Facing the back of your machine (adjust the bench so that your wrists are in line with your shoulders), your feet firmly on the ground. Catch your wrists (over pronation or supination depending on the device), your elbows slightly bent (avoid fully extending your arms). Spread your arms out so they are level with your shoulders.
The exercise is performed with arms almost straight (if possible, depending on the machines). Bending your arms only makes your biceps and triceps work harder. In addition, it reduces the lever arm, forcing you to put more weight to do the same job.
Main: shoulders (posterior bundle in priority), latissimus dorsi, teres major, triceps (long portion)
Secondary: trapezius (middle and lower), forearm
The long portion of the triceps participates in the movement because it shortens at the level of the scapula during the elevation.
The trapezius muscles can participate in the movement if instead of spreading your arms apart, you think of pulling by bringing the shoulder blades together. In this case, the back of the shoulder will no longer be truly isolated.
Butterfly reverse interest
This bench exercise is technically very easy and happens to be the safest of all the posterior deltoid bundle exercises.
Depending on the variation in resistance imposed by the machine, the exercise will be more or less effective.
The exercise can be done with an overhand grip depending on the machines. This allows for better “pulling” in the axis of the shoulders and therefore really localizes the work in the posterior bundle of the shoulder.
Danger / contraindication