Abstract This study aimed to investigate the influence of unknown additional eccentric loading on bench-press kinematics (peak velocity, peak acceleration and accelerative percentage of the concentric phase) and muscle activation (pectoralis major and anterior deltoid) in professional rugby and handball players. Seventeen professional athletes were randomly assigned to complete three separate bench-press repetitions with different AEL schemes (100/40%, 100/60% and 100/80% of 1RM eccentric/concentric loading, respectively) under two conditions: known- and unknown-concentric load (KL and UL, respectively). Results indicate that the lack of knowledge regarding the additional eccentric load induced a significant increase in peak acceleration and agonist-muscles electromyographic activity, with no changes regarding peak velocity or accelerative percentage during the concentric phase. These results support the use of unknown loads as a practical strategy in eliciting rapid muscle activation and force production, which is critical in many sports, such as handball or rugby.
Keywords: EMG; Load knowledge; barbell acceleration; barbell velocity.