VHA

Constricted abdominal muscles

Constricted abdominal muscles inhibit diaphragmatic descent

External Intercostals

External intercostals raise the ribs and widen the ribcage 

Lungs

Lungs are not active in inspiration or expiration

For inspiration

Alveolar pressure must be lower than atmospheric pressure; the reverse occurs for expiration

Respiratory muscles

Respiratory muscles naturally recoil toward functional residual capacity (FRC), approximately 35-40% of vital capacity (VC)

Expiratory muscles

Expiratory muscles do not need to contract immediately after a sufficient breath

Abdominal contraction

Abdominal contraction is not associated with sound-pressure level (SPL) in trained singers’ habitual singing behaviours 

Locking or rigidity

Locking or rigidity in the body is unhelpful during respiration 

Vocal fold vibration

Vocal fold vibration is a passive result of aeromechanical forces: airflow and pressure 

The diaphragm

The diaphragm can be voluntarily controlled

Breathing exercise

Allow air to enter manually; no sucking in required

Ribcage

Never lock ribcage while singing; allow natural movement according to pitch (frequency) and intensity