A ten-stage treadmill test was developed and standardized to secure the VO2max of male and female rats assigned to various cross-sectional and longitudinal experimental groups. Repeated measurements indicated that the test procedure was reliable and could be used for research purposes. When the test was used with different strains, the untrained Sprague-Dawley rats had significantly higher VO2max values than animals of the Wistar-Kyoto (WKY) or the Okamoto-Aoki (SHR) strains. Exercise schedules were evaluated that were similar to those previously used by various investigators and it was found that most were exercising their rats at levels exceeding 75% VO2max. After 6--10 wk of chronic exercise, significant increases in VO2max occurred that ranged between 12 and 26%. Longitudinal studies (1 yr) with hypertensive (SHR) rats revealed that it was more desirable to logarithmically evaluate the relationship between VO2max and body mass than by the conventional method of ml . kg-1 . min-1. When this approach was used with SHR animals, the VO2max differences between the sexes were not apparent until the animals were 1 yr of age. On the other hand, training by male SHR rats caused significant increases in VO2max regardless of the method used to express the results. It is recommended that future studies designed to elucidate exercise mechanisms in rats should include a standardized VO2max test.

New Zealand children, particularly those of Māori and Pacific ethnicity, may be at risk for low vitamin D status because of low vitamin D intakes, the country's latitude (35-46 degrees S), and skin color. The aim of this study was to determine 25-hydroxyvitamin D concentrations and their determinants in a national sample of New Zealand children aged 5-14 y. The 2002 National Children's Nutrition Survey was designed to survey New Zealand children, including oversampling of Māori and Pacific children to allow ethnic-specific analyses. A 2-stage recruitment process occurred using a random selection of schools, and children within each school. Serum 25-hydroxyvitamin D concentration [mean (99% CI) nmol/L] in Māori children (n = 456) was 43 (38,49), in Pacific (n = 646) 36 (31,42), and in New Zealand European and Others (NZEO) (n = 483) 53 (47,59). Among Māori, Pacific, and NZEO, the prevalence (%, 99% CI) of serum 25-hydroxyvitamin D deficiency (<17.5 nmol/L) was 5 (2,12), 8 (5,14), and 3 (1,7), respectively. The prevalence of insufficiency (<37.5 nmol/L) was 41 (29,53), 59 (42,75), and 25 (15,35), respectively. Multiple regression analysis found that 25-hydroxyvitamin D concentrations were lower in winter than summer [adjusted mean difference (99% CI) nmol/L; 15 (8,22)], lower in girls than boys [5 (1,10)], and lower in obese children than in those of "normal" weight [6 (1,11)]. Relative to NZEO, 25-hydroxyvitamin D concentrations were lower in Māori [9 (3,15)] and Pacific children [16 (10,22)]. Ethnicity and season are major determinants of serum 25-hydroxyvitamin D. There is a high prevalence of vitamin D insufficiency in New Zealand children, which may or may not contribute to increased risk of osteoporosis and other chronic disease. There is a pressing need for more convincing evidence concerning the health risks associated with the low vitamin D status in New Zealand children.

OBJECTIVE -The extent to which lifestyle must be altered to improve insulin sensitivity has not been established. This study compares the effect on insulin sensitivity of current dietary and exercise recommendations with a more intensive intervention in normoglycemic insulinresistant individuals.RESEARCH DESIGN AND METHODS -Seventy-nine normoglycemic insulinresistant (determined by the euglycemic insulin clamp) men and women were randomized to either a control group or one of two combined dietary and exercise programs. One group (modest level) was based on current recommendations and the other on a more intensive dietary and exercise program. Insulin sensitivity was measured using a euglycemic insulin clamp, body composition was measured using dual-energy X-ray absorptiometry, and anthropometry and aerobic fitness were assessed before and after a 4-month intervention period. Four-day dietary intakes were recorded, and fasting glucose, insulin, and lipids were measured.RESULTS -Only the intensive group showed a significant improvement in insulin sensitivity (23% increase, P ϭ 0.006 vs. 9% in the modest group, P ϭ 0.23). This was associated with a significant improvement in aerobic fitness (11% increase in the intensive group, P ϭ 0.02 vs. 1% in the modest group, P ϭ 0.94) and a greater fiber intake, but no difference in reported total or saturated dietary fat.CONCLUSIONS -Current clinical dietary and exercise recommendations, even when vigorously implemented, did not significantly improve insulin sensitivity; however, a more intensive program did. Improved aerobic fitness appeared to be the major difference between the two intervention groups, although weight loss and diet composition may have also played an important role in determining insulin sensitivity. Diabetes Care 25:445-452, 2002L ifestyle intervention reduces the risk of progression from impaired glucose tolerance (IGT) to type 2 diabetes (1). It is widely assumed that current advice regarding physical activity (2) and dietary modification (3) is sufficient (presumably mediated via an improvement in insulin sensitivity) to reduce the risk of type 2 diabetes. All the large intervention trials either underway or completed have focused on intervention in subjects with IGT (1,4,5). However, it appears that once abnormal glucose levels have developed, significant ␤-cell dysfunction has already occurred, and there is less chance of improving insulin sensitivity (6).Intervention before IGT has developed may offer the best opportunity to reduce progression to IGT and type 2 diabetes. Although increased physical activity and dietary modification have been shown to improve insulin sensitivity, there are no data that clearly show the extent of lifestyle change required. This study is the first to compare two levels of practical lifestyle intervention in normoglycemic insulin-resistant individuals on insulin sensitivity, one based on current recommendations (modest) and the other on a more intensive dietary and exercise program. This will help to answer the importa...

Serum Se concentrations and dietary Se intakes have been determined in relation to age, sex, ethnicity, region and index of deprivation in a nationally representative sample of New Zealand children aged 5–14 years from the 2002 National Children's Nutrition Survey. Dietary intake was assessed from computer-assisted, multiple-pass 24 h diet recall interviews (n3275). Serum Se concentrations were obtained from a subset of urban-based children (n1547). Mean (95 % CI) serum Se concentration in children was 0·96 (0·93, 1·00) μmol/l. Males (1·00 μmol/l) had higher serum Se levels than females (0·93 μmol/l;P = 0·027). Mäori children had lower serum Se than Pacific Islands children (P = 0·038) and New Zealand European and Other children (P = 0·005). Children in the Upper North Island (1·06 μmol/l) had higher mean serum Se values than those in the Lower North Island (0·98 μmol/l,P < 0·0005) and South Island (0·79 μmol/l,P < 0·0005), and serum Se in the Lower North Island was higher than that in the South Island (P < 0·0005). Mean dietary Se intake was 36 (34, 37) μg/d. The intakes of children aged 5–6 years (31 μg/d) were lower than those of children aged 7–10 and 11–14 years (35 and 38 μg/d, respectively;P < 0·00 005) and the intakes of 7–10-year-olds were lower than those of 11–14-year-olds (P = 0·002). Serum Se was associated with dietary Se after adjusting for all variables, including region (P = 0·006). The Se status of our children falls in the middle of the international range of serum Se concentrations, but that for children in the South Island is among the lowest values reported and may be a cause for concern.

We present an application of the Scanlan Collaborative Interview Method (SCIM) to the Project on Elite Athlete Commitment (PEAK). PEAK examines three samples of elite international athletes to further test and expand the Sport Commitment Model and assess its external validity. This first article in the series provides detailed descriptions of the study rationale, methods, procedures, interview schedule, and analysis strategy common to the three samples, along with participant characteristics and selection criteria. It also shares participants’ observations of the centrality of commitment to their athletic success, and their evaluation of the interview process.