Sometimes, as I'm working with a client, they'll ask what I'm doing. Usually, they ask if they're getting a "deep tissue massage." I wish I had a quick answer for them.
Most people assume that a firm massage is deep tissue, when that can actually be fairly far from the truth. I can press hard into your soft tissue, but only be affecting the superficial structures. You're feeling a lot of pressure, but I haven't begun to address the deep tissue.
Real deep tissue work affects the deeper layers of muscles and soft tissue—instead of the prime movers, it addresses the postural and structural layers. Surprisingly, patience and precision count for a lot more than pressure when you're doing deep tissue work. Most of my continuing education has focused on getting deep tissue results without the kind of brutal pressure on your muscles that may make you sore during or after massage therapy. Craniosacral Therapy smooths and realigns the connective tissue around your brain and spinal core, but with only a few grams of pressure. Kinesio Tape is applied to the skin with a precise level of stretch in a specific direction. It doesn't require any pressure at all, but the nerve sensations directed by the tape can change how the deeper tissue functions.
There's a perception that the harder you push, the deeper you get. Firm pressure can feel very satisfying, but it's not directly correlated to corrective results. There are a whole family of deep tissue massage methods that are gentle, effective, and can do more for your long-term wellness than if I just wring you out. I recommend that you always have a chat with your massage therapist before your session so that you can be on the same page about your preferences and expectations about pressure and therapeutic benefits.