title: Critical power in adolescent boys and girls--an exploratory study.
abstract: The purpose of the study was to identify critical power (CP) in boys and girls and to examine the physiological responses to exercise at and 10% above CP (CP+10%) in a sub-group of boys. Nine boys and 9 girls (mean age 12.3 (0.5) y performed 3 constant-load tests to derive CP. Eight of the boys then exercised, in random order, at CP and CP+10% until volitional exhaustion. CP was 123 (28) and 91 (26) W for boys and girls, respectively (p < 0.02), which was equivalent to 75 (6) and 72 (10) % of peak oxygen uptake, respectively (p > 0.47). Boys' time to exhaustion at CP was 18 min 37 s (4 min 13 s), which was significantly longer (p < 0.007) than that at CP+10% (9 min 42 s (2 min 31 s)). End-exercise values for blood lactate concentration (B[La]) and maximal oxygen uptake were higher in the CP+10% trial (5.0 (2.4) mmol.L-1 and 2.15 (0.4) L.min-1, respectively) than in the CP trial, (B[La], 4.7 (2.1) mmol.L-1; maximal oxygen uptake, 2.05 (0.35) L.min-1; p > 0.13). Peak oxygen uptake (expressed as a percentage of the peak value) was not attained at the end of the trials (94 (12) and 98 (14) % for CP and CP+10%, respectively). These results provide information about the boundary between the heavy and severe exercise intensity domains in children, and have demonstrated that CP in a group of boys does not represent a sustainable steady-state intensity of exercise.
authors.affiliation: Children's Health and Exercise Research Centre, School of Sport & Health Sciences, University of Exeter, Exeter, UK. c.a.williams@exeter.ac.uk
authors.forename: Craig A
authors.initials: CA
authors.lastname: Williams
authors.forename: Jeanne
authors.initials: J
authors.lastname: Dekerle
authors.forename: Kerry
authors.initials: K
authors.lastname: McGawley
authors.forename: Serge
authors.initials: S
authors.lastname: Berthoin
authors.forename: Helen
authors.initials: H
authors.lastname: Carter
mesh_terms: D000293:Adolescent / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D012016:Reference Values; D017678:Sex Distribution; D013997:Time Factors
chemical_list: D019344:Lactic Acid