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Biomechanics of Hockey Slap Shot
Transcript of Biomechanics of Hockey Slap Shot
The Slap Shot
The slap shot is a type of shot in hockey where the hockey player takes a shot with a wind-up motion followed by a follow through motion. The slap shot is one of hardest shots that a player can perform in the game of ice hockey.
The main purpose of a slap shot is to generate as much force as possible at a high speed
. The slap shot is not necessarily the most accurate shot a hockey player can take, but it is the most powerful shot a hockey player can take.
Because the whole body is involved in the process of taking a slap shot, it can produce great amounts of force.
The slap shot is performed through 6 phases.
The 6 phases:
During the backswing phase the player will wind up to prepare for the slap shot. This wind up involves the player raising their hockey stick up in the air behind them as far as they can.
During the downswing phase the player will swing the stick down towards the puck.
The preloading phase involves the bending of the hockey stick before puck-blade contact
What is Hockey?
Hockey is a contact team sport played on ice, usually a rink, in which two teams of skaters use their sticks to shoot a puck into their opponent's net to score points.
Hockey teams usually consist of four lines of three forwards, three pairs of defencemen, and two goaltenders.
6 players from each team are on the ice at a time; 3 of these players will play the forward position, 2 of these players will play the defence position and 1 player will play the goaltender position.
Newton's 2nd Laws (Law of Acceleration)
Center of Mass
Summation of joint moments
Continuity of joint moments
How long should your hockey stick be?
Hockey sticks should be an optimum length. The optimum length for a hockey stick would be from the ice surface to the player's chin or from the ice surface to the player's nose.
This length will allow the player to generate maximum linear velocity, while at the same time not impairing their shooting technique.
If the hockey stick is too short it will result in a decreased radius which can result in a decreased linear velocity and decreased speed of the shot.
If the hockey stick is too long it will interfere with their swinging motion during the windup phase. This can have an affect on the angular velocity of the stick, which could result in a decrease in the linear velocity.
The players want to have their stick at a optimal length, as they do not want the length to impair their ability to swing the stick. The hockey player will want to be able to swing the stick in such a manner that it will generate maximum force and velocity.
Hockey players want to generate as much linear velocity in their slap shot as they can, as this will result in an increased speed of their shot.
Linear velocity is known as v=wr, where r represents the radius and w represents the angular velocity.
The hockey player needs to remain stable and balanced while performing the motions of the slap shot.
Center of mass is the point around which the mass of the body is balanced.
Stability refers to not easily moved or thrown off balance. It is the capacity of an object to return to equilibrium or to its original position after being displaced.
The base of support refers to the area beneath an object or person that includes every point of contact that the object or person makes with the supporting surface.
Center of Mass
In order for a hockey player to maintain stability during a slap shot they need a bigger base of support and a lower center of mass:
The bigger the base of support, the more stable they will be
. The hockey player should have a wide stance with their feet spread apart, the wider stance will create a bigger base of support and will allow them to be more stable.
The lower the players center of mass, the more stable they will be
. The hockey player should have their knees bent during the motion of a slap shot, this will allow them to be low to the ground resulting in a lower center of mass.
Center of Mass
In order for the hockey player to stay balanced during a slap shot their center of mass has to stay inside their base of support.
The closer the center of mass is to the base of support, the smaller the force required to push the center of mass outside the base of support. It is not just a matter of how big the player's base of support is, but the location of the player's center of mass within the base of support.
If the player's center of mass falls outside their base of support, then their stability will be disrupted. This does not necessarily mean they will fall, but it means they will be unstable and may need to take a couple of strides to regain their stability and their shot will be affected.
The greater the impulse generated during a slap shot, the greater the speed of the slap shot.
Impulse has a direct relationship with force and time (Impulse= force x time). An increase in time will result in an increase in impulse. Therefore, an increase in the amount of time the stick is in contact with the puck will in turn increase the impulse.
How would a player increase the amount of time that the stick is in contact with the puck?
The amount of time that the stick is in contact with the puck can increase by increasing the amount that the stick is bending. During the loading phase of the slap shot, the player will bend their stick as much as they can to increase the time contact between the stick and the puck. The ability of hockey players to flex their hockey stick will in turn increase the puck and stick contact time duration.
Summation of Joint Moments
A hockey player must use multiple joints when taking a slap shot to generate the most force. The more joints that are involved in a motion, the more force that will be generated.
This biomechanics principle is very important when a player is taking a slap shot because they are ultimately using their whole body.
The player must use their upper body, torso, hips, and lower body throughout this motion.
In order to generate maximum force they must use the joints of the upper body including the shoulder, elbow, wrist, and then as well the torso and hips, and then finally the lower body including knees and ankle joints.
The summation of these joint moments will ultimately generate maximal force, which will result in an increased speed of the shot.
Continuity of Joint Moments
In order for a slap shot to generate maximal force it has to be done in a coordinated, continuous manner. The motion of the slap shot should be continuous with regards to the joint moments and the timing of the player's movements should be coordinated.
Performing the slap shot in a coordinated manner will result in greater force production, which will result in an increased speed of the shot.
Continuity of Joint Moments
As the player proceeds with the backswing phase they should be using the joints of the upper body to generate force, as they move into the downswing they should start to shift their weight from their back foot to their front foot, pushing the energy forward allowing for maximal force production. During the weight transfer the player will use the joints of the lower body, torso and hips. The shift of the weight as the player is proceeding through the downswing phase will allow for a smooth continuous motion. As the player is completing the preloading and loading phase of the shot, the weight is already shifted to the front foot. The player then releases the puck and finishes with a smooth follow-through motion.
It is important for the player to use their whole body in a coordinated, timed manner when taking a slap shot in order to generate maximal force. Failure to perform these motions of the joints in a continuous, coordinated manner will result in a loss of force production which will result in a decreased speed of the shot.
Newton's Second Law: Law of Acceleration
Newton's second law states that force= (mass)(acceleration)
There is a direct relationship between the force applied to an object, the mass of object and the acceleration of an object.
The greater the force applied to an object, the faster it accelerates. Therefore, the greater the force the player applies to the puck, the faster the puck will accelerate down the ice.
An increase in the angular velocity of the stick will result in an increase in the speed of the slap shot.
Angular velocity is the change in angle over the change in time. Therefore, there is a direct relationship between the measurement of the angle between the stick and the ice and the angular velocity.
An increase in this angle will result in an increase in the angular velocity.
For a player to increase the angular velocity they should increase the angle between the stick and the ice.To increase this angle the player should raise their stick as high as possible during the first phase of the slap shot, the backswing phase.
As the player increases the height of their stick, they will increase the angle between the stick and the ice. As this angle increases this will result in an increase in the angular velocity, which will result in an increase in the speed of the slap shot.
Here's a look at the Slap Shot:
The loading phase involves the bending of the hockey stick when it is in contact with the puck.
The release phase is when the hockey player releases the puck off the blade of the stick.
6. Follow Through
The follow through phase includes the continuous motion of the hockey stick pointing forwards towards the target after the player has taken the slap shot.
In this video, Patrick Kane of the Chicago Blackhawks performs the Slap Shot. You can clearly see the 6 phases of the slap shot being performed here;
Kane starts off with the backswing phase. During this phase he has a great wind-up with his stick high in the air. The height of the stick during the wind up aids him to generate force during the shot. He then proceeds with the downswing phase, and then following with the preloading and loading phase. The preloading and loading phases are when the stick stores great amounts of energy. Kane then transfers this energy that is stored in his stick to the puck. This stored energy helps to generate force in his shot. Kane then releases the puck and finishes with a follow through.
Let's Look at the Biomechanics Involved:
How can a hockey player increase the amount of force that is applied to the puck during a slap shot?
The picture to the left illustrates a great height for the stick during the first phase of the slap shot, the backswing phase. This is a optimum height where the player can increase the angle between the stick and the ice, which can increase the angular velocity of the shot (as the previous slide discussed). This is a great height to allow for an increase in the angle, while at the same time the stick is not too high that it would interrupt the player's shot technique.
When a player is taking a slap shot the radius would be considered the length of the stick. The longer the hockey stick, the greater the radius.
Therefore, there is a direct relationship between the radius and linear velocity, as the radius increases, the linear velocity increases.
Thus, a longer hockey stick will result in a greater radius which will result in an increase in linear velocity, allowing the player to generate a greater speed during the slap shot.
Relationship Between the Radius and the Linear Velocity:
Relationship between Angular Velocity and Linear Velocity:
There is a direct relationship between the angular velocity and the linear velocity. Linear velocity = (radius)(angular velocity)
Therefore, as the angular velocity increases, the linear velocity increases.
The greater the impulse, the greater the change in momentum, which will result in a greater final velocity of the puck .
Therefore, as the hockey player has an increased time that the stick is in contact with the puck, the impulse will increase. As the impulse increases, the momentum increases which will result in the final velocity of the puck to be increased, ultimately resulting in an increased speed of the slap shot.
This player has a wide stance, which means he will be more stable.
Here's an Overview of the Phases:
As the angular velocity increases...
It will result in an increase in the linear velocity!
How does a hockey player stay balanced while taking a slap shot?
There is a direct relationship between the radius and the linear velocity, and the angular velocity and the linear velocity.
Change in angle
Change in time
The Biomechanics Behind the Bend in the Hockey Stick:
Hockey players bend their stick during the preloading and loading phase of the slap shot to increase the amount of contact between the stick and the puck, as previously noted.
The bending of the stick also allows the stick to store energy. The stick is ultimately behaving like an elastic band, storing energy as it is bending. As the stick is bending it is storing energy, as the puck is released the force is released from the stick allowing the stick to go back to its original shape. As the stick goes back to its original shape the energy from the stick is then applied to the puck.
The player transfers his weight from his back foot to his front foot.
The bending of the stick and the transfer of energy from the stick to the puck allows for an increased force generation which will result in an increased speed of the slap shot.
Hockey player's use their whole body during the motion of a slap shot, therefore they are using multiple joints during this motion.
Because they are using multiple joints, it is important that they use these joints in a coordinated, orderly manner. When the slap shot is done in a coordinated manner it will result in the greatest force production.
It is important to consider these 2 biomechanics principles during the motion of slap shot:
Summation of joint moments
Continuity of joint moments
It is important that multiple joints moments are involved during a slap shot. The arrows indicate some of the joints involved in the slap shot.
It is important that the player's center of mass stay inside their base of support to prevent a disturbance in their balance that may disrupt their slap shot.
In this picture the player's center of mass is within their base of support thus the player is balanced.
This player has a low center of mass, which means he will be more stable.
By: Krista Tobin 201333192
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A disturbance in the player's balance during a slap shot may result in a decreased force of the shot which can result in a decreased speed of the shot.
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