摘要:

Risk of medical events in a supervised health and fitness facility.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1233-1236, 1999.Purpose:This prospective epidemiological study examined the incidence of medical events during participation in a supervised health and fitness facility at a major medical center.Methods:Participants consisted of 7725 members of a corporate health and fitness program. Risk was defined by number of medical incidents per total number of event episodes multiplied by the average time of activity per episode (1000 participant-hours).Results:The first 2.5 yr of surveillance revealed 15 reported medically significant events (.048 per 1000 participant-hours). There were two medical emergencies yielding a rate of .0063 per 1000 participant-hours.Conclusion:The results of this study support the position that the expected health benefits of participation in a physical activity program at a supervised health and fitness facility outweigh the risks of such participation.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Exercise gas exchange responses in the differentiation of pathologic and physiologic left ventricular hypertrophy.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1237-1241, 1999.Purpose:The purpose of the present investigation was to examine differences that may exist in maximal and submaximal exercise gas exchange parameters and their use in differentiating pathological and physiological left ventricular hypertrophy.Methods:Exercise gas exchange responses were measured on-line during a maximal ramping cycle-ergometer exercise test in 10 young, male hypertrophic cardiomyopathy (HCM) patients, 11 elite triathletes, and 9 normal controls.Results:The HCM patients exhibited significantly lower &OV0312;O2max, anaerobic threshold (AT) in both absolute terms (AT&OV0312;O2) and as a percentage of &OV0312;O2max(AT%&OV0312;O2max), and oxygen-pulse (O2-pulse) compared with triathletes and normal controls. Elite triathletes exhibited significantly increased &OV0312;O2max, %&OV0312;O2max, AT&OV0312;O2, AT%&OV0312;O2max, and O2-pulse compared with controls. The &OV0312;E/&OV0312;CO2at AT was significantly increased in the HCM patients compared with triathletes and controls, whereas no difference was observed between triathletes and controls.Conclusions:Maximal and submaximal exercise gas exchange responses may be used as an additional noninvasive tool in the differential diagnosis of physiologic and pathologic left ventricular hypertrophy.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Energy metabolism during anaerobic exercise in children with cystic fibrosis and asthma.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1242-1249, 1999.Purpose:The nature of a child's daily physical activity requires both aerobic and anaerobic energy metabolism. Aerobic exercise becomes compromised with advancing airway obstruction in children with cystic fibrosis (CF) and asthma (AS). Whether children with CF will have altered metabolic responses to supramaximal exercise when compared with asthmatics or healthy controls is still undetermined.Methods:Twenty-five children with CF, 22 with AS, and 23 healthy controls (CN) performed an incremental graded aerobic and Wingate anaerobic test (WAnT) on a cycle ergometer. Analysis of gas exchange and ventilatory data was collected and averaged every 5 s to estimate ventilatory kinetics and energy system contributions during both tests.Results:The CF and AS groups had mild lower airway obstruction (FEF25-75% < 80%) as compared with the CN. All three groups demonstrated similar anaerobic (mean and peak power during the WAnT) and aerobic exercise performance (peak oxygen consumption). In contrast to the AS or CN groups, children with CF used a lower percentage of their peak &OV0312;O2and &OV0312;Eduring each phase of the WAnT, suggesting a preferential use of ATP/phosphocreatine and glycolytic energy stores compared with aerobic pathways. Greater reliance on anaerobic pathways during the WAnT in children with CF could be due to the physiologic sequelae underlying chronic obstructive lung disease.Conclusions:Oxygen uptake kinetics appeared similar for all three groups. Although the energy needed to perform the WAnT can be met by subjects with CF, abnormalities in energy metabolism may exist for this group during exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Reduced resting metabolic rate in athletes with menstrual disorders.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1250-1256, 1999.Purpose:This study investigated metabolic and nutritional determinants in association with menstrual disorders in athletes. Athletes with normal menstrual function (AN;N= 21) and athletes with menstrual disorders (AD;N= 12) participated in this study.Methods:The quality of the menstrual cycle was judged according to salivary progesterone concentrations. Resting metabolic rate (RMR) and diet-induced thermogenesis (DIT) were measured by indirect calorimetry. Body composition, energy intake and restrained eating scores were obtained.Results:When adjusted for body composition by ANCOVA, RMR was significantly (∼460 kJ,P< 0.02) lower in athletes with menstrual disorders than in athletes without menstrual disorders. The DIT and the daily energy intake of the groups did not differ. Athletes with menstrual disturbances scored significantly higher on the Restraint Eating Scale (TFEQ). Thyroid hormones (fT3and fT4), analyzed by a competitive chemiluminescent immunoassay, were in the normal range and not different between groups.Conclusions:The results provide evidence that restrained eating and low RMR are associated with menstrual cycle disturbances in athletes.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Reliability of submaximal exercise tests in patients with COPD.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1257-1264, 1999. Submaximal constant work rate exercise tests are often used to measure the efficacy of an exercise intervention, but the reliability of these tests in patients with chronic obstructive pulmonary disease (COPD) has not been established.Purpose:To examine the reproducibility of submaximal exercise responses of COPD patients compared with those of healthy elderly subjects.Methods:Sixteen COPD patients and 15 healthy subjects performed four weekly submaximal exercise tests against two different constant work rates: 20 W and 50% of the peak work rate (PWR). Spirometry was performed before each exercise test. COPD patients and healthy subjects were: age 69 ± 5 and 65 ± 5 yr, body mass index 26.4 ± 3.9 and 26.7 ± 3.0 kg·m−2, respectively.Results:Both groups had no change in minute ventilation (&OV0312;E), oxygen uptake (&OV0312;O2), breathlessness (RPB), and leg fatigue (RPLF) for either work rate over repeated measures (P> 0.05). At 50% PWR test-retest reliability coefficients for &OV0312;Eand &OV0312;O2ranged from r = 0.88 to r = 0.96 for COPD patients and from r = 0.72 to r = 0.97 for healthy subjects; for RPB and RPLF test-retest reliability ranged from r = 0.76 to r = 0.89 for COPD patients and from r = 0.70 to r = 0.91 for healthy subjects. Intrasubject mean absolute differences for repeated measures of &OV0312;E, &OV0312;O2, RPB, or RPLF were low and there were no group differences (P> 0.05). Percent error for &OV0312;Eand &OV0312;O2ranged from 6 ± 3 to 9 ± 7%, and for RPB and RPLF ranged from 19 ± 18 to 68 ± 65% for both groups at each work rate.Conclusions:Submaximal exercise responses were reliable over a 1-month period, and measures of the physiological and psychophysical responses of COPD patients were as reliable as those of healthy subjects.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Abnormal eating behaviors in military women.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1265-1271, 1999.Purpose:The purpose of this study was to evaluate the prevalence of abnormal eating behaviors in women on active duty in the Army.Methods:A total of 423 female soldiers from the general population on active duty volunteered to participate in this study. They completed the Eating Disorder Inventory (EDI) questionnaire. Each questionnaire was screened and any woman on active duty practicing abnormal eating behaviors (criteria set up by the authors) underwent an interview. A diagnosis, using DSMIV criteria, of one of the following was determined from the interview: 1) No eating disorder, (2) Anorexia nervosa, 3) Bulimia nervosa, 4) binge eating disorder, 5a) Eating disorder NOS, and 5b) Situational eating disorder. A situational eating disorder was defined as any abnormal eating behaviors consistent with an eating disorder NOS that was practiced intermittently and in response to external pressures associated with significant distress, such as military weigh-ins or army physical fitness testing (APFT).Results:Of the 423 women on active duty who participated, 33.6% (N= 142) met the questionnaire screening criteria for being "at risk" for abnormal eating behaviors and underwent an interview. Of the 142 women interviewed, 33 (8%) women were diagnosed with an eating disorder. The women with eating disorders exercised, felt dissatisfied with their weight, and felt significantly more pressure about their weight than the women without eating disorders. In addition, they also had significantly greater scores on the Drive for Thinness (DT), Bulemia (B), and Body Dissatisfaction (BD) subscales, and the total EDI scores for both the 8 and 11 subscales.Conclusion:In the women on active duty in the Army studied, there was an 8% prevalence of eating disorders.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Discus throwing performances and medical classification of wheelchair athletes.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1272-1279, 1999.Purpose:The purpose of this study was to identify those kinematic characteristics that are most closely related to the medical classification and measured distance of a throw.Methods:Two S-VHS camcorders (60 fields·s−1) were used to record the performance of 14 males of different classes. Each subject performed 10 trials and the best two trials from each subject were selected for analysis. Three-dimensional kinematics of the discus and upper body segments at the instant of release and the range of motion and average angular speed of different segments during the final forward swing were determined.Results:The speeds of the discus at release, ranging from 9.9 to 17.2 m·s−1, were smaller than those exhibited by elite male able-bodied throwers. However, the angles of release, ranging from 24.6 to 41.4°, were comparable with those observed in able-bodied throwers. Of the segmental kinematic parameters, (a) the inclination and angular speed of the upper arm at release; (b) the ranges of motion of the shoulder girdle, upper arm, and forearm during the forward swing; and (c) the average angular speed of the shoulder girdle during the forward swing were significantly correlated to both the classification and measured distance. The inclinations of different segments at the instant of release suggested that athletes with high level of spinal cord injury emphasized the elbow flexion to compensate for the deficiency in shoulder girdle movement.Conclusions:In addition to the speed of the discus at release, the shoulder girdle movement during the forward swing is an important determinant of classification and measured distance.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Carbohydrate-electrolyte ingestion during intermittent high-intensity running.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1280-1286, 1999.Purpose:The purpose of this study was to examine the effects of ingesting a carbohydrate-electrolyte beverage or a noncarbohydrate placebo on muscle glycogen utilization during 90 min of intermittent high-intensity running.Methods:Six trained games players (age 24.6 ± 2.2 yr; height 179.6 ± 1.9 cm; body mass 74.5 ± 2.0 kg; &OV0312;O2max56.3 ± 1.3 mL·kg−1·min−1; mean ± SEM) performed two exercise trials, 7 d apart. The subjects were university soccer, hockey, or rugby players. On each occasion, they completed six 15-min periods of intermittent running, consisting of maximal sprinting, interspersed with less intense periods of running and walking. During each trial, subjects consumed either a 6.9% carbohydrate-electrolyte solution (CHO-E: the CHO trial) or a noncarbohydrate placebo (the CON trial) immediately before exercise (5 mL·kg−1BM) and after every 15 min of exercise thereafter (2 mL·kg−1BM). Drinks were administered in a double-blind, counter-balanced order, and the total volume of fluid consumed during each trial was 1114 ± 30 mL. Needle biopsy samples were obtained from the vastus lateralis muscle before and after 90 min of exercise. Venous blood samples were collected from an antecubital vein at rest and every 30 min during exercise.Results:Muscle glycogen utilization in mixed muscle samples was lower (P< 0.05) during CHO [192.5 ± 26.3 mmol glucosyl units (kg·DM−1)] than CON [245.3 ± 22.9 mmol glucosyl units (kg·DM−1)]. Single fiber analysis on the biopsy samples of the subjects during the CON trial showed a greater glycogen utilization in the Type II fibers compared with Type I fibers during this type of exercise [Type I: 182.2 ± 34.5 vs Type II: 287.4 ± 41.2 mmol glucosyl units (kg·DM−1);P< 0.05). After 30 min of exercise, blood lactate was significantly greater (P< 0.05) and serum insulin concentration lower (P< 0.05) in CON.Conclusions:In summary, when trained games players ingested a carbohydrate-electrolyte beverage, muscle glycogen utilization was reduced by 22% when compared with a control condition.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Eccentric muscle action increases site-specific osteogenic response.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1287-1292, 1999.Purpose:Strain magnitude is known to be a primary determinant of the osteogenic response to loading. However, whether bone adaptation to muscle loading is determined primarily by load magnitude is unclear. The purpose of this study was to determine the contribution of load magnitude from muscle action on the site-specific osteogenic response.Methods:Twenty young women (12 exercise, 8 control) served as subjects. Bone mineral density (BMD) of the whole body and mid-femur segment and body composition were determined by dual-energy x-ray absorptiometry. Knee extension and flexion strengths were determined on a KinCom dynamometer, with surface electromyography of the vastus lateralis muscle. Exercise subjects trained three times weekly for 18 wk on a KinCom. One leg trained using eccentric knee extension and flexion, and the opposite leg trained using concentric knee extension and flexion.Results:Eccentric exercise demonstrated greater force production with lower integrated electromyographic signal (IEMG) compared with concentric exercise. Significant increases in muscle strength occurred in both exercised legs (P< 0.05), which were of similar relative change. However, only the eccentric trained leg significantly increased mid-femur segment BMD (+3.9%,P< 0.05) and mid-thigh segment lean mass (+5.2%,P< 0.05).Conclusions:These results suggest that eccentric muscle training is more osteogenic than concentric muscle training and that eccentric training is more efficient by attaining higher force production with lower IEMG.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Polycythemia decreases fatigue in tetanic contractions of canine skeletal muscle.Med. Sci. Sports Exerc.,Vol. 31, No. 9, pp. 1293-1298, 1999.Purpose:The effects of an acute polycythemia on muscle fatigue development were investigated in the self-perfused canine gastrocnemiusin situ.Methods:Following isolation of the gastrocnemius, dogs (N= 5) were made polycythemic through a bolus injection of packed erythrocytes (hematocrit (Hct) = 90-92%) to raise systemic Hct to 63.5 ± 0.5%. Subsequently, the gastrocnemius was stimulated, through the sciatic nerve, to perform 20 min of isotonic tetanic contractions (60·min−1, 200 ms, 50Hz). Control (normocythemic) animals (N= 5) underwent an identical contraction regimen.Results:Although blood flow to the gastrocnemius was not different at any time, oxygen delivery was significantly increased during polycythemia (peak = 33.7 ± 2.2 mL·100 g−1·min−1) over control (peak = 25.1 ± 2.1 mL·100 g−1·min−1) at all times during contraction. Oxygen uptake by the gastrocnemius, although consistently increased, was not significantly different between the normocythemic and polycythemic conditions at any time. The rate of fatigue was significantly decreased over the first 6 min of contraction in polycythemic animals (3.5 ± 0.6%·min−1) when compared with controls (5.8 ± 0.7%·min−1). Subsequent fatigue development was not different between groups. As a result of the early rate differences in fatigue, however, the work production in polycythemic animals was significantly greater than in normocythemic dogs for the duration of the contraction period.Conclusion:We conclude that during high metabolic rate isotonic tetanic contractions, muscle fatigue development is diminished by polycythemia, but the ergogenic effect appears to be transient.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID