If this question is asked a teacher experienced weight, it is common to hear the following answer: "just breathe" ...
This simple and objective response aims to encourage students, especially beginners, to create a continuous pattern of breathing during exercise series, thus avoiding the Valsalva maneuver.
The Valsalva maneuver is understood by a blockage of the glottis that prevents the expiration of the inhaled air, resulting in increased intra-abdominal pressure (chest), decreased venous return and increased blood pressure. For this reason it is advisable that realization is avoided in order to educate beginners and special groups such as hypertensive.
However, it is common to observe experienced individuals on weight training performing this maneuver because of increasing intra-abdominal pressure, which provides security to the spine and help in performing exercises with heavy loads. In such cases, the maneuver happens involuntarily. Note that this technique should only be applied by advanced students. In beginning to intermediate students, breathing should always be continuous.
As the pattern of breathing, this can be classified into two types, depending on the phase in which they inhale and exhale:
•Active breathing: draws during the concentric phase and expires during the eccentric phase of the movement.
•Passive breath: draws during the eccentric phase and exhale during the concentric phase of the movement.
Generally, the active and passive breaths are used in exercises that push and pull, respectively, however, this is not a rule. In fact, there is no consensus in the literature on what would be the best way to breathe during exercise.
Some scholars recommend, preferably, the adoption of passive breathing during exercise, especially in hypertensive and other special groups.
The most sensible, in my view, is that students are instructed to breathe so that there is as comfortable as possible, with a ratio of one respiratory cycle (inspiration and expiration) for each repetition, regardless of the type for which it was decided (active or liabilities).