Muscle contusions, along with muscle strains, account for about 90 percent of all sports injuries. Contusions are bruises caused by impact with a blunt object. They most often happen to the upper arms and thighs. Except for muscle strains, contusions are the most common type of muscle injury.
Contusions cause pain and swelling. They also reduce range of movement. In some cases, extra blood pools within the muscle tissues, forming a hematoma. Added problems can occur if the hematoma causes extra pressure on nearby tissues. Hematomas that form in the front of the upper arm or thigh run the risk of forming bone tissue inside the muscle, a condition called myositis ossification.
This article reviews current research on contusions, to help with diagnosis and treatment. What determines the severity of a contusion? Does tightening your muscles before impact lighten the blow? Research shows that, compared to relaxed muscles, contracted muscles do a better job of absorbing the energy of a direct hit. Tightened muscles stiffen against the impact, forming a wall against injury.
Muscles that are tightly taped or padded don’t fare as well. This is probably because they have less room to move as they absorb the force of the impact. Tired muscles are also more susceptible to injury, as are those that haven’t been warmed up. After injury, younger muscles may have more pain and swelling than older ones, yet younger muscles heal more quickly.
Diagnosis of contusions is usually straightforward. If patients have concentrated swelling and tenderness along with poor range of movement, they probably have a contusion. The extent of the injury may be harder to figure out. Ultrasound and magnetic resonance imaging (MRI) may help.
Researchers have studied the natural healing of contusions in animals. Most of the healing happens within the first few days. Inflammation draws healing cells to the injured area to help repair the injured muscle. Scar tissue forms. In rats, healing is complete within two to three weeks, with no lasting signs of injury.
Treatment depends on the severity of the contusion. If there’s a large tear in the muscle, healing may be improved with surgery to hold the torn edges together. However, it is sometimes challenging to surgically stitch the muscles together.
Rest is often recommended in the treatment of contusions. But too much rest can make joints stiff and muscles weak. Researchers generally agree that rest is best right after the injury (24 to 48 hours), followed by light movement. Resting early on can limit the formation of hematoma without affecting the muscles and joints. Icing may help, too, especially right after the injury.
Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce pain and swelling in the short term. So can corticosteroids. However, these treatments may reduce muscle strength and healing in the long run. The authors suggest only using NSAIDs within 24 to 48 hours of injury. More research is needed to fully understand the effects of these treatments. Other medications, such as growth factors and certain types of steroids, should also be explored.