How to do the Seated Developments on the Convergent Machine?

How to do the Seated Developments on the Convergent Machine?

https://youtu.be/Uo0TyeKmwmY?list=PLCWubRD1e4Lvt_nUo-hyRx6FyazpP5NAN The limitations of this type of machine, like all guided machines, are The stabilizing muscles are much less solicited than with free loads. How to carry out the exercise? By varying the height of the seat, one can solicit different parts of the pectoral muscles. An adjustment of the seat lower will allow a more important solicitation of the top of the pectoral muscles...