You want to breathe very deeply and fully while lifting weights. Most physical therapists and personal trainers recommend that when lifting weights, it is good to breathe out on the extension and in on the flexion. This is not a bad advice, as it keeps you from holding your breath, and it ensures that you are not breathing at even shorter time intervals. You certainly do not want to alternate between inhalation and exhalation during any instance of flexion or extension. I believe that it is beneficial to breathe at longer intervals. For instance, try breathing in during the entire repetition – both the flexion and the extension. I try to inhale for a rep or two, and then exhale for two or three reps. Doing so convinces your nervous system that the muscles that you are using can be exercised strenuously. You should also breathe deeply, at long intervals, before and after exercise.
Right after you complete a set, you also want to relax the muscles as much as possible. To relax them, continue to breathe deeply and actively in order to dissipate the tension that you created during the exercise. Usually when people lift heavy weights, tension accumulates in the muscles. Simply by paying attention to the level of tone after you complete a set, you can consciously counteract it and thereby enhance recovery, healing, and muscle gain.
Once you are done with the exercise, it is very important to “listen” to the tension in your muscles. You will feel the muscles that you just used tighten up on their own. The muscle tonus is resetting to a harmfully high level, resulting in an elevation in passive but continuous contraction. After a set, lie down and close your eyes while breathing deeply, you can really notice these small intrusions of tension. Usually, when we feel this, because it is uncomfortable, we stop breathing, or we breathe more shallowly. Moreover, when we feel these small, unconscious muscular spasms, we have a tendency to maintain the tension within this area. When you do not notice it, it stays contracted! Instead, you want to notice the tension, concentrate on relaxing it, and breathe through it until it subsides. Your focus should be on being completely limp.
Let us assume that you were to do 16 reps of bench press. Try to breathe all the way in for two reps at a time, and then all the way out for two at a time. Thus, for 16 reps you should have taken 8 complete breaths. Then lie down and try to notice the tension in your chest, shoulders, and elbows. It actually feels great as you calm wave after wave of tension. During sets make sure that you breathe diaphragmatically, focusing on the burn. Between sets you want to feel that burning sensation completely dissipate. The more you do this, the more you teach the muscles to relax after being fatigued. You will finish working out without feeling tight and high-strung, and you will wake up the next morning feeling relaxed.
The physical exertion involved in lifting heavy weights makes it very difficult to concentrate on breathing diaphragmatically. When lifting light weights it is very easy to breathe diaphragmatically. Even lifting heavy weights may not exacerbate trigger points if done when breathing diaphragmatically. I know that I am not fit enough for it though and I know that if I were to start lifting heavy weights today that it would undermine the postural corrections that I have been making. Lifting light weights enhances these corrections.