Robbins, DW, Young, WB, Behm, DG, and Payne, WR. The effect of a complex agonist and antagonist resistance training protocol on volume load and power output, electromyographic responses, and efficiency. J Strength Cond Res 24(7): 1782-1789, 2010-The objective of this study was to investigate the acute effects of performing traditional set (TS) vs. complex set (CS) agonist-antagonist training over 3 consecutive sets, on bench press throw (BPT) throw height (TH), peak velocity (PV), peak power (PP), bench pull volume load (VL), and electromyographic (EMG) activity. Eighteen trained men performed 2 testing protocols: TS comprising 3 sets of Bpull followed by 3 sets of BPT performed in approximately 20 minutes or CS comprising 3 sets of both Bpull and BPT performed in an alternating manner in approximately 10 minutes. Throw height, PV, PP, and EMG activity were not different within, or between, the 2 conditions. Bench pull VL decreased significantly from set 1 to sets 2 and 3, under both conditions. Decreases from set 1 to set 2 were 14.55 ± 26.11 and 9.07 ± 13.89% and from set 1 to set 3 were 16.87 ± 29.90 and 14.17 ± 18.37% under CS and TS, respectively. There was no difference in VL per set, or session, between the conditions. Although there was no augmentation of the power measures, CS was determined to have approximately twice the efficiency (ouput/time) as compared to TS. Efficiency calculations for VL, TH, PV, and PP are 103.47 kg·min−1, 26.25 cm·min−1, 1.98 m·s−1·min−1, 890.39 W·min−1 under CS and 54.71 kg·min−1, 13.02 cm·min−1, 0.99 m·s−1·min−1, 459.28 W·min−1 under TS. Comparison of EMG activity between the protocols suggests the level of neuromuscular fatigue did not differ under the 2 conditions. Complex set training would appear to be an effective method of exercise with respect to efficiency and the maintenance of TH, PV, PP, and VL.