Calf Strain

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Description[edit | edit source]

The lower leg is a vital biomechanical element during locomotion, especially during movements that need explosive power and endurance.[1][2][3] The calf complex is an essential component during locomotive activities and weight-bearing and injuries to this area impacts various sporting disciplines and athletic populations.[1] Calf muscle strain injuries (CMSI) occur commonly in sports involving high-speed running or increased volumes of running load, acceleration and deceleration as well as during fatiguing conditions of play or performance.[1][4]

Calf strain is a common muscle injury and if not managed appropriately there is the risk of re-injury and prolonged recovery. Muscle strains commonly occur in the medial head of the gastrocnemius or close to the musculotendinous junction. The gastrocnemius muscle is more susceptible to injury as it is a biarthrodial muscle extending over the knee and ankle. Sudden bursts of acceleration can precipitate injury as well as a sudden eccentric overstretch of the muscle involved.[5]

Clinically Relevant Anatomy[edit | edit source]

Muscles of the calf complex[6]

The calf muscle, on the posterior aspect of the lower leg, is composed of three muscles: gastrocnemius, soleus and plantaris, which together constitute the triceps surae. These muscles come together as the achilles tendon and all three muscles insert into the calcaneus. Gastrocnemius, in conjunction with soleus, provides primarily plantar flexion of the ankle joint and flexion at the knee joint. [7][8] This muscle provides the propelling force for locomotion. Although it spans over two joints, gastrocnemius is not able to exert its maximum power on both joints simultaneously. If the knee is flexed, gastrocnemius cannot produce maximum power at the ankle joint and vice versa.[7]

Soleus is located beneath the gastrocnemius muscle in the superficial posterior compartment of the lower leg. Its main function is plantar flexion of the ankle and stabilising the tibia on the calcaneus limiting forward sway. [8]

Plantaris is located in the posterosuperficial compartment of the calf. Functionally, plantaris is not a major contributor and acts with gastrocnemius as both a flexor of the knee and a plantarflexor of the ankle. [9]

Epidemiology/Etiology[edit | edit source]

Muscle strains most commonly occur in bi-articular muscles such as the hamstrings, rectus femoris and gastrocnemius. During sporting activities such as sprinting, these long, bi-articular muscles have to cope with high internal forces and rapid changes in muscle length and mode of contraction. However, muscle strains have also been reported to occur during slow-lengthening muscle actions such as those performed by ballet dancers, but also during common daily activities. [10] Gastrocnemius is considered at high risk for strains because it crosses two joints (the knee and ankle) and has a high density of type two fast twitch muscle fibres. [8] A tear of the medial head of the gastrocnemius muscle is due to an eccentric force being applied to the muscle when the knee is extended and the ankle is dorsiflexed. The gastrocnemius muscle attempts to contract in the already lengthened state leading to tear of the muscle. [11] The soleus muscle, on the other hand, is injured while the knee is in flexion. Strains of the proximal medial musculotendinous junction are the most common type of soleus muscle injuries. Unlike gastrocnemius, soleus is considered low risk for injury. It crosses only the ankle and is largely comprised of type one slow twitch muscle fibres. Soleus strains also tend to be less dramatic in clinical presentation and more subacute when compared to injuries of gastrocnemius. [8] This condition frequently occurs in the middle-aged, poorly conditioned and/or physically active patient. [12]

Various sporting codes such as rugby, football, tennis, athletics and dancing are impacted by calf muscle strain injuries. In football, 92 % of injuries are muscular injuries, 13% of these are calf injuries.[13] In Australian rules football CMSI represented one of the highest soft tissue injury incidences (3.00 per club per year) and there was a 16% recurrence rate.[1]

Symptoms[edit | edit source]

Gastrocnemius strain[edit | edit source]

Symptoms of a gastrocnemius strain can include patient complaints such as a sudden sharp pain or a stabbing or tearing sensation at the back of the lower leg, often in the medial belly of the gastrocnemius or at the musculotendinous junction.[5] The calf muscle will often be tender to touch at the point of injury and swelling and bruising may appear within hours or days. Stretching of the muscle will reproduce pain and resisted plantarflexion will also elicit pain at the site of the muscle strain.[5]

Depending on the extent of the injury, the individual may be able to continue exercising although they will have some discomfort and/or tightness during or after activity. Where injuries are more severe, the exact mechanism of injury is easier to recall and/or the individual may be unable to walk due to severe pain.

A calf muscle tear is graded from I to III, with grade III being the most severe. Treatment and rehabilitation depends on the severity of the muscle strain.

Grading of calf strains[5][edit | edit source]

Grade Symptoms Signs Average time to return to sport
I Sharp pain at the time of activity or after

May have a feeling of tightness

May be able to continue activity, without pain or with

mild discomfort

Post activity tightness and/or aching

Pain on unilateral calf raise or hop 10 - 12 days
II Sharp pain at the time of activity in calf

Unable to continue activity

Significant pain with walking afterwards

May have swelling in muscle

Mild to moderate bruising may be present

Pain with active plantarflexion

Pain and weakness with resisted

plantarflexion

Loss of dorsiflexion

Bilateral calf raise pain

16 - 21 days
III Severe and immediate pain in the calf, often at

musculotendinous junction

Unable to continue with activity

May present with considerable bruising and swelling

within hours of injury

Inability to contract calf muscle

May have palpable defect

Thomson's test positive

6 months after surgery

Characteristics/Clinical Presentation[edit | edit source]

It is important to differentiate between muscle strains within the calf complex in order to formulate a correct prognosis, an appropriate treatment programme and prevention of recurrent injury. [14]

Gastrocnemius strains
Calf strains are most commonly found in the medial head of the gastrocnemius. [8] In an effort to contract, the forces of the eccentric movement on the already lengthened gastrocnemius muscle lead to injury at the myotendinous junction. The physical examination immediately following injury reveals a palpable defect in the medial belly of the gastrocnemius just above the musculotendinous junction. [15] A sudden pain is felt in the calf, and the patient often reports an audible or palpable "pop" in the medial aspect of the posterior calf, or they have a feeling as though someone has kicked them in the back of the leg. Substantial pain and swelling usually develop during the following 24 hours. [16] Strains in the gastrocnemius are also referred to as a “tennis leg” as the classic presentation was a middle aged tennis player who suddenly extended the knee [8]

Soleus strains
Soleus is considered low risk for injury in contrast to the gastrocnemius as it crosses only the ankle and is largely composed of type one slow twitch muscle fibres. [8] Soleus strains tend to be less dramatic in clinical presentation and more subacute when compared to injuries of the gastrocnemius. Injury of the soleus muscle may be under reported due to a misdiagnosis of thrombophlebitis or lumping of soleus strains with strains of the gastrocnemius. [8] A soleus strain causes pain when activating the calf muscle or when applying pressure on the achilles tendon approximately 4 cm above the insertion point on the heel bone or higher up in the calf muscle. Stretching the tendon and walking on tip-toe will also aggravate pain. [17]

Plantaris strains
Plantaris is considered largely vestigial and rarely involved in calf strains, although it crosses both the knee and the ankle joint as well. [8] Rupture of the plantaris muscle may occur at the myotendinous junction with or without an associated hematoma or partial tear of the medial head of the gastrocnemius muscle or soleus. [9] Injury to the plantaris muscle can present with similar clinical features as those of the gastrocnemius and soleus muscle. [18]

Differential Diagnosis[edit | edit source]

Strains are most common during sporting activity, but pain in the lower leg could indicate medial tibial stress syndrome, achilles tendinitis, plantar fasciitis, muscles strains and/or joint sprains which can be caused by lack of extensibility of the plantar-flexors and decrease in ankle dorsiflexion. [19]. Other lower leg injuries related to sports with the same symptoms and treatment as a calf strain are discussed below. 

Runners often complain about lower leg pain along the posteromedial border of the tibia. [20] This is medial tibial stress syndrome (MTSS) or commonly known as shin splints. [21] The pain is described as tenderness located a few centimetres proximal to the medial malleolus, spreading proximally about 4 to 10 centimetres. The cause of MTSS may be associated with repetitive stress or an overuse injury.  

Pain located anterior or anteromedial of the tibia could indicate a tibial stress fracture, a typical injury seen in runners and footballers [21] [20] It can occur following abrupt changes in intensity, duration and frequency of training, but other personal and environmental factors can also contribute to this injury. Radiographs are initially negative, but with time fracture lines become visible. Operative treatment may occasionally be necessary, but it can be treated the same way as a calf strain: rest, restriction from aggravating activity, strengthening of the lower extremity musculature, NSAIDs and appropriate footwear.[18]

Repetitive exercise without adequate rest for recovery can cause chronic exertional compartment syndrome (CECS). [21] CECS begins with mild pain during periods of training and can disappear after training. In the latter stages, pain presents earlier, becoming more painful and of a greater duration forcing a halt in activity. Common complaints are; cramps, paraesthesia, numbness and weakness in the lower leg. CECS is caused by the increased intramuscular blood flow during exercise so compartmental pressure arises, capillaries become compressed and ischemia develops. 

Leg pain around the same area as a gastrocnemius strain can be caused by Popliteal Artery Entrapment Syndrome (PAES), an abnormal course of the popliteal artery. Medial and cranial migration of the medial head of the gastrocnemius can catch the popliteal artery and swipe it medially. This is called anatomical PAES, an abnormal relationship between the popliteal artery and the surrounding myofascial structures. Functional PAES is caused by muscle contraction, often active plantarflexion of the ankle that compresses the artery between the muscle and underlying bone. [22] See

See also:

Achilles tendinopathy

Plantar fasciitis

Posterior knee pain

Diagnostic Procedures[edit | edit source]

A thorough clinical examination and history may be enough to conclude a diagnosis, but it is often difficult to reach an accurate diagnosis due to the clinical picture being shared with other pathological conditions. Diagnostic imaging is usually necessary and ultrasound (US) is considered to be the gold standard. It can also be used to evaluate the degree and extent of the muscular lesion and to exclude other pathologies such as ruptured Baker's cyst and deep vein thrombosis. [23]

Ruptures are usually associated with the presence of fluid collection between the soleus muscle and the medial head of the gastrocnemius. This can occur with or without hemorrhage. The measurement of fluid collection informs about the extent of the lesion. The degree of the lesion (partial or complete rupture) can be defined by the distance between the two muscles. Axial US scans are the most useful for differentiating between partial and complete rupture, as it is possible to depict the whole muscle belly in one single image. [16]

A calf muscle tear is a most common in sports which require quick acceleration and changes in direction such as running, volleyball and tennis, Muscle strains are graded I to III. The more severe the strain, the longer the recovery time. Typical symptoms are stiffness, discoloration and bruising around the strained muscle. [17]


Grade I: A first degree or mild injury is the most common and the most minor. A sharp pain is felt at the time of injury or pain with activity. There is little to no loss of strength and range-of-motion with muscle fibre disruption of less than 10%. A return to sport would be expected within 1 to 3 weeks. [20]

Grade II: A second degree or moderate injury is a partial muscle tear halting activity. There is a clear loss of strength and range of motion. [20] with marked pain, swelling and often bruising. Muscle fibre disruption between 10 and 50%. 3 to 6 weeks is a usual recovery period for a return to full activity. [17]

Grade III: A third degree or severe injury results in a complete rupture of the muscle and is often concomitant with a hematoma. [20] Pain, swelling, tenderness and bruising are usually present. Recovery is highly individualised and can take months before you are fully recovered for a full return to activity. [17]

Outcome Measures[edit | edit source]

  • LEFS: Lower Extremity Functional Scale
  • VAS: Visual Analogue Scale
  • NPRS: Numeric Pain Rating Scale
  • Muscle Strength testing: grade 0 is the lowest grade where the patient isn’t capable of doing any contraction of the muscle. Grade 5 is the highest grade where the patient is able to move his leg against a maximum resistance given by the therapist.

Examination[edit | edit source]

The physical examination isolates the site and severity of the injury. A combination of palpation, strength testing and passive and active range of motion is necessary to help distinguish between strains of the soleus and gastrocnemius muscles.

Palpation of the calf should occur along the entire length of the muscles and the aponeuroses. This is required to identify swelling, thickening, tenderness, defects and masses if present. Strains of the gastrocnemius muscle usually present with tenderness in the medial belly or musculotendinous junction, while soleus strains often occur with lateral pain.

As the origin of gastrocnemius is situated above the knee (epicondylus lateralis and medialis femoris) and the origin of the soleus is below the knee (caput fibulae), activation of the muscles can be isolated by varying the degree of knee flexion. Soleus becomes the main source of force in plantar flexion, with the knee in greater flexion. With the knee in full extension, it is gastrocnemius which provides the most strength. This relationship allows for more accurate strength testing of the individual calf muscles and enables the examiner to describe which muscle has been injured.

Additional tests include the Thompson test for complete disruption of the achilles tendon. Simultaneous tears of the gastrocnemius and soleus are possible, which can complicate the clinical picture. [24] [25]

The patient is also observed in both standing and prone positions, looking closely for swelling, bruising and deformity, as well as possible postural issues such as over-pronation

Medical Management[edit | edit source]

Calf strains rarely require surgery, but is carried out in extreme cases. such as in a complete rupture. Recommended conservative management includes RICE, injection of local anesthetic and cortisone in and around the area [26] and graded and active recovery treatment. Where a hematoma is present, its removal as quickly as possible is essential, otherwise complications may occur such as myositis ossificans.

A compression bandage can be applied immediately to help stop swelling, but it should only be applied for 10 minutes at a time as restricting blood flow completely to the tissues could cause more damage, whereas a calf support can be applied for longer.

In the case of a more severe injury, a temporary heel pad to shorten the calf muscle to reduce tension in the muscle whilst it heals may be useful. It may be advisable to put heel pads in both shoes however, to avoid creating a gait imbalance.

Prevention:

Regular stretching ensures that good joint mobility is maintained. [16] Under extension, a greater force can also be delivered and the muscles are less tense, improving blood flow. [27] [9]

Physical Therapy Management[edit | edit source]

Treatment aims to:

  • Reduce pain
  • Restore flexibility
  • Restore strength

The principal treatment of a calf strain consists of rest and allowing adequate healing time, but in severe cases, surgery is necessary. Conservative treatment includes gentle passive stretching, isometric then moving onto concentric exercises.[L4] [26] In the latter stages, massage and electrotherapy can be used. [L4] [9] 

Initial treatment aims to limit bleeding, pain and to prevent complications. [L4][8]Cryotherapy can be used to decrease inflammation, pain and cell metabolism. Tape or a compressive wrap can be applied and the leg elevated where possible.[L4] [26] If major bleeding has occurred, the use of NSAIDs has to be carefully controlled as they have an antiplatelet effect which can increase bleeding, just as the premature application of heat and massage also can. [L4] [8]

Gentle passive stretching exercises without pain to maintain range of motion in the plantar flexors, which can become limited by shortening and contractures. [L1b] [27] In the latter stages, once inflammation has resolved, applying superficial heat simultaneously with a low load static stretch improves the flexibility of muscles.[L4] [26] 

Isotonic exercises for the antagonists tibialis anterior, and the peronei are recommended as well as light exercises for the injured muscle. Gentle movements, within pain limitations, in the first few days following injury will help to promote healing,[L4] [26] Lack of extensibility of the plantar flexors will affect ankle dorsiflexion and cause disturbances in gait. Shoes with a low heel are recommended to encourage improved heel-toe gait. [L1b] [27] 

After 48 hours, ice is no longer an effective analgesic. short wave diathermy can be used as an alternative. A strain with abnormal swelling and bruising can be treated with interferential therapy. The aim is to relieve pain and to stimulate the muscle fibres. [L4][26] 

When the calf muscles can be fully extended painfree, a switch made can be from gentle passive stretching to active stretches, in both a flexed knee position (soleus) and a straightened knee position (gastrocnemius). [L4] [26]

Depending on the grade of strain and an individual's healing time, isometric, isotonic and dynamic exercises are introduced to re-gain tensile strength in the muscle. [L4] [8] Alternative treatments consist of vibration therapy (VT). Vibration therapy is applied specifically to the area of injury and treats muscle strains and other myo-tendinous injuries which involve trigger points. [L4] [9]  Broadbent et al. suggested that VT stimulates the sensory receptors, but it also causes a decrease in inflammatory cells and receptors like IL6 and histamine. [L1b] [28] The aim of this therapy is an increase in muscle strength, flexibility and extensibility. After a VT treatment, however, jumping and running are not permitted for at least 3 to 6 weeks and NSAIDS are discouraged, but other treatment routines can be continued. An advantage compared with other therapies like sound wave therapy and ESWT treatments, is that VT can be applied more frequently. [L1a] [29]

Strains may cause long lasting pain, despite an adequate early treatment. Treatment outcome is successfully when: pain is resolved, the calf muscle can be fully extended, strength is back to normal, knee and ankle ROM are normal and when excessive tenderness has disappeared. [L4] [26] 


Key Research[edit | edit source]

Millar, A. P., “Strains of the posterior calf musculature ("tennis leg")*.”The American Journal of Sports Medicine, vol. 7, no. 3, 1979, pp. 172-174.

Ellen, Mark I., Jeffrey L. Young, and James L. Sarni. "3. Knee and lower extremity injuries." Archives of physical medicine and rehabilitation 80.5 (1999): S59-S67.

Bryan Dixon J. Gastrocnemius vs. soleus strain: how to differentiate and deal with calf muscle injuries. Current Reviews in Musculoskeletal Medicine. 2009;2(2):74-77.

Clinical Bottom Line[edit | edit source]

Pain in the calf muscle is often due to a strain, however, there are other conditions which could cause similar symptoms, including deep vein thrombosis and contusions. Healing time is hugely variable depending on the severity of the strain and individual response to treatment. Conservative management of a graded exercise programme usually has the desired outcome for grade 1 an 2 strains, but in the case of rupture, surgery is required. Massage and electrical stimulation may also be a useful adjunct to strength and conditioning exercises.

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 Green B, Pizzari T. Calf muscle strain injuries in sport: a systematic review of risk factors for injury. Br J Sports Med 2017;51: 1189-1194 https://bjsm.bmj.com/content/51/16/1189 (accessed 24 July 2018)
  2. Abe T , Kumagai K , Brechue WF . Fascicle length of leg muscles is greater in sprinters than distance runners. Med Sci Sports Exerc 2000;32:1125–9 https://www.researchgate.net/profile/William_Brechue/publication/12455339_Fascicle_length_of_leg_muscles_is_greater_in_sprinters_than_distance_runners/links/5ae995f40f7e9b837d3bb254/Fascicle-length-of-leg-muscles-is-greater-in-sprinters-than-distance-runners.pdf (accessed 24 July 2018)
  3. Abe T , Fukashiro S , Harada Y , et al . Relationship between sprint performance and muscle fascicle length in female sprinters. J Physiol Anthropol Appl Human Sci 2001;20:141–7. https://www.jstage.jst.go.jp/article/jpa/20/2/20_2_141/_pdf (accessed 24 July 2018)
  4. Bengtsson H , Ekstrand J , Hägglund M . Muscle injury rates in professional football increase with fixture congestion: an 11-year follow-up of the UEFA champions league injury study. Br J Sports Med 2013;47:743–7.https://bjsm.bmj.com/content/47/12/743 (accessed 24 July 2018)
  5. 5.0 5.1 5.2 5.3 Brukner P, Khan K. Clinical sports medicine.3rd ed. Sydney: McGraw Hill, 2006.
  6. Wikimedia Commons contributors, "File:1123 Muscles of the Leg that Move the Foot and Toes b.png," Wikimedia Commons, the free media repository, https://commons.wikimedia.org/w/index.php?title=File:1123_Muscles_of_the_Leg_that_Move_the_Foot_and_Toes_b.png&oldid=276846515 (accessed July 25, 2018).
  7. 7.0 7.1 Palastanga N, Field D, Soames R. Anatomy and human movement: structure and function. 5th Ed.Edinurgh: Elsevier,2006.
  8. 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 8.10 8.11 Bryan Dixon J. Gastrocnemius vs. soleus strain: how to differentiate and deal with calf muscle injuries. Current Reviews in Musculoskeletal Medicine. 2009;2(2):74-77
  9. 9.0 9.1 9.2 9.3 9.4 Spina AA. The plantaris muscle: anatomy, injury, imaging, and treatment. The Journal of the Canadian Chiropractic Association. 2007;51(3):158-165.
  10. Marc Roig Pull and Craig Ranson, Eccentric muscle actions: Implications for injury prevention and rehabilitation, Physical Therapy in Sport 8 (2007), no. 2, 88 – 97.
  11. Watura C, Harries W. Isolated tear of the tendon to the medial head of gastrocnemius presenting as a painless lump in the calf. BMJ Case Reports. 2009
  12. Flecca D, Tomei A, Ravazzolo N, Martinelli M, Giovagnorio F. US evaluation and diagnosis of rupture of the medial head of the gastrocnemius (tennis leg). Journal of Ultrasound. 2007;10(4):194-198.
  13. Bengtsson H , Ekstrand J , Hägglund M . Muscle injury rates in professional football increase with fixture congestion: an 11-year follow-up of the UEFA champions league injury study. Br J Sports Med 2013;47:743–7
  14. Bryan Dixon J. Gastrocnemius vs. soleus strain: how to differentiate and deal with calf muscle injuries. Current Reviews in Musculoskeletal Medicine. 2009;2(2):74-77. doi:10.1007/s12178-009-9045-8. [L1b]
  15. Nsitem V. Diagnosis and rehabilitation of gastrocnemius muscle tear: a case report. The Journal of the Canadian Chiropractic Association. 2013;57(4):327-333.`
  16. 16.0 16.1 16.2 Kwak H-S, Han Y-M, Lee S-Y, Kim K-N, Chung GH. Diagnosis and Follow-up US Evaluation of Ruptures of the Medial Head of the Gastrocnemius (“Tennis Leg”). Korean Journal of Radiology. 2006;7(3):193-198.
  17. 17.0 17.1 17.2 17.3 Ellen, Mark I., Jeffrey L. Young, and James L. Sarni. "3. Knee and lower extremity injuries." Archives of physical medicine and rehabilitation 80.5 (1999): S59-S67.
  18. 18.0 18.1 Meininger, Alexander K., and Jason L. Koh. "Evaluation of the injured runner." Clinics in sports medicine 31.2 (2012): 203-215.
  19. Knight CA., et al. (juni 2001). “Effect of Superficial Heat, Deep Heat, and Active Exercise Warm-up on the Extensibility of the Plantar Flexors.” Physical Therapy, Vol 81 (6), pp. 1206-1214.
  20. 20.0 20.1 20.2 20.3 20.4 Nsitem V. Diagnosis and rehabilitation of gastrocnemius muscle tear: a case report. The Journal of the Canadian Chiropractic Association. 2013;57(4):327-333.`
  21. 21.0 21.1 21.2 Ellen, Mark I., Jeffrey L. Young, and James L. Sarni. "3. Knee and lower extremity injuries." Archives of physical medicine and rehabilitation 80.5 (1999): S59-S67.
  22. Stager, Andrew, and Douglas Clement. "Popliteal artery entrapment syndrome." Sports Medicine 28.1 (1999): 61-70.
  23. Flecca D, Tomei A, Ravazzolo N, Martinelli M, Giovagnorio F. US evaluation and diagnosis of rupture of the medial head of the gastrocnemius (tennis leg). Journal of Ultrasound. 2007;10(4):194-198
  24. Marc Roig Pull and Craig Ranson, Eccentric muscle actions: Implications for injury prevention and rehabilitation, Physical Therapy in Sport 8 (2007), no. 2, 88 – 97.
  25. Bryan Dixon J. Gastrocnemius vs. soleus strain: how to differentiate and deal with calf muscle injuries. Current Reviews in Musculoskeletal Medicine. 2009;2(2):74-77.
  26. 26.0 26.1 26.2 26.3 26.4 26.5 26.6 26.7 Pedret C, Rodas G, Balius R, et al. Return to Play After Soleus Muscle Injuries. Orthopaedic Journal of Sports Medicine. 2015;3(7)
  27. 27.0 27.1 27.2 Bartholdy, Cecilie, et al. "Local and Systemic Changes in Pain Sensitivity After 4 Weeks of Calf Muscle Stretching in a Nonpainful Population: A Randomized Trial." Pain Practice (2015).
  28. Broadbent, Suzanne, et al. "Vibration therapy reduces plasma IL6 and muscle soreness after downhill running." British journal of sports medicine 44.12 (2010): 888-894.
  29. Saxena, Amol, Marie St Louis, and Magali Fournier. "Vibration and pressure wave therapy for calf strains: a proposed treatment." Muscles, ligaments and tendons journal 3.2 (2013): 60.