The relationship between aerobic capacity (VO2max) and self-reported activity (SRA) was determined in 2071 third and fourth graders; 50.8% females. VO2max was predicted using the PWC170 cycle ergometer test. The SRA consisted of 25 commonly reported activities and the number of days a week utilized. The SRA activities were weighted similarly to the Minnesota Leisure-Time Activities Questionnaire and a weighted sum of the three most frequent reported activities was computed. The VO2max of the males was higher than the females (45.1+or-9.8 vs. 39.5+or-9.0 ml/kg/min; p=0.0001). The SRA scores for males were also higher than females (71.2+or-31.1 vs. 58.4+or-27.7; p=0.0001). Separate regressions by gender indicated weak correlations between VO2max and SRA for females (r=0.075) and males (r=0.070). ANOVA of the VO2max by quartiles on the SRA indicated significant differences between the first and fourth quartiles (females: 40 2+8.3 vs. 38.6+9.7 ml/kg/min p=0.028, R2 =0.009; males: 46.2+11.0 vs. 44.0+9.5 ml/kg/min, p=0.011, R2 =0.009). Multiple regression, predicting VO2max from body mass index (BMI), skinfolds (triceps+subscapular) and SRA, indicated that BMI accounted for 40.5% of the variance while the SRA accounted for only 1.8%. These results suggest little relationship between self-reported activity levels of children and predicted aerobic capacity. However, although the size of the child may be the most significant factor in predicting VO2max, activity levels may serve as a modifier by influencing BMI or physical conditioning.



Joanne S. Harrell, Annette C. Frauman, Robert G. McMurray, Shrikant I. Bangdiwala. Racial and Rural/Urban Difference in Cardiovascular Risk Factors in North Carolina Children. Cardiovascular Health in Children Study, University of North Carolina, Chapel Hill, NC.

Cardiovascular Health in Children (CHIC) is a randomized, controlled trial of the effects of two interventions to reduce CVD risk factors in 3rd and 4th graders in North Carolina. The subjects are 2209 children mean age 8.9 (SD 0.8) from 21 elementary schools across the state; half of the schools in each region are rural, half urban. Participation rate is 60.4%; 50.6% are females. The present analysis covers baseline characteristics of the 411 black and 1661 white children only. Age adjusted means of risk factors and proportion of children with risk factors are summarized below:

	Black		White		t-test p-values
	Rural	Urban	Rural	Urban	Blk/	Blk Rural/
Risk Factor:	(n=199)	(n=221)	(n=927)	(n=734)	White	Blk Urban
SBP	106.5	103.9	104.6	103.2	.0139	.0078
CHOL	172.6	169.9	164.5	164.0	.0001	.3474
BMI	19.4	18.5	18.6	17.9	.0004	.0079
VO2	39.7	43.5	41.8	43.2	.0696	.0001
					Mantel-Haenszel p
CHOL >= 200	20.1%	17.2%	10.9%	11.0%	<.001	.357
CH SMOKE	3.0%	5.9%	4.5%	2.9%	.851	.166

Risk factors for CVD are significantly more prevalent in black children, particularly those in rural areas. These findings identify black children as a population at risk for future CVD and indicate a need to target rural areas for further study.



R.G. McMurray, FACSM, S. Brown, J.S. Harrell, University of North Carolina, Chapel Hill, NC & Duke University, Durham, NC. Relationship of Leptin to Physical Activity Levels and Aerobic Power of Adolescents. Medicine & Science in Sports & Exercise, Vol. 38, Number 5, Supplement to May 1998.

This study examined the relationship between the ob gene hormone leptin and physical activity (PA) or aerobic power (VO2max) in 125 youth, aged 12-15 yr. PA was obtained from a 32-activity questionnaire, VO2max was estimated from submaximal cycle ergometry, sum of skinfold (SSF) was obtained from triceps and subscapular sites, while fasting leptin was measured via RIA kit. The sample was 63 girls, 62 boys, 39 African American, 81 Caucasian, and 5 of other races. Compared to the girls, the boys had higher PA scores (284 +or- 150 vs. 227+or-110; p=0.017), higher V02max (37.8+or-10.5 vs. 31.5+or-7.5 ml/kg/min, p=0.0002), and lower SSF (28.7+or-17.5 vs. 34.6+or-15.6 mm; p= 0.05). Leptin levels were higher for girls than boys: 15.7+or-10.3 vs. 9.7+or-9.6 ng/ml; p= 0.001. Significant (p=0.0001) gender-specific correlations between VO2max and leptin were found (boys: r= 0.597, girls: r=0.649). PA and leptin were not significantly correlated (boys: r= -0.057; girls: r= -0.010; p>0.65). Multiple regression analysis within genders for the association of PA, VO2max, SSF with leptin, were significant: boys r2=0.761; girls r2=0.744. SSF accounted for majority of the variance for boys (partial r2= 0.76) and girls (partial r2=0.705). The partial r2 for VO2max was 0.025 for girls (p=0.04), but did not contribute significantly for boys (p>0.15). PA was not a significant contributor for either gender. These data suggest that in early adolescents, aerobic power is only marginally associated with leptin levels, while PA levels appears unrelated to resting leptin concentrations.
Supported by Institute of Nutrition, Chapel Hill, NC, and NCNR #NR01837




Bradley C.B., McMurray R.G., FACSM, Harrell, J.S., Deng, S. University of North Carolina at Chapel Hill, Chapel Hill, NC. Attitudes Toward Exercise and Fitness/Activity Variables in Adolescents. (Sponsor: R.G. McMurray, FACSM).

The relationship between attitudes towards exercise (benefits/barriers) and physical activity (PA) or fitness (V02max) has been studied in adults; however, little has been done with attitudes towards exercise in youth. Thus, this study assessed attitudes towards exercise (AtE) in middle school-age children and examined the relationship between those attitudes and the children's VO2rnax, self-reported PA, body mass index (BMI), and sum of triceps and subscapular skinfolds (SSF). The AtE scale, which included both benefits and barriers to exercise, was developed and pilot tested by the Cardiovascular Health in Children and Youth Study. Middle-school aged children (1510 6th/7th graders; 49.8% female, 27.2% nonwhite) from 29 middle schools completed questionnaires to measure PA in the past week and AtE. Height, weight, triceps and subscapular skinfolds and VO2max (submaximal cycle ergometer) were measured. The overall mean AtE score was 32 (possible range= 10-40). Boys had more positive AtE than girls (32.4 vs. 31.9; p=0.02), but no racial differences were found. AtE was correlated with PA and VO2max (PA r=0.20; VO2max r=0.20; p=0.0001). AtE was also weakly but significantly inversely related to BMI (r= -0.14) and SSF (r=-0.17). Regardless of gender, subjects with high benefits scores, compared to those with high barriers scores had significantly (p=0.0001) higher mean PA scores (253.2 vs. 193.1), higher VO2max (39.6 vs. 35.7 ml/kg/min), lower mean BMI (20.3 vs. 22.2 kg/m2) and lower SSF (26.8 vs. 34.2 mm). These results suggest that, although youth tend to have positive attitudes towards exercise, their attitudes can differentiate between high active/fit and low active/fit youth of similar ages, regardless of gender.





Howell, Joanne, L. Johnston, T. Griggs, P. Schaefer, E. Carr, R. McMurray, A Meibohm, S. Munoz, B. Raines and O. Williams. An Occupation Based Physical Activity Intervention Program. American Association of Occupation Health Nurses, August 1996, p 377-384.

Purpose: To determine the effectiveness of an occupation based health and fitness program.
Subjects: 1,504 police trainees (85% male, 15% female) with an ethnic distribution of 82% white, 16% African American, and 2% of other races. Data was collected at 25 sites across the state of North Carolina. The sites were randomly assigned to either the experimental group (implemented the intervention) or the control group (continued usual training).
Intervention: The wellness and fitness program included 4 hours of lecture, 12 hours of testing, and 27 hours of supervised physical activity. The lecture had 3 areas of emphasis: health, nutrition, and fitness.
Results: As compared with controls, subjects at the experimental sites improved significantly in CV fitness (aerobic power), general muscular strength (number of sit-ups per minute), and flexibility, and lowered their body fat.
The intervention required minimal equipment and was taught primarily by peers who received a one week training program. This occupational approach to improving health could be particularly useful in occupation with many workers who seldom engage in leisure time physical activity.



McMurray, R.G., J.S. Harrell, L. Johnston, E. Sprow. Center for Health Promotion/Disease Prevention, University of North Carolina, Chapel Hill, NC 27599. Influence of Physical Activity and Aerobic Power on Cardiovascular Disease Risk Factors. Presented at: American College of Sports Medicine, Southeast Regional Chapter, Annual Meeting, January 1998.

The purpose of this study was to determine the relationship between aerobic power (VO2max), physical activity (PA) and cardiovascular disease (CVD) risk factors. The study also determined how improvements in VO2max and increased PA levels influence CVD risk factors of 576 low-fit adults (VO2max < 30 ml/kg/min). PA (Baeke questionnaire) and VO2max (submaximal cycle test) of 1664 law enforcement trainees were evaluated with respect to the CVD risk factors of total cholesterol, blood pressure [BP], smoking and obesity using separate logistic regression, adjusting for age, gender and the other major CVD risk factors. Compared to the lowest tertile of VO2max, the highest tertile was found to have a reduction in relative risk (RR) for elevated cholesterol (RR 0.56; 95% CI 0.36-.43), BP (RR 0.32; 95%C1 0. l5-.62) and obesity (RR 0.09; 95%CI 0.06-0.12). The middle tertile of VO2max compared to the lowest had reduced in RR for elevated diastolic BP (RR 0.44; 95%CI 0.23-0.66) and obesity (RR 0.38; 95%CI 0.28-.50). Moving from the low to high levels of PA caused significantly lower RR for high systolic BP (RR 0.48; 95%CI 0.23-.95). Moving from either the low PA to moderate or moderate to high resulted in no significant change in any of the RRs (p>0.05). Participation in a 9-week aerobic exercise program by low-fit individuals resulted in a significant 9% increase in PA levels; however, only those subjects who improved VO2max had a significant reduction in RR for high cholesterol (RR 0.62; 95%CI .42-.92) and systolic BP (RR 0.57; 95%CI 0.40-.80). No significant change in RRs were noted for diastolic BP or obesity. The results of these studies indicate that aerobic power has more of an effect on CVD risk factors than PA levels. Furthermore, in low-fit persons it appears that only PA that increases aerobic power is associated with a reduction in CVD risk factors of cholesterol and blood pressure.




McMurray, R.G., M. Bauman, & J.S. Harrell, Dept of Physical Education and School of Nursing, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599. The Relationship of Adiposity and Aerobic Power to Glycemic Status of Children. Presented at: The Annual Research Symposium of The Institute of Nutrition, UNC-CH, October 1997.

This study determined the influence of body fat and exercise on basal plasma levels of insulin and glucose of 11-14 yr. old children. Blood samples were obtained from 330 children after an overnight fast and analyzed for insulin (radioenzymatic kit) and glucose (glucose oxidase method). Height, weight, body mass index (BMI), and skinfolds (sum of triceps + subscapular sites) were measured. Physical activity (PA) levels were estimated from a questionnaire. Aerobic power (VO2max) was predicted from cycle ergometry. Plasma insulin levels were significantly correlated (p=.0001) to BMI (r=.560), skinfolds (r=.541), and VO2max (r=.395), but not related to PA (r=-.004). Stepwise multiple regression indicated that BMI accounted for 25% (p=.0001) of the variance in the model, whereas VO2max accounted for < 1% (p=.05): total r2 = .258. Simple correlations of glucose with BMI, skinfolds, VO2max, and PA were all low, r<.121. The multiple regression analysis for glucose was low, but significant (total r2 =.020; p=.011), with only skinfolds significantly associated (partial r2 =.020). Nine weeks of aerobic exercise resulted in a greater reduction in circulating insulin for those who improved VO2max than the non-responders (-23+or-56 vs. -10+or-93 pmol/L; p=0.015), with obese subjects (BMI>27) who improved VO2max had the most decrease (-50+or-51 pmol/L). Plasma glucose levels increased slightly (+0.1+or-0.8 mmol/L) for those who improved VO2max and decreased slightly (-0.1+or-0.9 mmol/L) for those who did not change VO2max (p=0.0001). These changes in glucose levels were not associated with changes in BMI or skinfolds (p>.12). The results of this study indicate that in children adiposity has a significant influence on resting glycemic status. However, exercise can improve glycemic status, particularly in obese children



NC Prevention Partners, Prevention Report Card Committee. Does North Carolina Make the Grade for Prevention? 1998 North Carolina Prevention Report Card. 1998 North Carolina Prevention Report Card.

Three areas of health in NC are evaluated and given a "grade," they are: tobacco (D+), nutrition (C-), and physical activity (D+). A summary of some of the key items follows:
Tobacco (D+)

• NC ranks 47^th in the nation in smoking. 28% of NC adults compared to 22% of adults in the US are current smokers.
  
• 16% of all NC pregnant women smoke versus 14% of pregnant women in the US.
  
• NC ranks 49th in cigarette tax per pack (5¢ vs. 24¢ for the nation)
  
• Smoke-free worksites are the #1 reason adults quit smoking. NC worksites that are smoke-free: 76% large businesses, 65% medium businesses, and 60% small businesses.
  
• 80% of NC smokers say they want to quit.
  

• NC ranks 43rd in the nation for adults eating daily requirements for fruits and vegetables. 81% of adults do not get 5 fruits and vegetables each day.
  
• NC ranks 49th in the nation for eating less and exercising more to lose weight.
  
• NC youth are 2-3 times more likely to be obese than other kids in the nation.
  
• 88 of 118 local school systems have been trained to lower the fat in food served in schools.
  
• 23% of adults report their doctors discussed diet or eating habits.
  

• NC ranks 49th in the nation for adults getting adequate physical activity. Less than 10% of adults reported getting regular, vigorous physical activity in the past month.
  
• NC children are less flexible, have more body fat, and have a poorer fitness level than youth nationally.
  
• NC is a leader in the nation in establishing local fitness and nutrition councils: more than 27% of NC counties have fitness councils.
  
• 25% of residents report that their doctors counseled them about physical activity or exercise.
  
• 13 Healthy Carolinian counties are identifying and mobilizing around physical activity.
  
• The Dept. of Public Instruction requires health and physical education for K-8th grade, and only one unit in health/physical education for grades 9-12 to graduate.