I am getting almost as fed up with the word “release” in massage therapy as I am with “toxins.”
“Release” does not (indeed, it cannot) refer to any known, specific state of soft tissue. It’s poetry, not biology. It’s massage-speak for “better in some way, hopefully for more than ten minutes.”
As commonly used, the word strongly suggests an actual change in the flesh … but this assumption derives only from vague, erratic, uninterpretable sensory cues. Most therapists say — not all of them, importantly, but most — that they can feel tissue changing texture as they work, but that could easily be misinterpreted muscle behaviour and palpatory pareidolia.
Patients may experience a kaleidoscopic array of sensations during massage, and often call it “release” if they perceive an especially significant improvement (from feeling “stuck” to feeling “relieved,” say) — but we have almost no idea what any of these sensations imply about tissue state, if anything. People also have profound shifts in sensation from a good back scratch, fervent prayer, and eating cheesecake!
There are several more paragraphs about “release” in my article about fascia.