Primary: Abs (abdominis transversus)
Secondary: Shoulders (infra-/supraspinatus, teres minor, subscapularis)
The two handed external rotation trains especially the lateral core muscles. These muscles support many movements while playing golf or tennis for example.
|Sling Training Bauchübung|
The hip turns away from the anchor point completely. Your chest and arms rotate away from the point of suspension. Thereby the arms remain stretched in front of the chest.
The PT gives in the pull of the trainee by either transferring the weight towards the anchor point or stretching the previously flexed arm. Afterwards he pulls his partner back into the initial position.