Abstract:
PURPOSE:To test our hypothesis that differences in urinary calcium excretion among blacks and whites may be secondary to ethnic variations in acid (H(+)) metabolism and to prove that increases in titratable acid excretion would be found among individuals predisposed to the development of stress fractures. METHODS:We administered 8 g NH(4)Cl acutely to 11 black and 18 white healthy volunteers and measured urinary sodium, calcium, and acid excretions. We measured the Na(+)/H(+) antiporter activity using acid-loaded platelets as surrogate markers for this exchanger expressed in renal epithelial cells. We also compared differences in titratable acid excretion among a cohort of subjects with, and without, a history of stress fracture. RESULTS:NH(4)Cl-induced increases in titratable urinary acid correlated with changes in the renal excretion of calcium and sodium, and stimulated acid excretion correlated with basal acid loss. Despite comparable changes in plasma pH, whites, when compared to blacks, had much greater basal acid excretion and NH(4)Cl-induced acid excretion. Whites also had much greater baseline calcium excretion rates when compared to blacks. Following acid loading, whites continued to exhibit greater calcium excretion rates than blacks. Acid loading significantly decreased sodium excretion in whites but not in blacks. Blacks also had significantly attenuated Na(+)/H(+) exchange activity. In a cohort of resting, athletic students, we found enhanced basal H(+) and phosphate excretion among subjects who experienced stress fractures during their rigorous physical training when compared to those individuals who did not. CONCLUSION:Blacks may have a greater endogenous buffering capacity than whites, or the reported ethnic differences in sodium and calcium excretion rates between blacks and whites may be secondary to racial variations in renal H(+) excretion. We conclude that both ethnic differences in bone mineralization and bone integrity in athletes are mediated by heritable differences in titratable acid excretion.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Vaitkevicius H,Witt R,Maasdam M,Walters K,Gould M,Mackenzie S,Farrow S,Lockette Wdoi
10.1097/00005768-200202000-00018subject
Has Abstractpub_date
2002-02-01 00:00:00pages
295-302issue
2eissn
0195-9131issn
1530-0315journal_volume
34pub_type
临床试验,杂志文章abstract::Twelve 9- to 12-year-old children (6 boys, 6 girls) performed four exercise-in-heat (35 degrees C, 45% RH) trials which differed in the composition of the fluids they drank. In each trial, subjects cycled for one 20-min and two 15-min bouts at 50% peak VO2 with 10-min rest periods in between. In a fourth bout, they cy...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章
doi:
更新日期:1995-06-01 00:00:00
abstract::Endurance performance is a common criterion used to evaluate training or dietary interventions. However, to accurately appraise the effects of an intervention, the endurance performance measure must be reliable. The purpose of the investigation was to establish the reliability of a 1-h endurance performance test. Twen...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199704000-00019
更新日期:1997-04-01 00:00:00
abstract:PURPOSE:High internal stress is considered to be a possible cause of heel-pad problems. External biomechanical measurements are used to attempt to understand the causes of heel pain. However, internal stress cannot be measured experimentally. Therefore, the purpose of this study was to quantify the relationship between...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:2005-06-01 00:00:00
abstract::This study assessed body density (BD) in an ethnically diverse sample of women (African American, Caucasian, Mexican American and Native American) (N = 139) who were between 20 and 30 or 40 and 50 yr of age and of normal weight for their height. BD was assessed using three methods: hydrostatically determined density (...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199701000-00013
更新日期:1997-01-01 00:00:00
abstract:PURPOSE:The purpose of this investigation was to examine the effects of differing amounts of beta-hydroxy-beta-methylbutyrate (HMB), 0, 36, and 76 mg x kg(-1) x d(-1), on hematology, hepatic and renal function during 8 wk of resistance training. METHODS:Thirty-seven, untrained collegiate males and were randomly assign...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1097/00005768-200012000-00023
更新日期:2000-12-01 00:00:00
abstract:PURPOSE:Cardiopulmonary exercise testing (CPX) provides valuable clinical information, including peak ventilation (V˙Epeak), which has been shown to have diagnostic and prognostic value in the assessment of patients with underlying pulmonary disease. This report provides reference standards for V˙Epeak derived from CPX...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000001740
更新日期:2018-12-01 00:00:00
abstract::Poliomyelitis is an acute viral disease that attacks the brain and the ventral horn of the spinal cord. Damage to the lower motor neurons usually results in atrophy and weakness of muscle groups, perhaps paralysis and possibly deformity. A second type, bulbar poliomyelitis, infects the medulla oblongata and may result...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:
更新日期:1993-04-01 00:00:00
abstract:PURPOSE:FRESH START is a randomized controlled trial that will test whether a personally tailored, distance-medicine-based program will increase exercise and fruit and vegetable consumption, and decrease fat intake of individuals recently diagnosed with breast or prostate cancer. METHODS:Early-stage breast and prostat...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1249/01.MSS.0000053704.28156.0F
更新日期:2003-03-01 00:00:00
abstract::In 1983 a representative sample of Danish adolescents 16-19 yr of age were selected to participate in a study to determine risk profile for coronary heart disease. Eight years later (1991), we performed a follow-up study of the same participants 23-27 yr of age to compare risk factors. In the young adults power was ge...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1994-08-01 00:00:00
abstract:PURPOSE:This study aimed to evaluate the relationship between race car cockpit temperature and thermal strain indicators among race car drivers. METHODS:Four male racing drivers' heart rate (HR), skin temperature (Tskin), and core temperature (Tcore) were measured continuously using the Equivital Life Monitor bio harn...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000002483
更新日期:2021-02-01 00:00:00
abstract::Nine male and five female college students were tested on four occasions to determine the effects of various exhaustive weightlifting stimuli on forearm blood flow as measured by strain-gauge plethysmography. Maximum voluntary dynamic wrist curl strength was determined in the first session, which was followed by rando...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1983-01-01 00:00:00
abstract:PURPOSE:To determine the prevalence of reversible airway obstruction in a group of professional football training camp participants. METHODS:All attendees at a Canadian Football League team rookie preseason training camp were invited to participate in a protocol designed to elicit symptoms and signs of reversible airw...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200012000-00003
更新日期:2000-12-01 00:00:00
abstract::Older adults have low rates meeting the physical activity (PA) guidelines and high sedentary time. Low PA and excessive sedentary time have been linked to adverse health outcomes. Less is known about whether exercise training influences sedentary time and PA in various intensities. PURPOSE:This study aimed to examine...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000002407
更新日期:2020-12-01 00:00:00
abstract::We sought to determine how a stationary activity such as playing a stringed instrument may affect energy expenditure (EE) in adolescents. Using automated indirect calorimetry, we measured EE in eight adolescents (1 male, 7 females, 14.2 +/- 2.1 yr) while they each performed the following activities: watching televisio...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1995-09-01 00:00:00
abstract:PURPOSES:To compare the claudication distances between men and women patients with peripheral arterial disease (PAD), and to determine whether sex differences in claudication pain persisted after controlling for potential confounders such as demographic, functional, and physiological measures. METHODS:A total of 488 m...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200211000-00001
更新日期:2002-11-01 00:00:00
abstract:INTRODUCTION:Chronic unimanual motor practice increases the motor output not only in the trained but also in the nonexercised homologous muscle in the opposite limb. We examined the hypothesis that adaptations in motor cortical excitability of the nontrained primary motor cortex (iM1) and in interhemispheric inhibition...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,随机对照试验
doi:10.1249/MSS.0b013e31820a94b8
更新日期:2011-07-01 00:00:00
abstract::This study examined the effects of age and physical activity on body composition and fat distribution by comparing differences between young and older endurance trained men and women with differences between young and older sedentary people. Although indices of total body adiposity (fat mass, percent body fat) were hi...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1992-07-01 00:00:00
abstract:PURPOSE:The purpose of this investigation was to evaluate the accuracy of a new air displacement plethysmograph, BOD POD Body Composition System, for determining %fat in collegiate football players. METHODS:Body fatness was estimated from body density (Db), which was measured on the same day using the BOD POD and hydr...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199909000-00019
更新日期:1999-09-01 00:00:00
abstract:INTRODUCTION:The prognostic value of peak V˙O2 and V˙E/V˙CO2 slope measured during cardiopulmonary exercise (CPX) testing has been well established in patients with advanced heart failure, but blood pressure response to exercise is less well characterized. METHODS:We retrospectively studied 151 outpatients who underwe...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000001587
更新日期:2018-07-01 00:00:00
abstract:UNLABELLED:Two recently identified glucose transporters, GLUT8 and GLUT12, are expressed in human skeletal muscle and may be involved in insulin-mediated sugar transport. PURPOSE:The purpose of this study was to measure GLUT8 and GLUT12 mRNA levels in endurance-trained versus sedentary individuals in an effort to dete...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.mss.0000222837.74015.f1
更新日期:2006-06-01 00:00:00
abstract:PURPOSE: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-speci...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199909000-00009
更新日期:1999-09-01 00:00:00
abstract:PURPOSE:The purpose of this study was to identify electromyographic (EMG) differences in the latent muscle reaction timing (LMRT) of the rotator cuff between trained overhead throwers and control subjects in response to sudden internal rotation perturbation (P < or = 0.05). METHODS:Subjects included 15 trained overhea...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199910000-00006
更新日期:1999-10-01 00:00:00
abstract:INTRODUCTION:Androgen deprivation therapy (ADT) is associated with significant bone loss and an increase in fracture risk among prostate cancer survivors (PCS). We investigated whether impact + resistance training could stop ADT-related declines in bone mineral density (BMD) among PCS on ADT. METHODS:We randomized 51 ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,随机对照试验
doi:10.1249/MSS.0000000000000265
更新日期:2014-08-01 00:00:00
abstract:PURPOSE:This study examines heavy episodic alcohol consumption and associated harms in collegiate athletes in the United States. The factors which may promote or deter such use are explored. METHODS:Randomly selected students in a nationally representative sample of 4-yr colleges in the United States completed self-re...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200101000-00008
更新日期:2001-01-01 00:00:00
abstract:PURPOSE:Unilateral strength training strengthens not only the muscles on the trained side but also the homologous muscles on the untrained side; however, the magnitude of this interlimb cross-education is modest. We tested the hypothesis that heightened sensory feedback by mirror viewing the exercising hand would augme...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,随机对照试验
doi:10.1249/MSS.0000000000000871
更新日期:2016-06-01 00:00:00
abstract:OBJECTIVE:To determine the optimal crank length and crank-axle height for maximum power production during standing arm cranking ("grinding"). METHODS:Nine elite professional America's Cup grinders (age = 36 +/- 2 yr, body mass = 104 +/- 1 kg, body fat = 13% +/- 2%) performed eight maximal 6-s sprints on an adjustable ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3181b46f3a
更新日期:2010-02-01 00:00:00
abstract:PURPOSE:The study purposes were 1) to study the differences between perceived exertion measured by a generic (/10) or an individualized (/max value obtained during the test) score on the OMNI cycle scale (OMNImax and OMNI10) and the actual effort (peak oxygen consumption) at different stages of a maximal cycling test i...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e31827bd397
更新日期:2013-05-01 00:00:00
abstract::The association between increasing age and decreasing vagal modulation is well known. However, the importance of fitness as a determinant of the decline in vagal modulation with age is not established. To test the hypothesis that decreasing vagal modulation is largely a function of declining fitness rather than increa...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199706000-00012
更新日期:1997-06-01 00:00:00
abstract:PURPOSE:Data from the general population suggest that habitual exercise decreases bronchial responsiveness, but the possible role of exercise in asthmatics is undefined. The leukotriene receptor antagonist montelukast decreases bronchial responsiveness and exercise-induced symptoms in asthmatic children. This randomize...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,随机对照试验
doi:10.1249/MSS.0b013e31815d9670
更新日期:2008-03-01 00:00:00
abstract:BACKGROUND:Interactive video game exercise leads to improved exercise adherence and health-related physical fitness in comparison to traditional stationary cycling. It has been postulated that interactive video game exercise has greater metabolic requirements than traditional cycling; however, this has not been tested ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e31819012bd
更新日期:2009-04-01 00:00:00