Tendons and ligaments are key structures in your body. Tendons connect muscles to bones, while ligaments attach bones to other bones and your joints. These tissues are what enables you to stand up, move at the joints and perform pretty much any physical action with your body.

Knee pain is common -- especially in athletes who run and jump a lot. Exercises can relieve pain and weakness that often accompany this condition.

Calcific tendonitis happens when calcium deposits in the shoulder cause one of the tendons to become inflamed, which limits range of motion and may be painful. You may experience calcific tendonitis in both or just one of your shoulders.

A snapped or ruptured Achilles tendon affects the back of your ankle. It most commonly occurs as a sports injury. If you suffer damage to your Achilles tendon, you may feel a sudden “pop” in your ankle. You will then be unable to walk properly. The rupture can be full or partial and usually requires surgery.

Torn tendons in your big toe can be the result of turf toe -- the result of excessively bending your big toe upward. Torn big toe tendons also can be the result of stubbing your big toe, spraining your toe or occur in conjunction with a big toe fracture.

Ligaments and tendons are part of the musculoskeletal system, with ligaments attaching bones to bones and tendons muscles to bones.They each serve very important functions to the joints and bones. Ligaments and tendons are made of dense layered collagen fibers, called fibrous connective tissue.

You have numerous foot tendons, but the one that most commonly causes pain is the Achilles tendon. Your Achilles tendon attaches your calf muscle to your heel bone. If the back of your heel hurts when you squat, Achilles tendonitis is the likely culprit.

Cycling is an aerobic activity that has many benefits, including aiding in weight loss, helping to lower blood pressure and reducing the risk of heart disease, diabetes and certain types of cancers. Unlike running, which is a weight-bearing activity, cycling is low-impact and gentle on the joints, especially the knees.

Tendonitis in the hand, wrist and forearm occurs when tendons passing though these areas become inflamed. In severe cases of tendonitis the result can be painful and debilitating.

Your Achilles tendon is the tendon that connects your calf muscle to your heel bone. Its function is to raise your heel off the ground to assist with walking, running or jumping.

Several diseases can affect the tendons.

Thumb tendinitis can make daily tasks that are normally taken for granted difficult. You may have pain while writing, typing or texting on your phone. Thumb tendinitis is typically caused by overuse of the muscles that move your thumb.