The Importance of Head Position While Freediving
Article written by Giray Yalçın - NAUI Freediver Instructor/ PFI Instructor
Incorrect head, neck and body position while ascending or descending is one of the most common mistakes that beginning freedivers make. Properly positioning yourself during dives will not only allow you to maintain a streamlined position and eliminate drag, but it will also help prevent pressure related injuries. In addition, a diver that is properly positioned during the entire course of the dive will find it easier to relax and equalize. Initially, it may not feel natural to keep your neck, head and chest in a “freediving-friendly” position, but with practice it will come natural. It is very important to understand the benefits, and also acknowledge the dangers associated with improper positioning.
As much as I hate to admit it, humans are not exactly marine mammals, we are land inhabitants. That truth will never change no matter how much time we spend in the water, and there are some traits associated with being a land inhabitant that we have to train to overcome. While we are walking or changing positions, naturally, our visual observation is directed at the position which we are moving towards. That means if we are walking towards some point in space, our head and eyes are generally directed at that point. Carrying this habit to the water, many new divers and even seasoned spear fishers have a habit of extending the head and neck forward to look toward the bottom (where they are headed) while diving. Diving with your head and neck in this position is a big problem that carries multiple layers of complexity.
When diving to great depths (30+ meters) this habit is often associated with pressure related injuries. Since depth and pressure are directly related, and pressure and volume are inversely related to one another, as we descend to depth, the air spaces we take down with us also reduce in volume. Imagine bringing a plastic water bottle filled with air down to depth. As we descend, the volume of that bottle will shrink and the bottle will become compressed. Our air spaces range from rigid to semi-rigid, and they are the lungs (this cavity has the most amount of air), neck, ears (middle ear is actually a rigid air chamber) and sinuses. During a freedive, all these air spaces are subject to great amounts of pressure. Much of this pressure change happens in a short amount of time when freediving. Considering the atmospheric pressure at 10m is 2 times that of on land, and at 20m is 3 times, for a 20m diver, all air spaces are subject to 3 times the pressure that they experience on land. This is equivalent to the reduction of air spaces by a factor of 3.
At depth, under pressure, given the reduced volume of air spaces in the lung and neck, movement must be very gentle to avoid injury. Lung tissues do not have pain receptors, therefore, injury may not feel painful, and may go unnoticed, but in the long run, repeated and untreated respiratory injuries will create scar tissue and eventually may turn into a very serious and irreversible problem. When we are descending or ascending, looking down or up, respectively, will extend the lung and trachea. The trachea and the connection to the lungs can be observed on Figure 1 below. A diver extending their head will expand the neck and trachea, which will ultimately pull the lungs upwards.
Figure 1One might ask “Well, how does all this relate to head positioning in freediving?” It is related because at depth, under pressure, stretching our neck and chest can cause extreme physical stress and potentially damage the sensitive tissues associated with these air spaces. As a diver descends, their natural urge to look where they are going will add more stress to the neck. If a diver is going to depth, keeping their eyes focused on the line and neck tucked will alleviate the risk of trachea or lung squeeze. Take a look at the picture labeled as Image 1 above. Both divers are kicking down to depth, but neither one is looking at their target, which is clearly below them. The divers are focused on looking at the line between them. To help with proper positioning while diving, imagine carrying an apple or a grapefruit under your chin throughout the dive in order to avoid extending your neck and keep your eyes focused forward on the dive line instead of trying to look for the bottom. Another method is to imagine you’re holding a hypothetical million dollar roll under your chin. The moment you look down while you descend or look up while you ascend, that money is gone, it’s fish chum... Don’t lose your million dollars and keep your head tucked in!
An added benefit of proper head position is being streamlined. If a diver is looking at their target while descending, they will naturally create an arch from their head to their lower back. This will add further drag and not only will it slow down the diver, but it will also require more effort to dive with a profile that is exposed to drag. Pay attention to the diver on the right side above, one hand is used for equalizing, while the other is the safety buffer, making sure she does not hit the ocean floor head first. This way, not only does she comfortably keep her streamlining position, but also keeps herself safe from head butting the reef! Note that we don’t need the line to practice proper positioning. While spearfishing, the non-equalizing hand carries the speargun, and the gun is extended above the head, effectively forming a safety buffer. When descending head down and hand extended, the ground come into view before you make contact. A safe and appropriate strategy would be to use your fins to maneuver your body into a position where you are parallel to the ground, still carrying that million dollar roll, so that you don’t extend your neck under pressure, while scouting for holes, structures or sand patches to lay on.
Finally, keeping your head tucked and avoiding extension of the neck will allow for easier equalization. In freediving, it is advised to equalize early and frequently. Missing an equalization may result in your ears locking and it may prevent you from further equalization, or it may make it harder and less enjoyable for the next iteration of equalization. Let us observe the ear anatomy before diving deeper in this topic. When talking about equalization, it is important to understand the role of the eustachian tubes. The eustachian tubes allow for equalization of pressure in the middle ear with respect to ambient pressure. They are partly a hollow tube in bone, partly elastic cartilage. The eustachian tubes are normally closed and must be opened voluntarily. In the freediving world we use either Frenzel or hands free methods to accomplish this.
As a diver descends, pressure builds around the airspaces, and the middle ear must be equalized so the pressure difference between the ambient environment and middle ear are the same. This takes place by pushing air through the eustachian tubes using one of the aforementioned equalization methods. If a diver is extending the head and neck, they are actually tightening the tubes and making equalization more difficult. Remember, there is already pressure built due to depth, further extension just makes the walls of the tube tighter and makes equalizing the middle ear harder. If you are keeping your head and neck in the correct position you will realize that pushing air through the eustachian tubes will be a lot easier, and the end result will be cleaner, more comfortable dives.
It may initially feel unnatural to avoid looking at your destination while freediving. Remember that your head position is totally within your control. Once you understand the realities of depth related lung and trachea injuries and experience the ease of equalizing and benefits of streamlining when properly positioned, you will get used to the feeling of keeping your chin tucked in.