Most of the time the use of ice is a better option after training, especially if there is a injury concern. Ice will aid the healing process by reducing inflammation. Since the effect of exercise will generally raise the body temperature and increase swelling, it is wise to "cool" the area down after exercise.
A process of contrast can be performed with an injury which means heating the injury up and then icing it down. This increases blood flow to aid in recovery and then stops the swelling with ice. A ratio of of 7 minutes of heat to 3 minutes of ice is recommended.