Back muscles are more important than abdominal muscles for singing

I have examined and studied the muscle movements of 6 male test subjects, in how they move the diaphragm when taking breaths during singing as well as overall performance.
I asked 3 of the 6 males to focus on training and work-out only their abnormal muscles. I asked the other 3 to train and work-out only their back muscles everyday for 1 month.
Then I ran the experiment and observed their movements of breathing while each sang. As a result, the men who trained only their back muscles everyday were able to move the diaphragm better than the men who trained only their abdominal muscles.
Furthermore, when asked for feedback, the men who only did abdominal muscle training stated that, “The singing is no different than before training and working out.” One man even exclaimed, “I’m feeling a choking sensation now.” Whereas all the men who only did back muscle training stated, “I can sing easier than before.” As wells as, “I feel improvement in my breathing and more control when singing now.”
Those statements were supported after reviewing the data I took regarding their movements before and after their focused training in those specific muscle groups.
In conclusion, training the back muscles is better than training the abdominal muscles for singing. Overall performance and breathing had improved more when the back muscles had been trained daily and were in good condition.

exercise illustration - side crunch

exercise illustration - plank

Note1:The voice is made by vibrating air and the airflow is made by breathing. Breath is mainly worked by the diaphragm and the internal and external intercostal muscles.
The diaphragm is composed of muscles and the tendinous tissues in the lower ribs. The diaphragm is attached to the legs at the third lumbar vertebrae.

Note2:In this test, the subjects who did training only with their back muscles seemed to also have a better posture. If the erector spinae muscles get stronger, you will improve posture of the spine and in the diaphragm’s mobility. However, if you do sit-ups please be aware of the following: Doing the upward movement strains the muscles and gets the larynx in a deep position in the throat. I don’t recommend sit-ups being good work-out training for the throat for that reason.