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Calf (leg)

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The calf is the back portion of the human lower leg. In anatomy, this area is known as the posterior compartment of the leg. It is a vital part of how humans move and maintain balance. The muscles here allow us to push off the ground when we walk or run. Understanding the calf helps us understand how the entire lower limb functions.

The calf works through a complex system of muscles and tendons. The two largest muscles in this compartment are the gastrocnemius and the soleus. Together, these two muscles are called the triceps surae. These muscles converge at the bottom to form the Achilles tendon. This thick tendon is also known as the calcaneal tendon. It attaches directly to the posterior surface of the calcaneus, which is the heel bone. Other smaller muscles also exist in this area. They attach to the knee, the ankle, or use long tendons to reach the toes. The sural nerve provides the necessary innervation to these muscles.

There are distinct ways to target the different muscles within the calf. You can isolate these muscles by performing movements called plantarflexion. This is the action of pointing your toes downward. Exercises are usually divided into two main categories based on the position of the knee. The first category involves maintaining an extended or straight knee. Examples include standing calf raises, donkey calf raises, and stair calves. The second category involves maintaining a flexed or bent knee. An example of this is the seated calf raise.

These two categories affect the muscles differently. Movements performed with a straight knee target the gastrocnemius muscle more directly. Movements performed with a bent knee target the soleus muscle more. However, both types of movement will still target both muscles to a large degree. When training, it is important to work close to technical failure. This means performing repetitions until you are only 0 to 4 reps away from failing. The calf muscles recover very quickly from this work. They often require rest times of only 10 to 60 seconds.

The word "calf" has a long history in the English language. It comes from the Middle English words kalf or kalfi. These words may come from an Old Norse root. This root is likely the same one used for the word "calf," meaning a young cow. We see the term "calf" documented in Middle English around AD 1350. The specific phrase "calf of the leg" appeared around AD 1425. Historically, some authors viewed the absence of a prominent calf muscle as a sign of inferiority. They noted that monkeys lack prominent calves.

Doctors use the calf to help identify various health risks and conditions. For example, swelling in the calf can be caused by deep vein thrombosis or varicose veins. It can also be caused by compartment syndrome or an Achilles tendon rupture. Some people experience idiopathic leg cramps, which often happen at night. Edema, or swelling, is also common. A study of factory workers showed that compression garments helped reduce edema and pain. Additionally, a study of runners found that knee-high compression stockings improved performance.

Measuring the circumference of the calf can provide important medical data. In Spain, researchers conducted a study of 22,000 people aged 65 or older. They found that a smaller calf circumference was linked to a higher risk of undernutrition. In France, another study looked at 6,265 people aged 65 or older. This study found an inverse correlation between calf circumference and carotid plaques. This means that as calf size changed, the presence of plaques changed as well. Today, medical professionals can even use surgery or prosthesis devices for calf augmentation and restoration.

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