KinX Learning

Kinesthesis is the ability to perceive your position and movement of the body and/or limbs in space. Kinesthesis relies on the use of various receptors in the joints, muscles and tendons. For example, the muscle spindle that lies in parallel with the muscle fibers is activated when the muscle is stretched during an eccentric contraction (This is known as the stretch reflex). The Golgi tendon organs are other receptors located at the junction of the tendon and the muscle. They respond to the amount of stretch taking place in the tendon and the muscle. It is important to understand that when a muscle stretches, the tendon also undergoes stretching. It is very elastic tissue and can withstand great tension. When activated, the Golgi tendon organs trigger the antagonistic muscle groups to stop the movement and to inhibit the agonist muscle contraction. This is done to avoid possible injury to the muscle-tendon complex. Because of their actions, it is much easier to fully stretch a muscle when the Golgi tendon organs are shut down. There are also receptors located in the joint capsules and in the ligaments that relay information to the brain. This includes a change in position, speed of movement, or the acceleration of the limbs that occur at the joints. These receptors are very sensitive and fire when there is a small change (up to two degrees) in joint position. There are also many pressure receptors that are very active in posture. When there is any deviation in position, they are fired so that a correction can be made to bring you back into the normal position.

The major abdominal muscles involved in expiration are the internal obliques and external obliques and the transverse abdominis. The rectus abdominis becomes involved when there is maximum expiration and you flex the spine to squeeze out more air. When at rest, the abdominals are not involved. Expiration occurs naturally due mainly to the elastic recoil of the thoracic cage. In forced expiration however, many changes take place. The internal and external obliques and the transverse abdominis participate vigorously. They are also involved in coughing, singing, birthing, straining (as in weightlifting) and defecation. Because of the difficulty in isolating the transverse abdominis with EMGs, their function is based on their anatomy and structure. They are ideally suited for expiration and holding in the abdominal viscera. You may read about trainers saying you should contract the transverse abdominis in a particular exercise, but it appears to be impossible to isolate this one muscle from the other abdominal muscles. The external and internal obliques are ideally suited for expiration because of their cross movements. They are very effective in compressing the abdominal wall. When coupled with the transverse abdominis they are very powerful in expelling the air quickly. The rectus abdominis on the other hand, is not involved, unless the spine also undergoes flexion.

Elbow joint extension and the muscles involved are very important in execution of many sports skills. For example, they are needed in many overhead hitting actions such as the tennis serve and smash and basketball shooting. Elbow joint extension is a key action in pushing and throwing actions as used in the shot put, pressing up into a handstand in gymnastics, in hand-to-hand balancing, pushing an opponent in football, jabbing in boxing, various actions in mixed martial arts, in some baseball pitches and so on.  The triceps push-down is critical in the iron sports, for example, in the jerk in weightlifting and in the bench press in powerlifting. This exercise is also very important for bodybuilders for developing the back of the upper arms.