A tricep strain is the injury to the Triceps Brachii muscle at the back of the upper arm. Symptoms include tender and swollen muscle, bruising and sudden pain while stretching the muscle. Causes include sudden force or jerk to the muscle and trauma. It can also occur as a result of overuse of the muscle. Most common in weight lifters and athletes. Treatment includes muscle rest, ice or cold therapy and a compression bandage to reduce swelling.