title: Exercise with a twist: left ventricular twist and recoil in healthy young and middle-aged men, and middle-aged endurance-trained men.
abstract: BACKGROUND
  The contribution of left ventricular (LV) twist and recoil in augmenting stroke volume during exercise is poorly understood, and few data are available describing the impact of endurance exercise on LV twist and recoil in middle-aged individuals. Therefore, the effects of chronic endurance training on these LV indices at rest and during submaximal exercise were examined in healthy, middle-aged untrained (MU) men and age-matched healthy, middle-aged endurance-trained (MT) men and in healthy, young untrained (YU) men as a healthy model.
  
  
  METHODS
  Two-dimensional echocardiography with speckle-tracking imaging was used to quantify LV twist and recoil in 11 YU (mean age, 24.0 ± 4.1 years), 9 MU (mean age, 54.8 ± 4.3 years), and 12 MT (mean age, 53.8 ± 4.1 years) subjects at supine rest and during submaximal supine cycle ergometry.
  
  
  RESULTS
  LV twist increased from rest to exercise in YU subjects (8.8 ± 3.8° to 12.8 ± 6.6°, P = .026) but not in MU subjects. LV twist also increased from supine rest to exercise in MT subjects (10.0 ± 3.1° to 13.1 ± 4.1°, P = .046). Time to peak untwisting velocity was significantly delayed in MU subjects during rest and exercise compared with both YU (P = .005 and P = .02, respectively) and MT (P = .018 and P = .045, respectively) subjects. No differences were detected in any of the timing indices of LV twist between YU and MT subjects.
  
  
  CONCLUSIONS
  This response pattern may help explain the mechanism underlying the training-induced augmentation in stroke volume during exercise, particularly the importance of the timing of key LV events that contribute to enhanced diastolic performance seen after endurance training.
authors: Graduate Department of Exercise Sciences, University of Toronto, Toronto, Ontario, Canada.
authors: Leanna S
authors: LS
authors: Lee
authors: Justin A
authors: JA
authors: Mariani
authors: Zion
authors: Z
authors: Sasson
authors: Jack M
authors: JM
authors: Goodman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002302:Cardiac Output / Q000502:physiology; D016022:Case-Control Studies; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D015203:Reproducibility of Results; D016277:Ventricular Function, Left / Q000502:physiology*