One of the biggest debates in bench press is, should you be arching your back? Well, according to Stephen Manuel, GB Powerlifter, it will actually make you safer and lift bigger.
The pecs are a big muscle group, however when you bench flat, the majority of the stability comes from just the front delt. As the front delt is a much smaller muscle in relation to the pecs, this will at some point, put your front delt in a lot of discomfort.
You need bigger muscles creating that stability, and this is just one reason as to why you should arch.
When you arch, you should be sticking the chest out and squeezing your shoulder blades together. By doing this, you’re incorporating the muscles of the shoulder blade, rhomboid, lats and traps, so more muscles, and bigger muscles, are all working together to create that stability to keep your pecs working. This is not to shut off the front delt, but to lessen the burden on it. More muscles equals more stability, and therefore a more efficient movement.
This provides a second reason to arch – making the movement more efficient. As the chest is high, there are more muscles moving to move the bar a shorter distance. A stronger press could lead to more kilos on the bar, or more reps at sub max loads.
Overall, more muscle contributing to pushing the same load over a shorter distance, will surely equate to a bigger and safer bench press.