ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BERTRAND METTAUER, BERNARD GENY, EVE LONSDORFER-WOLF, ANNE CHARLOUX, QUAN MING ZHAO, BERNADETTE HEITZ-NAEGELEN, ERIC EPAILLY, ELIANE LAMPERT, FRANÇOIS LEVY, and JEAN LONSDORFER. Exercise training with a heart device: a hemodynamic, metabolic, and hormonal study.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 000–000.Purpose:The mechanisms of the training-induced improvements in left ventricular assist (LVAD) patients are unknown.Methods:We measured the hemodynamic, gas exchange, and metabolic and hormonal effects of 6-wk exercise training in a cardiogenic shock patient who was assisted by an LVAD.Results:After training, the peak power and O2increased by 166% and 56%, respectively (80 W and 16.1 mL·min-1·kg-1), whereas the ventilatory drive decreased. Although the LVAD output increased little with exercise, the systemic cardiac output rose (adequately for the O2) from 5.91 and 4.90 L·min-1at rest to 9.75 and 9.47 L·min-1at peak work rate, before and after training, respectively. Thus, the left ventricle ejected again through the aortic valve. Unloading and/or retraining resulted in a left ventricular filling pressure decrease. Although the right ventricular ejection fraction increased with exercise, it decreased again at the maximal load after training. For a given work rate the arterial lactate, the norepinephrine (NE) and epinephrine (E) concentrations fell after training, but the enhanced maximal work rate elicited higher NE and E concentrations (4396 and 1848 pg·mL-1, respectively). The lack of right ventricular unloading might have kept the atrial natriuretic peptide higher after training, but the blood cyclic GMP and endothelin were lower after training.Conclusion:In an LVAD patient, retraining returns the exercise capacity to the class III level by peripheral and left ventricular hemodynamic improvements, but the safety of maximal exercise remains to be proven in terms of right ventricular function and orthosympathetic drive.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

MORRIS, F. L., and J. D. WARK. An effective, economic way of monitoring menstrual cycle hormones in at risk female athletes.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 9–14.Purpose:Female athletes, in response to intensive training, competition stress and a lean, athletic physique, are at increased risk of altered hypothalamic-pituitary ovarian (HPO) axis function associated with menstrual cycle disturbance and reduced secretion of the ovarian hormones estrogen and progesterone. Because there is evidence suggesting possible detrimental effects on skeletal health associated with deficiencies in these hormones, a suitable means to asses ovarian hormone concentrations in at risk athletes is needed. The aim of this study was to evaluate a simple, economical means to monitor the ovarian hormone production in athletes, in the setting of intensive training.Methods:Subjects comprised 14 adolescent rowers, 12 lightweight rowers, and two groups of 10 matched control subjects. Ovarian function was monitored during the competition season by estimation of urinary excretion of estrone glucuronide (E1G) and pregnanediol glucuronide (PdG), enabling the menstrual cycles to be classified as ovulatory or anovulatory.Results:Results indicated 35% and 75% of schoolgirl and lightweight rowers had anovulatory menstrual cycles, respectively. These findings were highlighted by significantly lower excretion of E1G and PdG during phases of intensive training in both the lightweight and schoolgirl rowers, compared with the control subjects.Conclusion:It was concluded that the urinary E1G and PdG assays were an effective means to assess the influence of intense training on ovarian hormone concentrations in at risk athletes. It is recommended that this technique be applied more widely as a means of early detection of athletes with low estrogen and progesterone levels, in an attempt to avoid detrimental influences on skeletal health.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

GREMION, G., R. RIZZOLI, D. SLOSMAN, G. THEINTZ, and J-P. BONJOUR. Oligo-amenorrheic long-distance runners may lose more bone in spine than in femur.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 15–21.Purpose:Strenuous training can be associated with amenorrhea leading to amenorrhea-related accelerated bone loss. Insufficient calorie energy, calcium, and/or protein intakes can also be frequently encountered in women with intense training, possibly contributing to bone loss. Long-distance runners with or without regular menses (age range 19-37 yr) were prospectively studied.Methods:Changes in areal bone mineral density (BMD) were measured at 1-yr interval.Results:Among 10 eumenorrheic, 11 oligo-amenorrheic, and 9 oral contraceptive users, there was no difference in energy, calcium, or protein intakes. Baseline BMD values were significantly lower in the oligo-amenorrheic group than in the two others at the level of lumbar spine (anteroposterior view: 0.941 ± 0.039 in oligo-amenorrheic vs 1.077 ± 0.029 or 1.051 ± 0.017 g·cm-2,P< 0.005, in the eumenorrheic and contraceptive user groups, respectively) but not in weight-bearing bone such as proximal and midshaft femur. Over a 1-yr interval, during which the three groups did not differ in terms of running distances and dietary intakes, oligo-amenorrheic women displayed a significant decrease in lumbar spine BMD in lateral view (−0.049 ± 0.012 in oligo-amenorrheic vs -0.001 ± 0.013 and 0.014 ± 0.012 g·cm-2,P< 0.005, in the eumenorrheic and contraceptive user groups, respectively). We did not detect any significant change in femoral neck, trochanter, or midshaft BMD.Conclusions:Oligo-amenorrhea in long-distance runners, with adequate dietary intakes, was associated with a decrease in BMD affecting more the lumbar spine than the proximal and midshaft femur during a 1-yr follow-up.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

NOSAKA, K., and K. SAKAMOTO. Effect of elbow joint angle on the magnitude of muscle damage to the elbow flexors.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 22–29.Purpose:It has been shown that eccentric actions at a long muscle length result in a larger decrease in force and more muscle tenderness compared with those at a short muscle length. To further investigate the effect of elbow joint angle on the development of muscle damage, this study compared two maximal eccentric exercise regimens in which the starting position of the action was different, but the range of movement was the same.Methods:One arm of 10 male students performed 24 maximal eccentric actions of the elbow flexors at the elbow joint angle from 0.87 to 2.27 rad (50–130°:Scondition) and the other arm at the elbow joint angle from 1.74 to 3.14 rad (100-180°:Lcondition). Maximal isometric force, range of motion, muscle soreness, plasma creatine kinase activity, upper arm circumference, and B-mode ultrasound pictures of the elbow flexors (US) were measured before and for 5 d postexercise in both conditions. Magnetic resonance imaging (MRI) of the transverse scans of the upper arm was taken at 4 d after exercise.Results:All measures changed significantly (P< 0.01) after exercise for both conditions; however, significantly (P< 0.01) larger changes in the measures were found in theLcondition compared with theScondition. MRI and US displayed that only the brachialis was damaged for theScondition but the biceps brachii was also damaged for theLcondition.Conclusion:The greater development of muscle damage in theLcondition compared with theScondition is likely to be associated with the elbow flexors muscles affected by the exercise.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

PATRICIA A. NIXON, DAVID M. ORENSTEIN, and SHERYL F. KELSEY. Habitual physical activity in children and adolescents with cystic fibrosis.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 30–35.Purpose:This study was conducted to: 1) measure total physical activity levels, including the intensities of the various types of activities, in children and adolescents with CF compared with non-CF healthy control subjects; and 2) determine whether vigorous activity level was related to aerobic fitness and disease status in patients with CF.Methods:Thirty patients with CF (18 male, 12 female) and 30 control subjects (17 male, 13 female), 7–17 yr old, participated in this study. Habitual physical activity was measured using Kriska’s Modifiable Activity Questionnaire (MAQ) and the past year’s average of total hours, MET-hours, and vigorous (VIG) hours (>6 METs) of activity per week were determined. Aerobic fitness was determined from peak oxygen uptake (O2peak) obtained via maximal exercise testing on a cycle ergometer. Standard spirometry was used to measure pulmonary function. Body mass index (BMI) was determined from height and weight measurements.Results:The CF and control groups were similar in age and gender distribution, but the patients were smaller (BMI, 98 vs 112% of predicted) and less aerobically fit (36.5 vs 41.4 mL·kg-1·min-1). Total and MET-hours of physical activity did not differ between groups; however, the CF group participated in significantly fewer hours of vigorous activities than the control group (2 vs 3.7 h·wk-1). In patients with worse lung disease, VIG-h·wk-1were significantly related to O2peak (r = 0.83).Conclusion:These results suggest that children with CF engage in less vigorous physical activities than their healthy non-CF peers, despite having good lung function. In view of the progressive nature of the disease, and the association between aerobic fitness and vigorous activity, patients should be encouraged to engage in more vigorous activities that promote aerobic fitness and may ultimately have an impact on survival.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HARRISON, B. C., D. ROBINSON, B. J. DAVISON, B. FOLEY, E. SEDA, and W. C. BYRNES. Treatment of exercise-induced muscle injury via hyperbaric oxygen therapy.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 36–42.Purpose:This study examined the role of hyperbaric oxygen therapy (HBO) in the treatment of exercise-induced muscle injury.Methods:21 college-aged male volunteers were assigned to three groups: control, immediate HBO (iHBO), and delayed HBO (dHBO). All subjects performed 6 sets (10 repetitions per set) of eccentric repetitions with a load equivalent to 120% of their concentric maximum. HBO treatments consisted of 100-min exposure to 2.5 ATA and 100% oxygen with intermittent breathing of ambient air (30 min at 100% O2, 5 min at 20.93% O2). HBO treatments began either 2 (iHBO) or 24 h (dHBO) postexercise and were administered daily through day 4 postexercise. Forearm flexor cross-sectional area (CSA) and T2 relaxation time via magnetic resonance imaging (MRI) were assessed at baseline, 2, 7, and 15 d postinjury. Isometric strength and rating of perceived soreness of the forearm flexors were assessed at baseline, 1, 2, 3, 4, 7, and 15 d postinjury. Serum creatine kinase (CK) was assessed on day 0 and on days 1, 2, 7, and 15 postinjury.Results:Mean baseline CSA values were: 2016.3, 1888.5, and 1972.2 mm2for control, iHBO, and dHBO, respectively. All groups showed significant increases in CSA in response to injury (21% at 2 d, 18% at 7 d) (P< 0.0001), but there were no significant differences between groups (P= 0.438). Mean baseline T2 relaxation times were: 26.18, 26.28, and 27.43 msec for control, iHBO, and dHBO, respectively. Significant increases in T2 relaxation time were observed for all groups (64% at 2 d, 66% at 7 d, and 28% at 15 d) (P< 0.0001), but there were no significant differences between groups (P= 0.692). Isometric strength (P< 0.0001), serum CK levels (P= 0.0007), and rating of perceived soreness (P< 0.0001) also indicated significant muscle injury for all groups, but there were no differences between groups (P= 0.459,P= 0.943, andP= 0.448, respectively).Conclusion:These results suggest that hyperbaric oxygen therapy was not effective in the treatment of exercise-induced muscle injury as indicated by the markers evaluated.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

NELSON, T. F., and H. WECHSLER. Alcohol and college athletes.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 43–47.Purpose:This study examines heavy episodic alcohol consumption and associated harms in collegiate athletes in the United States. The factors which may promote or deter such use are explored.Methods:Randomly selected students in a nationally representative sample of 4-yr colleges in the United States completed self-report questionnaires in the spring of 1997. Athletes were defined as students who participated in one or more hours of intercollegiate athletics per day. Heavy episodic or “binge” drinking for men was defined as consuming five or more alcoholic drinks on at least one occasion in the past 2 wk and four or more for women. Athletes were compared with other students at their colleges.Results:Athletes reported more binge drinking, heavier alcohol use, and a greater number of drinking-related harms. Athletes are more likely to exhibit the strong social ties found to be associated with binge drinking. Athletes, despite drinking more heavily than other students, report greater exposure to alcohol prevention efforts and possess unique motivations to limit their alcohol use.Conclusions:Athletes are a high-risk group for binge drinking and alcohol-related harms. Although special educational programs have targeted this group they have not sufficiently impacted the problem. Future prevention efforts targeted for athletes should address the unique social and environmental influences on athletes. Programs should also take advantage of motives of athletes for self-limiting alcohol intake. Colleges, athletic departments, coaches, and sports medicine professionals are urged to act to help reduce athletes risk of alcohol-related harms.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

TRAPPE, S., D. COSTILL, and R. THOMAS. Effect of swim taper on whole muscle and single muscle fiber contractile properties.Med. Sci. Sports Exerc., Vol. 32, No. 12, 2000, pp. 48–56.Purpose:To examine the changes in whole muscle function and single cell contractile properties of Type I and II muscle fibers from the deltoid muscle of highly trained swimmers before and after a 21-d reduction in training volume (taper).Methods:Six college male swimmers (age, 20 ± 1 yr; height, 187 ± 2 cm, weight, 79 ± 3 kg, fat, 7 ± 1%) who had been, on average, swimming 6200 m·d-1for 5 months before the taper participated in this investigation.Results:Whole muscle power increased (P< 0.05) 17% and 13% on the swim bench and swim power tests, respectively. Swim times improved by 4% (range: 3.0-4.7%;P< 0.05). There was no change in Type I fiber diameter, whereas Type IIa fibers were 11% larger (P< 0.05) after taper. Peak force (Po) of the Type I fibers was unaffected by the taper but increased (P< 0.05) from 0.63 ± 0.02 to 0.82 ± 0.05 mN in the IIa fibers. However, the specific force (Po/CSA) of the IIa fibers was unchanged. Shortening velocity (Vo) was 32% and 67% faster (P< 0.05) in the Type I and IIa fibers, respectively. Although Type I fiber power was unaltered, the IIa fibers increased 2.5-fold from 24.6 ± 2.8 to 56.2 ± 3.9 &mgr;N·FL·s-1. When power was normalized for cell size, the power was still elevated twofold.Conclusions:These data suggest that tapering induces alterations in the contractile properties of single muscle fibers. Further, it appears that the Type IIa fibers are more affected than the Type I fibers by the taper. The increased size, strength, velocity, and power of the IIa fibers may be responsible for the improvements in whole muscle strength and power after the taper.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

GAMBELUNGHE, C., R. ROSSI, G. MARIUCCI, M. TANTUCCI, and M. V. AMBROSINI. Effects of light physical exercise on sleep regulation in rats.Med. Sci. Sports Exerc., Vol. 33, No. 1, 2001, pp. 57–60.Purpose:Acute physical exercise is known to enhance slow-wave sleep (SWS) and reduce paradoxical sleep (PS) in humans. In this study, we examined the effects of moderate physical exercise on sleep in rats.Method:Young adult Wistar rats underwent a 4-h baseline electroencephalographic (EEG) recording session. The following day, they were induced to walk (0.8 m·min-1) or run (4 m·min-1) for 45 min in a rota-rod treadmill. Active control rats (ACR) were placed on the locked rota-rod for 45 min, whereas passive control rats (PCR) remained in their home cages. They were then left free to sleep for 4 h during which EEG activity was recorded. Rectal temperature (Tre) was monitored before and after exercise in ACR, walking and running rats (WR and RR, respectively) and at 45 min intervals in PCR.Results:WR were able to walk for 45 min consecutively whereas in RR performances differed. Posttraining Trewas unchanged in ACR, PCR, and WR and resulted about 1.8°C above baseline in RR. In both WR and RR after exercise i) length of SWS and PS, ii) intensity of SWS (spectral power density in 1-4 Hz range), and iii) propensity for falling asleep were enhanced. Interestingly, there was a more conspicuous increment in PS than SWS. In ACR and PCR there were no changes in sleep.Conclusions:Due to the complexity of sleep regulation, the interaction of several factors might underlie the observed increment in SWS and PS. Nevertheless, it is interesting that light physical exercise favors sleep and above all a harmonic enhancement of both sleep phases.

ISSN:0195-9131    

出版商:OVID    

年代:2001

数据来源: OVID