Both the gastrocnemius and soleus can cause posterior calf pain, but they are loaded differently. Gastrocnemius crosses both the knee and ankle, while soleus acts primarily across the ankle. Pain location, knee position, calf-raise behavior, running mechanics and imaging can therefore help identify which structure is involved.
The distinction matters because the two injuries tend to behave differently, recover on different schedules and need slightly different rehabilitation. It also matters because some calf pain is not a muscle injury at all.
Two muscles, one tendon
The gastrocnemius and soleus together form the triceps surae and share the Achilles tendon, but they are built and loaded differently.
- Gastrocnemius: the superficial muscle that gives the upper calf its shape. Its medial and lateral heads start above the knee, so it crosses both the knee and the ankle. It is placed under the most tension when the knee is straight and the ankle is pulled up into dorsiflexion, and it is heavily involved in fast, forceful push-off.
- Soleus: a broad, deep muscle beneath the gastrocnemius. It starts below the knee, so it does not cross the knee joint. It is relatively more isolated during bent-knee plantarflexion and does much of the sustained work of walking and running.
Knee position changes relative loading of the gastrocnemius and soleus, which can help guide the examination, but it is not a stand-alone diagnostic test. Pain with straight-knee calf raises does not prove a gastrocnemius injury, and pain with bent-knee raises does not prove a soleus injury. Both muscles contribute in both positions, and an irritable injury can hurt with almost any loading.
How the two injuries tend to present
| Feature | Gastrocnemius injury | Soleus injury |
|---|---|---|
| Location | Upper or mid calf, often the inner (medial) head | Deeper, mid to lower calf, sometimes toward the Achilles |
| Onset | Often sudden, during sprinting, lunging or push-off | Often gradual or vague, sometimes noticed after a run |
| Loading most likely to provoke | Straight-knee raises, push-off, sprinting | Bent-knee raises, sustained running, uphill work |
| Common confusion | “Tennis leg” and plantaris injury | Achilles tendinopathy or a gastrocnemius strain |
| Ultrasound visibility | Often well seen | Can be missed, especially deeper lesions |
These are tendencies. Overlap is common, and some people injure both muscles or the connective tissue between them.
Calf injuries are injuries to specific structures
Calf injuries are best understood as injuries to specific myoconnective structures rather than simply "a pulled calf." A 2026 anatomy-based review describes calf injuries as a heterogeneous group of lesions involving different muscles and myoconnective structures, and notes that the field is moving beyond a purely muscle-based diagnosis (Pedret, 2026). Within each muscle, an injury may involve an aponeurosis, an intramuscular or central tendon, a musculotendinous junction or the myofascial boundary.
Muscle strain injuries often involve connective tissue as well as muscle fibers. The location and extent of myofascial or myotendinous involvement may influence recovery. A systematic review and meta-analysis of 16 imaging studies of athletic strains found myotendinous lesions in about 68% of injuries and myofascial lesions in about 32%, while isolated muscle-fiber lesions accounted for about 13%. Evidence on how these connective-tissue lesions affect return-to-play time was mixed (Wilke, 2019).
The same 2026 review is cautious about how far anatomy alone can predict outcome. Evidence linking specific anatomical patterns to prognosis is limited and largely observational, and there are no validated calf-specific return-to-sport criteria yet. Anatomical characterization should inform management rather than determine it (Pedret, 2026).
Why soleus injuries are easy to miss
Soleus injuries are easy to underestimate because the muscle is deep, anatomically complex and can mimic Achilles or gastrocnemius pain. A 2025 narrative review and case report highlighted that soleus injuries are often unrecognized and can resemble Achilles tendinopathy and "tennis leg." The muscle contains three intramuscular tendons and a complex connective-tissue architecture. Because these injuries are often treated as minor, people may return to running quickly, which carries a high risk of reinjury. The authors recommended combining a thorough physical examination with high-resolution ultrasound and MRI (Trybulski, 2025).
In practice, a soleus injury may feel like a deep ache or tightness that builds during a run rather than a sudden tearing sensation. Many runners keep training through it, which can turn a manageable injury into a recurring one.
Soleus vs. Achilles
Deep soleus pain can mimic Achilles tendinopathy, particularly when symptoms are distal or provoked by running. Palpation, loading behavior and imaging may be needed when localization is unclear. Achilles tendinopathy usually produces pain that is more tendon-localized, often a few centimeters above the heel or at the heel insertion. A distal soleus injury tends to sit slightly higher and deeper, in muscle tissue on either side of the tendon. The distinction matters because the loading programs and the role of shockwave differ. Tendon problems are covered on the Achilles tendinopathy page.
Ultrasound or MRI?
Soleus injury is a good example of why imaging choice matters. In a prospective series of 55 MRI-confirmed soleus injuries, ultrasound detected only 27.2% of lesions. MRI was used as the reference standard, and no lesion was identified by ultrasound alone. The series included 24 myofascial injuries and 31 musculotendinous injuries (Balius, 2014). Ultrasound performed better for some superficial/posterior myofascial injuries than for deeper musculotendinous lesions. The authors suggested that sensitivity improves with an anatomically based examination and that timing may matter.
This finding is specific to the soleus. It does not mean ultrasound performs badly for every calf injury. Ultrasound is useful for many superficial calf injuries and can provide dynamic assessment, and a 2024 review of lower-limb ultrasound describes its broad role in assessing muscles and tendons and in monitoring healing (Maruszczak, 2024). MRI is particularly valuable when deep soleus or complex myoconnective injury is suspected.
A 2025 narrative review of calf strains in athletes found that ultrasound and MRI both provide useful information on grading and recovery, and that grading systems correlated with outcomes, but no single imaging modality or grading system was universally superior. Clinical assessment remained essential and was described as the gold standard for return-to-sport decisions (Pagan-Rosado, 2025). Imaging can improve anatomical characterization and prognosis, but return-to-sport decisions should not be based on imaging grade alone.
Not every sudden calf pain is a strain
Seek medical evaluation first. Calf swelling, warmth or pain accompanied by clot risk factors—or any chest pain or shortness of breath—requires prompt medical evaluation rather than routine soft-tissue treatment.
Sudden calf pain should not automatically be labeled a muscle strain. Deep-vein thrombosis and a ruptured Baker cyst can mimic musculoskeletal calf injury and require a different pathway. A 2024 ultrasound review made this point directly, noting that these non-musculoskeletal conditions can present like acute calf injuries and must be considered in sudden calf, posterior leg or ankle pain. The same review observed that soleus and gastrocnemius strains can mimic each other clinically, and that telling them apart helps tailor rehabilitation (Billone, 2024).
Other possibilities include an Achilles tear, chronic exertional compartment syndrome, nerve symptoms from the lower back or the tibial or sural nerves, vascular claudication and bone stress injury. These are covered in the chronic calf pain differential.
What a calf examination looks at
- Where the pain is, from the upper calf down to the Achilles tendon
- Bilateral and single-leg calf raises, with the knee straight and bent
- Plantarflexion strength and endurance compared with the other side
- Walking, and hopping or running when they are safe to test
- Palpation along the gastrocnemius heads, the soleus and the Achilles tendon
- Swelling, warmth or other features that point away from a muscle injury
- A neurologic screen when symptoms include numbness, tingling or burning
The goal is to find the pattern. A deep, lower-calf ache that is worse with bent-knee loading and running volume points toward the soleus. A sudden, upper-medial calf injury during push-off points toward the medial gastrocnemius. Unclear or atypical cases are the ones most likely to need imaging.
Why the distinction changes rehabilitation
Rehabilitation for either muscle aims to rebuild strength, endurance, length tolerance and sport-specific force production, progressing by criteria rather than a fixed calendar. Within that, the emphasis shifts. Bent-knee calf loading targets the soleus, which matters for runners because the soleus handles large forces during each stride. Straight-knee loading and faster, more explosive work become more important for gastrocnemius injuries and for sports that demand sprinting or jumping. Recurrent injuries also call for a closer look at what was missed the first time, including the possibility of persistent fibrotic remodeling after a strain.
Why calf strains recur
Recurrent calf strain can result from several factors, including incomplete strength recovery, inadequate endurance, rapid return to running or sport, altered myoconnective tissue healing and previous injury. A missed soleus component is a common example: the upper calf may feel better while a deeper soleus injury has not regained its capacity for sustained running. Fibrotic remodeling may contribute in some cases, but recurrent injury is multifactorial, so the examination looks at strength, endurance and training history as well as the tissue itself.
How Novo approaches calf pain
We first decide whether the problem is a muscle injury, the Achilles tendon, a nerve or a medical cause. If it is muscle, we work out which muscle and structure are involved, measure how the calf tolerates load, and decide whether imaging is needed before choosing progressive loading, manual treatment or shockwave therapy. See how we approach chronic calf pain and muscle injury.
References
- Pedret C, Palermi S, Mechó S, et al. Calf injuries: an anatomy-based approach to diagnosis, management and return to sport. Current Reviews in Musculoskeletal Medicine. 2026;19(1). PMID 42799963. (link)
- Trybulski R, Gałęziok K, Matuszczyk F, Halski T, Muracki J. Problems in diagnosis and treatment of soleus muscle injuries: narrative review and case report. Journal of Clinical Medicine. 2025;14(6):1955. PMID 40142763. (link)
- Balius R, Rodas G, Pedret C, Capdevila L, Alomar X, Bong DA. Soleus muscle injury: sensitivity of ultrasound patterns. Skeletal Radiology. 2014;43(6):805-812. PMID 24627005. (link)
- Pagan-Rosado R, Troyer W, Rosario-Concepcion R, et al. Calf strains in athletes: a narrative review of management, injury grading, and return to sport. Sports Medicine - Open. 2025;11(1):158. PMID 41385031. (link)
- Wilke J, Hespanhol L, Behrens M. Is it all about the fascia? A systematic review and meta-analysis of the prevalence of extramuscular connective tissue lesions in muscle strain injury. Orthopaedic Journal of Sports Medicine. 2019;7(12):2325967119888500. PMID 31903399. (link)
- Billone LM, Allred SJ, Flores DV. US of acute tendon tears. RadioGraphics. 2024;44(12):e240060. PMID 39612282. (link)
- Maruszczak K, Kochman M, Madej T, Gawda P. Ultrasound imaging in diagnosis and management of lower limb injuries: a comprehensive review. Medical Science Monitor. 2024;30:e945413. PMID 39223775. (link)
