Dance Anatomy & Kinesiology

The Ankle and Foot 313

as two separate bellies (medial and lateral) until about halfway down the back of the calf, where the

heads join onto an aponeurosis that becomes the tendocalcaneus or Achilles tendon. This tendon

continues down the lower leg to attach to the heel (calcaneus) and is the largest and strongest tendon

in the body (Whiting and Zernicke, 1998). The gastrocnemius contains a preponderance of fast-twitch

fibers (Smith, Weiss, and Lehmkuhl, 1996) and is a very powerful plantar flexor of the ankle, making it

vital for the execution of forceful movements such as jumping.

Because the gastrocnemius crosses the knee, it can also assist with knee flexion. And, because it

crosses the knee, position of the knee will also influence the ability of the gastrocnemius to be stretched

or produce force. Creating a position of passive insufficiency by extending the knee and dorsiflexing

the ankle-foot will favor effective stretching, while creating a position of active insufficiency by flexing

the knee and plantar flexing the ankle-foot will reduce the ability of the gastrocnemius to produce force

and require that the soleus play a greater role in producing necessary plantar flexion. One can capital-

ize on this differential use of these muscles by performing calf (plantar flexor) strengthening exercises

with the knees bent and straight.

Palpation: The gastrocnemius can be seen contracting and can be easily palpated at the upper calf

when you rise onto your toes (relevé; e.g., plantar flexion).

Soleus

The soleus (soleus, fish or sole) derives its name from its flat appearance, resembling the sole (a

flat fish). This muscle lies deep to the gastrocnemius as seen in figure 6.16. It can be seen below

the prominent double-bellied gastrocnemius and more medially in the lower posterior leg. Unlike the

gastrocnemius, it does not cross the knee joint. Rather it originates from the posterior tibia and fibula

and runs down the back of the lower leg to insert together with the gastrocnemius into the posterior

calcaneus via the Achilles tendon. The soleus muscle is an important plantar flexor of the ankle and

plays an important postural role to steady the leg upon the foot in standing. The soleus contains a

high percentage of slow-twitch fibers, allowing it to perform sustained tonic activity (Smith, Weiss,

and Lehmkuhl, 1996); and electromyographic data support the idea that it is the soleus that is active

FIGURE 6.15 The gastrocnemius (right foot, posterior
view).

FIGURE 6.16 The soleus (right foot, posterior view).

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