A bruise from exercise might just be a coincidence — you notice it when you put on your workout T-shirt or tank, but it's really from something you banged into during the day.
However, a bruise on your bicep, especially if accompanied by shoulder pain, weakness or a visual change in the shape of your biceps muscles, could indicate a serious injury, even a tear. Push-ups are unlikely the cause, but more likely the proverbial straw that broke a weakened muscle's back.
Read more: Push-Ups Causing Pain
What Is a Biceps Tendon Tear?
The biceps aren't even a primary mover in the push-ups, so it's definitely a puzzle as to how they get bruised from doing this exercise. The answer lies in your tendons.
Tendons are connective tissues that attach your muscle to bone. When the tendon becomes weak from overuse or sudden injury — such as overstretching — it can tear. In the case of the biceps, the tendon may tear at the shoulder or the elbow.
Tears most often occur at the long head of the biceps where it attaches at the shoulder. Tears at the elbow, known as distal tendon tears, are less common than tears near the shoulder.
Usually you notice a sharp pain at the time of the tear, followed by bruising and limited mobility. If that sharp pain happened during a push-up set and you see bruising at the elbow and forearm a few hours or day later, chances are the push-ups aggravated an already weak tendon.
Even in the unlikely case that you don't experience extreme pain, you might notice that it's hard to rotate your palm from face up to face down or bend your elbow.
Why Push-Ups Cause It
Push-ups themselves are unlikely the only cause of the bruising due to a biceps tendon tear. Most often, you experience this injury because of an unnatural movement of the arm or lifting something extremely heavy. A tear is thus more likely to occur during sports or a very heavy bench press.
You're only lifting about 70 percent of your body weight during a push-up, but poor form could aggravate a tendon that you've frayed with lots of bench pressing and heavy flyes. Your tendon may give out during the set of push-ups, especially if you're going for an especially long set or at a quick pace.
Adding weight plates or chains to your push-ups or rapidly increasing the number of push-ups you do too quickly can weaken the tendons and make them vulnerable to tears.
What to Do?
If the bruising persists and is accompanied by serious pain, a recoiled muscle and limited function, see a doctor immediately. In many cases, tears must be repaired with surgery.
Your doctor may initially recommend rest, from push-ups and other upper-body exercise, ice and over-the-counter anti-inflammatory medication. Physical therapy can also help restore muscle function for some people.
Read more: What are the Treatments for a Torn Tendon?