From the Research
Bilateral soleus muscle cramps during running are primarily caused by muscle fatigue, dehydration, electrolyte imbalances, and inadequate conditioning. When you run, especially for longer distances or at higher intensities, the soleus muscles (located in the calf below the gastrocnemius) can become overworked, leading to involuntary contractions. Dehydration reduces blood volume and impairs muscle function, while electrolyte imbalances—particularly low levels of sodium, potassium, calcium, and magnesium—disrupt normal muscle contraction and relaxation cycles.
Causes of Bilateral Soleus Muscle Cramps
- Muscle fatigue: Overuse of the soleus muscles during running can lead to fatigue, increasing the likelihood of cramps 1.
- Dehydration: Inadequate hydration can reduce blood volume and impair muscle function, contributing to cramp development 1.
- Electrolyte imbalances: Low levels of essential electrolytes like sodium, potassium, calcium, and magnesium can disrupt normal muscle contraction and relaxation cycles, leading to cramps 2.
- Inadequate conditioning: Insufficient training or sudden increases in running intensity and distance can contribute to muscle cramps 1.
Prevention and Treatment
To prevent these cramps, ensure proper hydration by drinking 16-20 ounces of fluid 2-3 hours before running and 7-10 ounces every 20 minutes during activity. Consider electrolyte replacement drinks or supplements containing sodium (500-700mg/L) and potassium during longer runs. Gradually increase running distance and intensity to improve muscle conditioning, and incorporate specific soleus strengthening exercises like seated calf raises into your routine. Proper warm-up and cool-down periods, along with regular stretching of the calf muscles, can also reduce cramp frequency. If cramps occur, stop running, gently stretch the affected muscles, and massage the area. These measures work by maintaining proper muscle function, electrolyte balance, and blood flow to the working muscles during exercise.
Recent Evidence
A recent study published in 2025 found that quinine sulfate can be effective in reducing muscle cramp intensity and frequency in patients with amyotrophic lateral sclerosis (ALS) 3. However, the study had a small sample size and was not specifically focused on runners. Another study from 2020 found that magnesium supplementation had minimal effect on reducing muscle cramp frequency and intensity in older adults with idiopathic cramps 2.
Recommendation
Based on the most recent and highest quality evidence, the best approach to preventing and treating bilateral soleus muscle cramps during running is to focus on proper hydration, electrolyte balance, and muscle conditioning. While quinine sulfate may be effective in certain populations, its use in runners is not well established, and magnesium supplementation has shown limited benefits 2, 3.