Natural forces affect the movements of swimmers in water. And it is often usefulto know how these forces act. This knowledge will help swimming teachers andcoaches analyze swimming skills and assist them to understand how these forcesinfluence movement, so that they can encourage beginners to be better swimmersor good swimmers to achieve there optimum potential. Biomechanics is the branchof science that is concerned with understanding the relationship between aliving body’s structure and function relative to movement. In this paper theswimming form of the front crawl stroke will be analyzed, which may result inimprovement in the following areas: Improving performance Preventinginjury Correcting weaknesses Identifying ways to alter human movementpatterns “Biomechanics is considered to be the physics of how the bodymoves.
When these physical principles are applied to sports skills it becomes anintegrated study between the internal forces produced by the body and thenaturally occurring external forces that act on the body as skills are executed(Carr, 1997, p4. )”. Although the final quality of movement will totallydepend upon the athlete’s (swimmer’s) ability to integrate both internal forcesgenerated by muscular actions with the external forces of gravity, buoyancy,fiction and mass that are present during swimming. When looking at swimming onemust first look at how the human body acts and generates forces in water.
“Water is a unique environment. It possesses qualities that will assist theswimmer, but it also has qualities that will impede the swimmer’s progressthrough the water. For instance, the water’s density provides a buoyant forcefor the swimmer, while at the same time providing resistance to the swimmerspropulsion (?????, 1995, p42)”. Topics to continue with: Main principlesand their application Density Water Resistance Skin/Frictional ResistanceFrontal/Wave Resistance Eddy/Turbulence Resistance Propulsion Water FrictionPropulsive Drag Lift Force Streamlining The main principles and theirapplication of the front crawl stoke Buoyancy & Flotation An object that isimmersed either totally or partially in water experiences an upward force as thewater’s density endeavors to stop it from sinking (Maglischo, 1982).
This upwardforce is known as the buoyant force and acts through the center of the displacedwater. This force therefore, tends to counteract the effect of gravity and theweight of the object, the net result being that the weight of the object isreduced by the upward force of buoyancy (Costill, 1992). (#Diagram#) Everyobject has an absolute center position where all forces exerted by the bodyequal zero. This central point of an object’s mass is known as the center ofgravity and is the point around which it balances. “The center of gravityis approximately 50-52% of an individuals height, as there is an equal spread ofmass above and below this point (Allen, 1999)”. The same can be said forthe center of buoyancy, as above and below this point there is an equal spreadof volume of the displaced water (Allen, 1999).
The location of the center ofbuoyancy which is the center of the water displaced by the body, is actuallycloser to the head than in the location of the center of gravity. The reasonsfor this are: The volume of water displaced has a greater mass then the chestarea. The chest has a lower density than the water because of its lungcapacity. Therefore the upward force of buoyancy acts thought a point higher upthe body than the center of gravity (Costill, 1992). (#Diagram#) (I may need toinclude more?) (And relate it back to the front crawl?) Density The termspecific gravity is used to describe the ratio between an object’s density tothat of water’s density.
“Pure water density being the “referencepoint” having a specific gravity of 1. 00 (Carr, 1997, p67)”. Thereforeanything placed in water will float or sink in accordance to it’s own specificgravity value. Anything greater than 1. 00, will sink. While anything less than1.
00 will float. In the human body there is variation from person to person,this is due to the amount of air in ones lungs and the percentage of bone,muscle and fat, which all vary in their own individual masses. Both bone andmuscle are heavier than fat. From this information one can assume that a leanand muscular body or one with a heavy bone structure, will not float as well asone that is the opposite. (Chart #1.) Relationship between Specific Gravity& Body Composition Studies have shown that: “in general, the specificgravity of women will .