title: Oxygen uptake kinetics during treadmill running in boys and men.
abstract: The purpose of this study was to compare the kinetics of the oxygen uptake (VO(2)) response of boys to men during treadmill running using a three-phase exponential modeling procedure. Eight boys (11-12 yr) and eight men (21-36 yr) completed an incremental treadmill test to determine lactate threshold (LT) and maximum VO(2). Subsequently, the subjects exercised for 6 min at two different running speeds corresponding to 80% of VO(2) at LT (moderate exercise) and 50% of the difference between VO(2) at LT and maximum VO(2) (heavy exercise). For moderate exercise, the time constant for the primary response was not significantly different between boys [10.2 +/- 1.0 (SE) s] and men (14.7 +/- 2.8 s). The gain of the primary response was significantly greater in boys than men (239.1 +/- 7.5 vs. 167.7 +/- 5.4 ml. kg(-1). km(-1); P < 0.05). For heavy exercise, the VO(2) on-kinetics were significantly faster in boys than men (primary response time constant = 14.9 +/- 1.1 vs. 19.0 +/- 1.6 s; P < 0.05), and the primary gain was significantly greater in boys than men (209.8 +/- 4.3 vs. 167.2 +/- 4.6 ml. kg(-1). km(-1); P < 0.05). The amplitude of the VO(2) slow component was significantly smaller in boys than men (19 +/- 19 vs. 289 +/- 40 ml/min; P < 0.05). The VO(2) responses at the onset of moderate and heavy treadmill exercise are different between boys and men, with a tendency for boys to have faster on-kinetics and a greater initial increase in VO(2) for a given increase in running speed.
authors: University of Brighton, Chelsea School Research Centre, Eastbourne BN20 7SP, United Kingdom. c.a.williams@exeter.ac.uk
authors: C A
authors: CA
authors: Williams
authors: H
authors: H
authors: Carter
authors: A M
authors: AM
authors: Jones
authors: J H
authors: JH
authors: Doust
mesh_terms: D000328:Adult; D000367:Age Factors; D002648:Child; D006801:Humans; D007700:Kinetics; D007773:Lactates / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D012420:Running / Q000502:physiology*
chemical_list: D007773:Lactates