Push-up position, one hand on the floor and the other hand supported on a medicine ball/helmet, both hands positioned at about shoulder height, the body practically forming a straight line (the head is held in extension of the spine), bend the arms at the elbow joint, lower the upper body to the ball (lower and raise the upper body) and return to the starting position by stretching the arms. After a few repetitions (or after each exercise), switch sides.
Attention:
Do not arch your back, tense your core.
Lighten:
Just hold the starting position; lower your upper body less (barely bend your arms).
Harder:
Additional weight (on the shoulders); legs on an unstable surface.
Variation:
Push-ups with hand change: roll the ball from one side to the other after each push-up.
