Dry needling is a skilled intervention used by physical therapists to treat pain and movement impairments by inserting thin, solid needles into trigger points in muscles and connective tissue. Research shows it is effective for pain control, reducing muscle tension, and facilitating rehabilitation. Two case studies found dry needling effective - one for reducing post-surgery knee pain, and the other for relieving shoulder pain and improving range of motion in elite athletes. While supported by physical therapy organizations, regulations of dry needling by physical therapists vary by state.