Final answer:
To lengthen soft tissue and mitigate pain, ultrasound diathermy is a recommended technique that uses high-intensity ultrasound for deep-heat treatments, thereby improving flexibility and relieving pain, while a thorough warm-up and stretching are essential to prevent injuries.
Step-by-step explanation:
To lengthen your client's soft tissue and alleviate pain, ultrasound diathermy is often considered an effective technique. This method uses high-intensity ultrasound to heat tissues, operating typically at frequencies of 0.8 to 1 MHz, which helps relieve pain and improve flexibility in injured or overworked muscles. However, it's essential for the therapist to exercise skill and caution to avoid complications such as "bone burns" and other tissue damage due to overheating and cavitation - phenomena that may be exacerbated by ultrasound reflection and focusing by joint and bone tissue.
In addition to ultrasound diathermy, a proper warm-up combined with stretching before exercising is critical to prevent muscle and tendon injuries. Warming up increases blood flow and prepares the muscles for stretching, which can then be done without causing damage to the muscle fibers or tendons.