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HÜTLER, M., D. SCHNABEL, D. STAAB, A. TACKE, U. WAHN, D. BÖNING, and R. BENEKE. Effect of growth hormone on exercise tolerance in children with cystic fibrosis.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 567–572, 2002.PurposeThe effect of growth hormone (GH) treatment on exercise tolerance in children with cystic fibrosis was investigated.Methods10 prepubertal children (mean ± SD; age: 12.1 ± 1.7 yr; height: 137.4 ± 9.2 cm; body mass: 27.8 ± 4.2 kg; forced expiratory volume in 1 s (FEV1): 68 ± 22% predicted) were randomly assigned to either control period (CON, standard therapy) or recombinant human growth hormone (GH) period (additional GH treatment, 0.11-0.14 IU·kg−1, daily, s.c.) for the first 6 months, and then assigned to the other period for the next 6 months. At study entry and after each period, anthropometric data, pulmonary function, and exercise capacity (peak exercise capacity, &OV0312;O2peak, and isokinetic muscle strength) were measured.ResultsChanges in height (+4.3 ± 1.0 cm), total body mass (+2.2 ± 0.8 kg), and lean body mass (LBM, +2.9 ± 0.7 kg) were significantly higher (P< 0.01) after GH treatment compared with CON. Pulmonary function did not significantly change in either of the periods. In contrast to CON, GH treatment improved absolute &OV0312;O2peak(+19%,P< 0.01), peak ventilation (+14%,P< 0.01), and peak oxygen pulse (+18%,P< 0.01). Analysis of variance revealed that most of the changes (71%) in &OV0312;O2peakcould be explained by those in LBM and FEV1(P= 0.001).ConclusionGH treatment clearly improved exercise tolerance, presumably resulting from the combined effects of GH on the muscular, cardiovascular, and pulmonary capacity.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

TESTA, V., G. CAPASSO, F. BENAZZO, and N. MAFFULLI. Management of Achilles tendinopathy by ultrasound-guided percutaneous tenotomy.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 573–580, 2002.PurposeTo report the middle to long-term results of ultrasound-guided percutaneous longitudinal tenotomy of the Achilles tendonMethodSeventy-five athletes with unilateral Achilles tendinopathy underwent ultrasound-guided percutaneous longitudinal tenotomy under local anesthetic infiltration after failure of conservative management. Sixty-three patients were reviewed at least 36 months after the operation (51 ± 18.2 months).ResultsThirty-five patients were rated excellent, 12 good, 9 fair, and 7 poor. Nine of the 16 patients with a fair or poor result underwent a formal exploration of the Achilles tendon 7–12 months after the index procedure. The operated tendons remained thickened and the ultrasonographic appearance of operated tendons remained abnormal even 8 yr after the operation, without interfering with physical training. Isometric maximal muscle strength and isometric endurance gradually returned to values similar to their contralateral unoperated tendon.ConclusionsPercutaneous longitudinal ultrasound-guided internal tenotomy is simple, can be performed on an outpatient basis, requires minimal follow-up care, does not hinder further surgery should it be unsuccessful, and, in our experience, has produced no significant complications. It should be considered in the management of chronic Achilles tendinopathy after failure of conservative management. However, patients should be advised that, if they suffer from diffuse or multinodular tendinopathy or from pantendinopathy, a formal surgical exploration with stripping of the paratenon and multiple longitudinal tenotomies may be preferable.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

LUO, Z-P., H-C. HSU, and K-N. AN. Anin vitrostudy of glenohumeral performance after suprascapular nerve entrapment.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 581–586, 2002.PurposeThe functional performance of athletes with suprascapular nerve entrapment remains unaddressed biomechanically. The purpose of this study was to investigate the glenohumeral joint kinematics, stability, and characteristics of joint contact.MethodsThe investigation used anin vitromodel simulating muscle palsy due to the suprascapular nerve entrapment. The experiment was performed in three clinically relevant positions: inferior, one by sulcus test; posterior, one with 90° flexion and maximal internal rotation; and anterior, one with 90° abduction and 90° external rotation (which is critically involved in several sports activities).ResultsSimulated palsy due to suprascapular nerve entrapment had effects on glenohumeral joint stability and contact characteristics. Changes in the humeral head displacement and the glenohumeral joint contact characteristics were the most significant in the anterior direction when the arm in 90° abduction and 90° external rotation.ConclusionGlenohumeral function is affected by muscle weakness at the position that is critical in sports activities. Because the infraspinatus supplies 90% of the external rotation power of the shoulder and the supraspinatus stabilizes the humeral head in the glenoid during elevation, residual weakness due to suprascapular nerve entrapment may preclude a safe return to athletics.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

SAGIV, M., D. BEN-SIRA, and E. GOLDHAMMER. Beta-blockers, exercise, and the immune system in men with coronary artery disease.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 587–591, 2002.PurposeThe purpose of the present study was to examine the effect of aerobic exercise training on the immune system in coronary artery disease patients treated with &bgr;-blockers.MethodsTwenty-five patients (46.1 ± 2 yr) treated with atenolol, a &bgr;-blocker agent, for 3 months before exercising were divided randomly into two groups: 15 underwent an aerobic exercise training program for 12 wk at 65–70% of their work capacity, whereas the other 10 patients served as controls.ResultsAfter training, levels of CD4 and CD8 cells were significantly (P< 0.05) higher and concomitantly the CD4/CD8 ratio decreased significantly (P< 0.05) in the exercising group compared with the control group.ConclusionsData suggest that coronary artery disease patients exercising aerobically at 65–70% of their work capacity gain a statistically significant higher lymphocyte T cell function as compared with their untrained counterparts.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

LEE, C. D., and S. N. BLAIR. Cardiorespiratory fitness and stroke mortality in men.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 592–595, 2002.PurposeWe examined the association between cardiorespiratory fitness and stroke mortality in men.MethodsThis is a prospective cohort study. We followed 16,878 men, ages 40–87 yr, who had a complete medical evaluation including a maximal treadmill exercise test and self-reported health habits. There were 32 stroke deaths during an average of 10 yr of follow-up (167,961 man-yr).ResultsAfter adjustment for age and examination year, there was an inverse association between cardiorespiratory fitness and stroke mortality (P= 0.005 for trend). This association remained after further adjustment for cigarette smoking, alcohol intake, body mass index, hypertension, diabetes mellitus, and parental history of coronary heart disease (P= 0.02 for trend). High-fit men (most fit 40%) had 68% (95% CI: 0.12, 0.82) and moderate-fit men had 63% (95% CI: 0.17, 0.83) lower risk of stroke mortality when compared with low-fit men (least fit 20%), respectively.ConclusionsModerate and high levels of cardiorespiratory fitness were associated with lower risk of stroke mortality in men in the Aerobics Center Longitudinal study population.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

CARROLL, J. F., and C. K. KYSER. Exercise training in obesity lowers blood pressure independent of weight change.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 596–601, 2002.PurposeWe used the rabbit model of obesity and exercise training to determine effects of exercise training during the development of obesity on resting blood pressure and heart rate, ventricular hypertrophy, blood volume, and hormonal profile.MethodsFemale New Zealand white rabbits were assigned to one of four groups: lean sedentary (L-S,N= 17), lean exercise-trained (L-EX,N= 16), obese sedentary (O-S,N= 18), and obese exercise-trained (O-EX,N= 15). Lean rabbits were fed a maintenance diet whereas obese rabbits were fed anad libitumhigh fat (10% added fat) diet. Simultaneously, exercise-trained animals underwent a progressive treadmill exercise training protocol for 12 wk. After 12 wk of diet and exercise regimens, resting blood pressure and heart rate were measured from a central ear artery catheter. Ventricular hypertrophy was evaluated using wet ventricular weights. Blood volume was measured using the Evans blue dye procedure; hormonal profile was evaluated from arterial plasma/serum samples.ResultsAfter 12 wk, O-S and O-EX had similar body weights and similar percentage increases in body weight. Despite similar body weights, O-EX had an approximate 6-mm Hg lower mean blood pressure compared with the elevated pressure seen in O-S (P≤ 0.05). Obese rabbits had greater resting heart rate, plasma cholesterol and triglycerides, and plasma renin activity compared with lean rabbits, and these values were unaffected by exercise training. Plasma and blood volumes, as well as plasma insulin, cortisol, and aldosterone were unaffected by exercise training.ConclusionThese data suggest that exercise training, in the absence of differences in body weight, may be useful in the reduction of obesity-induced hypertension but that other therapies may be needed in order to control other cardiovascular risk factors.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

LAMBERT, M. I., P. MARCUS, T. BURGESS, and T. D. NOAKES. Electro-membrane microcurrent therapy reduces signs and symptoms of muscle damage.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 602–607, 2002.PurposeDelayed onset muscle soreness (DOMS) occurs after unaccustomed physical activity or competitive sport, resulting in stiff, painful muscles with impaired function. Acustat®electro-membrane microcurrent therapy has been used to treat postoperative pain and soft tissue injury; however, its efficacy in reducing symptoms of muscle damage is not known.MethodsThirty healthy men were recruited for a double-blind, placebo-controlled trial. The muscles of their nondominant arms were damaged using an eccentric-exercise protocol. Subjects were then randomly assigned to treatment with either Acustat or a matching placebo membrane for 96 h and monitored for a total of 168 h.ResultsSubjects in both groups experienced severe pain and swelling of the elbow flexors after the eccentric exercise. After 24 h, the elbow joint angle of the placebo group had increased significantly more than those in the Acustat group (13.7 ± 8.9° vs 7.5 ± 5.5°; placebo vs Acustat,P< 0.05), possibly as a consequence of the elbow flexor muscles shortening. For the first 48 h after exercise, maximum voluntary contraction of the elbow flexor muscles was significantly impaired in the placebo group by up to 25% (P< 0.05), whereas muscle function was unchanged in the Acustat group. Peak plasma creatine kinase activity was also lower in the Acustat group (peak = 777 ± 1438 U·L−1) versus the placebo group (peak = 1918 ± 2067 U·L−1; (P< 0.05). The membranes were well tolerated by the subjects in both groups without any adverse effects.ConclusionThese data show that treatment of muscle damage with Acustat electro-membrane microcurrent therapy reduces the severity of the symptoms. The mechanisms of action are unknown but are likely related to maintenance of intracellular Ca2+homeostasis after muscle damaging exercise.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

NINDL, B. C., W. J. KRAEMER, P. J. ARCIERO, N. SAMATALLEE, C. LEONE, M. MAYO, and D. HAFEMAN. Leptin concentrations experience a delayed reduction after resistance exercise in men.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 608–613, 2002.PurposeLeptin is an important metabolic hormone providing the brain with information concerning energy balance. Most studies have reported that circulating leptin concentrations are unaltered by acute, moderate exercise. We hypothesized that these studies have been limited by short sampling schemes (<4 h) postexercise and may have missed a time-delayed reduction in circulating leptin concentrations.MethodsTen men (age = 21 ± 1 yr, height = 177 ± 2 cm, body mass = 79 ± 3 kg, body fat = 11 ± 1%BF, &OV0312;O2max= 51 ± 1 mL·kg−1·min−1) completed an acute heavy-resistance exercise protocol (AHREP) (50 total sets comprised of the squat, bench press, leg press, and lat pull-down) from 1500 to 1700 h. Blood was sampled hourly postexercise until 0600 h the next morning and also during a time-matched control period. Leptin concentrations were measured by an immunoradiometric assay. Resting energy expenditure (REE) was measured via indirect calorimetry using a ventilated hood beginning ∼0600 h after both overnight conditions.ResultsThe estimated caloric expenditure from the AHREP was 856 ± 114 kcal. No significant differences (P> 0.05) between the control and exercise conditions were observed for serum leptin concentrations until 9 h postexercise. Significant interaction effects (P< 0.05) indicated lower serum leptin concentrations postexercise at hours 9 (2.9 vs 2.2 ng·mL−1), 10 (2.7 vs 2.0 ng·mL−1), 12 (2.5 vs 1.8 ng·mL−1), and 13 (2.6 vs 1.8 ng·mL−1). This delayed reduction was accompanied by a 12% elevation (P< 0.05) in morning-after REE (0.25 ± 0.02 vs 0.28 ± 0.02 L·min−1).ConclusionLeptin concentrations experience a delayed (∼ 9 h) reduction in the systemic circulation after acute resistance exercise. This decline is likely associated with the disruption in metabolic homeostasis created by the high-intensity, long-duration, energy expenditure and subsequent excess post oxygen consumption from the AHREP and is not due to losses in fat mass.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

STEPHENS, T. J., M. J. McKENNA, B. J. CANNY, R. J. SNOW, and G. K. McCONELL. Effect of sodium bicarbonate on muscle metabolism during intense endurance cycling.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 614–621, 2002.IntroductionSodium bicarbonate (NaHCO3) ingestion has been shown to increase both muscle glycogenolysis and glycolysis during brief submaximal exercise. These changes may be detrimental to performance during more prolonged, exhaustive exercise. This study examined the effect of NaHCO3ingestion on muscle metabolism and performance during intense endurance exercise of ∼60 min in seven endurance-trained men.MethodsSubjects ingested 0.3 g·kg−1body mass of either NaHCO3or CaCO3(CON) 2 h before performing 30 min of cycling exercise at 77 ± 1% &OV0312;O2peakfollowed by completion of 469 ± 21 kJ as quickly as possible (∼30 min, ∼80% &OV0312;O2peak).ResultsImmediately before, and throughout exercise, arterialized-venous plasma HCO3−concentrations were higher (P< 0.05) whereas plasma and muscle H+concentrations were lower (P< 0.05) in NaHCO3compared with CON. Blood lactate concentrations were higher (P< 0.05) during exercise in NaHCO3, but there was no difference between trials in muscle glycogen utilization or muscle lactate content during exercise. Reductions in PCr and ATP and increases in muscle Cr during exercise were also unaffected by NaHCO3ingestion. Accordingly, exercise performance time was not different between treatments.ConclusionNaHCO3ingestion resulted in a small muscle alkalosis but had no effect on muscle metabolism or intense endurance exercise performance in well-trained men.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BENALLAL, H., C. DENIS, F. PRIEUR, and T. BUSSO. Modeling of end-tidal and arterial PCO2gradient: comparison with experimental data.Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 622–629, 2002.PurposeThe aim of this study was to test whether a tidally ventilated homogeneous lung model can correctly describe arterial and end-tidal gas partial pressures and thus the difference in end-tidal and arterial gas partial pressures at rest and during exercise.MethodsThe implemented mathematical modeling described variations during the breathing cycle in CO2and O2fractions, alveolar volume, and pulmonary capillary gas exchange. Experimental data were obtained from measurements performed by 17 healthy subjects at rest and during 40, 50, 65, and 75% exercise &OV0312;O2maxon a cycle ergometer. &OV0312;O2, &OV0312;CO2, and PET,CO2were continuously measured using the MedGraphics CPX/D gas exchange system. Arterial gases were measured in brachial artery blood samples drawn simultaneously with gas exchange. Cardiac output was measured using the CO2rebreathing method corrected by the blood sample data. The model was driven using experimental data for ventilation, &OV0312;O2, &OV0312;CO2, and cardiac output.ResultsThe mean difference and the upper and lower limits of agreement between measured and simulated data were −0.004, +0.84, and −0.84 Torr for Pa,CO2; −0.06, +0.64, and −0.76 Torr for Pa,O2; −1.96, +2.84, and −6.76 Torr for PET,CO2; and +7.20, +25.80, and −11.40 Torr for PET,O2. Actual PET,CO2-Pa,CO2difference increased significantly with workload (P< 0.0001) from 0.3 ± 3 Torr at rest to 4.7 ± 2.5 Torr at 75% &OV0312;O2max. Model-simulated PET,CO2-Pa,CO2difference also increased significantly with exercise (P< 0.0001) from 0.7 ± 1.7 Torr at rest to 9.1 ± 3.4 Torr at 75% &OV0312;O2max.ConclusionThe lung model described actual arterial CO2partial pressures better than variations in end-tidal CO2partial pressures and thus better than the gradient in end-tidal arterial CO2partial pressures.

ISSN:0195-9131    

出版商:OVID    

年代:2002

数据来源: OVID