Mechanical Principles   

      Teaching a new skill can often be achieved by various methods. The problem is how to determine which method should be used for athletes who may require different approaches to achieve the maximum result for the time and energy expended.  It is possible to transfer techniques developed and used successfully in one sport and utilize the knowledge in another sport.

      Sound mechanical principles can serve as a valuable guide in developing technique for specific sports; however, applying these principles must be accompanied by the sound application of training principles combined with effective teaching methods and an inspiring and motivating environment.

1. Law of Intertia
2. Relationships between force and accompanying change in motion
3. Law of Interaction

• Gravity - constant, energy conserving
• Spring forces - position dependent, velocity dependent, and energy dissipative
• Friction - direction dependent, energy dissipative
• Viscous drag force - velocity dependent, energy dissipative
• User interaction forces - direct controll of position and velocity is unnatural, a better choice is interaction through external force, e.g. mouse spring (time dependent, not energy conserving
• Constraint forces - restrictions on motion can be imposed using constraint forces, constraint with allowed positions/velocities force (position and/or velocity dependent

• An object will experience partial or complete cancellation by oppositional forces. Multiple forces apply to the same point will react of if there was a single force.

• To achieve skilled movements, athletes must effectively combine linear and angular motion. For example, a skater must takeoff and land on edges that represent the same curivature for high marks in execution.
  

• When two or more motions are necessary, an athlete must continuously execute the complete sequence of movements. For example, if a skater hesitates, skids, or stops at the end of the extended axel takeoff, the advantage of the skater's forward velocity is impeded and reduces the potential spring to achieve the desired elevation.
  

• Athletes can increase mass and/or velocity to achieve gains in momentum proportional to the energy expended. For example, in sports like football, basketball, hockey, etc., when a player increases his/her weight without any loss of speed, it is more difficult for an opposing player to alter the opponents forward progress.

• Efficient Transfer of momentum from individual segments to the entire body. For example, a skater performing a step sequence must use the driving action of his or her arms to contribute to the total momentum and direction of the body whwen performing their turns.

• Forward and backward acceleration is proportional to force. For example, a skater increases acceleration by increasing the force that he/she applies against the ice. Increasing force by 10% causes a 10% increase in acceleration. A loss of weight, while maintaining the same level of force (power), would cause acceleration to increase.

• Maximum acceleration is achieved when the entire body is coordinated so as to maximize and controll forward or backward momentum.

• Minimize body actions that do not contribute to a skill should be avoided to prevent wasted energy that can be otherwise applied towards completing productive movements.
  

• The speed of the body's rotation in spins or jumps is affected by the length of the radius. Lengthening the radius slows the rotation and shortening the radius increases rotation. For example, a spinner rotates faster, when the arms are pull in closer to the body because the spinning radius is shorten. A camel spin results in a slower spinning rotation because the spin's radius is greater (longer}.

• When jumping, the trajectory in the air is established at take off. Once a long jumper is in the air, his or her arms or legs may cause body rotation that is rotating off axis, but the flight path is not affected.

• The ice is a solid surface that offers the same amount of force back as is generated against it.  A softer surface absorbs a portion of the energy applied against it.  Note: there can be groves cut into the ice by the blades of other skaters that may cause an edge to slip sideways which can alter a skater's  ability to spring from the ice and alter the trajectory/arc of the jump.
  

• To achieve maximum jumping height, push directly downward upon take off. The direction of counterforce is directly opposite that of the applied force, and the applied force is most effective when it is perpendicular to the supporting surface because "the loss of the edge" is minimized.

• Maximize total force. When jumping the total elapsed time in the air depends upon the both the body's momentum over the ice and the upward spring (height) generated.