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Analisa Gerak di AirW. Prasasti Mutiadesi, M.D

Aquatic LocomotionThe problem of moving the body trough water is not so different from that moving on land.As in walking, it is necessary to push againts something to move the body from one place to another.

2Differences Between Locomotion In Water & On Land :The body is concerned with buoyancy rather than with the force of gravityThe medium through which it moves affords more resistance to the bodyCustomary to maintain a horizontal position

buoyancy : daya apung

Tubuh berkaitan dengan daya apung bukan dengan gaya gravitasiMedium yang bergerak melalui tubuh lebih memberi tahanan ke tubuhKebiasaan untuk mempertahankan posisi horizontal3

SwimmingIn swimming, as in all motion, the initial mechanical problem is to overcome the inertia of the body. Once the body is in motion, the problem is to overcome the forces that tend to hinder it.Water as supporting medium & source of resistance.The hands and feet depend on the reaction force of the water in order that the force may be transmitted to the body.At the same time, the body must overcome the resistance afforded by the water.Setelah tubuh bergerak, masalahnya adalah untuk mengatasi kekuatan yang cenderung menghambat itu.4The speed obtained in swimming any stroke depends on the stroke length and stroke frequency.Swimming stroke is repeating a specific body motion to propel that body forward.The length of the stroke : the result of the forces that move the swimmer forward in reaction to the movements of the arms and legs, and of the resistance of the water in the opposite direction.

Obtained : dperolehrepeating a specific body motion orswimming stroketo propel that body forward.5Lift & DragThe actions of the arms and legs appear to result in a combination of lift and drag forces that then propel the body forward.

Propel : mendorong64 Types of Water ResistanceAct to decrease the stroke length.

Form drag or pressure drag : is the resistance that is due to the surface area of the front of the body as it meets the oncoming water has the greatest effect on retarding the swimmer. Stream lining the body by changing its position in the water decreases form drag.Surface drag : caused by the resistance of the water next to the body. Although it has little effect on forward progress. Swimmers have been known to shave the hair from their bodies as a means of decreasing skin friction.

Retarding : perlambatanOncoming : yang mendekat7Wave drag : occurs at the surface as the body moves along, partially lift in water and partially in air . The amount of this resistance is a form an additional resistance to forward progress depends on both the speed and movements of the body as it progresses through the water.Turbulence : forms behind the body, causing it to pull some water along with it.

Stroke FrequencyThe frequency of the stroke depends on the amount of time spent per stroke cycle.Related to the nature of the stroke pattern and the muscles torques of the arms and legs

Mechanical Principles Applied to SwimmingLess force is needed to keep an object moving than to overcome that to overcome its inertia.The body will move in the opposite direction from that in which the force is applied.Forward motion in swimming is produced through a combination of drag force and lift force.Maximum force is attained by presenting as broad a surface as possible in the propulsive movement of the limbs and by exerting a backward pressure through as great a distance as possible, provided undesirable forces are not inadvertently introduced. Gaya maksimum dicapai dengan memberikan seluas mungkin permukaan saat gerakan mendorong dari anggota badan dan dengan mengerahkan tekanan mundur melalui jarak sebesar mungkin, asalkan gaya yang tidak diinginkan tidak ada.11Momentum may be transferred from one body or part to another body or part.The height of the body position in the water depends on the swimmers buoyancy and speed of moving through the water.When a body is free in a fluid, movement of part in one direction results in movement of the rest of the body in the opposite direction.

Dada, punggung lengan ke seluruh badan dan memberikan gaya ke kepala dan badan untuk maju Ketinggian posisi tubuh di dalam air tergantung pada daya apung dan kecepatan bergerak melalui air perenang.Ketika tubuh bebas dalam suatu cairan, gerakan suatu bagian ke satu arah menghasilkan arah gerakan seluruh tubuh ke arah yang berlawanan.12A rapidly moving body in the water leaves a low-pressure area immediately behind it.The more streamlined the body, the less the water resistance to progress through the water.The drag on a body in any fluid increases approximately with the square of the velocity. The sudden or quick movement of a swimmers body, or one of its parts, at the surface of the water tends to cause whirls. These create low-pressure areas that have a retarding effect on the swimmer.Gerakan tiba-tiba atau cepat tubuh perenang, atau salah satu bagiannya, di permukaan air cenderung menyebabkan berpusar dan pusaran. Ini membuat daerah tekanan rendah yang memiliki efffect perlambatan pada perenang.14Front CrawlYou will commonly hear the front crawl referred to as the freestyle stroke, the majority of the swimmers in a freestyle event use it because it provides the most speed. The front crawl calls for you to kick hard with your feet, while bringing your arms over your head and into the water one at a time. You must keep your body as straight as possible, as any lateral movements will slow you down. Your breathing also holds importance, as you must time the breaths that you take with your swimming strokes.

5 Types ofSwimming Styles

Anda harus menjaga tubuh Anda lurus sebisa mungkin, karena setiap gerakan lateral akan memperlambat Anda.Pernapasan Anda juga memegang penting, karena Anda harus mengatur waktu napas yang Anda ambil dengan stroke renang Anda15BackstrokeThe backstroke has many similarities to the front crawl, except that you float on your back, rather than propelling your front through the water first. You will begin this stroke by floating in the water with your lungs on the surface, but the rest of your body beneath the water. You must keep yourself horizontal as you move through the water, which you will achieve through your leg kicks. Your stroke will involve pulling the water beneath you, which will propel your body through the water.

Anda akan mulai langkah ini dengan mengambang di air dengan paru-paru Anda di permukaan, tetapi seluruh tubuh Anda di bawah air.Anda harus menjaga diri horisontal saat Anda bergerak melalui air, yang akan Anda capai melalui tendangan kaki Anda.Stroke akan melibatkan menarik air di bawah Anda, yang akan mendorong tubuh Anda melalui air.16ButterflyThe butterfly stroke calls for you to bring both arms over your head at the same time and push them into the water to propel yourself. The butterfly stroke uses a dolphin-style kick, which means that your legs will stay straight and together as you kick them through the water. When using the butterfly stroke, you must remember to stabilize yourself with your core and create a rhythm between the underwater and above-water portions of the stroke.

Bila menggunakan gaya kupu-kupu, Anda harus ingat untuk menstabilkan diri dengan bagian tengah Anda dan menciptakan irama stroke antara bagian bawah dan atas-air.17BreaststrokeThe breaststroke uses a frog-style kick, where you will bend your knees and then kick your legs out beneath the water. Your arm stroke will begin with a sweep out from your breast and then a sweep in back to your breast. Make sure that your body remains completely straight between your strokes, as this will allow your body to move through the water easily at this time

SidestrokeAlthough not used in competition, the sidestroke holds importance for swimmers because you can use it to rescue someone, since it only requires one arm. The stroke resembles picking apples, as you will float on your side, reach up like when picking an apple and then reach down like when putting the apple into a basket. You can glide in between strokes, which allows you to move easily through the water.

Analysis of the Sprint CrawlThe Head & TrunkThe Arm StrokeEntry & SupportCatch, pull, and pushRelease & recoveryThe KickNature of movementDownstrokeUpstroke

Analysis of the Sprint CrawlThe Head & TrunkThree important functions:1. Minimize resistance2. Enable the swimmer to breath3. Provide a stable anchorage for the arm and leg muscles to effect a maximum propulsive force

Anchorage : pelabuhan22The position of the body key to reducing resistance.The flatter the body, the less drag there will be to decrease the swimmers speed.Body is a horizontal as possibleFeet below the surfaceHead breaking the water at the hairline

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If head is held too high swimmers legs drop broader frontal surface more resistance.Static contraction of rectus abdominis holds spine in a slightly flexed position, or incomplete extension.Pelvis is in a position of slightly decreased inclination.

Broader : lebih luas24Lateral movements of the trunk will increase resistance to forward movements should be minimized.Circular movements of the arms, legs or head cause a counter movement of the rest of the body.Turning the head to breath must be accomplished with the least possible interferenceDo not lift the head to breathRotate it on longitudinal axis while tucking the chin

Least : sedikitTucking : menyelipkan

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After a quick inhalation, face is turned forward with the eyes in the horizontal plane and the nose and chin in the midsagital of body.Sprints are better swim with fewer breathing cycles because the turning of the head (even done properly) cause additional resistance.

Analysis of the Sprint CrawlArm Stroke: Entry and SupportEntry should place the arm in the most advantageous position for exerting force (because the arm stroke provides approx. 85% total power)Forearm high and elbow pointing to the sideHands passes in front of of shoulder, reaches forward, and driven forward and downward into the water directly in front of the shoulderElbow is slightly flexed, and extends during entryThe brief moment between entry and the beginning of the propulsive action is called the support phasePurpose is to keep the head and shoulders high in the waterPressure of forearm and hand is mostly downward and then backward, producing and upward and forward reactive force

Brief : singkat28Analysis of the Sprint CrawlArm Stroke: Catch, pull, & pushCatch: propulsive action changes form downward to backwardA quick inward movement to the hand and arm that serves to bring the hand to a position in front of the axis of the body Upper arm is vertical, and favors use of the large muscles; pectoralis major and latissimus dorsi for pulling downward and backward

Analysis of the Sprint CrawlArm Stroke: Catch, pull, & pushPull: elbow should be kept high during the first part of the pull By bending the elbow the arm is pulled under the bodyMaximum bend occurs halfway through the pull, when the hand begins to push water backwardElbow action assists in producing an S-curve, which creates propulsive lift

30Analysis of the Sprint CrawlArm Stroke: Catch, pull, & pushIn the pull phase the feel is as if the hand is being pushed backward through the water.The transition of pull to push occurs as the arm passes under the shoulder.Push : The upper arm remains nearly vertical as the forearm gradually extends until it is in front of the hip, at which time the upper arm extends and the hand gives a quick push backward.

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Analysis of the Sprint CrawlArm Stroke: Release & recoveryThe elbow is now near the surface with the hand slightly lower & posterior to it and the palm facing mostly upward.The pressure of the forearm and hand now being relaxed, the elbow and shoulder are raised until the hand is out of the water Analysis of the Sprint CrawlArm Stroke: Release & recoveryThe elbow leaves the water first and swings forward and upward with the hand trailing behind it, moving from a position near to the hip to a position in front of the shoulder, preparatory to new entry.

Analysis of the Sprint CrawlThe Kick : Nature of MovementMost often used is the flutter kickPrimary role is a stabilizer and neutralizertiming with arms is therefore criticalLegs are relatively close together as they alternate in an up and down movementFeet attain a maximum stride of 1 to 2 feetWhiplike or lashing action for both the up and downstroke

Flutter : bergetarWhip/lashing : mencambuk36Analysis of the Sprint CrawlThe Kick : DownstrokeBegins with downward drive of the thighThigh flexes only slightly, knee extends completely by the end of the strokeAnkle and foot remain in plantar flexionDorsiflexors contract statically to stabilize foot against pressure of the water

Analysis of the Sprint CrawlThe Kick : UpstrokeBegins with thigh extensionSlight knee flexion develops near the end ot he stroke Foot stops just below the surface

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Analysis of the Sprint CrawlAdditional Factors Timing and coordination of the arm and leg strokes and of the breathingRhythm of the stroke as a wholeRelaxation of the bodyFlexibility of the jointShoulders and ankles

Aquatic Locomotion Rowing, Canoeing, & Kayaking

RowingMuch of the propulsive force is generated by the legs.The rowing stroke, two distinct phase :The pull phaseThe recovery phase

RowingThe Pull PhaseForce applied to the water by the oar bladeThe pull is initiated through extension of the flexed lower extremities in a push like motion, followed by trunk extension and then upper extremity pull.

RowingThe Recovery PhaseThe oar blade is lifted clear of the water by downward pressure on the grip, or inboard, end of the oar.The oar is then feathered, or rotated so that blade slices through the air parallel to the airflow. The legs and trunk are flexed and the upper arms are horizontally adducted and elbows extended, pushing the oar into position for the next strokeRowingThe Recovery Phase

CanoeingThe paddle in canoeing is held in both hands, free of external support.In paddling, stroke is primarily performed by the arms, shoulders, and trunk.Paddler faces the direction of travel.Stroke is involve reaching out either in a forward or sideward direction and pulling the paddle blade through the water.

The beginning of the stroke produces a downward force and a lifting effect.The end of the stroke produces an upward force the depresses the canoe.Smooth canoeing emphasizes the backward movement of the blade.

KayakingA key difference between kayaks and other small craft is the use of a double-bladed paddle. (perpendicular to one another)Involve the wrist & arm motion in the propulsion phase of the stroke on one side will cause the blade on the opposite side to feather during recovery.

Feather : berputar51Because kayak is long and slender, it is less stable in the water than canoe, etc.To increase stability :Kayaker must sits low in the bottom of the boatLegs extended forwardKnees slightly flexedFeet braced on a rib of the board

The paddle stroke is produced primarily by the upper body in a continuous motion