title: Exercise volume and aerobic fitness in young adults: the Midwest Exercise Trial-2.
abstract: To examine the effect of exercise volume at a fixed intensity on changes in aerobic fitness. Ninety-two overweight/obese individuals (BMI 25-40 kg m(2)), age 18-30 years, 50 % women, completed a 10 mo, 5 d wk(-1) supervised exercise intervention at 2 levels of exercise energy expenditure (400 or 600 kcal session(-1)) at 70-80 % heart rate (HR) max. Exercise consisted primarily of walking/jogging on motor-driven treadmills. The duration and intensity of all exercise sessions were verified by a downloadable HR monitor set to collect HR in 1-min epochs. All participants were instructed to continue their typical patterns of non-exercise physical activity and dietary intake over the duration of the 10 mo intervention. Maximal aerobic capacity (indirect calorimetry) was assessed on a motor-driven treadmill using a modified Balke protocol at baseline, mid-point (5 mo), and following completion of the 10 mo intervention. VO2 max (L min(-1)) increased significantly in both the 400 (11.3 %) and 600 kcal session(-1) groups (14 %) compared to control (-2.0 %; p < 0.001); however, the differences between exercise groups were not significant. Similar results were noted for change in relative VO2 max (mL kg(-1) min(-1)); however, the magnitude of change was greater than for absolute VO2 max (L min(-1)) (400 group = 18.3 %; 600 group = 20.2 %) due to loss of body weight over the 10-mo intervention in both exercise groups. Our results indicate that exercise volume was not associated with change in aerobic fitness in a sample of previously sedentary, overweight and obese young adults.
authors.affiliation: Division of Internal Medicine, Cardiovascular Research Institute, The University of Kansas Medical Center, Kansas City, KS USA ; Department of Kinesiology, Auburn University at Montgomery, Montgomery, AL USA.
authors.forename: Matthew M
authors.identifier: 0000-0002-0994-8805
authors.initials: MM
authors.lastname: Schubert
authors.affiliation: Division of Internal Medicine, Cardiovascular Research Institute, The University of Kansas Medical Center, Kansas City, KS USA ; University of Kansas, Robinson Center Rm. 100, 1301 Sunnyside Avenue, Lawrence, KS 66046 USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Washburn
authors.affiliation: Division of Internal Medicine, Cardiovascular Research Institute, The University of Kansas Medical Center, Kansas City, KS USA.
authors.forename: Jeffery J
authors.initials: JJ
authors.lastname: Honas
authors.affiliation: Institute for Measurement, Methodology, Analysis, and Policy, Texas Tech University, Lubbock, TX USA.
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Lee
authors.affiliation: Division of Internal Medicine, Cardiovascular Research Institute, The University of Kansas Medical Center, Kansas City, KS USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Donnelly
keywords: Cardiovascular fitness; Intensity; Overweight; Supervised exercise