Soft tissue injuries and muscles strains: usually over stretching of the fibres of the muscles or ligaments through sudden movements or strains. Depending on the gravity of the injury small blood vessels can tear, causing swelling and colouring.
Rest, gentle movements and rubbing the injured part with an ice cube usually ease the acute pain. Avoid sudden, fast movement.
Physiotherapy can help to keep the scar tissue as small as possible, reduce the swelling and regenerate the injured structures. Exercises for proprioception, stability, strength and reaction will help you to a gradual return to the normal activity without a danger of a new injury.