Many people don't know that the calf muscle actually consists of two muscles. One is the large bulging muscle that becomes more noticeable when you stand on your toes; that's the gastrocnemius. The other, called the soleus, is the smaller muscle that lies below the gastrocnemius. It's harder to see on most people, and you might not even know it's there, unless you're a runner. Soleus pain is common in those who enjoy pounding the pavement, and there are a couple of different reasons for it.
Soleus pain in runners is usually caused by a sprain or overuse injury.
What Is the Soleus Muscle?
The soleus muscle is important for runners because it's responsible for plantar flexion of the ankle, or pointing your toe, as sports physiotherapist Sean Fyfe notes. When you push off the ground with each step, it's your soleus that's powering that movement.
Your soleus muscle has a higher proportion of slow-twitch muscle fibers, the type responsible for endurance activities. In contrast, the gastrocnemius has a higher composition of fast-twitch muscle fibers, which generate power for explosive movements like sprints. If you're a long-distance runner, your soleus bears a lot more of the burden than if you're a sprinter.
Pulled Soleus Muscle
Because of the demand on the soleus muscle in endurance running, soleus calf strains are common. A calf strain or muscle strain, in general, occurs when the muscle fibers are stretched beyond their natural range of motion. This may happen because the muscle was overstretched or because a particularly forceful muscular contraction caused trauma to the muscle fibers.
Because it's a slow-twitch muscle and not involved in producing a lot of force, soleus muscle strains are typically not as severe as gastrocnemius strains. While a serious gastrocnemius strain may prohibit you from walking, soleus strains tend to be more mild, according to Fyfe.
Muscle Strain Grades
In the common grading system used to rate the severity of muscle strains, soleus strains are often grade I strains. Grade I strains are minor injuries with mild pain that don't prohibit activity. There's likely no swelling and no bruising.
However, they may be more moderate, grade II injuries. These strains are more painful and likely accompanied by swelling. There may also be bruising and reduced muscle function.
In rare cases, the soleus may tear completely, resulting in a serious grade III strain. These injuries result in severe pain, swelling, bruising and a complete loss of muscle function.
What a Strain Feels Like
Comparing your symptoms to the typical symptoms associated with a soleus strain can help you get a better idea if that's what you're dealing with. According to running injury specialist Dr. Sebastian Gonzales, common symptoms of a soleus strain include:
- A dull throbbing ache in your midcalf
- Cramping in the lower calf
- Pain while walking down stairs
A Simple Test
Your doctor or physical therapist may perform a simple assessment to determine the location of the strain, reports Fyfe. You can try the following at home to get a better idea of where the pain is located:
Stand on a step facing toward the staircase. Allow your heels to extend over the edge. Perform a calf raise by rising onto your toes with your knees straight. Next, bend the knees slightly and perform the calf raise again. Did you feel more pain with the legs straight or bent?
Because bending into the knees puts more pressure on the soleus muscle, it's most likely your soleus is affected if that's when you feel the pain, says Fyfe. He also notes that you may need to do more reps or single-leg raises to get a better assessment, because soleus strains are usually mild.
Causes of Soleus Strain
Muscle strains have direct causes and indirect causes. Direct causes include:
- A fall, twist or blow to the body
- Awkward, sharp movements
You may have pushed off the ball of your foot in an unusual way or with undue force, resulting in trauma to your soleus muscle. This type of injury can happen to anyone.
However, indirect causes leave the soleus muscle vulnerable to strain. According to Gonzales, indirect causes of soleus muscle strains include:
- Overtraining, which causes weakened muscles that are prone to injury
- Wearing the wrong footwear, which can lead to excess wear and tear and improper running gait
- Hill training — especially tough on the soleus muscle
- Overpronation/flat feet, causing the soles of the feet to roll inward, which can affect your gait and foot strike
- Abnormal gait that affects running mechanics
- Poor hip strength, endurance and flexibility, which can cause muscular imbalances that result in injury to other muscle groups
- Poor core strength and endurance, resulting in poor biomechanics and overexertion
Soleus Overuse Injury
Overuse injuries are closely related to strains, because overuse can lead to acute injury. In the absence of acute injury, soleus overuse can also cause pain. Typically, this is a dull, chronic pain that shows up during your runs and even when you're not running.
Overuse injuries can be caused simply by pounding the pavement day after day. Just like strains, they can also be caused by overexertion, lots of hill training and wearing the wrong footwear. They also result from increasing your mileage or intensity too quickly.
The main difference between a sprain and an overuse injury is that sprains are acute while overuse injuries develop over time. Failing to properly treat soleus overuse may result in an acute injury down the road.
Treating Soleus Muscle Pain
Treatment for mild strains and overuse injuries is similar. The first priority is to stop placing stress on the muscle. This may require avoiding running for a period of time or reducing your mileage and intensity.
After an acute injury, or when an overuse injury flares up, ice, compression and elevation can be useful for relieving pain and inflammation. Apply an ice pack to the soleus muscle for 10 to 20 minutes at a time every hour or as often as possible. Wrap the calf in an elastic bandage and prop it up, at or above the level of your heart, whenever possible.
The next treatment steps depend on the severity of your injury. Mild strains should resolve within a couple weeks with rest and recovery. More serious strains, or mild strains that don't improve in a few weeks, may require a visit to your doctor.
Preventing Soleus Pain
Future occurrences of soleus pain can be avoided by making the proper adjustments to your running routine. If your footwear is to blame, head to a local running store to get some expert advice on your next pair of running shoes.
If your problem is overpronation and flat feet, you can do exercises to strengthen your foot and ankle complex. Examples include calf raises, toe lifts and single-leg squats. You should also focus on the position of your foot and ankle during your runs to correct poor technique.
- Alligator crawl
- Opposite-leg, opposite-arm reach
- Low-to-high woodchop
- Hip extension and abduction
Take It Slow
Finally, many injuries can be avoided by being conservative with your training program. Add miles and increase intensity gradually so your muscles have time to adapt to the load. Dartmouth-Hitchcock Orthopaedics and Sports Medicine recommends increasing your mileage and training volume by not more than 5 to 10 percent each week.
Also, be sure to include proper time for recovery. Running every day of the week is a recipe for acute and overuse injuries. Take time off and cross-train with other activities — such as cycling and swimming — that use muscles other than those used for running.
- WebMD: Picture of the Calf Muscle
- Sports Injury Bulletin: Rehabilitation of Soleus Muscle Injuries in Distance Runners
- Harvard Health Publishing: Muscle Strain
- Performance Place: The Definitive Guide: Calf Cramps & Other Calf Injuries Runners Encounter
- The American Orthopaedic Society for Sports Medicine: Overuse Injuries
- Road Runner Sports: Overpronation: What It Is and How It Can Derail Running
- Training Peaks: 7 Hip and Core Exercises for Endurance Athletes
- Dartmouth-Hitchcock: Ten Tips to Prevent Running Injuries