1. CHAPTER 19: LOCOMOTION: THE AQUATIC ENVIRONMENT KINESIOLOGY Scientific Basis of Human Motion, 12 th edition Hamilton, Weimar & Luttgens Presentation Created by TK Koesterer, Ph.D., ATC Humboldt State University Revised by Hamilton & Weimar KINESIOLOGY Scientific Basis of Human Motion, 12 th edition Hamilton, Weimar & Luttgens Presentation Created by TK Koesterer, Ph.D., ATC Humboldt State University Revised by Hamilton & Weimar Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin

2. 19-2 ObjectivesObjectives 1.Name the factors that contribute to the propulsion of a swimmer. 2.Name the factors that impede the swimmer. 3.Explain how these propulsive and resistive factors affect the length or frequency of the swimming stroke. 4.Complete a kinesiological analysis of a swimming stroke, identifying the anatomical and mechanical factors that enhance or limit performance. 1.Name the factors that contribute to the propulsion of a swimmer. 2.Name the factors that impede the swimmer. 3.Explain how these propulsive and resistive factors affect the length or frequency of the swimming stroke. 4.Complete a kinesiological analysis of a swimming stroke, identifying the anatomical and mechanical factors that enhance or limit performance.

3. 19-3 AQUATIC LOCOMOTION: SWIMMING  Differences between locomotion in water and on land: 1.The body is concerned with buoyancy rather than with the force of gravity. 2.Air affords less resistance to push than does water. 3.The medium through which it moves affords more resistance to the body. 4.Customary to maintain a horizontal rather than vertical position.  Differences between locomotion in water and on land: 1.The body is concerned with buoyancy rather than with the force of gravity. 2.Air affords less resistance to push than does water. 3.The medium through which it moves affords more resistance to the body. 4.Customary to maintain a horizontal rather than vertical position.

4. 19-4 Swimming  Initial mechanical problem is to overcome inertia.  Once the body is in motion, must overcome the forces that tend to hinder it.  Water is both the supporting medium and the source of resistance.  Hands and feet depend on reaction force of water to transmit force to the body.  At the same time, the body must overcome the resistance of the water.  Initial mechanical problem is to overcome inertia.  Once the body is in motion, must overcome the forces that tend to hinder it.  Water is both the supporting medium and the source of resistance.  Hands and feet depend on reaction force of water to transmit force to the body.  At the same time, the body must overcome the resistance of the water.

5. 19-5 Speed in Swimming  Depends on stroke length and stroke frequency.  Stroke length depends on forces that produce forward motion and resistance of water in opposite direction.  Actions of the arms and legs result in a combination of lift and drag forces that propel the body forward.  Depends on stroke length and stroke frequency.  Stroke length depends on forces that produce forward motion and resistance of water in opposite direction.  Actions of the arms and legs result in a combination of lift and drag forces that propel the body forward.

6. 19-6 Drag and Lift  Actions of the arms and legs result in a combination of lift and drag forces that propel the body forward. Fig 19.1

7. 19-7 Fluid Resistance  Form drag: resistance due to surface area of the front of the body.  Surface drag: resistance of the water next to the body.  Wave drag: occurs at the surface as the body moves along.  Turbulence: forms behind the body.  Form drag: resistance due to surface area of the front of the body.  Surface drag: resistance of the water next to the body.  Wave drag: occurs at the surface as the body moves along.  Turbulence: forms behind the body.

8. 19-8 Stroke Frequency  Depends on the amount of time spent per stroke cycle.  Related to the nature of the stroke pattern and the muscle torques of the arms and legs.  Depends on the amount of time spent per stroke cycle.  Related to the nature of the stroke pattern and the muscle torques of the arms and legs.

9. 19-9 Mechanical Principles Applied to Swimming 1.Swimming should produce even progress through the water. 2.The body will move in the opposite direction to the force applied. 3.Forward motion is produced through a combination of drag and lift forces. 4.To produce maximum force present as broad a hand surface as possible during propulsion and exert backward pressure through as great a distance as possible. 1.Swimming should produce even progress through the water. 2.The body will move in the opposite direction to the force applied. 3.Forward motion is produced through a combination of drag and lift forces. 4.To produce maximum force present as broad a hand surface as possible during propulsion and exert backward pressure through as great a distance as possible.

10. 19-10 Mechanical Principles Applied to Swimming 5.Momentum may be transferred from one body part to another body part as momentum is conserved. 6.The body position in the water depends on buoyancy and speed through the water. 7.When a body is free in a fluid, movement of a part in one direction results in movement of the rest of the body in the opposite direction. 8.A rapidly moving body in the water leaves a low pressure area immediately behind it. 5.Momentum may be transferred from one body part to another body part as momentum is conserved. 6.The body position in the water depends on buoyancy and speed through the water. 7.When a body is free in a fluid, movement of a part in one direction results in movement of the rest of the body in the opposite direction. 8.A rapidly moving body in the water leaves a low pressure area immediately behind it.

11. 19-11 Mechanical Principles Applied to Swimming 9.The more streamlined the body, the less the resistance to progress through the water. 10.The drag on a body in any fluid increases approximately with the square of the velocity. 11.The sudden or quick movement of a swimmer’s body, or one of its parts, at the surface of the water tends to cause turbulence that increases drag. 9.The more streamlined the body, the less the resistance to progress through the water. 10.The drag on a body in any fluid increases approximately with the square of the velocity. 11.The sudden or quick movement of a swimmer’s body, or one of its parts, at the surface of the water tends to cause turbulence that increases drag.

12. 19-12 Analysis of the Sprint Crawl Head and Trunk  Three important functions: 1.Minimize resistance. 2.Enable the swimmer to breath. 3.Provide a stable anchorage for the arm and leg muscles to effect a maximum propulsive force.  Three important functions: 1.Minimize resistance. 2.Enable the swimmer to breath. 3.Provide a stable anchorage for the arm and leg muscles to effect a maximum propulsive force.

13. 19-13 Analysis of the Sprint Crawl Head and Trunk  Body as horizontal as possible.  Feet below the surface.  Head breaking the water at the hairline.  Static contraction of rectus abdominis holds spine in a slightly flexed position, (prevents extension).  Pelvis is in a position of slightly decreased inclination.  Body as horizontal as possible.  Feet below the surface.  Head breaking the water at the hairline.  Static contraction of rectus abdominis holds spine in a slightly flexed position, (prevents extension).  Pelvis is in a position of slightly decreased inclination.

14. 19-14 Analysis of the Sprint Crawl Head and Trunk  Lateral movements of the trunk will increase resistance to forward movement.  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 interference.  Do not lift the head to breath.  Rotate it while tucking the chin.  Lateral movements of the trunk will increase resistance to forward movement.  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 interference.  Do not lift the head to breath.  Rotate it while tucking the chin.

15. 19-15 Analysis of the Sprint Crawl Head and Trunk  After a quick inhalation, face is turned forward.  Breathe every stroke for distance events, and less often for sprints.  By alternating actions of the left and right oblique abdominals and spinal extensors, the spine and pelvis are stabilized against the pull of the shoulder and hip muscles.  After a quick inhalation, face is turned forward.  Breathe every stroke for distance events, and less often for sprints.  By alternating actions of the left and right oblique abdominals and spinal extensors, the spine and pelvis are stabilized against the pull of the shoulder and hip muscles.

16. 19-16 Analysis of the Sprint Crawl Arm Stroke: Entry and Support  Entry should place the arm in the most advantageous position for exerting force.  Forearm high and elbow pointing to the side.  Hand passes in front of of shoulder, reaches forward, and is driven forward and downward into the water directly in front of the shoulder.  Elbow is slightly flexed, and extends during entry.  Entry should place the arm in the most advantageous position for exerting force.  Forearm high and elbow pointing to the side.  Hand passes in front of of shoulder, reaches forward, and is driven forward and downward into the water directly in front of the shoulder.  Elbow is slightly flexed, and extends during entry.

17. 19-17 Analysis of the Sprint Crawl Arm Stroke: Entry and Support  The brief moment between entry and the beginning of the propulsive action is called the support phase.  Purpose is to keep the head and shoulders high in the water.  Pressure of forearm and hand is mostly downward and then backward, producing and upward and forward reactive force.  The brief moment between entry and the beginning of the propulsive action is called the support phase.  Purpose is to keep the head and shoulders high in the water.  Pressure of forearm and hand is mostly downward and then backward, producing and upward and forward reactive force.

18. 19-18 Analysis of the Sprint Crawl Arm Stroke:Catch, Pull, and Push  Catch: propulsive action changes from downward to backward.  A quick inward movement of the hand and arm that serves to bring the hand to a position in front of the axis of the body.  Pull: begins with the first backward motion of the hand.  Upper arm is vertical, and favors use of the large muscles - pectoralis major and latissimus dorsi for pulling downward and backward.  Catch: propulsive action changes from downward to backward.  A quick inward movement of the hand and arm that serves to bring the hand to a position in front of the axis of the body.  Pull: begins with the first backward motion of the hand.  Upper arm is vertical, and favors use of the large muscles - pectoralis major and latissimus dorsi for pulling downward and backward.

19. 19-19 Analysis of the Sprint Crawl Arm Stroke:Catch, Pull, and Push  Pull: elbow should be kept high during the first part of the pull.  By bending the elbow the arm is pulled under the body.  Maximum bend occurs halfway through the pull, when the hand begins to push water backward.  Elbow action assists in producing an S- curve, which creates propulsive lift.  Pull: elbow should be kept high during the first part of the pull.  By bending the elbow the arm is pulled under the body.  Maximum bend occurs halfway through the pull, when the hand begins to push water backward.  Elbow action assists in producing an S- curve, which creates propulsive lift.

20. 19-20 Analysis of the Sprint Crawl Arm Stroke:Catch, Pull, and Push  Push: transition from pull to push occurs as the arm passes under the shoulder.  As forearm passes the front of the hip, the upper arm extends and the hands gives a quick push backward.  Release and Recovery: Pressure is relaxed, elbow & shoulder raised out of the water. Elbow swings forward and upward with hand trailing behind. Hand moves in front of shoulder ready for next entry.  Push: transition from pull to push occurs as the arm passes under the shoulder.  As forearm passes the front of the hip, the upper arm extends and the hands gives a quick push backward.  Release and Recovery: Pressure is relaxed, elbow & shoulder raised out of the water. Elbow swings forward and upward with hand trailing behind. Hand moves in front of shoulder ready for next entry.

21. 19-21 Analysis of the Sprint Crawl The Kick: Nature Of Movement  Most often used is the flutter kick.  Primary role is a stabilizer and neutralizer.  Timing with arms is therefore critical.  Legs are relatively close together as they alternate in an up and down movement.  Feet attain a maximum stride of 1 to 2 feet.  Whiplike action for both the up and down strokes.  Most often used is the flutter kick.  Primary role is a stabilizer and neutralizer.  Timing with arms is therefore critical.  Legs are relatively close together as they alternate in an up and down movement.  Feet attain a maximum stride of 1 to 2 feet.  Whiplike action for both the up and down strokes.

22. 19-22 Analysis of the Sprint Crawl The Kick: Downstroke  Begins with downward drive of the thigh.  Thigh flexes only slightly, knee extends completely by the end of the stroke.  Ankle and foot remain in plantar flexion.  Dorsiflexors contract statically to stabilize foot against pressure of the water.  Begins with downward drive of the thigh.  Thigh flexes only slightly, knee extends completely by the end of the stroke.  Ankle and foot remain in plantar flexion.  Dorsiflexors contract statically to stabilize foot against pressure of the water.

23. 19-23 Analysis of the Sprint Crawl The Kick: Upstroke  Begins with thigh extension.  Slight knee flexion develops near the end of the stroke.  Foot stops just below the surface.  Begins with thigh extension.  Slight knee flexion develops near the end of the stroke.  Foot stops just below the surface.

24. 19-24 Analysis of the Sprint Crawl Stroke Coordination  Six beat kick for every arm cycle.  Uneven number of leg beats for each arm serves to maintain balance around vertical axis.  Breathing occurs on one side.  Head is turned with chin toward axilla.  Inhalation only when head turns. Exhale under water.  As velocity increases, arm cycles will move closer together, so that entry of one arm occurs as other is finishing push.  Six beat kick for every arm cycle.  Uneven number of leg beats for each arm serves to maintain balance around vertical axis.  Breathing occurs on one side.  Head is turned with chin toward axilla.  Inhalation only when head turns. Exhale under water.  As velocity increases, arm cycles will move closer together, so that entry of one arm occurs as other is finishing push.

25. 19-25 Analysis of the Sprint Crawl: Additional Factors  Rhythm of the stroke.  Relaxation of the body.  Flexibility of the joint.  Shoulders and ankles.  Rhythm of the stroke.  Relaxation of the body.  Flexibility of the joint.  Shoulders and ankles.

26. 19-26 Fig 19.2 Sprint Crawl Stroke

27. 19-27 ROWING  Much of the propulsive force is generated by the legs.  Two distinct phases:  Pull phase  Recovery phase  Much of the propulsive force is generated by the legs.  Two distinct phases:  Pull phase  Recovery phase

28. 19-28 ROWING: Pull Phase  Force applied to the water by the oar blade.  Initiated through extension of flexed lower extremities, followed by trunk extension, then upper extremity pull.  Force applied to the water by the oar blade.  Initiated through extension of flexed lower extremities, followed by trunk extension, then upper extremity pull. Fig 19.3c

29. 19-29 ROWING: Recovery Phase  Blade lifted clear of water by downward pressure on the grip.  Oar is feathered to slice through the air.  Legs and trunk are flexed and upper arm extends.  Blade lifted clear of water by downward pressure on the grip.  Oar is feathered to slice through the air.  Legs and trunk are flexed and upper arm extends. Fig 19.3a

30. 19-30 CANOEING  Paddle is held in both hands.  Stroke is primarily performed by the arms, shoulders, and trunk.  Paddler faces the direction of travel.  Stroke involves reaching out either in a forward or sideward direction and pulling the paddle blade through the water.  Paddle is held in both hands.  Stroke is primarily performed by the arms, shoulders, and trunk.  Paddler faces the direction of travel.  Stroke involves reaching out either in a forward or sideward direction and pulling the paddle blade through the water.

31. 19-31 CANOEING  The beginning of the stroke produces a downward force and a lifting effect.  The end of the stroke produces an upward force that depresses the canoe.  Smooth canoeing emphasizes the backward movement of the blade.  The beginning of the stroke produces a downward force and a lifting effect.  The end of the stroke produces an upward force that depresses the canoe.  Smooth canoeing emphasizes the backward movement of the blade.

32. 19-32 Techniques for Steering the Canoe Fig 19.4

33. 19-33 KAYAKING  Kayak rides lower in the water than other boats.  Uses a double bladed paddle, set perpendicular to one another.  Can effectively stroke on both sides in a cyclic fashion.  Kayak rides lower in the water than other boats.  Uses a double bladed paddle, set perpendicular to one another.  Can effectively stroke on both sides in a cyclic fashion. Fig 19.5