Starting Strength

happens: it does. With varying degrees of precision based on your visualization skills, the bar will tend to line up vertically with the balance point because your knees and hips will have done the things needed to make it happen. And your visualization skills are just as trainable as everything else. This trick is a useful tool for all the pulls from the floor and for the press because the mechanics of balance and bar path are the same.
     

    Figure 2-53. The Master Cue.

    Breathing
     
    Much controversy exists about breathing patterns during exercise. It is thought by some that “inhaling on the way down and exhaling on the way up” is a good way to lower the peak blood pressure during the rep and thereby eliminate the possibility of cerebrovascular accidents occurring during exercise. Such advice reveals a misunderstanding of the mechanisms involved, overrates the likelihood of an exercise-related cerebrovascular injury (a breathtakingly uncommon event), and underrates the likelihood of an orthopedic injury, an all-too-common occurrence. If we are to put this controversy to rest, it behooves us to understand the function of the Valsalva maneuver during the squat. The Valsalva maneuver is the proper term for holding the breath against a closed glottis while pressure is applied by the abdominal and thoracic muscles.
    If your car runs out of gas in an intersection, and you have to push it out of the way or get killed, you will open your car door, put your shoulder on the door frame, take a great big breath, and push the car. You will probably not exhale except to take another quick breath until the car and you are out of the way. Furthermore, you will not even think about this because the many millions of years your ancestors have spent pushing on heavy things have taught your central nervous system the correct way to breathe while pushing. Or you might find yourself grunting aloud during the effort, a vocalization produced by a marked restriction in the airway at the glottis; this restriction produces a similar increase in pressure during the partial exhalation. This is perhaps the origin of the “kiyah” in martial arts, the vocalization that allows for an increased focus of power at the instant of the striking of a blow.
    When you inhale, your diaphragm contracts and the volume of your thoracic cavity increases. As air flows into your now larger lungs, pressure equalizes between the outside and the inside. When you clamp down to hold your breath and tighten your trunk muscles, you create a pressure gradient between the inside and the outside. This pressure increases markedly with the intensity of the squeeze. Since your thoracic and abdominal cavities are separated by only your diaphragm, abdominal pressure increases, too. The spinal vertebrae are being held in the correct anatomical position by your back musculature. This correct position is reinforced by static pressure transmitted to the spine across the essentially non-compressible contents of the abdominal cavity ( Figure 2-54 ). Pressure in your abdominal and thoracic cavities is therefore transmitted to your spine from the anterior and lateral directions, and the spinal erectors are generating pressure from the posterior. When pressure in the thoracic cavity increases with a big held breath, and this pressure is increased by the tightening of the abs and obliques, support develops for the spine as if a rigid cylinder were surrounding the spinal column. A weightlifting belt adds to this effect, its main function being to add support to the cylinder from the front and sides, rather than to apply pressure from the back.

    Figure 2-54. The combined effects of increased lung (intra-thoracic) pressure, intra-abdominal pressure produced by abdominal muscle contraction, and spinal erector contraction on spinal stability during loading. The Valsalva maneuver increases the ability to produce this pressure and stability. Exhalation during heavy efforts prevents the development of sufficient pressure to stabilize the spine. Best is a big, held breath during a heavy effort.

    The conventional wisdom is that this thoracic and abdominal pressure is also being applied to the cardiovascular system embedded in the trunk, that the increase in pressure is being transmitted up the vascular column to the head, and that this increase in pressure has the potential to cause a cerebrovascular accident (CVA), such as a stroke or a blown aneurysm.
    This assumption ignores several