What is the temperature range associated with achieving residual length change during superficial heating?

• A. 90–98
• B. 100–102
• C. 102–104
• D. 104–111.2

Answer: (D)

Achieving residual length change requires heating tissue to a higher temperature where connective tissue, especially collagen, becomes sufficiently pliable to elongate and maintain that length after cooling. When tissue temperature reaches about 40–44°C (roughly 104–111.2°F), collagen fibers soften and creep under a stretch, allowing a lasting increase in length. This is why the higher temperature range is the best choice—it provides the necessary change in tissue viscoelastic properties to produce a residual length change. Lower ranges warm the tissue and may improve comfort or transient extensibility, but they don’t produce the lasting length change seen at the higher temperatures.