Player shooting (the slap shot)

It happens again and again in hockey. A player streaks down the wing and winds up for a slap shot and before the goalie can move, the net behind him bulges. It's one of the most exciting moments in a game and yet it's over in the blink of an eye. Most of us think the slap shot has existed since the creation of hockey but to our surprise, the slap shot is a relatively recent development in the game of hockey. It is said that Bernie "Boom Boom" Geoffrion "invented" the shot in the 1950s, but Bobby Hull popularized it by slapping his way to several 50-goal seasons in the 1960s. Today, the slap shot is an essential weapon for all players. Even so-called defensive defensemen are expected to be able to serve up an impressive canon-like shot. The slap shot is without a doubt the fastest and strongest shot in hockey. It has been proven by a defenseman Al Iafrate who served up a shot that was clocked at well over 160 km per hour.

The secret in the slap shot, according to defenseman Doug Bodger, is "mostly technique and that the power comes from a weight transfer". The energy needed to make a slap shot is generated by the weight transfer from the persons back leg through the stick in his hands.

The slap shot consists of 6 steps.

�                    First of all, there is the preparation, the positioning, and the body stance.

�                    Secondly, the windup, it consists of a player drawing his stick back by raising his posterior arm and rotating both his trunks and hips to raise the blade of his stick as far behind and above him as possible. The further he winds up, the more strength the shot will have.

�                    Third, the downswing, the player rotates his hips, trunk and shoulder, causing the stick to accelerate forward and downward until the blade comes in contact with the ice approximately four inches behind the puck. This is done to cause the stick to bend when it reaches the puck, the curved stick releases the energy caused by the bending of the stick as it snaps towards the puck and as the swing follows through, the rest of the energy transferred by the weight, is then released in a single blow.

�                    Forth, "loading the stick", At this point, the shooter continues to apply pressure on the stick by pushing the lower hand against the shaft and holding the upper end of the stick close to the body. This causes the shaft to curve and thereby store energy. The height of the lower hand on the shaft is critical. If it is too high, the shooter will not be able to bend the shaft enough to maximize energy load, if it is too low, not as much energy will be transferred to the puck. The best compromise position is set by a variety of other factors. This step is the most important stage of the slap shot because so much of the velocity is generated here.

�                    Fifth, the impact. As the movement continues, the blade catches the puck, releases energy and accelerates the puck as it clears the ice. Ideally, the puck is struck by the heel of the blade, which is the "sweet spot" of a hockey stick: because it is closer to and in line with the shaft it offers better energy transfer. The further out on the blade, the more twisting force, there is. That's why players can take flick shots off the tip of the blade that rise quickly but lack the speed of shots taken at the heel. During this stage of the slap shot, the shooter rotates the shaft forward so that the blade turns over until it faces down toward the ice. This motion increases the acceleration of the puck by keeping the force on it instead of letting it roll off an open-face blade.

�                    And the last step, "the follow-through", The player allow the body to rotate and move forward so the stick moves forward and upward in front of the body. Not all the energy built up previously can be transferred so the body must reabsorb it and by following through the movement, the shooter reabsorbs it. If he did not reabsorb it, he would fall over or even risks doing some damage to his muscles.

The stick is made to be flexible in order to use torque movement to make stronger shots. After testing the resistance of a fiberglass hockey stick with a wooden replacement blade, the people at The Exploratorium's Science of Hockey discovered that it takes about one ton of force to break it. We can observe in the hockey games that many sticks are broken after the players make slap shots. This only shows how strong a slap shot is.

The puck's shape is an element that helps the accuracy of the slap shot; its flat surface prevents it from bouncing a lot because the puck is in some sort, aerodynamic, the air passes above and under it, maintaining it in the horizontal position, hence providing more friction on the vertical level and maintaining it at ground level. The NHL rulebook states that pucks must be one inch thick and three inches in diameter and weigh between five and one-half and six ounces. That�s the same puck normally used by all hockey players, except younger kids, who often use smaller, lighter pucks. Puck shooting works in the same way as a projectile. The force acting on it is caused by the energy transfer from the stick to the puck and an other force that acts on it is gravity which pulls the puck down and giving it a bit of acceleration as it falls if it is lifted (a= 9.8m/s) and an opposing force which is friction generated by the air on the puck. The initial velocity can be calculated by using the formula: Dx/t = v_xo .

Equations that describe the motion of a projectile are:

1. Dx = v_xot
2. Dy = v_yot - 4.9m/s² t²
3. v_y = v_yo - 9.8 m/s² t
4. v_y² - v_yo² = -19.6m/s²Dy

The force acting on the puck after it has been shot are:

F: Force from shot

Ff: Friction from air

Fg: Force exerted by gravity

In the NHL, they use frozen pucks. When a puck is frozen, a thin layer of ice forms on it, reducing the friction between the puck and the ice surface. After freezing, pucks slide better, go faster and bounce less, making it easier to puck handle, pass and shoot. This factor enhances game play and entertains the millions of hockey fans.

The slap shot is an essential weapon in this game. With the proper technique, speed and strength, these shots are practically impossible to stop if they are shot from a close enough range. These shots are the strongest and most interesting of the types of shot used in hockey.