidation, and depleted glycogen stores after a 40 km cycle. The energy cost (CR) of running during the cycle to run transition is also increased over that of control running. The increase in CR varies from 1.6% to 11.6% and is a reflection of triathlete ability level. This increase may be partly related to kinematic alterations, but research suggests that most biomechanical parameters are unchanged. A more forward leaning trunk inclination is the most significant observation reported. Running pattern, and thus running economy, could also be influenced by sensorimotor perturbations related to the change in posture. Technical skill in the transition area is obviously very important. The conditions under which the preceding cycling section is performed-that is, steady state or stochastic power output, drafting or non-drafting-are likely to influence the speed of adjustment to transition. The extent to which a decrease in the average 10 km running speed occurs during competition must be investigated further. It is clear that the higher the athlete is placed in the field at the end of the bike section, the greater the importance to their finishing position of both a quick transition area time and optimal adjustment to the physiological demands of the cycle to run transition. The need for, and current methods of, training to prepare junior and elite triathletes for a better transition are critically reviewed in light of the effects of sequential cycle to run exercise.

Suprascapular neuropathy in volleyball players

Abstract: Background—Suprascapular nerve entrapment with isolated paralysis of the infraspinatus muscle is uncommon. However, this pathology has been reported in volleyball players. Despite a lack of scientific evidence, excessive strain on the nerve is often cited as a possible cause of this syndrome. Previous research has shown a close association between shoulder range of motion and strain on the suprascapular nerve. No clinical studies have so far been designed to examine the association between excessive shoulder mobility and the presence of this pathology. Aim—To study the possible association between the range of motion of the shoulder joint and the presence of suprascapular neuropathy by clinically examining the Belgian male volleyball team with respect to several parameters. Methods—An electromyographic investigation, a clinical shoulder examination, shoulder range of motion measurements, and an isokinetic concentric peak torque shoulder internal/external rotation strength test were performed in 16 professional players. Results—The electrodiagnostic study showed a severe suprascapular neuropathy in four players which aVected only the infraspinatus muscle. In each of these four players, suprascapular nerve entrapment was present on the dominant side. Except for the hypotrophy of the infraspinatus muscle, no significant diVerences between the aVected and non-aVected players were observed on clinical examination. Significant diVerences between the aVected and non-aVected players were found for range of motion measurements of external rotation,horizontal flexion and forward flexion, and for flexion of the shoulder girdle (protraction); all were found to be higher in the aVected players than the non-aVected players. Conclusions—This study suggests an association between increased range of motion of the shoulder joint and the presence of isolated paralysis of the infraspinatus muscle in volleyball players. However, the small number of patients in this study prevents definite conclusions from being drawn. (Br J Sports Med 2000;34:174‐180)

Long term health impact of playing professional football in the United Kingdom

Abstract: Objective—To describe the long term impact of football on the health related quality of life (HRQL) of former professional footballers in the United Kingdom. Method—A cross sectional survey gathered data from 284 former professional players. Respondents reported medical treatments, osteoarthritis (OA) diagnosis, other morbidity, disability status, and work related disability since their football career. The EuroQol (EQ-5D) and global health rating scales were selected to assess HRQL. Results—Medical treatment for football related injuries was a common feature, as was OA, with the knee being the most commonly aVected joint. Respondents with OA reported poorer HRQL compared with those without OA. As with medical treatments and problems on each of the five EQ-5D dimensions (pain, mobility, usual activities, anxiety/depression, self care), frequency of disability and work related disability were higher among respondents with OA than those without. Conclusion—This exploratory study suggests that playing professional football can impact on the health of United Kingdom footballers in later life. The development of OA was associated with poorer outcomes on all aspects of HRQL. (Br J Sports Med 2000;34:332‐337)

Physiological and anthropometric characteristics of amateur rugby league players

Abstract: Objectives—To investigate the physiological and anthropometric characteristics of amateur rugby league players. Methods—Thirty five amateur rugby league players (19 forwards and 16 backs) were measured for height, body mass, percentage body fat (sum of four skinfolds), muscular power (vertical jump), speed (10 m and 40 m sprint), and maximal aerobic power (multistage fitness test). Data were also collected on match frequency, training status, playing experience, and employment related physical activity levels. Results—The 10 m and 40 m sprint, vertical jump, percentage body fat, and multistage fitness test results were 20‐42% poorer than previously reported for professional rugby league players. Compared with forwards, backs had significantly (p 0.05) between forwards and backs. When compared with professional rugby league players, the training status of amateur rugby league players was 30‐53% lower, with players devoting less than three hours a week to team training sessions and about 30 minutes a week to individual training sessions. The training time devoted to the development of muscular power (about 13 minutes a week), speed (about eight minutes a week), and aerobic fitness (about 34 minutes a week) did not diVer significantly (p>0.05) between forwards and backs. At the time of the field testing, players had participated, on average, in one 60 minute match every eight days. Conclusions—The physiological and anthropometric characteristics of amateur rugby league players are poorly developed. These findings suggest that position specific training does not occur in amateur rugby league. The poor fitness of non-elite players may be due to a low playing intensity, infrequent matches of short duration, and/or an inappropriate training stimulus. (Br J Sports Med 2000;34:303‐307)

Effects of physical training in asthma: a systematic review

Abstract: Objectives—To assess the evidence for the eVects of physical training on pulmonary function,symptoms,cardiopulmonary fitness, and quality of life in subjects with asthma. Methods—A search was conducted for randomised controlled trials of subjects with asthma undertaking physical training using the Cochrane Airways Group register of controlled clinical trials, Medline, Embase, Sportdiscus, Science citation index, and Current contents index. Studies were included in the review if the subjects had asthma, were 8 years of age or older, and had undertaken physical training for at least 20 minutes per session, twice a week, for a minimum of four weeks. The eligibility of trials for inclusion in the review and the quality of the trials were independently assessed by two reviewers. Results—Eight studies with a total of 226 subjects met the inclusion criteria for this review. Physical training had no eVect on resting lung function but led to an improvement in cardiopulmonary fitness as measured by an increase in maximum oxygen uptake of 5.6 ml/kg/min (95% confidence interval 3.9 to 7.2). None of the studies measured quality of life. Conclusions—Physical training improves cardiopulmonary fitness without changing lung function. It is not clear if the improvement in fitness translates into a reduction in symptoms or an improvement in the quality of life. There is a need for further randomised controlled trials of the eVects of physical training in the management of asthma. (Br J Sports Med 2000;34:162‐167)

“It's exercise or nothing”: a qualitative analysis of exercise dependence

Abstract: Objectives—To explore, using qualitative methods, the concept of exercise dependence. Semistructured interviews were undertaken with subjects screened for exercise dependence and eating disorders. Methods—Female exercisers, four in each case, were allocated a priori to four groups: primary exercise dependent; secondary exercise dependent, where there was a coincidence of exercise dependence and an eating disorder; eating disordered; control, where there was no evidence of either exercise dependence or eating disorder. They were asked about their exercise and eating attitudes and behaviour, as well as about any history of psychological distress. Their narratives were taped, transcribed, and analysed from a social constructionist perspective using QSR NUD*IST. Results—Participants classified as primary exercise dependent either showed no evidence of exercise dependent attitudes and behaviour or, if they exhibited features of exercise dependence, displayed symptoms of an eating disorder. Only the latter reported a history of psychological distress, similar to that exhibited by women classified as secondary exercise dependent or eating disordered. For secondary exercise dependent and eating disordered women,as well as for controls,the narratives largely confirmed the a priori classification. Conclusions—Where exercise dependence was manifest,it was always in the context of an eating disorder, and it was this comorbidity, in addition to eating disorders per se, that was associated with psychological distress. As such, these qualitative data support the concept of secondary, but not primary, exercise dependence. (Br J Sports Med 2000;34:423‐430)

Promoting physical activity in general practice: a controlled trial of written advice and information materials

Abstract: Objective —To investigate the impact of a simple written prescription for physical activity given by a general practitioner and the effect of supplementing this with mailed information materials about physical activity. Methods —A controlled trial was conducted in 27 general practices in New South Wales, Australia. Subjects were sequential routine care patients between 25 and 65 years old. Controls (n = 386) were recruited first, and intervention subjects two weeks later. Intervention subjects were randomised to receive a prescription only (n = 380) or a prescription plus a mailed booklet (n = 376). Self reported physical activity levels were measured by interview at baseline, 6–10 weeks, and seven to eight months. Results —By intention to treat, the average changes in minutes of total physical activity did not differ significantly between the groups. Inactive people in the prescription plus supplementary booklet group were significantly more likely than controls to report an increase in their physical activity by at least 60 min/week after 6–10 weeks (odds ratio 1.58, 95% confidence interval 1.06 to 2.35). No significant short term improvements in self reported activity were shown in the prescription only group. In the supplemented group, the proportion reporting an increase in physical activity to 3344 kJ/week at 6–10 weeks was not significant, and neither intervention group showed significant increases in any of the outcome measures at seven to eight months by intention to treat. Treatment received analysis showed greater improvements in intervention groups, especially the prescription plus booklet group, in which the odds of inactive people in this group reporting increased activity became significant at seven to eight months. Conclusions —A prescription for physical activity from a general practitioner, supplemented by additional written materials, can lead to modest short term improvements in self reported physical activity levels among inactive patients. A prescription alone was found not to be effective.

Sports injury incidence

Abstract: The aim of this paper is to give a “medical” viewpoint on sports injury data collection and analysis, and to emphasise the importance of epidemiological sports data collection with regard to incidence rates and exposure risk hours and highlight the need for uniform definitions within and across sport. It is designed not as a statistical or epidemiological paper but as a resource to be used by those involved in sports injury research so that they may confidently analyse, evaluate, and compare existing research and to enable them to collect accurate sports injury data in their own field. Scientifically, it is not sound to rely on case reports to indicate injury patterns in sport, and yet it is common practice. It is always problematical to compare injury statistics across sports because of the added factors of the number of people involved, the time played, and variable injury definition. Increasingly, sports injury data are reported as incidence rates—for example, injuries per 1000 hours played—that is, using numerator and denominator data—as this methodology takes account of the exposure time at risk. Sports injuries occur when athletes are exposed to their given sport and they occur under specific conditions, at a known time and place. The last point should relate to time missed in training days as well as competitive participation and may also consider time lost to work in the case of a semiprofessional athlete. The knowledge gained from asking these questions may help us to predict and thus prevent injury. In sports medicine, we are thus all epidemiologists “concerned with quantifying injury occurrence with respect to who is affected by injury, where and when injuries occur and what is their outcome—for the purposes of explaining why and how injuries occur and identifying strategies to control and prevent them”.1 To interpret the …

Redefining the overtraining syndrome as the unexplained underperformance syndrome

Abstract: Unexplained underperformance in athletes is a common problem, occurring in around 10–20% of elite endurance squads.1 The terms “overtraining syndrome”, “staleness”, “chronic fatigue in athletes”, and “sports fatigue syndrome” have been used.2 “Burn out” with depressed mood state may occur in power athletes. There has been some confusion in the literature on the definition and diagnostic criteria. On 19 April 1999 the authors held a round table discussion at St Catherine's College, Oxford in order to clarify the diagnostic criteria to be used in the future. The format of the meeting was modelled on the consensus meeting held at Green College, Oxford on 23 March 1990 on the criteria for diagnosis of patients with chronic fatigue.3 Unfortunately the term overtraining syndrome implies causation, which limits investigations of this …

Anthropometric characteristics of elite male junior rowers

Abstract: During the 1997 Federation Internationale des Societes d'Aviron World Junior Rowing Championships, anthropometric data on 383 male junior rowers were assessed With 430 participating athletes, the sample represented 89% of the population In addition to age, 27 dimensions were measured: body mass, six heights or lengths, four breadths, 10 girths, and six skinfolds The elite male junior rowers were tall (1874 (58) cm; mean (SD)) and heavy (822 (74) kg), with larger length, breadth, and girth dimensions than a nationally representative sample of Belgian boys of the same chronological age A rowing specific anthropometric profile chart with norms was constructed The stature of the junior rowers is similar to that of adult heavyweight elite rowers, except that the junior rowers are lighter Compared with non-finalists, finalists are heavier (but still lighter than the adult heavyweight elite rower) and taller, with greater length, breadth (except for the bicristal diameter), and girth dimensions

Do high impact exercises produce higher tibial strains than running

Abstract: Background—Bone must have sufficient strength to withstand both instantaneous forces and lower repetitive forces. Repetitive loading, especially when bone strain and/or strain rates are high, can create microdamage and result in stress fracture Aim—To measure in vivo strains and strain rates in human tibia during high impact and moderate impact exercises. Methods—Three strain gauged bone staples were mounted percutaneously in a rosette pattern in the mid diaphysis of the medial tibia in six normal subjects, and in vivo tibial strains were measured during running at 17 km/h and drop jumping from heights of 26, 39, and 52 cm. Results—Complete data for all three drop jumps were obtained for four of the six subjects. No statistically significant differences were found in compression, tension, or shear strains with increasing drop jump height, but, at the 52 cm height, shear strain rate was reduced by one third (p = 0.03). No relation was found between peak compression strain and calculated drop jump energy, indicating that subjects were able to dissipate part of the potential energy of successively higher drop jumps by increasing the range of motion of their knee and ankle joints and not transmitting the energy to their tibia. No statistically significant differences were found between the principal strains during running and drop jumping from 52 cm, but compression (p = 0.01) and tension (p = 0.004) strain rates were significantly higher during running. Conclusions—High impact exercises, as represented by drop jumping in this experiment, do not cause higher tibial strains and strain rates than running and therefore are unlikely to place an athlete who is accustomed to fast running at higher risk for bone fatigue. Key Words: bone; strain; biomechanics; stress fractures; impact

Impact energy attenuation performance of football headgear

Abstract: Objectives —Commercially available football head protectors were tested to determine their impact energy attenuation performance and ability to reduce the likelihood of concussion Methods —Prospective study using standardised impact test methods with both rigid (magnesium) and Hybrid III headforms Results —Eight commercially available head protectors from six manufacturers were tested The magnitude of the headform accelerations increased as the drop height was increased, ranging from a minimum of 64 g from a height of 02 m to a maximum of 1132 g from a height of 06 m The head injury criterion and maximum headform acceleration values followed a similar trend A steep increase was noted in the magnitude of maximum headform acceleration and head injury criterion when the drop height was increased from 04 to 05 m This indicates that the foam material was completely compressed at an impact energy above about 20 J and therefore offers little protection against impacts of greater severity Repeated tests using a drop height of 03 m showed that some helmets exhibit a “memory” effect, whereby impact performance is reduced by up to 50% with repeated impacts Conclusions —Laboratory tests indicate that current commercially available football headgear performance will not reduce the likelihood of concussion The absence of internationally recognised standards for soft headgear designed to ameliorate concussion is a major deficiency in sports injury prevention

Isokinetic performance and shoulder mobility in elite volleyball athletes from the United Kingdom

Abstract: Objectives —To evaluate the differences in strength and mobility of shoulder rotator muscles in the dominant and non-dominant shoulders of elite volleyball players. Methods —Isokinetic muscle strength tests were performed at speeds of 60 and 120°/s, and shoulder mobility was examined in ten players from the England national men9s volleyball squad. The subjects also completed a questionnaire that included a visual prompt and analogue pain scale. Results —The range of motion of internal rotation on the dominant side was less than that on the non-dominant side (p Conclusions —These elite volleyball players had a lower range of motion (internal rotation) and relative muscle imbalance in the dominant compared with the non-dominant shoulder.

Is exercise effective treatment for osteoarthritis of the knee

Abstract: Objective —To review and determine the effectiveness of exercise treatment in osteoarthritis of the knee Methods —A computerised literature search of Medline was carried out searching between June 1966 and January 2000 Results —Twenty three randomised controlled trials were identified from the literature Only three trials were sufficiently powered Small to moderate beneficial effects of exercise treatment were found for pain, small beneficial effects on disability outcome measures, and moderate to great beneficial effects were observed according to patient global assessment of effect It was not possible to obtain evidence on the content of exercise interventions, as studies were hampered by lack of attention to proper concealment, reporting of adverse effects, and long term effects of exercise treatment The lack of standard outcomes measures is also noted Conclusions —The available evidence indicates beneficial short term effects of exercise treatment in patients with osteoarthritis of the knee However, the number of available studies is limited, and more research is needed to expand this recommendation Specifically, additional trials should provide information on adherence, home based interventions, interaction with pharmacological treatments, functional outcomes measures relevant to exercise treatment in these patients, and long term effects At present, doctors should recommend exercise to all patients with mild/moderate disease Further study should be encouraged and exercise should be continued to be recommended as a mainstay of non-pharmacological treatment of osteoarthritis of the knee

Dietary creatine supplementation does not affect some haematological indices, or indices of muscle damage and hepatic and renal function

Abstract: Background —The use of creatine (Cr) as a nutritional supplement to aid athletic performance has gained widespread popularity among athletes. However, concerns have recently been expressed over potentially harmful effects of short and long term Cr supplementation on health. Methods —Forty eight young healthy subjects were randomly allocated to three experimental protocols aimed at elucidating any potential health risks associated with five days (20 g/day) to nine weeks (3 g/day) of Cr supplementation. Venous blood samples were collected before and after periods of Cr supplementation and were analysed for some haematological indices, and for indices of hepatic, muscular, and renal dysfunction. Findings —All measured indices were well within their respective normal range at all times. Serum creatinine concentration tended to be increased the day after Cr supplementation. However, values had returned to baseline six weeks after the cessation of supplementation. These increases were probably attributable to increased creatinine production rather than renal dysfunction. No indication of impairment to the haematological indices measured, hepatic function, or muscle damage was apparent after Cr supplementation. Interpretation —These data provide evidence that there are no obvious adverse effects of acute or more chronic Cr supplementation on the haematological indices measured, nor on hepatic, muscle, and renal function. Therefore there is no apparent health risk associated with Cr supplementation to healthy people when it is ingested in quantities that have been scientifically proven to increase muscle Cr stores.