title: Reliability of treadmill measures and criteria to determine VO2max in prepubertal girls.
abstract: OBJECTIVE
  The main objective of this study was to determine the reliability of measuring treadmill exercise economy (VO2submax) and the maximal oxygen uptake (VO2max) 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 VO2max and to describe methods that would allow a high proportion of young children to achieve criteria for reaching a true VO2max.
  
  
  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). VO2submax was determined while walking for 4 min at 2.5 mph with 0% grade. VO2max 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 VO2 were measured using a Sensormedics metabolic monitor.
  
  
  RESULTS
  There were no significant differences between visits I and 2 in mean HR, RR, RER, V, VO2submax (421 vs 422 mL x min(-1), respectively), and VO2max (1036 vs 1049 mL x 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 VO2 = 12.4%. Intra-individual CVs for the maximum tests were: HRmax = 2.1%, RRmax = 10.8%, RERmax = 5.3%, Vmax = 11.7%, and VO2max = 7.5%. A high proportion of the girls reached criteria for VO2max [RER> 1.00, HR>85% of age predicted maximum, and plateauing of VO2max] 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.
  
  
  CONCLUSIONS
  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 VO2max 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 VO2max.
authors.affiliation: Mead Johnson Nutritionals, Evansville, IN 47721, USA. Reinaldo.Figueroa@bms.com
authors.forename: R
authors.initials: R
authors.lastname: Figueroa-Colon
authors.forename: G R
authors.initials: GR
authors.lastname: Hunter
authors.forename: M S
authors.initials: MS
authors.lastname: Mayo
authors.forename: R A
authors.initials: RA
authors.lastname: Aldridge
authors.forename: M I
authors.initials: MI
authors.lastname: Goran
authors.forename: R L
authors.initials: RL
authors.lastname: Weinsier
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005080:Exercise Test; D005260:Female; D006801:Humans; D010100:Oxygen / Q000378:metabolism*; D015203:Reproducibility of Results
chemical_list: D010100:Oxygen