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Cemal Ozemek Mitchell H. Whaley W. Holmes Finch Leonard A. Kaminsky 《European Journal of Sport Science》2017,17(5):563-570
There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HRmax) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HRmax with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HRmax for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R2 (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HRmax explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HRmax. 相似文献
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Difrisco E Goodman KE Budin WC Lilienthal MW Kleinman A Holmes B 《The Journal of perinatal education》2011,20(1):28-35
Substantial evidence documents the superiority of breastfeeding for mothers and breastmilk for babies. Although the American Academy of Pediatrics and the U.S. Healthy People 2010 initiative promote breastfeeding, current breastfeeding rates often fall short of recommendations. This study determined factors associated with exclusive breastfeeding 2 to 4 weeks following discharge from a large, urban, academic medical center striving for Baby-Friendly designation. Results indicated that mothers who breastfed within the first hour of birth (61%) were significantly more likely to be exclusively breastfeeding 2 to 4 weeks after discharge. Incorporating care practices that include a number of the "Ten Steps to Successful Breastfeeding," as recommended by the Baby-Friendly Hospital Initiative, may increase the duration of exclusive breastfeeding after discharge. 相似文献