title: Influence of Differences in Exercise-intensity and Kilograms/Set on Energy Expenditure During and After Maximally Explosive Resistance Exercise.
abstract: With resistance exercise, greater intensity typically elicits increased energy expenditure, but heavier loads require that the lifter perform more sets of fewer repetitions, which alters the kilograms lifted per set. Thus, the effect of exercise-intensity on energy expenditure has yielded varying results, especially with explosive resistance exercise. This study was designed to examine the effect of exercise-intensity and kilograms/set on energy expenditure during explosive resistance exercise. Ten resistance-trained men (22±3.6 years; 84±6.4 kg, 180±5.1 cm, and 13±3.8 %fat) performed squat and bench press protocols once/week using different exercise-intensities including 48% (LIGHT-48), 60% (MODERATE-60), and 72% of 1-repetition-maximum (1-RM) (HEAVY-72), plus a no-exercise protocol (CONTROL). To examine the effects of kilograms/set, an additional protocol using 72% of 1-RM was performed (HEAVY-72MATCHED) with kilograms/set matched with LIGHT-48 and MODERATE-60. LIGHT-48 was 4 sets of 10 repetitions (4×10); MODERATE-60 4×8; HEAVY-72 5×5; and HEAVY-72MATCHED4×6.5. Eccentric and concentric repetition speeds, ranges-of-motion, rest-intervals, and total kilograms were identical between protocols. Expired air was collected continuously throughout each protocol using a metabolic cart, [Blood lactate] using a portable analyzer, and bench press peak power were measured. Rates of energy expenditure were significantly greater (p≤0.05) with LIGHT-48 and HEAVY-72MATCHEDthan HEAVY-72 during squat (7.3±0.7; 6.9±0.6 > 6.1±0.7 kcal/min), bench press (4.8±0.3; 4.7±0.3 > 4.0±0.4 kcal/min), and +5min after (3.7±0.1; 3.7±0.2 > 3.3±0.3 kcal/min), but there were no significant differences in total kcal among protocols. Therefore, exercise-intensity may not effect energy expenditure with explosive contractions, but light loads (~50% of 1-RM) may be preferred because of higher rates of energy expenditure, and since heavier loading requires more sets with lower kilograms/set.
authors.affiliation: Department of Health and Sport Sciences, Salisbury University, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Mazzetti
authors.affiliation: Department of Health and Sport Sciences, Salisbury University, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Wolff
authors.affiliation: University of South Carolina, SC, USA.
authors.forename: Brittany
authors.initials: B
authors.lastname: Collins
authors.affiliation: Department of Health and Sport Sciences, Salisbury University, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Kolankowski
authors.affiliation: Department of Health and Sport Sciences, Salisbury University, USA.
authors.forename: Brittany
authors.initials: B
authors.lastname: Wilkerson
authors.affiliation: Department of Health and Sport Sciences, Salisbury University, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Overstreet
authors.affiliation: Department of Health and Sport Sciences, Salisbury University, USA.
authors.forename: Troy
authors.initials: T
authors.lastname: Grube
keywords: Contraction-intensity; Power; Program Design; Repetition Speed; Weight Lifting; Work