title: Cardiopulmonary responses to eccentric and concentric resistance exercise in older adults.
abstract: BACKGROUND
  In older ambulatory persons, exercise strategies that are expected to generate beneficial muscle adaptations with low cardiopulmonary demands are needed.
  
  
  OBJECTIVE
  We hypothesised that eccentric resistance exercise would be less demanding on the cardiovascular and pulmonary systems than bouts of concentric resistance exercise.
  
  
  METHODS
  The effects of eccentric and concentric resistance exercise were compared during leg squats at a submaximal intensity known to increase muscle mass.
  
  
  METHODS
  19 Older persons (15 women/four men, age 65 +/- 4 years) and 19 young reference controls (10 women/nine men; age 25 +/- 2 years) were enrolled.
  
  
  METHODS
  Participants completed eccentric-only and concentric-only exercise bouts 5-7 days apart.
  
  
  RESULTS
  Cardiovascular and pulmonary measures were collected from subjects during bouts consisting of three sequential sets of 10 repetitions at 65% of their voluntary concentric 1-repetition maximum force (68+/-16 kg for older participants and 94 +/- 36 kg for young participants). Peak heart rate (119 +/- 10 versus 155 +/- 16 b.p.m.), systolic blood pressure (129 +/- 18 versus 167 +/- 14 mmHg), cardiac index (7.8 +/- 2.0 versus 9.2 +/- 1.5 l/min/m2) and expired ventilation (20.5 +/- 5.7 versus 29.8 +/- 9.1 l/min) were significantly lower during eccentric than during concentric bouts in the older subjects, respectively (P < 0.001 for all comparisons). Similarly, peak heart rate, systolic blood pressure, cardiac index and expired ventilation were significantly lower during eccentric bouts in the young control subjects.
  
  
  CONCLUSIONS
  Eccentric resistance exercise produced less cardiopulmonary demands and may be better suited for older persons with low exercise tolerance and at risk of adverse cardiopulmonary events.
authors.affiliation: University of Southern California, Biokinesiolgy, Los Angeles, CA, USA. avallejo@usc.edu
authors.forename: Alberto F
authors.initials: AF
authors.lastname: Vallejo
authors.forename: Edward T
authors.initials: ET
authors.lastname: Schroeder
authors.forename: Ling
authors.initials: L
authors.lastname: Zheng
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Jensky
authors.forename: Fred R
authors.initials: FR
authors.lastname: Sattler
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001794:Blood Pressure / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012119:Respiration