R. Figueroa-colon et al., Reliability of treadmill measures and criteria to determine VO2max in prepubertal girls, MED SCI SPT, 32(4), 2000, pp. 865-869
Purpose: The main objective of this study was to determine the reliability
of measuring treadmill exercise economy ((V) over dotO(2submax)) and the ma
ximal oxygen uptake ((V) over dotO(2max)) in prepubertal girls tested twice
, 6 wk apart. We also wanted to examine the percentage of young girls who w
ere able to reach the criteria for achieving (V) over dotO(2max) and to des
cribe methods that would allow a high proportion of young children to achie
ve criteria for reaching a true (V) over dot(2max). Methods: We studied 61
normal-weight, prepubertal girls with a mean (+/- SD) age 7.3 +/- 1.3 yr (r
ange 4.8 to 10.3 yr). (V) over dotO(2submax) was determined while walking f
or 4 min at 2.5 mph with 0% grade. (V) over dotO(2max) was measured during
a progressive, all-out, continuous treadmill test using standardized proced
ures and criteria. Heart rate (HR) was measured using a Polar monitor. Resp
iratory rate (RR), respiratory exchange ratio (RER), ventilation (V), and (
V) over dotO(2) were measured using a Sensormedics metabolic monitor. Resul
ts: There were no significant differences between visits 1 and 2 in mean HR
, RR, RER, V, (V) over dot(2submax) (421 vs 422 mL.min(-1), respectively),
and (V) over dot(2max) (1036 vs 1049 mL.min(-1), respectively). Intra-indiv
idual 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 (V) over dotO
(2) = 12.4%. Intra-individual CVs for the maximum tests were: HRmax = 2.1%,
RRmax = 10.8%, RERmax = 5.3%, V-max = 11.7%, and (V) over dotO(2max) = 7.5
%. A high proportion of the girls reached criteria for (V) over dotO(2max)
[RER>1.00, HR>85% of age predicted maximum, and plateauing of (V) over dotO
(2max)] in both visits: 99% reached one of three criteria, 92% reached two
of three criteria, and 70% reached all three criteria. Twenty girls [mean a
ge 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 vi
sits. Conclusion: Exercise measurements using treadmill testing were reliab
le in healthy, normal-weight, prepubertal girls. Older girls when compared
to the younger girls were able to reach criteria for (V) over dotO(2max) mo
re often. Thus, we recommend that one testing should give researchers an ac
curate measure of walking economy and aerobic capacity, and that two criter
ia are enough for determining (V) over dotO(2max).