Which muscle group is primarily engaged during the stomach massage group, excluding the round back position?

The stomach massage group in Pilates is designed to target the core muscles comprehensively. During this exercise, the primary engagement comes from all the abdominal muscles, which include the rectus abdominis, obliques, and transverse abdominis, as well as the back extensors. This coordinated engagement is crucial for stabilizing the spine and pelvis while performing movements that involve flexion and rotation.

The movement pattern of the stomach massage emphasizes both the engagement of the abdominal wall to facilitate control and the involvement of the back extensors to maintain proper alignment and support the spine. By incorporating these muscle groups, the exercise not only strengthens the core but also promotes better posture and functional movement patterns.

While other muscle groups listed may play a role in different contexts or exercises, they do not represent the primary focus of the stomach massage. The reinforcing of abdominal strength and back extension work is what fundamentally defines the effectiveness of this exercise in the Pilates repertoire.