In general, surfing consists of gliding down a gradient of water formed by a wave that breaks when it reaches the sea shore.
There are many forms, standing, sitting, kneeling or lying down, with or without a float, and many sports are derived from it, surfing, windsurfing, body surfing, kayaking, paddle-surfing, tow-in surfing, etc.
In all cases, surfing can be broken down into two stages:
– Getting behind the breaking waves, by going through or around them
– Descending the breaking waves, sliding down the moving face.
In surfing, the surfboard and surfer gliding across the water is subject to a multitude of forces, Archimedes’ force, gravity, centrifugal force, friction, hydrodynamic resistance, lift and so on.
When in motion, balance is achieved by moving the surfer’s centre of gravity so that all these forces are equalised.
The model is quite complex (the gradient of the wave changes, the human body moves, and so on), but actually, the practice is very instinctive:
In the prone position, to paddle and move in flat water, the surfer must place his centre of gravity on top of the board’s centre of buoyancy, just slightly behind it to stay horizontal, and can keep their balance just by moving their head (which is almost 7% of total body weight) to one side or the other, forwards or backwards.
When they cannot go around breaking waves, in order to get past them, the surfer must tilt the board steeply forward, or dive “like a duck”, to go under the wave and come out behind it. In order to do this, they must move their centre of gravity forward so that the board pierces and goes under the wave, and then move backwards quickly to exit the wave. This technique only works with low volume boards. With higher volume boards, one of the techniques used is for the surfer to protect themself from the impact of the water, using the board as a shield by rolling over with it. The last technique is to leave the board (which is attached to the ankle with a leash), and to go underwater while the wave is breaking, then resurface, get back on the board and continue paddling.
To surf the wave, the surfer must first synchronise his speed with that of the wave, paddling for a brief moment and accelerating strongly. This is the part that requires patience (waiting for the right wave and the right time), strategy (choosing the right place to start accelerating, anticipating the point where the wave will first break), dynamism (without enough acceleration, the wave escapes) and balance (as the gradient of the wave increases, the surfer must keep balance by moving their centre of gravity). As soon as you have achieved this synchronization, you must turn quickly away from the peak, to stay on the face without being enveloped by the closing wave, with a trajectory parallel to that of the waves, and for this you must move your centre of gravity towards the rails of the board. Standing on the board is a variant that makes it possible to move your centre of gravity more easily, but with the increased difficulty of “popping up”, where the surfer gets to their feet at the end of the synchronization.
The different modes of surfing – bodyboard, SUP, windsurfing, kayak surfing and tow-in surfing – have brought a variety of solutions to the problem of propulsion (fins, a paddle, a sail, towing by a jet ski) and ways of engaging with the board (bodyboard always in a prone position, SUP, windsurf and tow-in always standing and kayak surfing always seated).
Surfing can be practised at any age, gradually and safely if the usual precautions are followed. As with everything, the level of risk can be increased by those who choose to do so. Known risks include the size and power of the waves, the nature of the seabed and certain animals.
Some forms of surfing are practised by people with disabilities. But these are still a minority and are very courageous people with considerably superior abilities.
SUP has been adapted with a paraplegic seat, but only in flat water conditions.
Kayak surfing is suitable for some paraplegics.
Bodyboarding and windsurfing are not suitable for paraplegics.
Basic surfing is practiced by some paraplegics, but they are high-level athletes with slightly adapted boards.
VELTO SURF is the form most appropriate for everyone, paraplegic or not. It helps surfers to align their centre of gravity with the centre of buoyancy of the board, leaving their arms free to move their centre of gravity forward and back, to act on the water by pushing, braking or acting as a rudder. With leg support, paraplegics can control their entire body.