What is a common use of infra-red radiation before a massage?

The common use of infra-red radiation before a massage is primarily to warm the tissues. When infra-red radiation is applied to the body, it penetrates the skin layers, causing the deeper tissues to heat up. This warming effect can facilitate increased blood circulation, loosen tight muscles, and prepare the body for the massage. The thermal benefits also help in reducing stiffness, making the massage more effective as the muscles are more pliable and receptive to manipulation.

The other options, while they may have relevance in different contexts, do not accurately reflect the primary purpose of infra-red radiation. For instance, while hydrating the skin is important in skincare, it is typically achieved through topical products rather than infra-red radiation. Exfoliating dead skin cells involves physical or chemical means but does not relate to the heating provided by infra-red. Analyzing skin types is a diagnostic procedure that does not involve infra-red radiation, which is more focused on therapeutic applications.