Sian Barris, studying for a PhD in sports at Queensland University of Technology, explains how to make the perfect dive.
Diving is one of the most graceful and spectacular sports in the world, and every four years, at the Olympics, it captures the attention of audiences worldwide. So what goes into the perfect dive?
Diving is physically demanding, requiring stamina and strength as well as speed, agility and flexibility to perform an incredible range of somersaults, pikes, and twists.
Many changes have occurred in competitive diving since its inclusion in the modern Olympics in 1904. Springboards which were once rigid wooden planks sloping upwards have undergone a radical transformation into tapered and perforated aluminium alloy boards mounted level and fitted with moveable fulcrums.
Training methods have become more sophisticated, with an emphasis on dry-land exercises and drills. The difficulty of dives performed in competition have also steadily increased during the last 30 years.
Where once, only a few elite competitors were capable of performing a forward 1½ somersault, dives such as a forward 4½ somersault are now being performed routinely.
But just how do these athletes launch themselves from towers or springboards and disappear beneath the water with almost no splash?
At the moment of take-off from the platform or springboard, two critical aspects of the dive are determined, and cannot subsequently be altered during the execution. One is the trajectory of the dive, and the other is the magnitude of the angular momentum.
Because the initial conditions of the flight, specifically, the angle of projection at take-off, velocity of the centre of mass, and angular momentum, are established during the take-off, this phase plays a major role in determining the outcome of the dive.
During the take-off, divers must produce sufficient vertical momentum for the flight of the dive, adequate horizontal momentum to clear the take-off surface and enough angular momentum to execute the required number of twists and/or somersaults.
The success of the dive is determined by a combination of the divers' position at last contact with the take-off surface and the magnitude and direction of the forces and that have been applied during the take-off phase.
In the air, most dives are performed in a tucked or piked position. The tucked position is the most compact (body folded up in a tight ball, hands holding the shins and toes pointed), and as such, gives the diver the most control over rotational speed. Dives in this position, are therefore, easier to perform.
In a piked position the moment of inertia is larger (as the body has an increased radius) and consequently, the dives tend to have a higher degree of difficulty.
As the diver completes the required number of somersaults or twists, they open the body out ready for entry into the water. The action of opening out and changing body position does not stop the diver's rotation, but merely slows it down.
The vertical entry achieved by expert divers is largely an illusion created by starting the entry slightly short of vertical, so that the legs are vertical as they disappear beneath the surface.
A good entry into the water in competitive diving is one which appears to be "splash-less", is accompanied by a characteristic "rip" sound, and simulates the sound of tearing paper.
The rip entry, considered the "hallmark of a master" looks to a viewer as if the diver is being sucked into the water without a splash.
To achieve a rip entry, the diver's arms must be extended forwards in line with the ears, the elbows must be locked and the stomach and back of the diver must be tight.
One hand grabs the other with palms facing down to strike the water with a flat surface. Impact with the water creates a vacuum between the hands, arms and head which, as the diver enters vertically, pulls any splash down and under the water with the diver until they are deep enough (1-2m) to have minimal effect on the surface of the water.
To be successful at international competitions, divers must be able to perform high degree-of-difficulty dives with reasonable consistency, training 28-30 hours per week.
Training programmes are written for each individual diver for each training session and cover basic water entries (to correct technique), take-off skills, compulsory dives (lower degree of difficulty dives performed in the preliminary rounds at competitions) and optional dives (dives with a higher degree of difficulty performed in competition).
Between each repetition, the athletes receive external feedback from the coach and delayed video replays of their performance from multiple angles, allowing them analyse their dives and constantly fine-tune the execution of these complex skills.
But these Olympic athletes don't do it alone. Behind the divers are a team of dedicated coaches and support staff (trainers, psychologists, dieticians and analysts), who equally commit as many hours to training, sharing their experience and expertise to help these athlete in the pursuit of gold in London.
Editor's Note: Sian Barris is a postgraduate research student at Queensland University of Technology.
She writes for The Conversation