Diving Techniques

Diving Techniques

Track Start Video

Biomechanics of Block Phase

Forward Dive: Grab Start

• Newton's 3rd Law- For every action, there is an equal, opposite, and collinear reaction
• Force- The hands gripping the block increases the force that the block pushes on the swimmer and increases frictional force
• A= F/m
• On an inclined block, both frictional force and block force work in a horizontal direction
• On a flat block, only frictional forces work in a horizontal direction
• Incline of the block affects angle of the body of a dive
• Optimal angle is 3-7 degrees
• Like a long jump, the optimal angle would be 45 degrees but speed is more important than the angle in a projectile motion when it comes to distance
• Center of gravity- Position center of gravity close to the front of the boundary of the base of support

• Traditional diving start
• Swimmer is off the block quicker, but doesn't get as far
• More force applied to block

• Both feet next to each other, 1 foot apart
• Toes curled over the edge
• Knees slightly bent
• Weight is on toes! Not on the heels (hamstring flexibility is key)
• Eyes looking straight down at toes
• Hands on outside of feet gripping the block
• First movement is the arms and fingers, pull up and back on the block
• Pull gives starting momentum
• Push from both feet at the same time

Forward Dive: Track Start

• Stand on starting block, and curl the toes over the front edge of the starting block. For the track start, the swimmer places one foot forward with toes over block edge while the other leg/foot is behind.
• Grab the front of the starting block upon command.
• Put head down.
• Flex knees slightly.
• Keep hips above feet.
• Lift the head, throw the arms forward and push off the block upon command.
• Swimmer drives from the block with the legs.
• Swimmer drops head just before entering water.

Forward Dive

Types of Diving Boards

Types of Dives

So what does this have to do with biomechanics?

• Used in competitive swimming
• Two common dives
• Track start vs. Grab start
• Estimated by Corssor and Mason that the 2000 Sydney Olympic games start times comprised of 8%-26% of overall race times
• An average in a sprint time is a quarter of their race
• 4 Phases of a dive

1. Block phase

2. Flight phase

3. Entry phase

4. Underwater

1.) Forward Dives

2.) Back Dives

3.) Reverse Dives

4.) Inward Dives

5.) Twisting Dives

6.) Armstand Dives

-Springboards: mounted on a spring; allows diver to jump high in air

-Platforms: rigid and inflexible; used from higher elevations

-Diving Blocks: sloped; used by competitive swimmers

• Center of Gravity
• Newtons 3rd law
• Force
• Acceleration
• Friction
• Drag
• Momentum

Grab Start Video

Biomechanics in Other Phases

Is the track start or grab start more efficient?

• Drag force - Force acting on a moving body opposite in direction to the movement of the body
• Acts parallel to the relative velocity

• Swim suits - made with surface pockets that hold air or water particles in the surface layer of the suit (like dimples in a golf ball) reduces surface drag and friction

Track Start vs. Grab Start

The track start is more efficient because COG is placed more in the middle of the block so the swimmer can shift body mass back and forth. The track start allows for more propulsive force. Also there is a greater buildup in potential energy, which can produce a greater force.