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Reliability of treadmill measures and criteria to determine VO2max in prepubertal girls

FIGUEROA-COLON, REINALDO; HUNTER, GARY R.; MAYO, MATTHEW S.; ALDRIDGE, RUBY A.; GORAN, MICHAEL I.; WEINSIER, ROLAND L.

Medicine & Science in Sports & Exercise: April 2000 - Volume 32 - Issue 4 - p 865-869
Special Communications: Methods

REINALDO FIGUEROA-COLON, GARY R. HUNTER, MATTHEW S. MAYO, RUBY A. ALDRIDGE, MICHAEL I. GORAN, and ROLAND L. WEINSIER. Reliability of treadmill measures and criteria to determine V̇O2max in prepubertal girls. Med. Sci. Sports Exerc., Vol. 32, No. 4, pp. 865–869, 2000.

Purpose: The main objective of this study was to determine the reliability of measuring treadmill exercise economy (V̇O2submax) and the maximal oxygen uptake (V̇O2max) in prepubertal girls tested twice, 6 wk apart. We also wanted to examine the percentage of young girls who were able to reach the criteria for achieving V̇O2max and to describe methods that would allow a high proportion of young children to achieve criteria for reaching a true V̇O2max.

Methods: We studied 61 normal-weight, prepubertal girls with a mean (± SD) age 7.3 ± 1.3 yr (range 4.8 to 10.3 yr). V̇O2submax was determined while walking for 4 min at 2.5 mph with 0% grade. V̇O2max was measured during a progressive, all-out, continuous treadmill test using standardized procedures and criteria. Heart rate (HR) was measured using a Polar monitor. Respiratory rate (RR), respiratory exchange ratio (RER), ventilation (V), and V̇O2 were measured using a Sensormedics metabolic monitor.

Results: There were no significant differences between visits 1 and 2 in mean HR, RR, RER, V, V̇O2submax (421 vs 422 mL·min−1, respectively), and V̇O2max (1036 vs 1049 mL·min−1, respectively). Intra-individual coefficients of variation (CV) between visits 1 and 2 for submaximal tests were: HR = 5.1%, RR = 12.4%, RER = 7.2%, V = 12.5%, and V̇O2=12.4%. Intra-individual CVs for the maximum tests were: HRmax = 2.1%, RRmax = 10.8%, RERmax = 5.3%, Vmax = 11.7%, and V̇O2max = 7.5%. A high proportion of the girls reached criteria for V̇O2max [RER>1.00, HR>85% of age predicted maximum, and plateauing of V̇O2max] in both visits: 99% reached one of three criteria, 92% reached two of three criteria, and 70% reached all three criteria. Twenty girls [mean age 7.2 ± 1.2 yr] reached at least two criteria in both visits, whereas 32 girls [mean (± SD) age 8.6 ± 1.0 yr] reached three criteria in both visits.

Conclusion: Exercise measurements using treadmill testing were reliable in healthy, normal-weight, prepubertal girls. Older girls when compared to the younger girls were able to reach criteria for V̇O2max more often. Thus, we recommend that one testing should give researchers an accurate measure of walking economy and aerobic capacity, and that two criteria are enough for determining V̇O2max.

Mead Johnson Nutritionals, Evansville, IN; Department of Human Studies; Division of Gastroenterology and Nutrition, Departments of Pediatrics and Nutrition Sciences, Children’s Hospital; Department of Medicine, General Clinical Research Center, Biostatistics Unit, Comprehensive Cancer Center; and Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL

Submitted for publication June 1998.

Accepted for publication October 1998.

Address for correspondence: Reinaldo Figueroa-Colon, M.D., Mead Johnson Nutritionals (R20), 2400 West Lloyd Expressway, Evansville, IN 47721; E-mail: Reinaldo.Figueroa@bms.com.

© 2000 Lippincott Williams & Wilkins, Inc.