by Benjamin Boehme
In this article I will write about the importance of stretching for freediving and how and when it is best done. I believe that stretching plays an important role for any kind of sport as stiffness in muscles cannot be of good use. In all sport I did so far I used to stretch at least a bit from time to time, but only when I started to freedive stretching became more and more important for me.
Often you see freediving schools who are linked with yoga centers or offer yoga classes. Many people found yoga through freediving and vice versa. In general, the flexibility that yoga and stretching provides is very useful to prevent muscle cramps, which could be very annoying on the ascent of a deeper dive or actually at any time. I’ve been diving with people who told me they use to get cramps at the end of almost each session. So stretching and proper hydration would be a way to get rid of those cramps. Other than that stretching plays a major role for your diving technique. If it is the flexibility of your ankles for a proper bi-fin (or flutter) kick or the shoulder flexibility to properly and comfortably raise the arms above your head for better balance and streamlining in monofin swimming.
Swimming with a monofin requires great flexibility in the shoulders, lower back, feet and ankles. Photo credit Jacques de Vos Photography
One of my spearfishing friends broke his ankle once and now has a metal plate in his foot. Since then he can’t properly stretch out his right foot which negatively affects his finning so that he ends up bending his knee too much and therefore loosing efficiency during his diving. Of course, I told him to stretch his ankle at least once a day to slowly get more flexible and maybe get back or at least close to normal. This ankle also affected his freefalling as his brain thought his foot was fully stretched out which it was not so he had to constantly focus on it which leaves less space to focus on other things like for example proper equalization.
Another very, very important benefit of stretching is to avoid/ prevent squeezing the lungs, of which a lot of freedivers have at least suffered once, or suffer regularly and struggle to overcome this annoying problem. Of course flexibility is not the only factor playing an important role when it comes to causes of lung squeeze, but it is one more variable less if you stretch your diaphragm and chest properly. I will go more in detail about causes of lung squeezes and squeezes in general later. For now we only focus on inflexibility as a cause. The science behind lung squeeze (also called lung barotrauma) is still being discussed, but it is quite safe to assume that one of its causes is the breaking of alveoli (tiny air sacs in the lungs) which will let blood flowing inside the alveoli (as nature wants to equalize the difference in pressure between the ambient pressure and the freediver airspaces’ pressure). If your diaphragm and rib cage are not flexible enough, they cannot compensate for the volume decrease of the lung volume, To make a comparison that is easy to understand, imagine taking an empty plastic water bottle which is taken down to depth. You will observe that the bottle starts to shrink as the pressure increases. At some point the plastic will not be flexible enough and will break and therefore allow water to get inside in order to equalize the pressure.
So what does stretching has to do with it?
You can increase the flexibility of your diaphragm and your rib cage to decrease the probability of a squeeze. One simple stretch that helps you do this consists in exhaling fully and then pulling up your diaphragm into your chest. Of course, the more you are able to exhale the more will you be able to pull up your diaphragm as your lungs are getting smaller. You should not try it out for the first time without proper instructions and always slowly progress to bigger and bigger exhales up to reverse packing. This is the most basic form of empty lung stretching, which is actually a yoga practice. There are numerous variations becoming more and more advanced but the purpose stays the same.
We always do a stretching session at the Blue Hole before training. Freedive Dahab instructor Waleed running one during our last training week.
Another benefit of being flexible is that equalizing actually gets easier. Even if you use the Frenzel equalization method which is the safer and better way of equalizing compared to the Valsalva technique, you will notice as you get deeper that it eventually becomes harder and harder to equalize the increasing pressure in your middle ear. One of my spearfishing friends got the same problem at around 28 meters. He was puzzling: “How comes that people dive deeper than 100 meters and I am not able to pass the 30 meter mark?” Clearly he hasn’t heard of the residual volume before.
Our lungs are not collapsible; there is always a relatively small amount of air left in the alveoli. That means that after you fully exhale the air of your lungs there is still air left inside which is normally around 20 to 25 % of the total lung volume. On land you can reach the residual volume by exhaling fully but another way is also to dive to depth until your lungs eventually compress to the residual volume. So if residual volume means that you cannot exhale air from your lungs anymore it also means that you won’t be able to equalize with the normal techniques you’re used to do. And that’s exactly the problem my spearfishing friend has. One option would be to change your way of equalization and learn the “mouthfill” technique but stretching can also help hugely: in fact there are a few top freedivers who don’t use mouthfill and dive very deep (100 meters and below), and they can do that because they are extremely flexible in their chest and diaphragm. This flexibility has to benefits: it increases the air you can breathe-in before a dive and it reduces your residual volume, which allows you to bring air up from the lungs at greater depth so that you can equalize your middle ears further.
As you can see there are numerous advantages of stretching. And what are the disadvantages? Well, it takes time and consistency but correct me if I’m wrong, I guess that’s it! So if you want to take freediving serious and prepare for depth you should bring some stretching into your daily routine to improve your flexibility of your muscles for your equalization, to avoid injuries and perfect your technique. And of course it’s also a great way to wake you up!