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ABSTRACT: Hispanics comprise one of the fastest-growing segments of the U.S. population. Mexican-American adults are more likely to be overweight, physically inactive, diabetic, and to have higher levels of hypertension than are white adults. However, studies addressing the relationship between physical fitness and coronary artery disease (CAD) risk factors among Mexican-Americans are much less conclusive. Therefore, understanding the etiology of factors influencing resting systolic (SBP) and diastolic blood pressure (DBP) in Hispanic women was the aim of this investigation. SBP, DBP, peak oxygen uptake (peak VO (2)), weekly physical activity, waist (WC) and hip circumference, blood glucose, and levels of plasma lipids (triglyceride, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol) of 39 Hispanic women age 22 - 51 years were measured. Factors with significant correlation to SBP were age, WC, sagittal diameter, and weight. Similarly, significant correlations were observed between anthropometric indices, age, and DBP. Peak VO (2) ( r = - 0.53, p < 0.01) and heart rate at maximal effort ( r = - 0.34, p </= 0.05) were inversely associated to DBP. There was also a strong inverse correlation ( r = - 0.53, p < 0.01) between peak VO (2) and CAD risk profile (created from one or the combination of: hypertension, obesity, hyperglycemia, dyslipidemia, smoking). Stepwise multiple linear regression revealed that 33 % of the variance in SBP is attributed to age (25 %), and WC (8 %), while DBP is explained by WC alone (26 %). The addition of peak VO (2) did not make significant contributions to the variances in SBP or DBP. The findings of this study suggest that central adiposity is an important predictor of resting blood pressure in Hispanic women. The inverse association between aerobic fitness and diastolic blood pressure as well as CAD risk factors suggests that recommendations regarding prevention of hypertension in this population should be based on the interrelationships between physical fitness and obesity.
International Journal of Sports Medicine 11/2004; 25(8):599-606. · 2.43 Impact Factor
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ABSTRACT: Understanding the etiology of factors influencing bone mineral density (BMD) in Hispanic women for the prevention of osteoporosis was the aim of this investigation. Whole body BMD (WBBMD) of 39 Hispanic, premenopausal women aged 22 - 51 years was measured using dual-energy X-ray absorptiometry (DXA). Maximal aerobic capacity ((.-)VO(2max)) was determined by treadmill ergometry with direct measurement of oxygen consumption. Fat-free mass (FFM) and fat mass were estimated from two independent techniques, DXA and bioelectrical impedance analysis (BIA). A questionnaire was administered to determine weekly physical activity, age of menarche, oral contraceptive (OC) use, parity, and lactation. Factors with significant correlation to WBBMD were weight ( r = 0.74), body mass index ( r = 0.66), fat mass ( r = 0.68 - 0.69), FFM ( r = 0.55 - 0.65), percent fat ( r = 0.43 - 0.55), sagittal diameter ( r = 0.58), waist circumference ( r = 0.53), hip circumference ( r = 0.66) and weekly activity ( r = 0.40). Stepwise multiple linear regression revealed that 73 % of the variance in WBBMD is attributed to fat mass (55 %), FFM (10 %), and (.-)VO(2max) (8 %). When BIA was used instead of DXA in the regression, (.-)VO(2max) was no longer an independent predictor of WBBMD. Fat mass and FFM accounted for 43 % and 20 % of the variance in WBBMD, respectively, explaining a total of 63 % of the variance. The addition of age, age of menarche, weekly physical activity, OC use, parity, and lactation did not make significant contributions to the variance. The findings of this study suggest that fat mass is a stronger predictor of bone mineral density than fat-free mass to BMD; aerobic capacity is another important predictor of BMD in Hispanic premenopausal women.
International Journal of Sports Medicine 08/2004; 25(5):384-90. · 2.43 Impact Factor
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ABSTRACT: The use of master athletes to describe an idealized rate of physiological loss associated with aging is quite common. The results of such studies suggest that older athletes may be able to reduce the rate of decline in functional loss. The findings of such studies have been questioned due to their limited sample size and the age range and gender of their subjects.
We examined a group of 146 male and 82 female master athletes over the age of 40 years. Physiological parameters included maximal oxygen uptake (VO2max), body composition, muscle strength, bone density, and blood chemistries. Medical histories and training records were obtained via questionnaire.
Results demonstrated gender differences in body composition, blood chemistries, blood pressure, VO2max, muscle strength, bone density, and performance (p <.05). All metabolic parameters for men and most for women demonstrated significant losses across the age range (p <.05). In addition, strength and performance for men and women and bone density for women declined significantly with age (p <.05). The demonstrated loss rates did not differ by gender.
Although limited by the lack of a sedentary comparison group, these data suggest that age-related losses in VO2max may not be different from data previously reported for older sedentary adults and that loss in muscle strength and performance with aging is not linear.
The Journals of Gerontology Series A Biological Sciences and Medical Sciences 10/2001; 56(10):M618-26. · 4.60 Impact Factor
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ABSTRACT: Previous studies have demonstrated equivocal findings on the effect of chronic running on bone mass in post-menopausal women. The purpose of this study was to determine the effect of chronic running alone and in conjunction with hormone replacement therapy (HRT) on bone mineral density (BMD) in postmenopausal women.
Forty-three women [15 premenopausal 48.1 +/- .4 yrs (Pre); 13 postmenopausal 57.3 +/- 2.3 yrs (Post); and 15 HRT-treated postmenopausal 56.8 +/- 1.5 yrs (PostE)] served as subjects. All were chronic runners (duration > 5 yrs, > 10 miles per week). BMD was determined by dual energy x-ray absorptiometry, VO2 max on a treadmill, body composition by hydrostatic weighing, knee strength by KinCom dynamometer, and training and menstrual history by questionnaire. Analysis of covariance with Tukey post hoc tests was utilized to compare the groups.
The groups were similar in body weight, VO2 max, years training, and miles run per week. Pre and PostE did not differ in total or spine BMD. However, Pre had greater hip BMD than PostE (.973 +/- .03 vs .876 +/- .03 g/cm2; p < .05). As well, Pre had greater BMD of the hip (.973 +/- .03 vs .805 +/- .03 g/cm2; p < .05), spine (1.047 +/- .04 vs .870 +/- .04 g/cm2; p < .05), and total body (1.115 +/- .02 vs .996 +/- .03 g/cm2; p < .05) than Post.
These results suggest that (a) chronic running + HRT is insufficient to protect hip BMD and (b) chronic running alone provides no protection for bone mass in postmenopausal women.
The Journals of Gerontology Series A Biological Sciences and Medical Sciences 10/1999; 54(9):M451-5. · 4.60 Impact Factor
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ABSTRACT: 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.
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.
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).
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.
Medicine & Science in Sports & Exercise 09/1999; 31(9):1287-92. · 4.43 Impact Factor
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ABSTRACT: This nonplacebo-controlled, open label, randomized study was conducted to test the hypotheses that pharmacological doses of nandrolone decanoate would increase lean body tissue, muscle mass, and strength in immunodeficient human immunodeficiency virus-infected men, and that these effects would be enhanced with progressive resistance training (PRT). Thirty human immunodeficiency virus-positive men with fewer than 400 CD4 lymphocytes/mm3 were randomly assigned to receive weekly injections of nandrolone alone or in combination with supervised PRT at 80% of the one-repetition maximum three times weekly for 12 weeks. Total body weight increased significantly in both groups (3.2 +/- 2.7 and 4.0 +/- 2.0 kg, respectively; P < 0.001), with increases due primarily to augmentation of lean tissue. Lean body mass determined by dual energy x-ray absorptiometry increased significantly more in the PRT group (3.9 +/- 2.3 vs. 5.2 +/- 5.7 kg, respectively; P = 0.03). Body cell mass by bioelectrical impedance analysis increased significantly (P < 0.001) in both groups (2.6 +/- 1.0 vs. 2.9 +/- 0.8 kg), but to a similar magnitude (P = NS). Significant increases in cross-sectional area by magnetic resonance imaging of total thigh muscles (1538 +/- 767 and 1480 +/- 532 mm2), quadriceps (705 +/- 365 and 717 +/- 288 mm2), and hamstrings (842 +/- 409 and 771 +/- 295 mm2) occurred with both treatment strategies (P < 0.001 for the three muscle areas); these increases were similar in both groups (P = NS). By the one-repetition method, strength increased in both upper and lower body exercises, with gains ranging from 10.3-31% in the nandrolone group and from 14.4-53.0% in the PRT group (P < 0.006 with one exception). Gains in strength were of significantly greater magnitude in the PRT group (P < or = 0.005 for all comparisons), even after correction for lean body mass. Thus, pharmacological doses of nandrolone decanoate yielded significant gains in total weight, lean body mass, body cell mass, muscle size, and strength. The increases in lean body mass and muscular strength were significantly augmented with PRT.
Journal of Clinical Endocrinology & Metabolism 04/1999; 84(4):1268-76. · 6.50 Impact Factor
