You always hear your stretching instructor remind you to breathe, and breathe deeply. Have you wondered why that is?
The main reason is that exhalation slows down the heart rate and forces a decrease in blood pressure and muscle tension.
Slow, deep breathing with the exhalation longer than the inhalation results in your body thinking it is in a state of lesser stress and greater relaxation.
The more relaxed your body is, the easier it will be to stretch the muscles!
How should you be breathing? Regardless of how you are stretching, take deep breaths, not shallow ones, and allow your abdomen to expand. Establish a regular breathing pattern and employ counting in your head or out loud, if needed.
If you are stretching dynamically, find a breathing pattern that works for you: exhale on the contraction, or as you go deeper into a certain move. In "flow" classes or self-practices, we can borrow a technique from yoga called "vinyasa", which is synchronizing physical movement to the breath. Each movement you do will trigger an inhalation or exhalation, with the inhalation treated as an intake of energy, and the exhalation treated as as a release of anything that is not serving you (physically or mentally).
If you are stretching statically, try to go a little bit deeper on each exhale, and hold each position until your body is able to relax in it. The stretch reflex is controlled by your nervous system, and by breathing deeply and holding the stretches through the exhales and beyond, you train your body to adapt to deeper ranges of motion and tolerate more "stretch". Don't ever try to push "through" the stretch reflex and stretch through the contraction in the muscle - you are risking a chance of injury because your body hasn't had a chance to adapt.
Keep stretching, keep breathing, FLEXSPACE friends!