Sit on your back on the flat bench (straight/flat position), hold the weights in front of your chest with your arms bent (elbows close to your body pointing downwards), grasp the dumbbells with a neutral grip so that your palms are facing the respective side, push the weights upwards to bring your almost fully extended arms to the holding position, then lower/bend your arms back to the starting position.
Attention:
Do not fully extend your arms in the holding position and do not place the weights completely on your chest when lowering.
Lighten:
Less weight.
Harden:
More weight.
Variant I:
Alternately push one arm up and lower it back to the starting position.
Variant II:
Bench upwards in an incline position (incline bench) or even in a decline position (decline).
Variant III:
Press dumbbells against each other during the entire exercise sequence.
Variant IV:
Replace dumbbells with a weight disc. Hold the weight disc with both hands at the edge (disc horizontal to the floor), or clamp the disc between your palms for additional strain on the chest muscles (disc horizontal to the floor).