What is a Calf Strain?
The calf consists of three separate muscles: the gastrocnemius, soleus and plantaris (Kilic et al., 2024). These muscles connect your lower leg to your achilles tendon, allowing you to point your toe (a movement called plantarflexion) and bend your knee. In practice, this ensures that forces are effectively generated and transferred through your body during weightbearing activities, such as walking and running, creating smooth and efficient movement. Injuries, however, change this.
A calf strain involves a disruption of its muscle fibres, the building blocks that make up its structure. This leads to a wound healing response beginning with local swelling and inflammation, after which the body attempts to rebuild and remodel itself. It can take months to years for this process to unfold, though this does not directly reflect how long it may take to regain function (Haskell & Coughlin., 2024). Any one of the calf muscles can be injured, and each requires a different, targeted approach to optimise its rehabilitation and reduce the risk of recurrence.
What Causes Calf Strains?
In its simplest sense, a calf strain occurs when there is a meaningful mismatch between the force that a muscle is exposed to, compared to its ability to tolerate this load (Maffulli et al., 2014). The mechanism of this appears to vary between the calf muscles. Gastrocnemius injuries typically present suddenly during acceleration, jumping and sprinting activities. Whereas, soleus strains are more frequently reported as a gradual onset of calf pain and tightness during walking or jogging tasks (Bahr et al., 2005). The soleus is only involved in movement of the ankle, whereas the gastrocnemius crosses the knee and ankle – this exposes it to more complex loads and a greater risk of injury (Armfield et al., 2006).
Other risk factors exist which influence the likelihood of a person suffering a calf strain. Particularly heavy resistance training can temporarily reduce the tissue tolerance of the gastrocnemius and soleus as the body recovers from the initial exercise (Green et al., 2022). In a similar vein, recent interruptions to, and/or increases, in running workloads are common culprits for calf injuries. Changes in footwear and environmental factors, such as the surface a person is running on, also regulate the physical demands on the calf and whether it is likely to tolerate the activities it is exposed to.
Diagnosis
Treatment
A panel of expert sports clinicians proposed the following rehabilitation sequence with the view to optimising recovery and minimising injury recurrence (Green et al., 2022):
- Acute injury protection phase
- Early rehabilitation with emphasis on tissue load development
- Intermediate rehabilitation including return to running
- Return to training
- Return to play
- Post return to play
Beginning in the acute phase, the priority is adequate protection of the injured site; this involves preventing further structural damage, optimising the injured person’s walking pattern, and commencing loading of the calf complex within reason to stimulate tissue healing. This evolves in the early rehabilitative stage to include deliberate calf strength and endurance training, a deliberate walking/locomotor regime, and starting the management of risk factors for subsequent injuries. The rate of loading of the calf is increased during the intermediate phase through plyometric and ballistic exercises, leading to a reintroduction of running demands. Once sport-specific strength, endurance, and power-based functions have been restored, and an adequate baseline of running-related fitness has been established, then a return to training can be facilitated. For a return to competition, the experts agreed that the athlete must have returned to a suitable level of performance at training and with no adverse events. Once this has transpired, the attention shifts to monitoring and managing the risk factors for injury recurrence.
References
Armfield, D. R., Kim, D. H.-M., Towers, J. D., Bradley, J. P., & Robertson, D. D. (2006). Sports-Related Muscle Injury in the Lower Extremity. Clinics in Sports Medicine, 25(4), 803–842. https://doi.org/10.1016/j.csm.2006.06.011
Bahr, R., & Krosshaug, T. (2005). [Rev. of Understanding injury mechanisms: a key component of preventing injuries in sport]. British Journal of Sports Medicine, 39(6), 324–329. https://doi.org/10.1136/bjsm.2005.018341
Bryan Dixon, J. (2009). Gastrocnemius vs. soleus strain: how to differentiate and deal with calf muscle injuries. Current Reviews in Musculoskeletal Medicine, 2(2), 74–77. https://doi.org/10.1007/s12178-009-9045-8
Green, B., McClelland, J. A., Semciw, A. I., Schache, A. G., McCall, A., & Pizzari, T. (2022). The Assessment, Management and Prevention of Calf Muscle Strain Injuries: A Qualitative Study of the Practices and Perspectives of 20 Expert Sports Clinicians. Sports Medicine – Open, 8(1), Article 10. https://doi.org/10.1186/s40798-021-00364-0
Haskell, A., & Coughlin, M. J. (2024). Coughlin and Mann’s surgery of the foot and ankle (Tenth edition). Elsevier.
Kilic, K. K., Yuncu, M., Dogruoz, F., Buyukarslan, V., Ertan, M. B., & Kose, O. (2024). Correlation between MRI findings and functional outcomes in patients with calf muscle strain injuries: a retrospective study on 78 patients. BMC Musculoskeletal Disorders, 25(1), Article 1001. https://doi.org/10.1186/s12891-024-08119-0
Maffulli, N., Del Buono, A., Oliva, F., Giai Via, A., Frizziero, A., Barazzuol, M., Brancaccio, P., Freschi, M., Galletti, S., Lisitano, G., Melegati, G., Nanni, G., Pasta, G., Ramponi, C., Rizzo, D., Testa, V., & Valent, A. (2015). Muscle Injuries: A Brief Guide to Classification and Management. Translational Medicine @ UniSa, 12, 14–18.