Which of the following interventions would be considered a 'modality'?

A modality in the context of sports medicine refers specifically to a treatment method or therapeutic approach that utilizes physical agents or techniques to promote healing. Therapeutic ultrasound is a prime example of this, as it involves the use of sound waves to penetrate tissues deep within the body, producing effects such as increased blood flow and tissue healing.

In contrast, the other options involve different aspects of treatment or performance. Strength training exercises focus on enhancing physical capability and conditioning, but they do not fall into the category of modalities since they do not directly use physical agents for therapeutic effects. Hydration strategies are vital for overall athlete performance and recovery but emphasize fluid intake rather than therapeutic application. Team building activities, while important for enhancing group cohesion and communication, do not pertain to physical therapy or modalities aimed at healing or treating injuries. Thus, therapeutic ultrasound stands out as the correct choice due to its classification as a treatment modality in sports medicine practices.