Final answer:
Thermolysis, diathermy, high frequency, and radio frequency refer to medical treatments that use heat generated by electromagnetic energy to relieve musculoskeletal pain and improve flexibility.
Step-by-step explanation:
Thermolysis, diathermy, and high frequency all refer to medical and therapeutic techniques that use heat generated by electromagnetic energy to treat various conditions. Methods such as ultrasound diathermy utilize intensities between 10³ to 10⁴ W/m² and frequencies of 0.8 to 1 MHz to relieve pain and improve flexibility in muscles. Similarly, microwave diathermy penetrates tissue to accomplish 'deep heating', effectively used for muscular pains, spasms, tendonitis, and rheumatoid arthritis. It is crucial for a therapist to skillfully apply these treatments to avoid tissue damage such as 'bone burns' caused by overheating and cavitation.