Kinesiology of Soccer Kick by sanmelody

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									 Kinesiology of a
   Soccer Kick

By: Monica Vasquez, Joanna Tan,
   Rahila Saeed, Archita Patel
 The history of soccer dates back to the 2nd and
  3rd centuries B.C. in China. “Tsu Chu” is a
  physical education exercise that consisted of
  kicking a leather ball filled with feathers and hair
  into a small net that was fixed onto long bamboo
  canes. The game later flourished from the 8th to
  19th centuries in the British Isles. Games often
  took the form of a heated competition between
  whole village communities. Nine years later in
  1863, soccer rules had been established for the
  first time, hence, the creation of the Soccer
  Association. The 1st match that was played with
  the prearranged duration of one and a half hours
  was between London & Sheffield in 1866.
  Kicking movement in soccer is a series of rotational movements.
  In this movement, the aim is to produce through the kinematic
   chain of body segments, high angular velocity to the foot.
  “The role of the arms in kicking is primarily to maintain the balance
   of the body. The arms are usually extended out to the sides of the
   body during the forward motion of the kicking leg, to help to keep
   the center of gravity over the support foot, and to increase the
   moment of inertia of the trunk and increase resistance to rotation
   around the spine, or the long axis of the body.
  As the kicking foot contacts the ball, the opposite arm moves
   forward and upward across the body to help keep the trunk down
   and the body in balance.”
Goals of a Soccer Kick

  Production of Accuracy – stable basis
   and body support
  Production of Speed – Successive
   generation of each link of speed from
   proximal to lateral
  Production of Force – Successive use of
   body segments from initiation of
   movement through the action phase
Video of a Soccer Kick
Phases of a Soccer Kick

  The soccer kick is broken down into six
 1. The approach
 2. Plant-foot forces
 3. Swing-limb loading
 4. Hip flexion and knee extension
 5. Foot contact
 6. Follow-through
Phase 1- The approach
  Children between two and three years of age generally
   waddle straight into the ball to try and kick it. As adults,
   they have learned a paced run-up and have adjusted their
   approach to the ball from front-on to a more diagonal
  The diagonal approach produces greater swing-limb
   velocity for greater ball speed. Researchers have shown that
   a 45-degree angle of approach produces the greatest peak
   ball velocity, compared to a 15-degree or 30-degree run-up.
  Elite players tend to take longer strides than novices as they
   approach the ball.
Phase 2 – Plant-foot Forces

   When kicking, there is a direct relationship
    between the direction that the plant foot faces
    and the direction in which the ball travels. The
    optimal foot plant position for accurate
    direction is perpendicular to a line drawn
    through the centre of the ball for a straight
  Phase 3 – Swing-limb Loading

 Swinging or cocking of the kicking limb in
  preparation for the downward motion
  towards the ball
 The opposite arm to the kicking leg is raised
  and pointed in the kicking direction to
  counter-balance the rotating body.
 As the plant foot strikes the ground
  adjacent to the ball, the kicking leg is
  extending and the knee is flexing. Before
  the end of the swing phase when the hip is
  nearly fully extended and the knee flexed,
  the leg is slowed eccentrically by the hip
  flexors and knee extensors.
 This is the phase of the kick where there is
  maximal eccentric activity in the knee
Phase 4 - Hip flexion and
knee extension
 The powerful hip flexors
  initiate this next phase of the
 The thigh is swung forward
  and downward with a
  concomitant forward rotation
  of the lower leg/foot. As the
  forward thigh movement
  slows, the leg/foot begins to
 The knee extensors then powerfully contract to swing the
  leg and foot forwards towards the ball. As the knee of the
  kicking leg passes over the ball, it is forcefully extended
  while the foot is forcefully plantarflexed.
Phase 5 – Foot Contact
           At the point of impact 15% of the
            kinetic energy of the swinging limb is
            transferred to the ball. The rest is
            dissipated by the eccentric activity of
            the hamstring muscle group to slow
            the limb down.
           Because of the large forces involved,
            this stage in the kicking action is the
            most likely to produce injury to the
           At the instant of impact on the
            kicking leg, the hip and knee are
            slightly flexed and the foot is moving
            upwards and forwards.
Phase 6 – Follow Through

                    The follow-through of the kick serves
                      two purposes: to keep the foot in
                      contact with the ball for longer; and
                      to guard against injury.
                    As in all ballistic movements, a
                      longer contact time will maximize
                      the transfer of momentum to the
                      ball and thus increase its speed. The
                      body protects itself from injury by
                      gradually dissipating the kinetic and
                      elastic forces generated by the
                      swinging, kicking limb after contact.
Any sudden slowing of the limb would increase the risk of
hamstring strain.
Role of the Arms in Kicking

  Essential in helping to maintain body balance.
  Arms extend horizontally during forward motion
   of the kicking leg. This helps to keep the center
   of mass over the supporting foot and also
   increases moment of inertia of the trunk.
  It also increases rotational resistance around
   the spine.
  As the kicking foot strikes the ball, the opposite
   arm moves forward and upward to help keep
   the trunk of our body in balance.
 Muscle Groups
 Agonist - Hip Flexors: rectus femoris, iliopsoas, sartorius
          - Knee extensors
          - Dorsiflexors

 Antagonists – Hamstrings

 Synergists – Hip: Internal & external rotators,
                    adductors, abductors
               Knee: Adductors, Abductors
               Ankle: Peroneals (lateral), post tibialis (medial)

 Stabilizers – Trunk stabilizers: Abdominal, psoas major, erector spinae
                                 & postural muscles
              - Muscles of the plant foot and leg
Muscular Action during kicking
Muscular action during approach and kick
Muscular action during follow-through
                      Newton’s Laws
 Newton’s 1st Law
      - Mass distribution about an AOR can be modified by changing the
      limb position.

 Newton’s 2nd Law and Angular Motion
      - The amount of force applied by the kicker against the ball and the
      distance the ball moves in the direction the force applied during
      the kick.
      - When the ball is kicked, angular momentum of a limb is
      increased if the angular velocity is increased.

 Newton’s 2nd Law: Impulse-Momentum
      - Impulse is exerted by contact of the foot to the ball.
      - To give the ball higher momentum, impulse must be higher.

 Newton’s 3rd Law
      - F=ma; The kicker and the ball experience accelerations effect,
      that is dependent on its mass.
      - The ball will exert a force equal in magnitude to contact but
      opposite in direction.
Linear and angular velocity
 The linear velocity of the rotating foot hitting the ball is direction
   proportional to the sum of both the angular velocity and the radius of
   rotation of the consecutive segments.
 Knee linear velocity reaches its peak between 40-70 ms after peak hip
   velocity is reached The angular motion on the thigh segment stops
   when the knee is approximately in a position over the ball.

 The release velocity of the ball with respect to timing had the strongest
  relationship to the maximal torque produced during the 1. hip flexion 2.
  knee extension and 3. short ankle stabilizing in the kicking leg.

Velocity, Acceleration, & Mass
 Mass & Velocity – Greater mass of leg + greater velocity of foot =
  greater resultant velocity of ball
 Acceleration – Acceleration of the kicking leg & resultant velocity are
  determined by the muscle forces that are applied by the kicker (speed
  of ball is directly related to strength of kicker.)
 Pelvic on Femoral Rotation on a relatively
  stationary trunk is limited by lumbar spine
  rotational limitations. If the lumbar spine
  rotation accompanies hip rotation, hip
  rotation becomes limited by hip joint capsular
  or boney limitations
Work, power, reactive forces
 The largest positive power occurs by hip flexion
  torque during middle to latter part of kicking.
 A Force applied along a line that does not pass
  through the center of mass will produce a torque
  and will induce a rotation. Think of the kick as an
  applied force along a direction.
Radius of Gyration
 The radius of gyration in kicking is the distance
  between the hip of the planted leg and the
  opposing hip is the axis of rotation of the kicking
Hip Flexors, Knee extensors, dorsiflexors of tailor
Moment Arm
 The moment arm is defined as the perpendicular distance from the axis
   of rotation (usually through a body joint), to the center of gravity of the
   resistance, in this case the ball. The greater the distance from the
   center of the ball, to the center of the active joints in the kick, the longer
   the lever system acting, the faster the speed of the kick. By fully
   extending the leg at impact, and leaning away from the ball, the kicker
   will increase the speed at the end of the foot.
External Forces
 Gravity, friction, and time (duration of contact)
 The ball will exert an equal force in magnitude to contact but opposite in
Internal Forces
 Specifically sense organs within the muscles, joints and tendons and
   nerve endings in the skin (allow sensation of the movement)
 Includes the following phases: preparation, approach & kick, and follow-
              Soccer Shoe
 The soccer shoe generally has a poor protective
  function mainly because it has poor ankle stability.
 Little attention has been paid to shock reduction or rear
  foot characteristics of the shoe. Artificial surfaces
  produce different injury profiles when compared to
  natural turf pitches. Players are at a higher risk of injury
  if they change frequently between surface types.
 Careful instruction and skill development as well as
  correct equipment would seem to be necessary for
  young players.
Closing Statement
 Neumann, D. Kinesiology of the Musculoskeletal
  System. 2002. Human Kinetics.
            Kinesiology of a Soccer Kick - Questions
1. How many phases are used in the soccer kick?
            a. 4
            b. 2
            c. 9
            d. 6

2. Which 1 of Newton’s Laws are not used during the kicking motion?
              a. 1st
              b. 2nd
              c. 3rd
              d. All are used

3. Which AOR’s are used in the soccer kick?
            a. hip & knee
            b. knee & hip
            c. hip, knee, & ankle
            d. None of the above

4. The release velocity of the ball with respect to timing had the strongest relationship to the maximal torque produced
     during the ____ ? Choose the one that does not belong.
              a. hip flexion
              b. hip extension
              c. knee extension
              d. short ankle stabilizing in the kicking leg.

5. Which of the following are trunk stabilizers?
              a. All of the below
              b. abdominal
              c. psoas major
              d. erector spinae

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