How could you reduce muscle swelling (impact injury)?

Rest, elevate, cold. To reduce swelling to muscles after injury, one needs to not use the the affected muscle (rest), elevated as much as possible, and use cold compresses for 20 minutes followed by a 20 minute break, and repeat as necessary.
RICE. Most clinicians use the letters rice rest ice compression and elevation.

Related Questions

How does one reduce muscle swelling (impact injury)?

Rest and cold packs. The simplest way is to rest the arm or leg, keep it elevated for a while, and apply cold packs continuously until it is better.