RESUMO
AIM: 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. CONCLUSION: 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.
