Here is a little more on the messa di voce exercise: The Mechanics of Messa di Voce
All of these techniques really need a good teacher working with you in person to learn them correctly. No matter what kind of music a person wants to perform to the public, learning these basic skills and the exercises and practice repertoire that develop the muscles really helps to have a great deal of control and ability to use your voice to its potential. One of the best advantages of using these techniques in singing, I think, is that you don't damage your vocal cords, and can sing well far into old age.

When I first met my teacher and she said, "Alice, singing is athletic." I didn't quite understand. I didn't realize at the beginning how much was known physiologically about the voice and how long the techniques had been studied and developed over the years. I think in another thread Escamillo made the point that those primitive humans who learned how to use their voice with volume and support had an advantage in communication. Now I know that serious singers are like athletes, training the muscles on a regular schedule with supervision from coaches who can see if the technique is being done right, if the muscles are being used to get optimum results. Not everyone will feel the need to develop their singing this seriously, we can all sing, not everyone will be a marathon runner, we can all run. The difference is in the natural physical talent and the serious development of skills to use the talent.

Alice