Safe diving: from what height and in what position?

Do I throw myself out of my head or the candle? Wouldn’t that boulder be too high? In your assessments of more or less dangerous diving this summer, you can take into account new biomechanics research, which has assessed the potential for injury when a non-professional diver impacts water from different altitudes and in different locations. The results constitute “scientifically proven” evidence not to let go of the adrenaline-fueled gesture, and to do so safely.

Heights not to be exceeded. Based on the study published in science progressFor untrained divers, the risk of trauma to the spine or neck is likely to be greater than 8 metres, if you choose to jump straight from the head (with your arms at your sides); The risk of a broken collarbone is likely to be more than 12 meters if you decide to dive head first, but you enter First in the water with your hands; Finally, the risk of hitting the knee is more than 15 meters if you jump in it from the feet.

These are the height limits that should not be exceeded based on the position chosen for diving (professional divers, trained to contract specific muscles to reduce impact, and also jump from a height of 58 metres, but that is another matter).

water wall. “Water is a thousand times denser than air, so you’re going from a very dilute medium to a very dense medium, and you have to withstand a very strong impact,” explains Songhwan Jung, professor of biological engineering. New york university). “Humans can choose how to dive, so we wanted to understand the effects of diving posture. But also to come up with a more general theory of how objects of different shapes affect the water.”

The researchers made 3D printed copies of a human torso and head, or a human torso and head with outstretched arms, or human feet of various heights. They did the same with 3D models of a porpoise’s head in the harbor (Phocoena phocoena: a small dolphin-like oceanic mammal), beaked bassana gannet (Moros Basanos, a large seabird) and the leg of a basilisk (a type of lizard). In this way they examined the effect of curved, pointed or flat objects on the surface of the water.

Better be a candle. They also compared the magnitude of the impact to the force that human muscles, ligaments and bones could withstand, to derive the potential for injury of different types – spine, knee or collarbone – depending on the position one is in the water. .

For men, the safest option is to dive “with your feet”, especially if you jumped from too high a height. But it’s also interesting to see how animal anatomy has evolved to reduce the risk of infection for specimens that dive a lot. For example, dolphins have fused cervical vertebrae that cushion the trauma to the spine as they pass from air to water.

More resistant machines. The work is also interesting from an engineering point of view: it is not often the case that you are working on vehicles, such as drones, that travel from one vehicle to another, from air to water or vice versa. Studies of this kind will help to better study its design.