You are exercising on bench and the backrest is sloping approximately at an angle 30° (when is the angle bigger than 45° then is the effect too much transferred to the deltoid muscles).
You keep dumbbells in almost outspread the arms over thorax (arms are vertically to floor).
Dumbbells compress angle 90° each other with peak by the thumbs.
With tinge you trigger the arms after bow to sides approximately to the level of shoulders. Dumbbells compress angle 90° each other with peak by the thumbs all the time eventually it is possible to use holding of dumbbells with palms on – concurrently all the time.
Don´t exercise this exercising with the thumbs on (like if it would have been one bell without middle) – deltoid muscles are too much engaged.
Primary:
m. pectoralis major - clavicular part
m. pectoralis major - sternal part
Secondary:
m. deltoideus - front part
m. triceps brachii
Dumbbells are to each other at an angle of 90 degrees or collaterally.
