PLOS ONE is a peer-reviewed open access scientific journal published by the Public Library of Science. Unlike traditional peer-reviewed publications it does not use the perceived importance of a paper for acceptance or rejections. Instead it rigorously reviews how experiments and analysis were done and the significance of the research is left up to the scientific community. Recently researchers published in PLOS One, "A systematic review of surface electromyography analyses of the bench press movement task."
The bench press is arguably the most popular lifting exercise. It is used in homes and gyms throughout the world, in athletic development for competition and as a standard criteria to measure upper body strength in individuals. The methodologies used to enhance development are complex and wide ranging.
The authors of the aforementioned study looked to answer two questions, "Which muscles show the greatest activity during the BP? Which changes in muscle activity are related to specific conditions under which the BP is performed?" They defined 'intensity' as percentage of ones 1 repetition maximum (1RM).
Looking through 3847l citations and 2635 articles the researchers determined the most relevant articles and examined velocity, intensity, range of motion, stable and unstable surfaces, fatigue, mental focus, sticking points, compression sleeves and sticking points. They concluded that the triceps brachii and pectoralis major muscles had similar electrical activity during the bench press and their activity is significantly higher than the activity of the anterior deltoids. Of all the various constructs of training that were listed above (from velocity to sticking points) that effect muscle activity, the most important factor is exercise intensity. The load on the bar relative to ones strength effects all other factors when bench pressing and Getting Strong.