Kinesiology of a Soccer Kick

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Kinesiology of a Soccer Kick

• By Monica Vasquez, Joanna Tan, Rahila Saeed,
  Archita Patel

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History

• 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.

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Introduction

• 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.

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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

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Video of a Soccer Kick
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Phases of a Soccer Kick

• The soccer kick is broken down into six stages
• 1. The approach
• 2. Plant-foot forces
• 3. Swing-limb loading
• 4. Hip flexion and knee extension
• 5. Foot contact
• 6. Follow-through

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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 angle.
• 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.

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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
  kick.

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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 extensors.

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Phase 4 - Hip flexion and knee extension

• The powerful hip flexors initiate this next phase
  of the kick.
• 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 accelerate.

• 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.

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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 hamstrings.
• At the instant of impact on the kicking leg, the
  hip and knee are slightly flexed and the foot is
  moving upwards and forwards.

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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.

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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.

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Muscle Groups

• Agonist - Hip Flexors rectus femoris, iliopsoas,
  sartorius
  
  
• - Knee extensors
• - Dorsiflexors
• Antagonists Hamstrings
  Gastrocnemius
  Plantarflexors
• 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

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Muscular Action during kicking preparation
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Muscular action during approach and kick
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Muscular action during follow-through
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Newtons Laws

• Newtons 1st Law
• - Mass distribution about an AOR can be
  modified by changing the limb position.
• Newtons 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.
• Newtons 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.
• Newtons 3rd Law
• - Fma 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.

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• 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.
• Torque
• 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.)

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• 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

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• 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 motion.
• IMA EMA
• Hip Flexors, Knee extensors, dorsiflexors of
  tailor joint.

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• 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 direction.
• 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-through.

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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.

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Closing Statement
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References

• http//www.sportsinjurybulletin.com/archive/biomec
  hanics-soccer.htm
• http//www.coachesinfo.com/article/106/3
• http//www.coachesinfo.com/category/soccer/86/
• http//congress.akm.ch/abstract/abstract/abt.ausg_
  pkt_ses?xsspracheENGxsdesignOPTxnkon_nr31xnS
  ESSION_NR3382xnCO_PROFILE372087
• Neumann, D. Kinesiology of the Musculoskeletal
  System. 2002. Human Kinetics.
• www.rad.washington.edu/atlas
• www.fifasoccer.com

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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 Newtons Laws are not used during
  the kicking motion?
• a. 1st
• b. 2nd
• c. 3rd
• d. All are used
• 3. Which AORs 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.