Holding the breath comes naturally to us when underwater or when lifting something heavy. This is the closed-jug technique (my name). Picture a jug with a cork in the top. We fill our lungs with air, close the glottis (bring the vocal folds together to block further inflow and outflow of air), and leave it at that for as long as we need to. We can relax the breathing muscles themselves since the closed glottis is doing the work. In fact, we can even tighten our abs and push.
In both of the cases I mention above, swimming and lifting, that’s a good strategy.
But for singing, this is not so helpful. We want to maintain a sense of inhalation and expansion. We want to reduce excessive abdominal pressure. We want onsets that aren’t glottal attacks.
Think of your body as an open jug. Inhale and then leave the body in the position of inhalation. The ribs remain expanded, the remains belly gently down and out, and the glottis remains open. The air in the lungs remains as long as the lungs remain open. Any collapse leads to the air leaving, and any expansion allows more air in.
We’re holding our breath, but we’re not trapping it. Instead, our breathing muscles are doing the work instead of the glottis.
From here, we can practice remaining in the position of inhalation, or we can sing a note.