title: Effect of maximal and slow versus recreational muscle contractions on energy expenditure in trained and untrained men.
abstract: OBJECTIVE
  The primary purpose of this study was to compare energy expenditure among resistance exercise protocols using maximally explosive or slow contractions versus recreational in trained and untrained men.
  
  
  METHODS
  Seven trained (21.9±2.1 yrs) and seven untrained men (20.1±2.2 yrs) performed three nearly identical exercise protocols, and a no-exercise (CONTROL) session in a randomly assigned, counterbalanced order. Subjects performed three sets of squats, dumbbell-row, deadlift, bench press, lat-pulldown, shoulder press, arm curls and dips using either recreational (REC), 2s (SLOW) or maximally explosive contractions (MAX). Expired air was collected continuously for 15 min before, ~37-43 min during, and 2 hr postexercise. Finger prick samples (25 µL) were collected and analyzed for blood lactate (BL) (mmol.L-1) before, immediately after, and during 120 min of recovery.
  
  
  RESULTS
  Rates of energy expenditure were significantly (P≤0.05) greater for MAX than SLOW and REC during all exercises and +5 min after exercise in trained men, and MAX was greater than REC during all exercises except deadlift in untrained men. In trained men, total kcal were significantly greater (P≤0.05) with MAX (507±48) compared to REC (431±47), but not in untrained. Conversely, BL was significantly greater (P≤0.05) after SLOW compared to REC in trained and untrained men, while BL was only greater after MAX versus REC in trained men.
  
  
  CONCLUSIONS
  For whole-body resistance exercise programs, maximally explosive contractions optimize energy expenditure in trained men, but slow contractions are recommended for untrained exercisers. Therefore, contraction intensity should be considered a program design variable for exercise prescriptions aimed to improve general health and fitness.
authors: Laboratory for Human Performance, Salisbury University, Salisbury, MD, USA. samazzetti@salisbury.edu
authors: S
authors: S
authors: Mazzetti
authors: C
authors: C
authors: Wolff
authors: A
authors: A
authors: Yocum
authors: P
authors: P
authors: Reidy
authors: M
authors: M
authors: Douglass
authors: M
authors: M
authors: Cochran
authors: M
authors: M
authors: Douglass
mesh_terms: D000704:Analysis of Variance; D019540:Area Under Curve; D001823:Body Composition; D004032:Diet; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D055815:Young Adult