In the context of staged physical exercise or body movement during daily activities, one can categorize these movements into either simple or complex motions. One fact that holds constant in all body movements is that the brain coordinates contraction and relaxation of every muscle during motion. This means that our muscles cannot more without instructions from the brain. In practice, uncontrolled contraction and relaxation of muscles results during spasm attacks, especially in patients with tetanus infections. Such uncontrolled movements results in tearing of cartilages and ligaments from bones. In extreme ends, spasms can cause bone fractures in arms and legs. Therefore, the central nervous system plays a significant role in coordinating all body movements (Melik and Witts 34). Simple motions like walking are normally controlled by primitive parts of the brain which have not evolved to perform any human adaptive function. However, certain body movements categorized as complex motions require careful thinking. One such complex motion is that of the shoulder joint in athletics or in daily living.
With respect to sporting activities like javelin or discus throws, one has to exercise shoulder movements thoroughly. Regular and objective exercise of the shoulder joint in such sports will enhance intrinsic movements during athletic performances. Consequently, an athlete will be able to act stronger, faster and with substantial agility. In addition, focusing training on certain muscles in complex motions of the shoulder will lessen fatigue during performance. During a javelin throw, an athlete will have to coordinate a series of rotational movements that will result in the most efficient transfer of kinematic energy from the other body parts to the hand (Ludewig 21). Once in the hand, the athlete will have to employ appropriate sequencing of muscles in order to cause optimal power for every throw, and also in order to avoid incidences of shoulder injury. The muscles responsible for coordinating javelin throwing are deltoid anterior, posterior and deltoid lateral fibers. The three muscles work in a sophisticated and complex sequence in order to deliver power into the projectile being thrown.
At the beginning of every throw, the sequence starts by contraction of posterior deltoid fibers with a subsequent relaxation of lateral and anterior fibers. Once the posterior has reached maximum contraction, the lateral deltoid fibers induce a forward motion that transfers kinematic power from the posterior to the anterior muscles. Consequently, the projectile held by the hand will be released once an optimal contraction of the anterior fibers is achieved (Melik and Witts 32). At this juncture, it is worth acknowledging the fact that all contractions are concentric because lateral, posterior and anterior fiber disks share the same axis of origin. In order to improve performance of the three muscles mentioned above, one should consider doing one of the following exercises;
- Shoulder stretches
- Shoulder strengthening
- Side deltoid raise
- Overhead press
- Side lying deltoid raise
Works Cited
Ludewig, Peter. “Motion of the shoulder complex during multiplanar humerial elevation”. Journal of Bone and Joint Surgery 2009: 21-24. Print.
Melik, Michael and Witts, Kelvin. The athlete’s shoulder. Harrisburg: Elsevier Health Sciences Publishers, 2010. Print.
