1 / 63

Locomotion on Solid Surfaces

Locomotion on Solid Surfaces. Chapter 19. Objectives. 1. Identify and classify motor skills belong in the categories that fall under the heading of moving one’s body on the ground or another resistant surface

keisha
Télécharger la présentation

Locomotion on Solid Surfaces

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Locomotion on Solid Surfaces Chapter 19

  2. Objectives 1. Identify and classify motor skills belong in the categories that fall under the heading of moving one’s body on the ground or another resistant surface 2. Describe the anatomical and mechanical nature of motor skills of the major types of locomotor patterns 3. Name and state anatomical and mechanical principles that apply to the locomotor patterns 4. Evaluate performance of motor skills of major locomotor patterns 5. Analyze performance of a locomotor skill

  3. LOCOMOTION • The act or power of moving form place to place by means of one’s own mechanisms or power • In human being, is the result of the action of body levers propelling the body • Ordinarily is by lower extremities • Occasionally by all four extremities • Sometimes by upper extremities alone

  4. WALKINGDescription • Alternating action of the two lower extremities • Translatory motion of the body brought about by rotary motion of some of its parts • Two Phases: • Swing & Support Fig 19.1

  5. WALKINGDescription • Kinematics are often described in terms of strides and steps • One stride is one full lower extremity cycle • Stride: form hell strike to the next hell strike of the same leg • Stride length: distance covered in one stride • Step: form hell strike of one leg to hell strike of opposite leg

  6. WALKINGDescription • Gravity and Momentum: chief sources of motion in the swing phase, ballistic movement • Source of motion for support phase is • 1st Half: momentum of forward moving trunk • 2nd Half: contraction of extensor muscles of supporting leg

  7. WALKINGAnatomical Analysis • Major Component of Walking 1. Pelvic rotation 2. Pelvic tilt 3. Knee flexion 4. Hip flexion 5. Knee and ankle interaction 6. Lateral pelvic displacement

  8. WALKINGAnatomical Analysis: Swing Phase Spine and Pelvis: 1. Movements: Rotation of pelvis toward the support leg and of the spine in the opposite direction; slight lateral tilt of pelvis toward unsupported leg

  9. WALKINGAnatomical Analysis: Swing Phase Spine and Pelvis: 2. Muscles: Semipinalis, rotatores, multifidus, and external oblique abdominals on side toward which pelvis rotates • Erector spinae and internal oblique abdominals on opposite side • Psoas & quadratus lumborum support pelvis of swinging limb

  10. WALKINGAnatomical Analysis: Swing Phase Hip: 1. Movements: Flexion; outward rotation; adduction at beginning and abduction at the end of phase 2. Muscles: Iliopsoas prime mover of hip • assisted by; rectus femoris, sartorius, gracilis, adductor longus • possibly tensor fasciae latae, pectineus, short head of biceps femoris

  11. WALKINGAnatomical Analysis: Swing Phase Knee: 1. Movements: Flexion during 1st half; extension during 2nd half 2. Muscles: Quadriceps extensors contract slightly at end of phase • Sartorius & short head of biceps femoris chiefly following toe off

  12. WALKINGAnatomical Analysis: Swing Phase Ankle and Foot: 1. Movements: Dorsiflexion; prevention of plantar flexion 2. Muscles: Tibialis anterior, extensor digitorum longus, extensor hallucis longus, and peroneus tertius contract with slight to moderate intensity at the beginning of swing phase and taper off during middle portion of this phase • Contract again to prepare for hell strike

  13. WALKINGAnatomical Analysis: Support Phase Spine and Pelvis: Rotation of pelvis toward same side and spine to opposite side; lateral tilt away from support leg

  14. WALKINGAnatomical Analysis: Support Phase Hip: 1. Movements: Extension through foot flat to toe off • Reduction of outward rotation • Followed by slight inward rotation • Prevention of adduction of the thigh and dropping of pelvis to opposite side

  15. WALKINGAnatomical Analysis: Support Phase Hip: 2. Muscles: During hell strike gluteals and hamstrings contract statically with moderate intensity, Taper off during foot flat and disappear at midstance • Only muscles that contract during last part of phase - adductor magnus, longus, and brevis

  16. WALKINGAnatomical Analysis: Support Phase Knee: 1. Movements: Slight flexion form heel strike into foot flat, followed by extension form midstance until hell lift 2. Muscles: Quadriceps extensors contract moderately in early part of phase, then gradually relax • Vastii contract throughout the 1st half of this phase • Hamstrings at the end of phase

  17. WALKINGAnatomical Analysis: Support Phase Ankle and Foot: 1. Movements: Slight plantar flexion, followed by slight dorsiflexion • Prevention of further dorsiflexion • Plantar flexion of ankle and hyperextension of metatarsophalangeals at end of propulsive phase

  18. WALKINGAnatomical Analysis: Support Phase Ankle and Foot: 2. Muscles: Tibialis anterior, Extensor digitorum longus and hallucis longus early in phase • Gastrocnemius and soleus active form midstance to heel off • Tibialis posterior middle part of phase • Flexor digitorum longus slightly during middle portion of phase, increase to moderate in the last portion • Toe and intrinsic muscles respond to pressure of ground against toes

  19. Action of Upper Extremities in Walking • Arms tend to swing in opposition to the legs • This reflex action is usually without obvious muscular action and serve to balance rotation of the pelvis • Maximum flexion of shoulder and elbow occurs at heel strike of opposite foot • Maximum extension of shoulder and elbow occurs at heel strike of same foot

  20. Neuromuscular Considerations • Walking relies heavily on reflex • Reflexes also control movements of supporting limb and trunk is resisting the downward pull of gravity • Stretch reflex: at extremes of motion • Extensor thrust reflex: may facilitate the extensor muscles of lower extremity as weight rides over the foot on the support leg

  21. Anatomical Principles in Walking 1. Alignment a. Reduces friction and decreases the likelihood of strain and injury b. Stability of weight bearing limb and balance of trunk over this limb

  22. Anatomical Principles in Walking 2. Unnecessary lateral movements decrease gait economy a. Excessive trunk rotation b. Pelvis may drop on one side c. Pelvic rotation should be just enough to enable the leg to move straight forward

  23. Anatomical Principles in Walking 3. Normal flexibility of the joints a. Tendons of two joint muscles of lower extremity contribute to economy of muscular action in walking 4. Properly functioning reflexes contribute to a well coordinated, efficient gait a. Injury, disease, or substance abuse can interfere with the walking reflex

  24. Mechanical Analysis • Translation of the body’s center of gravity forward as a result of the alternating pattern of the lower extremity joint movements during the stance and swing phases • Force the control walking are; • external forces of weight, normal reaction, friction, air resistance • internal muscular forces • Direction & interaction of these forces determine the nature of the gait

  25. Mechanical Analysis • Translation of the body’s center of gravity forward as a result of the alternating pattern of the lower extremity joint movements during the stance and swing phases • Force the control walking are; • external forces of weight, normal reaction, friction, air resistance • internal muscular forces • Direction & interaction of these forces determine the nature of the gait

  26. Mechanical Principles in Walking 1. Inertia of the body must be overcome with every step 2. A brief restraining action of the forward limb serves as a brake on the momentum of the trunk in order to not move the center of gravity beyond the base of support 3. Translatory movement is achieved by alternating the lower extremities’ rotary movement between the foot (support phase) and hip (swing phase)

  27. Mechanical Principles in Walking 4. The vertical component of ground reaction force serves to counteract the pull of gravity • The horizontal component serves to; • check forward motion during hell strike • produce forward motion during toe off 5. Speed is increased by increasing stride length or stride rate, or both 6. Speed is directly related to magnitude of force and direction of application

  28. Mechanical Principles in Walking 7. Efficiency of locomotion partially depends on friction and ground reaction force 8. Most efficient gait is one that is so timed to permit pendular motion of the lower extremities 9. Alternating loss and recovery of balance 10. Lateral distance between feet is a minor factor in maintaining balance, since momentum (inertia) caries the body forward

  29. Walking VariationsIndividual Variation in Gait • Variations may be structural or functional • Structural: body proportions & limb differences • Functional: personality characteristics • Age: decreases in strength and flexibility • Balance becomes a concern • Obesity: Increased impact and propulsive forces • Medial and lateral forces increase

  30. Walking VariationsWalking Up & Down Stairs & Ramps • Up stairs or a ramp: Forward lean of body to direct the push of legs through the body’s center of gravity • Swing phase is an exaggerated knee lift and dorsiflexion of the ankle • Down stairs or a ramp: Eccentric contraction of muscles to lower body at a controlled rate, and maintain line of gravity toward to back of the base of support • swing phase has a slight lifting of rear foot to clear the step

  31. Walking VariationsRace Walking • Adaptations to produce maximum speed • Must show a period of double support • Minimizes double support period; • increasing stride rate • decreasing stride length

  32. RUNNINGDescription • Difference from walking is that there is no double support phase • Running has a flight phase Fig 19.7

  33. RUNNINGDescription • Two major types of running • Races: concerns are time and distance • Games and Sports: also concerned with change of direction, pace, and stability

  34. RUNNINGAnatomical Analysis • The difference in joint actions between walking and running are a matter of degree and coordination • Essentially the same action, but the ROM is generally larger in running

  35. RUNNINGAnatomical Analysis: Swing Phase • More muscular than pendular and is longer than support phase • Initial foot contact: • Fast running - ball of foot • Slow running - heel or whole foot • The flexed leg brings the mass of the leg close to the hip, reducing inertia and increasing angular velocity

  36. RUNNINGAnatomical Analysis: Support Phase • The knee and ankle “give” in flexion, then extend as the body passes over the foot • Support time decrease as speed increases • Movements and muscles in spine and pelvis are the same as walking, but more vigorous in reaction to leg movements

  37. RUNNINGMechanical Analysis • Speed is governed by length and frequency of stride • Length of Stride: determined by length of leg, ROM of hip, and power of leg extensors • Body becomes a projectile and depends on; • Angle of take off • Speed of projection • Height of center of gravity at takeoff & landing • Stride rate: determined by speed of contraction and skill of performer

  38. Mechanical Principles in Running 1. The problem of overcoming inertia decreases as speed increases 2. Acceleration is directly proportional to power of the leg drive 3. The smaller the vertical component of ground reaction force the greater the horizontal or driving component 4. The more completely the horizontal force is directed straight backward, the greater its contribution to forward motion of the body

  39. Mechanical Principles in Running 5. The length of leg in the driving phase should be as great as possible when speed is concerned 6. Internal resistance forces due to sarcolemma viscosity or tightness of the tendons, ligaments, and fascia can be reduced by warm-up and stretching

  40. Mechanical Principles in Running 7. By flexing the free leg at the knee and carrying the heel high up under the hip, the leg is moved more rapidly as well as more economically 8. The force of air resistance can be altered by shifting the center of gravity.

  41. The Sprint Start • The crouch start enables the runner to exert maximum horizontal force at take off, providing maximum acceleration against inertia Fig 19.8

  42. JUMPING, HOPPING AND LEAPING • Goal is to propel the body into the air with sufficient force to overcome gravity and in the direction to accomplish the desired height or horizontal distance • Path of the body is determined by the conditions at the instant of projection • Differences between them relates to the take off and landing

  43. Hop, Leap, and Jump • Hop: the same foot is used for the take off and landing • Leap: take off is from one foot and landing is on the other foot • Jump: take off from one or both feet and lands on both feet • Each may be initiated from a stationary position or preceded by some locomotor pattern

  44. Total Horizontal Distance • Sum of three distances: 1. Horizontal distance between take off foot and the line of gravity of performer 2. Horizontal distance the center of gravity travels in the air 3. Horizontal distance the center of gravity is behind the body part the lands closest to the take off point

  45. Total Height • May be considered to be divided into; • Distance between the ground and the line of gravity at the moment of take off and • Maximum distance the center of gravity is projected vertically

  46. Mechanical Principles in Jumping, Hopping, and Leaping 1. For movement to occur, inertia must be overcome 2. Work done by muscles shortening immediately after stretching is greater than that done by those shortening form a static state 3. Jumpers project themselves into the air by exerting force against the ground that is larger than the force supporting their weight

  47. Mechanical Principles in Jumping, Hopping, and Leaping 4. The upward thrust of the arms seen in the high jump accelerates the support leg downward, which in turn causes a reaction thrust from the ground - Arm swing action also raises the center of gravity immediately prior to take off, which may result is increased jump height or distance

  48. Mechanical Principles in Jumping, Hopping, and Leaping 5. The magnitude of the impulse that the jumper exerts against the ground is a product of the forces and the time over which they act 6. The path of motion of a body’s center of gravity is space is determined by the angle at which it is projected, speed of projection, height of the center of gravity at take off, and air resistance

  49. Mechanical Principles in Jumping, Hopping, and Leaping 7. Angular momentum may be developed by the sudden checking o linear motion or by an eccentric thrust Fig 19.9

  50. ADDITIONAL FORMS OF LOCOMOTIONWheels, Blades, and Runners • Designed to allow humans to move farther faster for less effort, or to enable them to move quickly and easily over difficult surfaces • Most common and efficient forms is the bicycle Fig 19.10

More Related