title: Eccentric cycle exercise: training application of specific circulatory adjustments.
abstract: OBJECTIVE
  Despite identical oxygen uptake (VO2), enhanced heart rate (HR) and cardiac output (Q) responses have been reported in eccentric (ECC) versus concentric (CON) cycle exercise. The aim of this study was to describe the specific circulatory adjustments (HR and stroke volume (SV)) to incremental ECC cycle exercise in order to: 1) determine the HR values leading to identical VO2 in ECC and CON cycling; and 2) estimate the interindividual variability of this HR correspondence between the two exercise modes, with emphasis upon rehabilitation and training purposes.
  
  
  METHODS
  Eight healthy male subjects (age, 28 +/- 2 yr) participated in this study. They performed CON and ECC cycle incremental exercises (power output increases of 50 W every 3 min). Breath-by-breath gas exchange analysis and beat-by-beat thoracic impedancemetry were used to determine VO2 and Q, respectively.
  
  
  RESULTS
  At the same metabolic power (VO2 of 1.08 +/- 0.05 L x min(-1) in CON vs 1.04 +/- 0.06 L x min in ECC), SV was not different, but HR was 17% higher in ECC (P < 0.01), leading to a 27% enhanced Q (P < 0.01). Q and HR net adjustments (exercise minus resting values) in ECC versus CON muscle involvement demonstrated important interindividual variability with coefficients of variation amounting to 32% and 30%, respectively.
  
  
  CONCLUSIONS
  In practice, if a given level of VO2 is to be reached, ECC HR has to be set above the CON one. Taking into account the interindividual variability of the circulatory adjustments in ECC versus CON muscle involvement, a precise HR correspondence can be established individually from the VO2/HR relationship obtained using ECC incremental testing, allowing prescription of accurate target HR for rehabilitation or training purposes.
authors.affiliation: Respiratory, Cardiocirculatory and Exercise Functional Explorations Department, Civil Hospital, Strasbourg, France. sdufour@ulp.u-strasbg.fr
authors.forename: Stephane P
authors.initials: SP
authors.lastname: Dufour
authors.forename: Eliane
authors.initials: E
authors.lastname: Lampert
authors.forename: Stephane
authors.initials: S
authors.lastname: Doutreleau
authors.forename: Evelyne
authors.initials: E
authors.lastname: Lonsdorfer-Wolf
authors.forename: Veronique L
authors.initials: VL
authors.lastname: Billat
authors.forename: Francois
authors.initials: F
authors.lastname: Piquard
authors.forename: Ruddy
authors.initials: R
authors.lastname: Richard
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010806:Physical Education and Training / Q000379:methods*; D013318:Stroke Volume / Q000502:physiology*