ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

HAYES, S. C., D. ROWBOTTOM, P. S. W. DAVIES, T. W. PARKER, and J. BASHFORD. Immunological Changes after Cancer Treatment and Participation in an Exercise Program.Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 2–9, 2003.PurposeThe purpose of this investigation was to evaluate the impact of undertaking peripheral blood stem cell transplantation (PBST) on T-cell number and function, and to determine the role of a mixed type, moderate intensity exercise program in facilitating the recovery of T-cell number and function.MethodsImmunological measures of white blood cell, lymphocyte, CD3+, CD4+, and CD8+counts, and CD3+cell function were assessed pretransplant (PI), immediately posttransplant (PII), and 1 month (I1), 2 months (I2) and 3 months (PIII) posttransplant. After PII, 12 patients were divided equally into a control group (CG) or exercise intervention group (EG).ResultsLower total T-cell, helper T-cell, and suppressor T-cell counts (P< 0.01), as well as lower T-cell function (P< 0.01), when compared with normative data, were found at PI. More specifically, 88% of the group had CD3+, CD4+, and CD8+counts that were more than 40%, 20%, and 50% below normal at PI, respectively. Undertaking a PBST caused further adverse changes to the total leukocyte, lymphocyte, CD3+, CD4+and CD8+count, and the helper/suppressor ratio. Although CD8+counts had returned to normal by PIII, CD3+, CD4+, and the CD4+/CD8+ratio remained significantly lower than normative data (P< 0.01), with 66%, 100%, and 100% of the subject group reporting counts and ratios, respectively, below the normal range.ConclusionThe PBST patients were immunocompromised before undertaking the transplant, and the transplant procedure imposed further adverse changes to the leukocyte and lymphocyte counts. The leukocyte and CD8+counts returned to normal within 3 months posttransplant; however, the other immunological parameters assessed demonstrated a delayed recovery. Although participation in the exercise program did not facilitate a faster immune cell recovery, neither did the exercise program hinder or delay recovery.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

CUSSLER, E. C., T. G. LOHMAN, S. B. GOING, L. B. HOUTKOOPER, L. L. METCALFE, H. G. FLINT-WAGNER, R. B. HARRIS, and P. J. TEIXEIRA. Weight Lifted in Strength Training Predicts Bone Change in Postmenopausal Women.Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 10–17, 2003.PurposeThe aim of this study was to examine the relationship between weight lifted in 1 yr of progressive strength training and change in bone mineral density (BMD) in a group of calcium-replete, postmenopausal women.MethodsAs part of a large clinical trial, 140 calcium-supplemented women, 44–66 yr old, were randomized to a 1-yr progressive strength-training program. Half of the women were using hormone replacement therapy. Three times weekly, subjects completed two sets of six to eight repetitions in eight core exercises at 70–80% of one repetition maximum. BMD was measured at baseline and 1 yr.ResultsIn multiple linear regression, the increase in femur trochanter (FT) BMD was positively related to total weight lifted (0.001 g·cm−2for a SD of weight lifted,P< 0.01) after adjusting for age, baseline factors, HRT status, weight change, cohort, and fitness center. The weighted squats showed the strongest (0.002 g·cm−2for a SD of weight lifted,P< 0.001), whereas the back extension exhibited the weakest (0.0005 g·cm−2for a SD of weight lifted,P< 0.26) association with change in FT BMD. The amount of weight lifted in the weighted march exercise was significantly related to total body BMD (0.0006 g·cm−2for a SD of weight lifted,P< 0.01). The associations between weight lifted and BMD for the femur neck or lumbar spine were not significant.ConclusionEvidence of a linear relationship between BMD change and total and exercise-specific weight lifted in a 1-yr strength-training program reinforces the positive association between this type of exercise and BMD in postmenopausal women.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

RUNDELL, K. W., B. A. SPIERING, D. A. JUDELSON, and M. H. WILSON. Bronchoconstriction during Cross-Country Skiing: Is There Really a Refractory Period?Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 18–26, 2003.PurposeThe asthmatic airway responds to exercise by bronchodilation (BD) during and bronchoconstriction (BC) after exercise. A refractory period induced by an initial exercise challenge that provides protection against BC during a subsequent exercise bout has also been observed. However, no studies examining during-exercise response or refractoriness during long-duration field exercise by elite athletes have been performed. This study examined airway response and refractoriness during ∼42-min cross-country ski time trial preceded by a 6- to 9-min 2.5-km high-intensity warm-up ski.MethodsEighteen elite athletes cross-country skied seven successive 2.5-km loops. Spirometry was performed pre- and at 5, 10, and 15 min post loop 1; loops 2–7 were treated as a race (XCR) with maneuvers performed within 20 s after loops 2–6 and serially for 15 min after lap 7.ResultsNine of 18 subjects demonstrated a ≥10% fall from baseline in FEV1(EIB+): five after lap 1 and four during or after laps 2–7. FEV1for EIB+ athletes during XCR was not different from post lap 1 FEV1. Only one EIB+ subject demonstrated significant refractoriness. Four EIB+ athletes had a less than 10% fall in FEV1after the initial 2.5-km exercise challenge but developed EIB (≥10% fall) during the subsequent 6 × 2.5 km XCR exercise challenge. FEF25–75falls mirrored FEV1, but demonstrated greater BD during XCR.ConclusionBronchoconstriction occurs in athletes during prolonged exercise and may thus influence performance. Variability in bronchial hyperresponsiveness onset and the lack of significant refractoriness in our study cohort of athletes is consistent with an exercise bronchoconstrictive dysfunction that is different than frank asthma and is yet to be clearly defined.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

KUBO, H., J. R. LIBONATI, Z. V. KENDRICK, A. PAOLONE, J. P. GAUGHAN, and S. R. HOUSER. Differential Effects of Exercise Training on Skeletal Muscle SERCA Gene Expression.Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 27–31, 2003.IntroductionExercise training induces significant changes in the performance of skeletal muscle.PurposeTo determine whether changes in the gene expression of rat hind-limb muscle sarcoplasmic reticulum Ca2+-ATPase isoforms (SERCA1a and SERCA2a) in response to either moderate- or high-intensity exercise training underlie the functional remodeling.MethodsSERCA1a and SERCA2a isoform mRNA expression was determined in predominantly fast-twitch, gastrocnemius muscle and predominantly slow-twitch, soleus muscle with northern analysis. SERCA mRNA was normalized by the 18S rRNA measured in the same sample.ResultsSignificant increases in the gastrocnemius SERCA2a mRNA expression were observed after both moderate- and high-intensity training. No significant change in SERCA1a expression was found under any conditions.ConclusionThese results indicate that both moderate and high intensity exercise increase the relative SERCA2a expression in the gastrocnemius.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

TAMAKI, T., T. SHIRAISHI, H. TAKEDA, T. MATSUMIYA, R. R. ROY, and V. R. EDGERTON. Nandrolone Decanoate Enhances Hypothalamic Biogenic Amines in Rats.Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 32–38, 2003.PurposeTo identify possible mechanisms for an anabolic-androgenic steroid induced increase in aggressive behavior and work capacity, the levels of some biogenic amines considered to be closely related to a systemic hyper-adrenergic state were measured in selected regions of the brain.MethodsWistar male rats were divided randomly into five groups: nontreated (control), oil-vehicle-treated (vehicle) or one of three (therapeutic dose and 10- or 100-fold higher dose) anabolic-androgenic steroid-treated (steroid-1, -2, -3) groups. Rats in the steroid and vehicle groups were given a single dose of nandrolone decanoate or oil vehicle, respectively, one week before tissue sampling. The levels of norepinephrine (NE) and its metabolite, 4-hydroxy-3-methoxyphenylglycol (MHPG), serotonin (5-HT) and its metabolite, 5-hydroxy-indole-3-acetic acid (5-HIAA) were measured in the cerebral cortex, hypothalamus and cerebellum by high-performance liquid chromatography. Immunostaining for c-fos was performed as a confirmation of increased neural activity.ResultsThe levels of NE and MHPG were increased by ∼2- and ∼7-fold in the hypothalamus of the steroid-2 compared with the control and vehicle groups. The levels of 5-HT and 5-HIAA were ∼40 and ∼50% higher in the steroid-2 compared with the control and vehicle groups. A significantly higher number of c-fos expressing neurons were observed in the periventricular region of the steroid-2 than the control and vehicle groups, indicating enhanced neuronal activity after nandrolone decanoate treatment.ConclusionsThe present results, combined with previously reported findings of physical performance enhancement after anabolic-androgenic steroid treatment, are consistent with the interpretation that elevated levels of adrenergic and serotonergic amines in the hypothalamus could contribute to aggressive behaviors as well as improved physical performance.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

KUBO, K., H. KANEHISA, K. AZUMA, M. ISHIZU, S.-Y. KUNO, M. OKADA, and T. FUKUNAGA. Muscle Architectural Characteristics in Women Aged 20–79 Years.Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 39–44, 2003.PurposeThe purpose of this study was to investigate the muscle architectural characteristics, i.e., muscle thickness, pennation angle, and fascicle length, in women aged 20–79 yr.MethodsA total of 224 sedentary healthy women participated in this study. Muscle thickness and pennation angle of the vastus lateralis (VL), medial gastrocnemius (MG), and triceps brachii (TB) muscles were measured by B-mode ultrasonography, and the fascicle length was estimated.ResultsRelative muscle thickness of VL and MG decreased significantly with advanced age (VL:P< 0.01, MG:P< 0.05). In addition, the ratio of muscle thickness of VL to that of MG decreased significantly with advanced age (r = −0.206,P< 0.05). The pennation angle decreased significantly with aging for VL (P< 0.001) but not for MG. For TB, no significant age-related changes in relative muscle thickness or pennation angle were observed. There were no significant correlations between age and relative fascicle length (to limb length) in any of the studied muscles.ConclusionThese results suggested that the declines in muscle thickness and pennation angle with aging were remarkable in the vastus lateralis muscle and slight in the medial gastrocnemius muscle. For the triceps brachii muscle, the muscle thickness and pennation angle did not decrease with advanced age. Furthermore, no significant age-related changes in relative fascicle length (to limb length) were observed in any of the studied muscles.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

KYRÖLÄINEN, H., R. KIVELÄ, S. KOSKINEN, J. MCBRIDE, J. L. ANDERSEN, T. TAKALA, S. SIPILÄ, and P. V. KOMI. Interrelationships between Muscle Structure, Muscle Strength, and Running Economy.Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 45–49, 2003.PurposeThe present study was designed to investigate possible differences in running economy (RE) among elite middle-distance runners by examining muscle structure and maximal isometric force (MVC).MethodsTen young male runners ran at six different running speeds. During the running bouts, respiratory gases, and blood lactate were measured. Muscle biopsies were obtained from the vastus lateralis muscle for analyzing fiber type distribution, muscle fiber area, myosin heavy chain (MHC) composition, activities of a number of metabolic enzymes (citrate synthase, lactate dehydrogenase, phosphofruktokinase, and 3-hydroxyacyl-CoA-dehydrogenase), and titin isoforms.ResultsEnergy expenditure (EE) increased linearly up to the speed of 6.0 m·s−1. The relative distribution of the MHC isoforms was MHC I: 67.0%, MHC IIA: 31.5%, and MHC IIX: 1.5%. The present results demonstrated that higher the area of Type II fibers, higher the MVC (r = 0.59,P< 0.05). The amount of MHC II correlated inversely with EE when running close to the competition speed (r = −0.61,P< 0.05). Enzyme activities did not correlate significantly with either RE or EE. Titin analysis revealed that a faster-mobility titin band was observed in all subjects, whereas a lower-mobility titin band was observed only in the most economical runner.ConclusionDifferences in RE among homogeneous group of middle-distance runners were observed at various running speeds. This may partly be explained by differences in muscle fiber distribution, MHC composition, and titin isoforms.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BORRANI, F., R. CANDAU, S. PERREY, G. Y. MILLET, G. P. MILLET, and J.-D. ROUILLON. Does the Mechanical Work in Running Change during the &OV0312;O2Slow Component?Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 50–57, 2003.PurposeThe origin of the slow component is not fully understood. The mechanical hypothesis is one of the potential factors, because an increase in external mechanical work with fatigue was previously reported for a constant velocity run. The purpose of this study was to determine whether a change in mechanical work could occur during the development of the &OV0312;O2slow component under the effect of fatigue.MethodsTwelve regional-level competitive runners performed a square-wave transition, corresponding to 95% of the speed associated with peak &OV0312;O2obtained during an incremental test. The &OV0312;O2response was fit with a classical model including two exponential functions. A specific treadmill with three-dimensional force transducers was used to measure the ground reaction force. Kinetic work (Wkin), potential work (Wpot), external work (Wext), and an index of internal work (Wint) per unit of distance were quantified continuously.ResultsDuring the slow component of &OV0312;O2, a significant increase in Wpot(P< 0.01), no change in Wext, and a significant decrease in Wkinand Wintindex (P< 0.05,P< 0.001, respectively) were observed.ConclusionThe present study showed that the slow component of &OV0312;O2did not result partly from a change in mechanical work under the effect of fatigue. Nevertheless, the decrease in stride frequency (P< 0.001) and contact time (P< 0.001) suggested an alternative mechanical explanation. The slow component during running may be due to the cost of generating force or to alterations in the storage and recoil of elastic energy, and not to the external mechanical work.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BELL, C., K. D. MONAHAN, A. J. DONATO, B. E. HUNT, D. R. SEALS, and K. C. BECK. Use of Acetylene Breathing to Determine Cardiac Output in Young and Older Adults.Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 58–64, 2003.PurposeThe aims of this investigation were: 1) to establish the day-to-day reproducibility of open-circuit acetylene breathing for measuring exercise cardiac output (&OV0422;C) in young and older adults; and 2) to compare estimates of &OV0422;Cfrom open-circuit acetylene breathing with estimates of &OV0422;Cfrom previously established closed-circuit acetylene rebreathing.MethodsTwenty men (10 young: 28 ± 1 yr; 10 older: 61 ± 1 yr (mean ± SE)) performed cycle ergometry exercise on 3 separate days. &OV0422;Cwas estimated using open-circuit acetylene breathing on 2 d, and closed-circuit acetylene rebreathing on 1 d.ResultsOpen-circuit acetylene breathing was highly reproducible (young: standard error of measurement (SEM) = 1.52 L·min−1, limits of agreement (LOA) = 0.2 ± 4.2 L·min−1, coefficient of variation 6% < CV < 8%, day 2 = (0.9 × day 1) + 2.4, r = 0.90,P< 0.001, r2= 0.82; older: SEM = 0.94 L·min−1, LOA = 0.1 ± 2.8 L·min−1, 4% < CV < 10%, day 2 = (1.0 × day 1) + 0, r = 0.91,P< 0.001, r2= 0.82). Estimates of &OV0422;Cfrom open-circuit acetylene breathing demonstrated good agreement with closed-circuit acetylene rebreathing (young: SEM = 1.52 L·min−1, LOA = 0.9 ± 4.4 L·min−1, 5% < CV < 10%, open-circuit = (1.0 × closed-circuit) + 1.5, r = 0.89,P< 0.001, r2= 0.79; older: SEM = 1.13 L·min−1, LOA = 0.1 ± 3.2 L·min−1, 5% < CV < 9%, open-circuit = (0.9 × closed-circuit) + 1.6, r = 0.88,P< 0.001, r2= 0.78).ConclusionThese results demonstrate that open-circuit acetylene breathing provides reproducible measurements of &OV0422;Cduring exercise that demonstrate good agreement with values obtained from the acetylene rebreathing procedure in young and older healthy men.

ISSN:0195-9131    

出版商:OVID    

年代:2003

数据来源: OVID