A.) Breathing is a vital mechanical function requiring the integrated and coordinated action of several muscle groups, whether a person is consciously aware of this or not.

For most exercises, inhalation will begin as the movement begins, which is often the eccentric phase of the movement. Inhalation should be initiated with the uninhibited contraction of the diaphragm. This creates a downward pressure on the viscera in the abdominal cavity while simultaneously helping the lungs to draw in more air. The downward pressure forces the contents of the abdominal cavity down, back, and forward causing a slight distension and tightening of the abdominal wall. This results in increased intra-abdominal pressure and combines with associated neurological reactions of the other core muscles to create joint stiffness of the spine and increase stabilization of the pelvis and sacroiliac joints.

As inhalation continues, there should be an expansion and slight elevation of the rib cage, which allows for maximal lung volume and also further straightens the spine and helps to stabilize optimal posture. However, inhalation should not produce any significant elevation of the scapula or shrugging of the shoulders, because these muscle actions will increase stress to the structures of the cervical spine. During the eccentric-isometric phase, the breath can be held momentarily and the abdominal muscles can be isometrically contracted to produce a momentary Valsalva maneuver and provide maximal spinal stability.

Exhalation begins as the movement is reversed, which is typically during the concentric phase. To assist with maintenance of optimal posture and avoid the tendency to flex the spine upon exhalation, the person should activate a contraction of the transverse abdominis and draw the abdominal wall in slightly toward the spine. This helps to maintain higher levels of intra-abdominal and intrathoracic pressure, and again is linked to co-contractions of other core muscles that will assist in stabilizing the spine and pelvis. You should also note that full exhalation during most resistance exercises is not recommended. Maintenance of some air in the lungs helps maintain intrathoracic pressure and keep the rib cage partially expanded and elevated, which helps to continue stabilization of optimal posture.

At the concentric-isometric phase, a tight contraction of the transverse abdominis (just short of concaving the abdominal wall) along with an isometric contraction of the outer abdominal and trunk muscles can often be felt. As inhalation and the eccentric movement begins, the person should again initiate a contraction of the diaphragm and somewhat relax the transverse abdominis to allow for the slight distension of the abdominal wall to repeat the inhalation process.

For a few exercises, inhalation will begin with the concentric phase, and the entire process will be reversed from what has just been described. This is because of the inverse maximal stability demands for the particular movement. These breathing methods will take time to master and integrate into every exercise. .

~Jonathan Mike MS, CSCS, NSCA-CPT