摘要:

The ethics of blood testing as an element of doping control in sport.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 497-501, 1999. Sport authorities continue to confront a variety of perplexing issues as they attempt to address effectively and efficiently the problems posed by doping. The emergence of the phenomena of blood doping and the administration of erythropoietin have added to the challenges faced by doping control authorities. Some sport organizations have introduced blood tests in an attempt to deal with these issues despite the absence of any effective test for the detection of the administration of homologous blood products or eythropoietin. A number of ethical issues are raised by such developments. Even in the presence of an effective test it is suggested that the decision to implement a specific testing approach can be reached by considering the wishes of a hypothetical "Fair Competitor" and an analysis of the costs involved. In this respect the Fair Competitor assumes in the sport community the role that the "reasonable person" occupies in law, permitting an analysis of a proposed course of action. In making any decision regarding the implementation of any test, a Fair Competitor would be guided by considerations of the postulated advantage and incidence of a doping technique, the likelihood of false positive and negative results, the risk of unwanted consequences of a testing process, and a concern that a specific test not accelerate the likelihood of the use of other doping methods. This approach is applied to a consideration of the appropriateness of blood testing in sport. It is concluded, using such an analysis, that in their present state of development, blood tests should not be implemented. It is recognized that certain sport authorities currently use blood tests to exclude competitors whose blood values exceed certain predetermined levels on the grounds of concerns regarding health and safety. Screening of this kind is beyond the purview of this discussion.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Enlargement of remaining patella after partial patellectomy in rabbits.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 502-506, 1999.Purpose:The purpose was to study the radiographic patellar tendon calcification and evaluate the histology of the healing interface between the patellar tendon and the remaining patella after partial patellectomy.Methods:We removed the distal one-third of the patella in 24 rabbits. Specimens were harvested at 8, 12, and 24 wk postoperatively (N= 8 each).Results:Histological observation demonstrated that healing interfaces between the patellar tendon and patella were structurally connected by scar tissue. The radiographic patellar tendon calcification next to the healing interface was in fact trabecular bone outgrowth histologically, resulting in an enlargement of the remaining patellar in length from 0.93 ± 0.28 mm at week 8, 1.26 ± 0.33 mm at week 12, to 2.5 ± 1.12 mm at week 24. Metaplasia of the scar tissue observed next to the healing interface of the remaining patellar articular cartilage and the outgrowth of trabecular bone from the remaining patella with healing over time may increase the articular surface of the remaining patella after partial patellectomy.Conclusions:The remaining patella might be enlarged in length after partial patellectomy because of trabecular bone outgrowth and metaplasia with healing over time. Its theoretical advantages are an increased patellofemoral contact area and a diminished patellofemoral contact pressure following surgery.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Basophil releasability in young highly trained and older athletes.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 507-513, 1999.Purpose:Exercise-induced hypoxemia in highly trained athletes is associated with an increase in histamine release during exercise. The cells most implicated in blood histamine release are basophils. The aim of this study was to determine whether high-level endurance training induces modifications in histamine releasability from human basophils.Methods:Seven young highly trained athletes (YA) [aged 26.1 ± 1.3 yr (mean ± SEM)] and seven master athletes (MA) (64.4 ± 4.1 yr), all known to develop exercise-induced hypoxemia, were respectively compared with seven young untrained men (YC) (23.0 ± 1.5 yr) and seven older untrained men (OC) (61.6 ± 1.3 yr). During an incremental exhaustive exercise, blood samples for measurement of anti-IgE-induced histamine release from leukocytes were drawn at rest, &OV0312;O2max, and recovery.Results:Basophils from "leukocyte-rich" supernatant in YA and MA showed significantly higher histamine release induced by anti-IgE (1 μg·mL−1) than, respectively, YC (P< 0.01) and OC (P< 0.05) at rest, &OV0312;O2max(P< 0.01), and recovery (P< 0.01). Basophils in YA and MA also showed a histamine release induced by anti-IgE that was higher at &OV0312;O2maxthan at rest (respectively,P< 0.01 andP< 0.05), but this change was not found in the control groups.Conclusion:In conclusion, the basophils in highly trained endurance athletes, both young and older, showed higher anti-IgE-induced histamine release than those of untrained men. This effect of high-level training seemed to be potentiated by exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Effects of anabolic-androgenic steroids on weight-lifters' myocardium: an ultrasonic study.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 514-521, 1999.Background:Recent bioptical data have shown that in weight-lifters (WL) under the pharmacological effects of anabolic-androgenic steroids (AAS), a focal increase in myocardial collagen content might occur as a reparative mechanism against a myocardial damage.Objective:The aim of this study was to investigate whether by using videodensitometry an early identification of the changes in myocardial texture is possible or a potential sign of myocardial damage, which can potentially occur in WL who have used AAS.Methods:Ten males WL (mean age: 32 ± 6 yr) who had regularly used AAS (users), were compared with 10 male WL at same training level (nonusers), who had not used any drugs and with 10 healthy sedentary controls (controls). The three groups were age and sex-matched. Echocardiographic parietal, septal thickness, and left ventricular mass (LVMbs) were evaluated. Left ventricular systolic and diastolic functions were evaluated with Doppler examination. Quantitative analysis of echocardiographic digitized data was carried out with a calibrated 256 gray level digitization system, in order to calculate the mid-septum and the mid-posterior mean gray level (MGL) and to derive the cyclic variation index (CVI), i.e., the percent MGL variation during cardiac cycle.Results:The weight and relative body mass index were significantly higher in WL (P< 0.001); also the diastolic blood pressure was slightly but significantly higher in users in comparison both with nonusers and controls (P< 0.01). Systolic and diastolic functional parameters overlapped in the three groups. LVMbswas significantly higher in users (145 ± 17) and in nonusers (122 ± 27) vs C (104 ± 18 g·m−2) (P< 0.001). CVI at septum level showed significant differences: users: (−2.3 ± 31%) vs nonusers: (23 ± 8) and controls (29 ± 5) (P< 0.005); although no significant difference was found between nonusers and controls. CVI at posterior wall level followed a similar pattern. No relationship was found between CVI and LVMbsor wall thickness.Discussion:As brought out by videodensitometry, despite an increase in septal and parietal thickness and consequently in LVMbs, the physiological pressure overload that happens in WL during sport activities, in absence of any drugs, does not modify the myocardial ultrasonic texture. The abuse of AAS in WL, on the other hand, determines some alterations of the myocardial textural parameters. The real significance of these changes of myocardial texture detected with videodensitometry in WL who use anabolic-androgenic steroids, present also in the absence of other systolic and diastolic left ventricular functional indexes alterations, needs to be further explored with a larger population through the comparison with endobioptical data and with a follow-up study approach.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Short-term effects of exercise on plasma very low density lipoproteins (VLDL) and fatty acids.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 522-530, 1999.Purpose:In the fasted state the lipid fuels for muscle metabolism are free fatty acids (FFA) released either from intramuscular triglycerides (TG), plasma albumin, or TG in circulating very low density lipoproteins (VLDL). The purposes of this study were to determine the influence of acute exercise of moderate intensity on 1) plasma total concentration of TG and VLDL components, 2) the plasma concentration and distribution of individual albumin-bound long-chain FFA, and 3) lipid peroxidation as measured by thiobarbituric acid reactive substances (TBARS).Methods:Eight healthy male subjects each participated in one exercise (EX) and one rest (RE) experiment. In EX the subjects exercised for 90 min at 58 ± 5% (mean ± SD) of maximal O2uptake on a cycle ergometer followed by 4.5 h bedrest. RE followed the same protocol, but without exercise.Results:In EX there was no immediate change in VLDL concentration during the exercise. After exercise there was a decrease in VLDL, VLDL-TG, -cholesterol, -protein and -phospholipids compared with those after RE. There was no change in percentage composition of VLDL as result of exercise. Total plasma FFA concentration increased appreciably during exercise and remained elevated for several hours postexercise. There was no correlation between the change in FFA concentration and VLDL-TG. There was a significant positive correlation between the exercise-related increments in the various long-chain FFA, but the effect varied so that the relative abundance of oleic acid increased and that of stearic and arachidonic acid decreased during exercise. Plasma TBARS concentration increased during the day in both experiments.Conclusion:The results indicate that there is a delay in the effect of an exercise bout on plasma VLDL and confirm that exercise affects various FFA in plasma differentially.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Fibroblast responses to variation in soft tissue mobilization pressure.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 531-535, 1999. Augmented soft tissue mobilization therapy (ASTM), a newly developed massage therapy, has been successfully used in the treatment of chronic tendinitis patients. We theorized that the ASTM technique promotes healing through a controlled application of microtrauma.Purpose:The purpose of this study was to determine morphologic changes in the rat Achilles tendon after enzyme-induced injury with collagenase and subsequent pressure variations in ASTM therapy.Methods:Thirty male white rats were randomly assigned to one of five groups with six animals per group: tendinitis (A), tendinitis plus light ASTM (B), tendinitis plus medium ASTM (C), tendinitis plus extreme ASTM (D), and control with surgery only (E). ASTM was performed for 3 min, for a total of six treatment sessions. The Achilles tendons of each group were harvested 1 wk after the last ASTM treatment. Fibroblast numbers were assessed by light microscopy. An electron microscope was used to observe enlargement of fibroblasts.Results:Statistical analysis of the number of fibroblasts present indicated a significant difference (P< 0.00) between group D and all other groups.Conclusion:The morphological evidence indicated that the application of heavy pressure promoted the healing process to a greater degree than light or moderate pressure.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Neuroendocrine responses to running in women after zinc and vitamin E supplementation.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 536-542, 1999.Purpose:The study was undertaken to determine whether acute supplementation with zinc or vitamin E would modify neuroendocrine responses to physiologic stress.Methods:Specifically, the effects of exhaustive running on blood glucose, lactate, ACTH, cortisol, growth hormone, prolactin, catecholamine, and interleukin 6 (IL-6) concentrations were determined in 10 eumenorrheic runners after supplementation with zinc (25 mg), vitamin E (400 IU), or placebo. Subjects ran at 65-70% of their &OV0312;O2max, to exhaustion, on a treadmill during the follicular phase of their menstrual cycles over three cycles.Results:There were no significant differences associated with supplementation for any of the hormonal and metabolic measures. Exercise, however, significantly (P< 0.05) increased plasma lactate, ACTH, prolactin, and catecholamine concentrations, all of which peaked immediately after exercise (POST). Plasma cortisol concentrations were significantly (P< 0.05) elevated at POST, and a further increase was noted 1 h after exercise. IL-6 concentrations rose linearly throughout exercise and reached peak values at POST. Exercise-induced changes were transient in that all measures returned to baseline within 24 h.Conclusions:Acute supplementation with zinc or vitamin E did not influence the effects of exhaustive running on metabolic and endocrine responses in women. The effects of chronic supplementation on neuroendocrine responses to exercise remain to be determined.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Effects of acute exercise on plasma erythropoietin levels in trained runners.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 543-546, 1999.Purpose:The purpose of this study was to investigate further the influence of exercise on erythropoietin.Methods:We observed the effects of high intensity running on plasma erythropoietin concentration in competitive distance runners. A repeated measures design was used to compare the responses of intermittent high intensity (HIGH) exercise to continuous moderate intensity (MOD) exercise and rest (REST). The HIGH treatment consisted of 60 min of exercise alternating 5 min of running at ∼90% of &OV0312;O2maxwith 5 min of brisk walking. The MOD treatment consisted of a continuous 60-min run on the treadmill at 60% of &OV0312;O2max. Blood samples were collected immediately before the exercise (PRE), immediately following the exercise (POST), and 4 (heart rate (4HR), 12 (12HR), 24 (24HR), and 48 (48HR)) h following the exercise. The variables examined included plasma erythropoietin concentration ([EPO]), hemoglobin (Hb) concentration ([Hb]), hematocrit (Hct), red blood cell count (RBC), and mean corpuscular volume (MCV).Results:ANOVA revealed the expected treatment-by-time interaction for Hct and [Hb] suggesting a hemodilution at 24 and 48 h postexercise for the MOD and HIGH treatments. However, no significant treatment-by-time interactions were observed for [EPO], RBC, or MCV.Conclusion:These results indicate that intermittent high intensity exercise does not have a significant effect on [EPO] in trained distance runners.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The hormonal response to ad-fenfluramine challenge in trained and sedentary men.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 547-553, 1999.Purpose:The purpose of the present study was to examine the responsiveness of serotonergic receptors in endurance trained and sedentary men.Methods:The serum prolactin and cortisol responses to the oral administration of 30 mg of the serotonin releaser and reuptake inhibitord-fenfluramine were determined in eight male endurance-trained subjects and seven male sedentary controls.Results:A Friedman's repeated-measures test for both the endurance-trained (P= 0.006) and sedentary (P= 0.018) prolactin results demonstrated a change in the mean prolactin concentration over time, but no difference in prolactin response was observed between the subject groups (P= 0.81). In both subject groups, the serum cortisol concentration remained unchanged. However, the mean serum concentration of cortisol for the endurance-trained subjects at each time point tended to be lower than at the corresponding time point for the sedentary subject group and was significantly lower at 180 min (P= 0.04).Conclusion:The present study suggests that, in contrast to an earlier report of down-regulation of 5-HT1Areceptor function in endurance-trained subjects in response to a nonspecific challenge, postsynaptic 5-HT2function as determined by thed-fenfluramine-evoked alteration in the plasma concentration of prolactin is not altered by endurance training.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Exercise and recovery responses of adrenal medullary neurohormones to heavy resistance exercise.Med. Sci. Sports Exerc.,Vol. 31, No. 4, pp. 554-559, 1999.Purpose:The purpose of this study was to examine the effect of dynamic resistance exercise on the response patterns of adrenal medullary neurohormones in strength-trained men.Methods:Ten strength-trained men (21.7 ± 0.58 yr) gave informed consent and performed two resistance exercise protocols, high force and high power, of equal total work in a randomized order separated by 1 wk. Blood samples were obtained pre-exercise (baseline), 0 (R-0), 15 (R-15), and 240 (R-240) min postexercise and under resting control conditions for each time point.Results:There were no significant differences in control concentrations for each time point and no difference in pre-exercise values between the two resistance exercise protocols for plasma lactate, epinephrine, plasma peptide F (P-F), or norepinephrine (NE). Plasma lactate significantly (P≤ 0.05) increased from baseline for both protocols; however, concentrations were higher in response to the high force protocol. Plasma epinephrine was significantly increased from baseline at R-0 and returned to baseline at R-15 for both protocols. In contrast, plasma P-F was significantly decreased at R-0 from baseline; however, at R-240 P-F had significantly increased to >80% baseline for both protocols.Conclusions:These results indicate that the adrenal medulla was activated in response to the acute stress of both types of heavy resistance exercise. Furthermore, during longer recovery periods, the adrenal medulla was also active above baseline conditions as increased concentrations of proenkephalin fragments (i.e., P-F) were detected in the circulation.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID