There has been an ongoing discussion on the correct bar path in the bench press ever since this exercise has existed.
The following article shall shed some light on the two different schools of thought on what the bar path in the bench press should ideally look like to get the best out of this exercise.
L-SHAPE
The first school of thought is that after the bar has been driven off the chest, it will move into an L-shape curve at lockout – meaning the bar is moving slightly backwards towards the level of the head (imagine the little “hook” part of the letter L). The aim of this is to bring the bar perpendicular to the shoulder joint, which is the spot where the bar feels the lightest. Anything deviating from this – either forward or backward – makes the bar feel heavier in that top position, according to this line of thought. As part of this approach, the lifter is instructed to press the bar slightly diagonally as he or she presses it upwards.
There is one major drawback with this approach: we need to understand that the weight of the bar is pushing down VERTICALLY into our chest as we are bringing it down. In other words: the gravity of the weight doesn’t push down at an angle – it pushes STRAIGHT DOWN into our chest.
To get the bar off our chest, are we therefore stronger pressing straight into it, or pressing into it at an angle?
If we press the bar upwards and backwards diagonally, we are not applying all the force our muscles produce into the bar into a straight line as some of it is applied at an angle.
STRAIGHT LINE
The second school of thought is that objects travelling in a non-linear fashion are heavier than objects travelling in a straight line. Simple physics holding true 100% of the time: when the bar is pressed upwards in the bench press in a straight line, the weight will feel the lightest.
There is one major consideration to be made for this: the shoulder joint has to be placed as a closely as possible underneath the contact the point of the bar on the chest. We have to picture it this way: the shoulder joint represents the centre of balance on which the bar is “resting” at lockout.
The question now arising: how do we get the shoulder joint as closely as possible underneath the contact point of the bar on the chest to press it off the centre of balance?
The most efficient way to achieve this is to make the biggest arch in the lower and mid back as possible. This will bring our rib cage and chest up as high as possible – which paves the way for the shoulder joint to slide down on our body. Picture your lower spine and shoulder joint moving towards each other when you obtain this position.
The best way to slide the shoulder joint down on the body is to tighten the lats as hard as possible once the arch is obtained. As the lats have the function of depressing the shoulder joint, this action is crucial for getting the "socket" of the joint as closely as possible underneath the bar contact point on the chest. Not only does this position the shoulder joint further down on our back, it also increases the muscular surface area that is in contact with the bench (i.e. the upper back and lat muscles). As we know, the larger the platform, the stronger the movement it is pressed off from.
Moral of the story: arch as high as you possibly can, slide your shoulders down into your rib cage by contracting your lats, and move the bar up in the straightest line possible.
Go do it, and tell us what you observe in this classic of all upper body lifts.