Soleus
The soleus is a muscle in the lower leg that runs from below the knee to the heel, primarily responsible for plantarflexion, where the foot is pointed downward.
It helps in walking, running, and stabilizing the leg, and also assists in circulating blood back to the heart.
Soleus
Anatomy
[Origin]
- Posterior aspect of head and superior quarter of posterior surface of fibula
- Soleal line and middle third of medial border of tibia
- Tendinous arch extending between the body attachments
[Insertion]
- Posterior surface of calcaneus via calcaneal tendon
[Action]
- Plantarflexes ankle independent of position of knee
- Steadies leg on foot
Clinical Relevance
To act as Muscle:
-
- In moderate force, the soleus is preferentially activated in the concentric phase, whereas the gastrocnemius is preferentially activated in the eccentric phase.
- It is a major postural muscle designed to stop the body from falling forwards at the ankle during stance.
- Human soleus muscle tissue consists predominantly of slow twitch fibers, though the composition can range between 60% and 100% slow fibers.
To act as Pump:
-
-
- The soleal pump assists with venous return from the periphery to the heart when upright as the venous circulatory system passes through the muscle tissue.
-
~ Evidence-Based Exercises ~
According to an EMG study, the exercises that demonstrated significant muscle contractions of Soleus are;
- Calf Raises with knee flexed 90 degrees
- Squat on unstable surface
- Pedaling with the front sole
Calf Raises
Squat
Pedaling
< Reference >
- Keith L. Moore, Anne M. R. Agur, Arthur F. Dalley. Moore Clinically Oriented Anatomy 7th Edition, Lippincott Williams & Wilkins, 2013
- Nardone A, Romanò C, Schieppati M. Selective recruitment of high-threshold human motor units during voluntary isotonic lengthening of active muscles. J Physiol. 1989;409(1):451–71.
- Ariano MA, Armstrong RB, Edgerton VR. Hindlimb muscle fiber populations of five mammals. J Histochem Cytochem. 1973;21(1):51–5.
- Burke RE, Levine DN, Salcman M, Tsairis P. Motor units in cat soleus muscle: physiological, histochemical and morphological characteristics. J Physiol. 1974;238(3):503–14.
- Gollnick PD, Sjödin B, Karlsson J, Jansson E, Saltin B. Human soleus muscle: a comparison of fiber composition and enzyme activities with other leg muscles. Pflugers Arch. 1974;348(3):247–55.
- Anderson K, Behm DG. Trunk Muscle Activity Increases With Unstable Squat Movements. Can J Appl Physiol. 2005;30(1):33-45. doi:1139/h05-103
- Ohira T, Okabe H, Kawano F, et al. Reconsideration of exercise prescription as the countermeasure for prevention of muscle atrophy in space. The FASEB Journal. 2010;24(S1). doi:1096/fasebj.24.1_supplement.616.10