Time to get tough on doping!
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Doping in Sports↗
Biomedical subjects
R Bahr
Publications and source records attributed to R Bahr.
Ligament force and joint motion in the intact ankle: a cadaveric study.
The aims of this study were to measure the forces in the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) and the motion in the tibiotalar and subtalar joints during simulated weight-bearing in eight cadaver ankle specimens. An MTS test machine was used to apply compressive loads to specimens held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantarflexion and supination-pronation) could be varied in a controlled manner. The forces in the ATFL and CFL were measured with buckle transducers. Tibiotalar motion and total ankle joint motion were measured with an instrumented spatial linkage. The specimens were positioned sequentially at 10 degrees dorsiflexion, neutral, and 10 degrees and 20 degrees plantarflexion, and this sequence was repeated at 15 degrees supination, neutral pronation/supination, and 15 degrees pronation. Force and motion measurements were recorded in each of these positions with and without a 375 N compressive load simulating weight-bearing. From 10 degrees dorsiflexion to 20 degrees plantarflexion, all motion occurred in the tibiotalar joint. In contrast, the ratio of subtalar motion to tibiotalar motion was 3:1 for supination-pronation and 4:1 for internal-external rotation. Inverse loading patterns were observed for the ATFL and CFL from plantarflexion to dorsiflexion. Compressive loading did not affect CFL tension, but it magnified the pattern of increasing ATFL tension with plantarflexion. The largest increase in ATFL force was observed in supination and plantarflexion with a compressive load (76 +/- 23 N), whereas CFL tension mainly increased in supination and dorsiflexion with a compressive load (109 +/- 28 N). In conclusion, the results showed that the ATFL acted as a primary restraint in inversion, where injuries typically occur (combined plantarflexion, supination and internal rotation). Also, the subtalar joint was of primary importance for normal supination-pronation and internal-external rotation.
Adult↗
Effect of beta-adrenoceptor blockade on postexercise oxygen consumption and triglyceride/fatty acid cycling.
In the recovery period after strenuous exercise, there is increased O2 uptake, termed the excess postexercise O2 consumption (EPOC). One of the mechanisms suggested to explain EPOC is activation of the triglyceride/fatty acid (TG/FA) cycle by catecholamines. The purpose of this study was to determine the effect of selective beta1- and nonselective beta-adrenoceptor blockade on EPOC and the TG/FA cycle. Seven healthy young men each participated in three control and three exercise experiments in a randomized and balanced sequence. In the exercise experiments, subjects exercised for 90 minutes at 58% +/- 2% (mean +/- SD) of maximal O2 uptake on a cycle ergometer, followed by a 4.5-hour bedrest. The control experiments followed the same protocol, but without exercise. In one control and one exercise experiment, the selective beta1-adrenoceptor antagonist atenolol (0.062 mg.kg(-1) body weight) was administered intravenously immediately after the exercise (EXAT) and at the corresponding time in the rest-control experiment (REAT). In a second set of control and exercise experiments, the nonselective beta-adrenoceptor antagonist propranolol (0.15 mg.kg(-1) body weight) was administered (REPRO and EXPRO). In a third set of rest and exercise experiments, an injection of saline was given instead of beta-antagonist (RE and EX). TG/FA cycling was calculated by combining results obtained with a two-stage glycerol infusion and indirect calorimetry. O2 uptake was significantly increased above control levels throughout the recovery period after exercise with the nonselective beta-adrenoceptor antagonist, beta1-adrenoceptor antagonist, and saline. However, there was no difference between the time course or magnitude of EPOC in the three situations. After 4.5 hours of bedrest, the mean increase in O2 uptake was 8% to 9% in all three conditions. TG/FA cycling was increased after exercise, but no effects of beta-antagonists were observed. We conclude that EPOC and the rate of TG/FA cycling are not attenuated by selective beta1- or nonselective beta-adrenoceptor blockade after an acute prolonged exercise protocol.
Adrenergic beta-Antagonists↗
Effect of beta-adrenoceptor stimulation on oxygen consumption and triglyceride/fatty acid cycling after exercise.
The purpose of this study was to characterize the effects of prolonged beta-adrenoceptor stimulation on O2 uptake and triglyceride/fatty acid (TG/FA) cycling during rest with and without previous exercise. Eight men performed two exercise (90 min cycling at 56 +/- 3 (SD)% of maximal O2 uptake, followed by 4.5 h bed rest) and two rest-control experiments. In one rest and one exercise experiment a bolus dose (5 micrograms) of the beta-adrenoceptor agonist isoprenaline was given immediately after exercise, followed by a continuous infusion (20 ng kg-1 min-1), and at the corresponding time in the rest experiment. In the other experiments saline was given instead. The O2 uptake increased in the post-exercise period both with and without beta-stimulation. The total excess post-exercise oxygen consumption (EPOC) was not different between saline (8.1 +/- 1.8 (SE) L) and isoprenaline administration (10.8 +/- 1.8 L, P = 0.40). Also, the total accumulated increase in O2 uptake for the 4.5 h period after isoprenaline infusion was not different between the rest (12.5 +/- 2.0 L) and the exercise experiments (15.2 +/- 1.7 L, P = 0.40). The rate of TG/FA cycling increased after both exercise and isoprenaline treatment, but no interaction effect was found. In conclusion, the increases observed in O2 uptake and the rate of TG/FA cycling during beta-adrenoceptor stimulation were not increased by a previous exercise bout.
Adrenergic beta-Agonists↗
Adrenergic control of post-exercise metabolism.
After strenuous exercise there is a sustained increase in resting O2 consumption. The magnitude and duration of the excess post-exercise O2 consumption (EPOC) is a function of exercise intensity and exercise duration. Some of the mechanisms underlying the rapid EPOC component (<1 h) are well defined, while the mechanisms causing the prolonged EPOC component (>1 h) are not fully understood. It has been suggested that beta-adrenergic stimulation is of importance for the prolonged component. There is an increased level of plasma adrenaline and noradrenaline during exercise, and it is shown that catecholamines stimulate energy expenditure through beta-adrenoceptors. After exercise an increased fat oxidation and an increased rate of triglyceride fatty acid (TG-FA) cycling may account for a significant part of the prolonged EPOC component. These processes may be stimulated by catecholamines. However, the return of plasma concentration of catecholamines to resting levels after exercise is more rapid than the return of O2 uptake. But plasma concentration of catecholamines may be an insensitive indicator of sympathetic activity, since the clearance rate of catecholamines is high. Also, the sensitivity to catecholamines may be increased after exercise. A decreased post-exercise O2 uptake has been shown when beta-blockade is administered in dogs before the exercise bout. In a pilot study in humans, administration of beta-antagonist after exercise did not seem to change EPOC.
Animals↗
Prevalence of doping in sports: doping control in Norway, 1977-1995.
OBJECTIVE: To examine the results from doping controls conducted by the Norwegian Confederation of Sport (NCS) from 1977 to 1995. METHODS: Data were collected by combining three computerized databases and manual records on samples taken and results from analyses in the International Olympic Committee (IOC)-accredited laboratories in London, Huddinge, Cologne, and Oslo. Samples were declared positive if they contained any banned substance on the IOC list that was in effect at any given time. RESULTS: A total of 15,208 samples were taken; most of them (12,870; 85%) were from Norwegian athletes (90% unannounced tests) belonging to national federations under NCS jurisdiction (NCS members), 461 (3%) were from external Norwegian athletes (either users of private gyms or athletes in organized sports federations not affiliated with the NCS), and 1,874 (12%) were from foreign athletes (three cases with unknown affiliation). There were 130 positive samples and 24 refusals among NCS members (1.2%; men, 1.4%; women, 0.3%), 86 positive samples and 8 refusals among external Norwegian athletes (20%; men, 24%; women, 8%), and 39 positive samples and 1 refusal among foreign athletes (1.6%; men, 2.1%; women, 0.7%). A gradual decrease in the percentage of positive samples was observed among NCS members as testing frequency was increased gradually from 1987 to 1995 in the three high-prevalence sports: powerlifting, weightlifting, and athletics. CONCLUSION: An increase in the test frequency of doping tests was associated with a decrease in the percentage of positive samples in targeted sports.
Adult↗
A prospective cohort study of anterior cruciate ligament injuries in elite Norwegian team handball.
The purpose of this study was to examine gender differences in the incidence of anterior cruciate ligament (ACL) injuries in a population of high-level team handball players. We also wanted to examine injury mechanisms and possible risk factors for ACL injuries, including menstrual status. The study was done prospectively during the 1993-94, 1994-95, and 1995-96 seasons. We found 28 ACL injuries, 23 among women (incidence: 0.31 +/- 0.06 injuries per 1000 player hours) and 5 among men (0.06 +/- 0.03 inj./1000 h; P < 0.001 vs women; risk ratio: 5.0). Of the 28 injuries, 24 occurred during competition (0.91 +/- 0.19 inj./1000 h; women: 1.60 +/- 0.35 inj./1000 h; men: 0.23 +/- 0.13 inj./1000 h; P < 0.001 vs. women; risk ratio: 7.0) and 4 during training (0.03 +/- 0.02 inj./1000 h; P < 0.001 vs. competition; risk ratio: 29.9). Nearly all the injuries (n = 25) occurred in non-contact situations when the players performed high-speed plant-and-cut movements which they were well accustomed to. A reliable menstrual history could be obtained in 17 of the 23 cases among females. Five of the injuries occurred in the menstrual phase, 2 in the follicular phase, 1 in the early luteal phase and 9 in the late luteal phase (chi-square3 d.f. = 13.2; P < 0.01). The results suggest that there may be an increased risk of ACL injury during the week prior to or after the start of the menstrual period.
Adult↗
Normal bone mass in bulimic women.
The aim of this study was to examine the relationship among exercise, menstrual function, and bone mineral density (BMD) in different groups of age-matched patients with eating disorders. Dieting and eating disorder history, physical activity history, and menstrual history were assessed by clinical interview in 43 bulimic and 13 anorectic young women as well as in 17 healthy control subjects (18-29 yr). BMD was assessed by dual x-ray absorptiometry. All the anorectics but only 30% of the bulimics exercised regularly from the onset of their eating disorder (P < 0.01), mainly using aerobic dancing and running. All of the anorectics had been amenorrheic since the start of their symptoms, and 68% of the bulimics had a history of menstrual dysfunction. Within the exercise subgroups of bulimic patients, there was no significant relationship between BMD and current or previous menstrual function. Anorectic patients had lower BMD than bulimics and controls in all skeletal regions studied (P < 0.01). Bulimic patients who had exercised regularly during their illness had higher total body BMD than bulimics classified as sedentary (P < 0.01). Bulimics who had exercised regularly or intermittently since the onset of their eating disorder had higher BMD than sedentary bulimics in the lumbar vertebrae, femoral neck, and legs (P < 0.05). It appears that weight-bearing exercise can prevent or attenuate bone loss at specific skeletal sites in normal weight bulimic patients, but not in anorectics.
Absorptiometry, Photon↗
Muscle performance--fatigue, recovery and trainability.
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Animals↗
Incidence of acute volleyball injuries: a prospective cohort study of injury mechanisms and risk factors.
The purpose of the study was to examine the incidence and mechanisms of acute volleyball injuries, with particular reference to possible risk factors for ankle injuries. Coaches and players in the top two divisions of the Norwegian Volleyball Federation were asked to keep records of exposure time and all acute volleyball injuries causing a player to miss at least one playing day during one season. We found 89 injuries among 272 players during 51588 player hours, 45837 h of training and 5751 h of match play. The total injury incidence was 1.7 +/- 0.2 per 1000 h of play, 1.5 +/- 0.2 during training and 3.5 +/- 0.8 during match play. The ankle (54%) was the most commonly injured region, followed by the lower back (11%), knee (8%), shoulder (8%) and fingers (7%). Of the ankle injuries, 79% were recurrences, and the relative risk of injury was 3.8 (P < 0.0001) for previously injured ankles (38 of 232) vs. non-injured ankles (10 of the 234). Moreover, a reinjury was observed in 21 of the 50 ankles that had suffered an ankle sprain within the last 6 months (42.0 +/- 7.0%; risk ratio: 9.8 vs. uninjured ankles; P < 0.000001). The data indicate that external supports should be worn for 6-12 months after an ankle sprain and that specific injury prevention programs may be developed for ankle sprains in volleyball.
Adolescent↗
A twofold reduction in the incidence of acute ankle sprains in volleyball after the introduction of an injury prevention program: a prospective cohort study.
The purpose of this study was to examine the effects of an injury prevention program, consisting mainly of an injury awareness session, technical training (with emphasis on proper take-off and landing technique for blocking and attacking) and a balance board training program, for players with recurrent sprains. Baseline data were collected during the 1992-93 season and the program was introduced during the 1993-94 season. The 1994-95 season was used to evaluate the effects of the prevention program. The coaches and players in the top two division of the Norwegian Volleyball Federation kept monthly records of exposure time and acute injuries (causing a player to miss at least one playing day). The total exposure time was 149968 h, 132757 h of training and 17211 h of match play during the three seasons. The incidence of ankle injuries was reduced from 0.9 +/- 0.1 per 1000 player hours during the 1992-93 season (48 injuries) to 0.7 +/- 0.1 during the 1993-94 season (38 injuries; NS vs. 1992-93) and to 0.5 +/- 0.1 during the 1994-95 season (24 injuries, P < 0.01 vs. 1992-93).
Adult↗
Hemisection and vital treatment of a fused tooth--literature review and case report.
Fusion and gemination of permanent teeth are developmental anomalies of the dental hard tissues which may require endodontic and surgical treatment for functional, orthodontic or aesthetic reasons. Following a review of the dental literature on tooth fusion and gemination, a case of fusion of a maxillary central incisor and a supernumerary tooth and its endodontic and surgical treatment is presented.
Child↗
Mechanics of the anterior drawer and talar tilt tests. A cadaveric study of lateral ligament injuries of the ankle.
We analyzed the changes in lateral ligament forces during anterior drawer and talar tilt testing and examined ankle joint motion during testing, following an isolated lesion of the anterior talofibular ligament (ATFL) or a combined lesion of the ATFL and calcaneofibular ligament (CFL). 8 cadaver specimens were held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantarflexion and supination-pronation) could be varied in a controlled manner. Ligament forces were measured with buckle transducers, and joint motion was measured with an instrumented spatial linkage. An anterior drawer test was performed using an 80 N anterior translating force, and a talar tilt test was performed using a 5.7 Nm supination torque with intact ligaments, after sectioning of the ATFL, and again after sectioning of the CFL. The tests were repeated at 10 degrees dorsiflexion, neutral, and 10 degrees and 20 degrees plantarflexion. In the intact ankle, the largest increases in ATFL force were observed during testing in plantarflexion, whereas the largest increases in CFL force were observed in dorsiflexion. Isolated ATFL injury caused only small laxity changes, but a pronounced increase in laxity was observed after a combined CFL and ATFL injury.
Adult↗
Relationship between symptoms of jumper's knee and the ultrasound characteristics of the patellar tendon among high level male volleyball players.
This study assessed the ultrasound characteristics of the patellar tendon in two groups of volleyball players, one group without knee symptoms and one group with symptoms of jumper's knee. Of 47 male elite players, 25 were diagnosed to have current and seven to have had previous symptoms of jumper's knee, as determined by clinical examination. Since some players had bilateral problems, there were 34 knees with current problems and nine with previous problems. Seven of the 30 knees with a clinical diagnosis of jumper's knee in the patellar tendon had normal ultrasound findings, and ultrasound changes believed to be associated with jumper's knee (tendon thickening, echo signal changes, irregular paratenon appearance) were observed in 12 of 51 knees without symptoms. Specific ultrasound findings such as paratenon changes, hypoechoic zones or pathological tendon thickness proximally did not correlate significantly with the degree or the duration of symptoms. This study suggests that the specificity and sensitivity of ultrasonography is low in the evaluation of patients with mild symptoms of jumper's knee.
Adolescent↗
High prevalence of elbow problems among goalkeepers in European team handball -- 'handball goalie's elbow'.
The aim of this study was to describe elbow problems among goalkeepers in team handball. A questionnaire was sent to the coaches of 449 senior and 32 junior teams in Norway in 1992. Of these, 304 coaches responded (63%) and their teams were included in the study. A total of 329 out of 729 goalkeepers (45+/-1.8%) and 166 out of 4120 court players (4.0+/-0.3%) were reported by their coaches to have current or previous symptoms from one or both elbows when playing handball. In response to a second questionnaire sent to all the goalkeepers (729; response rate 81%), 41+/-2.0% reported current elbow problems and an additional 34+/-2.0% reported previous problems. During a 2-year observation period from 1992 to 1994, 8.6+/-1.8% of the goalkeepers with previously healthy elbows experienced elbow problems. The typical complaint was recurrent pain and disability episodes, each with an acute onset, but with varying duration. The mechanism of injury for the goalkeepers appears to be repeated hyperextension traumas. We conclude that elbow pain and disability is a significant problem for a large number of goalkeepers in team handball. These problems may be described as a syndrome called 'handball goalie's elbow'.
Adolescent↗
Early heart-attack care--the critical paradigm shift toward prevention. Interview by Michael Villaire.
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Coronary Care Units↗
Single (culprit) vessel disease in octogenarians with acute myocardial infarction and unstable angina.
It is generally thought that coronary artery disease (CAD) in octogenarians would involve multiple vessels. The purpose of the current study was to determine the relative importance of single vessel disease in octogenarians with acute myocardial infarction (AMI) and unstable angina and its outcome from a revascularization procedure such as percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG). Our study included 70 patients (25 men, 45 women) aged 80 or older (mean, 84.5 +/- 0.5) admitted for the first time to the St. Agnes Hospital coronary care unit during 1994 for AMI or unstable angina. Patients admitted primarily for congestive heart failure, cardiogenic shock, hypertensive heart disease, or cardiomyopathy were excluded. Fifty patients (71.4%) had AMI and 20 (28.6%) had unstable angina. Of the 19 patients who had cardiac catheterization done, 10 had single vessel disease, 8 had flow-limiting disease in 2 or more coronary arteries, and 1 had no flow-limiting disease. The mean ejection fraction was 56.5 +/- 6.9 in patients with single vessel disease, 48.0 +/- 3.3 in those with multiple vessel disease, and 38.7 +/- 1.7 in those who did not have cardiac catheterization done. Fourteen PTCA (20%) and 3 CABG (4.3%) were performed without inhospital mortality from the procedures. There were 9 deaths (12.9%) overall: none among 10 patients with single vessel disease, 1 (12.5%) among 8 patients with widespread CAD, and 8 (15.7%) among 51 patients who did not have cardiac catheterization. Study results emphasize the need for recognition and treatment of single vessel disease by revascularization procedures to reduce mortality from CAD in octogenarians.
Aged↗
American College of Emergency Physicians information paper: chest pain units in emergency departments--a report from the Short-Term Observation Services Section.
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Angina Pectoris↗