ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

HEINRICH, C. H., S. B. GOING, R. W. PAMENTER, C. D. PERRY, T. W. BOYDEN, and T. G. LOHMAN, Bone mineral content of cyclically menstruating female resistance and endurance trained athletes.Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 558–563, 1990.The bone mineral content (BMC) at four sites on the axial and appendicular skeleton was compared among four groups of young adult (age = 17–38 yr) cyclically menstruating athletes (N= 40) who regularly performed either weightlifting resistance exercise (body builders) or nonresistance endurance exercise (runners, swimmers) and an inactive group of females (N= 18) of about equal age. Forearm BMC was measured using single photon absorptiometry at proximal (shaft) and distal sites on the radius. Dual photon absorptiometry was used to measure BMC at the lumbar vertebrae (L2–4) and femur at the femoral neck, Ward's triangle, and greater trochanter. Fat-free body mass (FFBM) was estimated from densitometry. Body builders had greater BMC than swimmers, collegiate runners, recreational runners, and controls. Mean differences in BMC among runners, swimmers, and controls were not significant (P≤ 0.05). FFBM was correlated significantly with BMC (r = 0.35–0.56) at each site in the combined group of athletes (N= 39), whereas total body weight and BMC were correlated significantly at the distal radius site (r = 0.38) only. The results suggest that weight training may provide a better stimulus for increasing BMC than run and swim training.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

BUNT, J. C., S. B. GOING, T. G. LOHMAN, C. H. HEINRICH, C. D. PERRY, and R. W. PAMENTER. Variation in bone mineral content and estimated body fat in young adult females.Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 564–569, 1990. This study was designed to determine whether variability in bone mineral content (BMC) at the lumbar vertebrae (L2–4), radius shaft (RS), femoral neck, and distal radius can significantly contribute to the variability observed in body density (Db) among 89 females (age = 25.1 ± 5.3 yr) of varying activity levels and menstrual status. Theoretical differences in Db were calculated at ±1 and ±2 standard deviations of BMC (SDBMC) for the population as well as for the subgroups: eumenorrheic inactive controls (C), recreational runners (RR), collegiate runners (CR), body builders (BB), swimmers (S), and amenorrheic runners (AR). Multiple regression to predict Db yielded significant coefficients (b) for BMC at L2–4 (b = 0.0190,P< 0.001) and RS (b = 0.0425,P< 0.01) when added separately to the sum of four skinfolds (subscapula, abdomen, thigh, calf). The differences in % BFHWat ±1 and ±2 SDBMCfor the sample mean for RSBMCwere ±1.0% and ±2.0%, respectively. Variability in L2–4 contributed differences of ±1.3% and ±2.6% at ±1 and ±2 SDBMC. The subgroup % BFHWdifferences (due to L2–4 and RS combined) ranged from an average overestimation of 1.3% for the AR to an average underestimation of 1.4% for the BB. Estimated mean errors for remaining groups were ≤ 0.5%. Individual differences ranged from a 3.3% underestimation (BB) to a 3.0% overestimation (AR). It is concluded that variability in BMC among young adult females may significantly contribute to variability in Db, independent of fatness. While the impact of high or low bone mineral content on %BFHWis modest for most individuals, those athletes with extremely high or low BMC values may require adjustments in the equations used to convert Db to %BF. It is suggested that correlations between Db and total BMC (or BM density) be evaluated in a similar manner as presented here before stronger conclusions can be made concerning the impact of bone on estimations of %BF.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

RISSER, W. L., E. J. LEE, A. LEBLANC, H. B. W. POINDEXTER, J. M. H. RISSER, and V. SCHNEIDER. Bone density in eumenorrheic female college athletes.Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 570–574, 1990. Information is limited on the effect of exercise on bone density in young eumenorrheic athletes. We studied 12 Caucasian intercollegiate volleyball players (V), nine basketball players (B), ten swimmers (S), and 13 non-athletes (N) with bone density measurements by photon absorptiometry of their calcaneus and lumbar spine (L2–L4). The effect of athletic status on bone density was analyzed by multivariate analysis of covariance, with height and weight as covariates. The bone densities reported below are mean ± SE, adjusted for the covariates; units = g.cm−2,P< 0.05. The swimmers had a significantly lower mean density in the lumbar spine than all other groups; the non-athletes' mean density was also lower than that of volleyball players (V = 1.31 ± 0.03, B = 1.26 ± 0.04, N = 1.18 ± 0.03, S = 1.05 ± 0.03). The volleyball and basketball players' mean calcaneal densities were greater than those of the swimmers and non-athletes (V = 0.530 ± 0.017, B = 0.564 ± 0.023, N = 0.438 ± 0.018, S = 0.375 ± 0.019). The higher bone densities for athletes in vertical weight-bearing activities are consistent with some but not all published data. The swimmers' low bone density in the lumbar spine, less than published values for amenorrheic runners, was unexpected.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

DE SOUZA, M. J., M. S. MAGUIRE, K. RUBIN, and C. M. MARESH. Effects of menstrual phase and amenorrhea on exercise responses in runners.Med. Sci. Sports. Exerc., Vol. 22, No. 5, pp. 575–580, 1990. There are few well controlled studies in terms of subject selection, menstrual classification, and exercise protocol that have examined both maximal and submaximal exercise responses during different phases of the menstrual cycle in eumenorrheic runners and compared these runners to amenorrheic runners. Thus, the purpose of this study was to measure selected physiological and metabolic responses to maximal and submaximal exercise during two phases of the menstrual cycle in eumenorrheic runners and amenorrheic runners. Eight eumenorrheic runners (29.0 ± 4.2 yr) and eight amenorrheic runners (24.5 ± 5.7 yr) matched for physical, gynecological, and training characteristics were studied. The eumenorrheic runners performed one maximal and one submaximal (40 min at 80% &OV0312;O2max) treadmill run during both the early follicular (days 2–4) and midluteal (6–8 d from LH surge) phases. The amenorrheic runners performed one maximal and one submaximal (40 min at 80% &OV0312;O2max) treadmill run. Cycle phases were documented by urinary luteinizing hormone and progesterone assays and by plasma estradiol and progesterone assays. No differences were observed in oxygen uptake, minute ventilation, heart rate, respiratory exchange ratio, rating of perceived exertion, time to fatigue (maximal), and plasma lactate (following the maximal and submaximal exercise tests) between the follicular and luteal phases in the eumenorrheic runners and the amenorrheic runners. We conclude that neither menstrual phase (follicular vs luteal) nor menstrual status (eumenorrheic vs amenorrheic) alters or limits exercise performance in female athletes.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

IRVING, R. A., T. D. NOAKES, S. C. BURGER, K. H. MYBURGH, D. QUERIDO, and R. VAN ZYL SMIT. Plasma volume and renal function during and after ultramarathon running.Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 581–587, 1990. Plasma volume (PV) and renal function were studied in eight subjects for 3 d prior to and 6 d after a 56 km footrace. Immediately following the race, PV, creatinine clearance, and urine flow were unchanged from pre-race values. Over the subsequent 3 d, PV increased due initially to a 17 g influx of serum albumin and an associated increase in plasma sodium content, which persisted throughout the study period. A reduction in urine sodium secretion occurred during the race day. Creatinine clearance increased after the race and remained elevated for 48 h. Increases serum enzyme activities, C-reactive protein concentration, serum uric acid content, and plasma creatinine concentration and production suggest muscle damage. We suggested the following. First, the persistent post-exercise plasma volume expansion is initiated by an influx of albumin into the intravascular space with an associated increase in plasma sodium content. A decrease in urine sodium excretion during the race day would contribute to the latter. Second, the interpretation of post-race changes in serum constituents must take account of changes in plasma volume. Third, there is an increase in creatinine clearance, indicating an increase in glomerular filtration rate, after both standard and ultramarathon running. This may be caused by the products of muscle cell damage although the physiologic mechanism for this is unclear.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

GOODYEAR, L. J., D. R. VAN HOUTEN, M. S. FRONSOE, M. L. ROCCHIO, E. V. DOVER, and J. L. DURSTINE. Immediate and delayed effects of marathon running on lipids and lipoproteins in women.Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 588–592, 1990. The purpose of this investigation was to examine the immediate and delayed effects of prolonged strenuous exercise on plasma lipid and lipoprotein concentrations in female runners. Venous blood samples were collected from 12 female runners 24 h before, 10 min after, and 1, 3, and 5 d after running a 42 km marathon. Whole blood was analyzed for hematocrit and hemoglobin to determine plasma volume shifts. Plasma aliquots were assayed for total cholesterol, high-density lipoprotein cholesterol (HDL-C), and triglyceride concentrations, while low-density lipoprotein cholesterol (LDL-C) was estimated. Total cholesterol concentrations were significantly reduced 1 d following the exercise and were still lower 3 and 5 d post-marathon. LDL-C was lower immediately and 1 d after the marathon. HDL-C concentrations, corrected for changes in plasma volume, were elevated 24 h post-exercise. The ratio of HDL/total cholesterol was increased 24 h post-exercise. Triglyceride concentrations were elevated immediately following the marathon but returned to baseline levels by 24 h post-exercise. These results demonstrate that prolonged strenuous exercise in women produces changes in blood lipid profiles that can last for several days.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

PASCOE, D. D., D. L. COSTILL, R. A. ROBERGS, J. A. DAVIS, W. J. FINK, and D. R. PEARSON. Effects of exercise mode on muscle glycogen restorage during repeated days of exercise.Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 593–598, 1990. The purpose of this study was to examine differences in muscle glycogen storage during three successive days of running or cycling. In a crossover design, seven male subjects performed two 3-d trials of either running (trial R) or cycling (trial C) for 60 min at 75% &OV0312;O2max. Biopsy samples were obtained before and after each day's exercise from the gastrocnemius (trial R) or vastus lateralis (trial C) muscle. Diets in the 2 d preceding and during each trial contained 5 g carbohydrate·kg−1·d−1and 14,475 ± 402 kJ·d−1. Mean pre-exercise glycogen content (mmol·kg−1wet wt.) was significantly reduced in both trials on day 3 (103.4 ± 6.0) when compared to day 1 and day 2 (119.9 ± 6.8 and 116.4 ± 5.7, respectively). Day 1 glycogen reduction was significantly greater in trial C (P< 0.03), and glycogen restorage was greater (P< 0.02) only in trial C between the 1st and 2nd d. On day 3, spectrophotometric analysis of PAS strains showed that pre-exercise glycogen content in either muscle group was significantly (P< 0.01) less in Type I as compared to Type II fibers. This difference in fiber glycogen storage did not appear to be attributable to muscle damage as negligible leukocyte infiltration and low blood CK levels were obtained. No difference between modes were observed for CK values throughout the trials. These data suggest that the depressed glycogen storage before the 3rd d of exercise was due to the moderate carbohydrate intake.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

HORSWILL, C. A., S. H. PARK, and J. N. ROEMMICH. Changes in the protein nutritional status of adolescent wrestlers.Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 599–604, 1990. The protein nutritional status of adolescent wrestlers was studied to determine whether changes occur during a season of competition and weight loss. Subjects (N= 18) were measured prior to the start of the season (PRE), twice in the midseason, and once during late season (LATE) for weight, percent body fat, and height. At each of these times, a venous blood sample was obtained from the subjects, who were fasted, and analyzed for concentrations of albumin, prealbumin, retinol binding protein (RBP), blood urea nitrogen (BUN), hemoglobin, hematocrit, and 23 amino acids. Diet records were kept by subjects to assess daily energy, protein, fat, and carbohydrate intake. Data were analyzed by repeated measures ANOVA. Results showed that wrestlers decreased weight by an average of 6.6 ± 0.9% and that percent body fat, fat-free weight, plasma levels of prealbumin and RBP, the ratio of total essential amino acids to total amino acids, and dietary energy nutrient intakes were significantly lower at LATE compared to PRE. RBP decreased during midseason and averaged (± SE) 3.21 ± 0.15 mg·100 ml−1at LATE; prealbumin was significantly lower at LATE with a mean value of 19.8 ± 1.0 mg·100 ml−1. Total energy intake decreased from PRE values by 35%, to approximately 27 kcal·kg−1·d−1during the season. In conclusion, in these high school wrestlers who lost approximately 6.6% of weight, there were adverse effects on some of the indices of protein nutritional status.

ISSN:0195-9131    

出版商:OVID    

年代:1990

数据来源: OVID