Heavy strict pressing, locked to the bench.
Brace hard and keep your ribs down, the seated position takes away leg drive so press strict.
Pressing a barbell from your upper chest to lockout while anchored to an upright bench strips the lift down to shoulders and triceps, with no leg drive available to bail you out. The bar path stays close to your face and finishes stacked over your shoulders, and the fixed torso means your delts eat every kilo honestly. It is the strict strength test of the pressing family.
Seated isolates the shoulders more because your legs and hips cannot contribute, and the bench supports your torso so you can often handle comparable weight strictly. Standing trains more total-body strength. Pick based on the goal, most programmes benefit from both at some point.
Arching turns the lift into a high incline press so your chest can help. Keep your ribs pulled down, brace before the bar leaves your chest, and if the arch keeps creeping in, the bar is too heavy for a strict press.
Directly over your shoulders, arms locked, with your head coming slightly through at the top. If the bar drifts forward you lose the stacked position and your shoulders end up fighting leverage instead of lifting weight.
