Course:KIN366/ConceptLibrary/Throwing 2

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Movement Experiences for Children
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KIN 366
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Instructor: Dr. Shannon S.D. Bredin
Email: shannon.bredin@ubc.ca
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Throwing is a movement skill that is defined as the propulsion of an object through the air by the movements of the arm and hand. It is one of the fundamental movement skills that all children should develop between the ages of zero and nine. The development of fundamental movement skills in children are important because they are the building blocks or foundational movements for more complex and specialized skills required for sports and recreational activities (Kids at Play, 2014). Throwing occurs in multiple phases and depending on the maturity of the throw, these phases can vary significantly.


Types of Throwing Patterns

Throwing takes many forms and the form that a person uses, especially among children, often depends on the task constraints, particular rules and the size of the object. The two most common throwing patterns are the overhand throw and the underhand throw.


Overhand Throwing

The overhand throwing pattern is a single-handed throw where the object is thrown from above the shoulders. This throwing pattern requires very complex motor skills that involve the entire body in a series to propel the object forward. By age three, children should have developed the gross motor skills to participate in organized sports and activities that require the overhand throw (Kids at Play, 2014). This movement demands more concentration than other routine activities such as walking and running; therefore it gets developed a little later in a child’s life. The quality of the throw is affected by the physical attributes of the child such as height, strength, and flexibility. However it is mainly the thrower’s mechanics that largely determine the quality of the throw (Parenting Counts, 2014). If the child has developed proper throwing maturity, taking a stride towards the target with the leg opposite to the throwing arm before the release of the object enhances the overhand throw. This forward step, commonly known as the stride step, allows more energy to be produced that transfers up to the body. The stride step should be performed while raising the throwing arm above the shoulders to maximum external shoulder rotation. At this point, the arm is considered to be “fully cocked” (Parenting Counts, 2014). The release and follow-through of the arm depends on the distance and position of the target. This throwing pattern is very similar to the straight sidearm throw, but it is thrown from above the shoulders for greater range of motion. The overhand throwing pattern is the most common type of throw in sport games, some include baseball, football, water polo, dodgeball and javelin (Parenting Counts, 2014).


Underhand Throwing

The underhand throwing pattern is a single-handed throw where the object is thrown from below the waist. This type of throwing pattern also requires complex motor skills in order for proper throwing techniques (Kids at Play, 2014). Children normally use this throwing pattern to launch objects up in the air. It could also be done with both hands if the object is too large to grasp in one hand. The movement sequence for the underhand throw starts off with facing the target. With your dominant hand, grasp the object with your palms up and thumbs outside (Physical and Health Education of Canada, 2014). The cocking phase is just like the overhand throw but instead of maximum external rotation of the shoulders, it is maximum extension at the shoulder joint. At the time of drawback, the thrower takes a stride step forward with the foot opposite to the throwing arm towards the target while swinging the throwing arm forward from below the waist. The point of release depends on where the target is. Releasing the object at waist level would lead to the object propelling forward and the later you release the object, the more vertical the object will be propelled. Although the underhand throwing pattern is not as popular as the overhand throw, it is still used quite frequently in sports and activities. Some of these sports/activities include bowling, softball, volleyball and tennis.


Phases of Throwing

Throwing an object comprises four phases: the preparation phase, the force production phase, the critical instant phase, and the follow-through phase.


Preparation/Wind-up Phase

The first stage of the throwing motion starts at the initiation of the wind-up and ends when the shoulder has reached its maximum external rotation. The entire motion of throwing takes approximately two seconds to complete, and the preparation phase consumes almost 1.5 seconds of the total time (Parenting Counts, 2014). It is the beginning of the throwing motion that prepares the body for the act of throwing. The motion starts in the lower extremities and torso where the vast majority of the power to throw is generated. The arm is brought back in preparation for the throw. Depending on the development of the child and the maturity of the throwing quality, this phase can vary widely. When children first start learning how to throw, most of them don’t even take a stride step in their preparation phase (Parenting Counts, 2014). As the child develops proper throwing technique, contralateral stride step should be performed. Children in the earlier stages often prepare to throw an object by running towards the target. One of the common difficulties for young children when running is swinging their arms across the midline. Either there is absolutely no arm swing at all, or an over exaggerated arm swing, which leads to the rotation of the trunk. These factors in the preparatory phase would ultimately alter the quality of the throw.

The goals in this phase are:

  • To give some momentum to the projectile before the start of the force production phase
  • To put the body in a position that will allow maximum range of motion for the projectile
  • To provide most of the momentum for the thrower and the projectile system


Force Production

This phase begins at the point of maximum external rotation of the throwing shoulder and ends when the object is released. This phase is extremely quick lasting an average of only 50 msec. The distance of the object that is propelled depends on the amount of force that is exerted. The more developed the child is at throwing, the better he/she is at transferring the potential energy from the lower extremities to the upper extremities where it is then transformed into kinetic energy as the projectile is released (Physical Therapy & Sport Medicine Institute, 2013). Strength is a very important aspect in this phase. If the child does not have sufficient upper body strength, the object will not be propelled to the desired distance. The movement of the legs provides additional momentum for the thrower. More specifically, the legs need to move the shoulders of the throwing arm in the direction of the throw. This provides maximum range of motion for the projectile and aids the arm muscles to produce a larger force. The body is brought forward while the arm follows behind so that the energy developed by the body’s forward motion can be transferred to the throwing arm. The primary goal in this phase is to exert a large force on the object over a long range of motion to maximize the distance of the throw.


Instant of Release

This phase is defined as the instant when the object leaves the hand. Where the object is released depends on the distance of the thrower’s target. The farther the target is, the higher the release point so that you can get some vertical translation as well as horizontal. When holding objects that are too big for the child to grasp comfortably, the instance of release can be unpredictable.


Follow-through

The follow-through is the final phase in throwing. This phase slows down all body motions and stops the forward movement of the body and the muscle activity returns to its resting state. If this phase is completed correctly, the thrower’s body position is “under control” and balanced. For children that have just learnt to stand or walk, their balance and coordination are not fully developed yet. Therefore, the inability to control the follow-through and the deceleration of the throwing arm may lead to them falling down. It is very important for children with poor balance to be very careful with the deceleration of the throw because this rapid deceleration is actually the most violent part of the entire throwing motion. The greatest amount of joint loading occurs at this stage.


Five Stages of Maturity for Throwing

The maturity of a child’s throwing ability occurs in a progression and these progressions can be explained by five stages. The quality of the throw depends on many factors such as the size of the child’s hand, the size, shape and weight of the object, and the biomechanics of the thrower. Because throwing is a fundamental movement skill, it is imperative that all children learn and perfect proper throwing technique (Physical Therapy & Sport Medicine Institute, 2013).


Stage 1

  • Feet are stationary
  • Lack of preparatory back swing
  • The arm is taken well behind the head leading to a slight backwards lean of the body
  • Little to no truck rotation
  • Facing forward so the ball is moved directly forward
  • The force for projecting the ball comes from hip flexion, shoulder protraction and elbow extension

(Physical Therapy & Sport Medicine Institute, 2013)

Stage 2

  • Little forward step either ipsilateral or contralateral
  • Arm is brought forward in the transverse plane
  • A little more trunk rotation
  • Arm usually extended through throw
  • A small hop forward may be present before the toss
  • There is a greater use of momentum in projecting the object forward
  • The form of the throw resembles a “sling”

(Physical Therapy & Sport Medicine Institute, 2013)

Stage 3

  • Unilateral arm-leg action
  • Throwing arm positioned above the shoulder by a vertical and posterior motion of the arm at the same time as the ipsilateral leg moves forward
  • There is greater use of the shoulders, but little or no twisting of the trunk
  • Follow-through includes flexion at the hips and some trunk rotation

(Physical Therapy & Sport Medicine Institute, 2013)

Stage 4

  • Contralateral arm-leg action
  • Wind up during prep phase
  • Little or no trunk rotation of the hips and spine during the wind up
  • Strides forward with the contralateral leg for a wider base of support and stability

(Physical Therapy & Sport Medicine Institute, 2013)

Stage 5 (mature movement pattern)

  • Distinct wind up
  • Downward arc and backward
  • Rotation of the hips and the spine
  • De-rotating sequence of hip, spine shoulders
  • Equal and opposite reactions
  • Extended knee to arm action
  • Follow-through across the body

(Physical Therapy & Sport Medicine Institute, 2013)


Application to Sports

The capability to throw a ball effectively is a very important principle across a wide variety of sports. Throwing sports can be traced back to their ancestries back to pre-historic man, when spear or rock throwing hunters evolving into javelin throwers or shot putters. Throwing is a skill that is developed at a very young age but to do it effectively requires precision, coordination, and the proper biomechanics. The ability to throw effectively can make the difference between winning and losing in throwing sports.


Baseball

Baseball is a bat-and-ball game played between two teams of nine players who take turns batting and fielding. This is a game that is played by children at a very young age either in physical education class or recreationally with family and friends. It is a sport that requires a lot of accurate throwing in both long and short distances (The Complete Pitcher, 2002). Due to the frequency of throwing in the game of baseball, it is imperative to teach a child the importance of proper throwing techniques. Large amounts of stress is placed on the elbow, shoulder and wrist when throwing, especially throwing at great distances or pitching the baseball (The Complete Pitcher, 2002). The pitchers role in baseball is to throw the ball from the pitcher’s mound toward the catcher to begin each play, with the goal of delivering the pitch to the catcher without allowing the batter to hit the ball. The ball thrown by the pitcher must pass through the strike zone for it to be considered a valid pitch, therefore, the point of release is crucial for optimal accuracy. Great pitchers use a variety of different pitches to gain competitive advantage against the batter. Once the ball strikes the bat and lands in the outfield, the outfielders would have to beat the runners to the base with a very rapid throw(The Complete Pitcher, 2002).


Tennis (serve toss)

The sport of tennis is predominantly striking the ball with a tennis racket. However there is a small portion of the game that requires a very precise throw and this is the tennis serve toss. The tennis serve toss is perhaps one of the most important phases of the serve in tennis (Optimum Tennis, 2009). Learning and practicing the proper tennis toss will build consistency and accuracy into a person’s tennis serves motion. You may think that tossing a tennis ball a few feet above your head during a tennis serve is the easiest part of the whole game; many players find it to be one of the more elusive skills in the sport. Like all of the other throwing sports, tennis serve toss requires an immense amount of practice because consistency is the key to an effective serve (Optimum Tennis, 2009). The tennis serve can be your weapon in winning the game if your tosses are perfected. Depending on when you release the ball, the direction of the ball may vary widely. Gripping the ball differently could also alter your serve in many ways. Failing to toss the tennis ball consistently will almost always lead to an unsuccessful serve and frustration that may change the whole dynamics of the game (Optimum Tennis, 2009).


Bowling

Bowling refers to a series of sports or leisure activities that require the players to roll or throw a bowling ball towards a target, most likely bowling pins. The underhand motion of bowling is learned by children at a very young age. Whether it is rolling a toy ball towards the mother or underhand tossing a ball into the air, the motion is very similar to that of bowling. Bowling is a game of accuracy; therefore, the success in the game depends on many developmental factors such as gross and fine motor skills, balance, hand eye coordination and upper body strength (Reaching Higher, 2014). This sport requires a lot of technique and handiness in order to properly toss a ball towards the target with precision. There are different variations as to how to hold the bowling ball and these variations dictate how you will be releasing the ball. The release and the follow through are very important in controlling the speed and the spin of the ball. Aiming in bowling is like throwing a ball in football. You have to establish the target and find the right spot that will knock down the most amount of pins, transforming your shot to the best one possible.


References

  1. Kids at Play. (2014). Fundamental Movement skills. Retrieved from http://health.act.gov.au/kids-at-play/active-play-everyday/fundamental-movement-skills
  2. Optimum Tennis. (2009). The proper technique of the tennis serve toss. Retrieved from http://www.optimumtennis.net/tennis-serve-toss.htm
  3. Parenting Counts. (2014). Can throw a ball overhand. Retrieved from http://www.parentingcounts.org/information/timeline/can-throw-a-ball-overhand-42-49-months/
  4. Physical and Health Education Canada. (2014). Fundamental movement skills. Retrieved from http://www.phecanada.ca/programs/physical-literacy/what-physical-literacy/fundamental-movement-skills
  5. Physical Therapy & Sports Medicine Institute. (2013). The five phases of throwing a ball. Retrieved from http://www.ptsmi.org/062713.html
  6. Reaching Higher, Canadian Herritage., (2014). Retrieved from http://www.coach.ca/files/FMS_PD__Powerpoint_EN_v5_2011_1.pdf
  7. The Complete Pitcher. (2002). Different baseball pitches. Retrieved from http://www.thecompletepitcher.com/different_baseball_pitches.htm