The purpose of this study was to determine the contribution of body composition and muscle strength to racial differences in bone mineral density (BMD) in chronically active older adults. Participants were 49 men and 56 women grouped according to self-selected race (Black, Asian, or White). BMD, body composition, and knee strength were measured. Asian men had significantly lower body mass, strength, and BMD than White and Black men did (p < .05). Asian and White women had significantly lower body mass and BMD than Black women did (p < .05), with few strength differences between groups. When lean mass was controlled by ANCOVA. racial differences in BMD disappeared for all bone sites in both sexes. Controlling for body mass eliminated most racial differences in BMD. Controlling for strength did not alter racial differences in BMD for either sex. These results suggest that racial differences in BMD might in part result from differences in lean mass.
Youn Soo Jung, Steven A. Hawkins and Robert A. Wiswell
Richard J. Bloomer, Bradford Cole and Kelsey H. Fisher-Wellman
High-kilocalorie feedings induce oxidative stress. Acute exercise has the potential to attenuate postprandial oxidative stress. No study has determined whether there are racial differences in postprandial oxidative stress with and without a preceding bout of acute exercise.
To investigate the impact of acute exercise on blood oxidative- stress biomarkers, triglycerides (TAG), and glucose in African American (AA) and White (W) women.
10 AA (age 29 ± 3 yr, body-mass index [BMI] 31 ± 3 kg/m2) and 10 W (age 30 ± 2 yr, BMI 30 ± 3 kg/m2) women consumed a meal of 1.2 g of fat and carbohydrate and 0.25 g of protein per kilogram body mass, on 2 occasions—with and without a session of aerobic exercise 15 min preceding the meal (45 min cycling at 65% heart-rate reserve)—in a random-order crossover design. Blood samples were collected premeal (fasted), and at 1, 2, 4, and 6 hr postmeal and assayed for TAG, glucose, xanthine oxidase activity, hydrogen peroxide (H2O2), and malondialdehyde (MDA). Area under the curve (AUC) was calculated for each variable.
AUC was lower for AA compared with W for both the exercise and the no exercise conditions for H2O2, MDA, and TAG (p < .01). However, acute exercise had no effect on decreasing the AUC for any variable in either AA or W women (p > .05).
Postprandial lipemia and oxidative stress are lower in AA than in W overweight/obese women. However, acute exercise, performed at the intensity and duration in the current study, does not influence postprandial lipemia or oxidative stress in AA or W women.
Kelliann K. Davis, Deborah F. Tate, Wei Lang, Rebecca H. Neiberg, Kristen Polzien, Amy D. Rickman, Karen Erickson and John M. Jakicic
African-Americans lose less weight during a behavioral intervention compared with Whites, which may be from differences in dietary intake or physical activity.
Subjects (30% African American, 70% White; n = 346; 42.4 ± 9.0 yrs.; BMI = 33.0 ± 3.7 kg/m2) in an 18-month weight loss intervention were randomized to a standard behavioral (SBWI) or a stepped-care (STEP) intervention. Weight, dietary intake, self-report and objective physical activity, and fitness were assessed at 0, 6, 12, and 18 months.
Weight loss at 18 months was greater in Whites (–8.74 kg with 95% CI [–10.10, –7.35]) compared with African Americans (–5.62 kg with 95% CI [–7.86, –3.37]) (P = .03) in the SBWI group and the STEP group (White: –7.48 kg with 95% CI [–8.80, –6.17] vs. African American: –4.41kg with 95% CI [–6.41, –2.42]) (P = .01). Patterns of change in dietary intake were not different between groups. Objective physical activity (PA) changed over time (P < .0001) and was higher in Whites when compared with African Americans (P = .01).
Whites lost more weight (3.10 kg) than African American adults. Although there were no differences in dietary intake, Whites had higher levels of objective PA and fitness. Thus, the discrepancy in weight loss may be due to differences in PA rather than dietary intake. However, the precise role of these factors warrants further investigation.
Neil A. Doldo, Matthew J. Delmonico, Jason A. Bailey, Brian D. Hand, Matthew C. Kostek, Karma M. Rabon-Stith, Kalapurakkal S. Menon, Joan M. Conway, Craig R. Carignan and Ben F. Hurley
To determine sex and race differences in muscle power per unit of muscle contraction, knee-extensor muscle power normalized for knee-extensor muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50–85 years). Results revealed that women displayed a 38% faster peak movement velocity than men and African Americans had a 14% lower peak movement velocity than Whites of a similar age when expressed per unit of involved muscle (p < .001). As expected, men exhibited greater knee-extensor strength and peak power per unit of muscle than women, but women had a faster knee-extension movement velocity per unit of muscle than men at the same relative strength level. Moreover, African Americans had greater knee-extensor muscle volume than Whites but exhibited lower knee-extensor strength and lower movement velocity per unit of muscle when tested at the same relative strength levels.
Justin B. Moore, John C. Hanes Jr., Paule Barbeau, Bernard Gutin, Roberto P. Treviño and Zenong Yin
The Physical Activity Questionnaire for Older Children (PAQ-C) is a validated self-report measure of physical activity widely used to assess physical activity in children (8-14 years of age). To date, however, the instrument has been validated in largely White Canadian samples. The purpose of the present article is to determine the psychometric properties of the PAQ-C for African American, European American, and Hispanic children. Two studies were conducted in which independent samples were administered the PAQ-C, along with varying indices of cardiovascular fitness, fatness, and psychological measures related to physical activity. Results showed that the reliability and validity of the PAQ-C varied by race and that modifications might be necessary.
Rebecca E. Hasson, Kirsten E. Granados, David Xavier Marquez, Gary Bennett, Patty Freedson and Barry Braun
Racial differences in psychological determinants of exercise exist between non-Hispanic blacks (blacks) and non-Hispanic whites (whites). To date, no study has examined racial differences in the psychological responses during and after exercise. The objective of this study was to compare psychological outcomes of single exercise bouts in blacks and whites.
On 3 separate occasions, sedentary black (n = 16) and white (n = 14) participants walked on a treadmill at 75%max HR for 75 minutes. Questionnaires assessing mood, state anxiety, and exercise task self-efficacy were administered before and after each exercise bout. In-task mood and rating of perceived exertion (RPE) were measured every 5 minutes during exercise.
Exercise self-efficacy and psychological distress significantly improved in both blacks and whites. However during exercise blacks reported more positive in-task mood and lower RPE compared with whites.
These data suggest that racial differences exist in psychological responses during exercise. Further research should confirm these findings in a larger, free-living population.
Joan L. Duda and Maria T. Allison
The-role of race and ethnicity in explaining variability in human behavior has long been considered in the anthropological and sociological studies of play, games, and sport. This paper suggests ways in which the field of sport and exercise psychology might more systematically begin to incorporate factors of race and ethnicity into its research agendas. The paper is divided into four major sections. The first section provides evidence of a dearth of such research in the field of sport and exercise psychology. The second section presents an overview of current work that highlights ethnic/racial differences in motor performance, physical activity levels, and recreational sport participation. The third section explores the theoretical relevance of comparative research on ethnic/racial similarities and differences in psychological processes and behavior. Finally, potential research methodologies that might be used in psychological research in sport and exercise contexts are presented. Implications for both basic and applied work are offered.
John R. Sirard, Karin A. Pfeiffer, Marsha Dowda and Russell R. Pate
The purpose of this study was to identify racial differences in physical activity (PA), fitness, and BMI in female 8th-grade sports participants and nonparticipants. Girls from 31 South Carolina middle schools (N = 1,903, 48% White; mean age = 13.6 ± 0.63) reported PA and previous year sports-team participation, completed a submaximal fitness test, and had height and weight measured. Sports team participation was positively associated with PA and negatively associated with television viewing and BMI, in a dose-response manner. Compared with Whites, African-Americans reported less PA and more television viewing, and had greater BMI scores. Whereas PA intervention programs that incorporate a sports-team component could benefit all girls, African-American girls could be specifically targeted because of their lower physical activity.
Mary H. Slaughter, Constance B. Christ, Rachel J. Stillman, Timothy G. Lohman and Richard A. Boileau
This study was designed to determine the association of selected circumferences with height among black and white, male and female, prepubescent and postpubescent children. Volunteers (N = 232) were grouped according to gender, race, and maturation level. Regression of the logs of the circumferences on the log of height revealed regression coefficients ranging from .74 to 1.3, except for the upper arm circumference (1.7), thus confirming the theoretical expectation of a linear relationship between circumference and height. Within-gender relationships of each circumference with height were determined using regression analysis. In general the prepubescent circumferences deviated below the within-gender line while the postpubescent circumferences typically deviated above it; however, there were exceptions in both sexes. Moreover, the racial differences in the circumference deviation scores were not consistent within either the male or female samples. The consideration of gender, race, and maturation is important in determining the association of circumference with height. The use of circumferences adjusted for height can be useful in studying muscle development in children.
Gina M. McCaskill, Olivio J. Clay, Peng Li, Richard E. Kennedy, Kathryn L. Burgio and Cynthia J. Brown
Birmingham (UAB) Study of Aging (SOA). Furthermore, we examined the data for racial differences on all-cause mortality. Methods Study Design and Participants The UAB SOA was a longitudinal 8.5 years investigation that examined racial differences in mobility in a sample of Black and White community