Humans have been swimming inefficiently for hundreds of years and could move more quickly in the water by imitating eels and jellyfish, scientists believe.
Experiments by Stanford University have shown for the first time just how the sea creatures undulate through the water, and it has thrown up some surprises.
But new research has found that their undulating motion actually sucks water towards them creating a current which propels them forward. It saves energy and allows them to glide in elegant pulsating movements through the water.
The effect is similar to the dolphin kick used by professional swimmers when they first enter the water and suggests that undulating motion is the best technique in the pool.
“It confounds all our assumptions,” said John Dabiri, professor of civil and environmental engineering and of mechanical engineering at Stanford University.
“Our experiments show that jellyfish and lampreys actually suck water toward themselves to move forward instead of pushing against the water behind them, as had been previously supposed.
“There could be an opportunity to improve human swimming if the torso could play a greater role in generating low pressure via body undulations, as in the eel.
“You can see hints of this in the underwater ‘dolphin kick’ swimming stroke, although the action of the legs pushing the water is often more prominent there.
“The challenge is that humans typically don’t have the same flexibility of motion as the eel, and swimming at the water surface significantly increases the water’s resistance to forward motion.”