Deep tissue massage focuses primarily on muscles and connective tissues located below the surface of the top layer or muscles. It is designed to relieve severe tension and knots (known as "adhesions") and is often recommended for clients who experience consistent pain, are involved in heavy physical activity (such as athletes), and those who have sustained a physical injury.
Deep tissue massage should not be confused with "deep pressure" massage. Deep tissue employes a specific set of techniques and strokes to achieve a measure of relief for specific focus areas. It is not merely a Swedish massage with heavy pressure.
It is not uncommon for clients who receive deep tissue massage to have their pain replaced with a new muscle ache for a day or two after the massage session. It is important to stay hydrated after a deep tissue massage session to help flush lactic acid out of the tissues. If the lactic acid isn't flushed, you could be quite sore the next day.