April 21, 2016 Vincent Vis

So you think you can land?

 

I was talking a few weeks ago about landing mechanics, showing from a bigger perspective how disconnected we are from our bodies. Today as promised, I’ll go over some concepts to satisfy the appetite of the knowledge-nerds in the audience.

Technique VS “Oh Shit” Moments

I am about to introduce you to the correct mechanics of landing on your feet after a jump. We will therefore consider landing in a context of longevity: what are the joints supposed to do, how and why, discarding the context of life, where alignment doesn’t exist 24/7, and where shit happens. As such, there is a growing school of thoughts that promotes “out of alignment” drills, in order specifically to prepare the body for these kinds of situations instead of sugarcoating it in an incubator environment. I’d suggest you look into the Eartquake concept from RootlessRoot if you want to learn more about this.

Please also have a look at my forewords about the scope of these kinds of posts here.

A (slightly technical) definition of landing

Landing on our feet is the final phase of a jump and is all about decelerating properly. It is the landing time that will make a difference between a hard jump and a soft jump. It is therefore deceleration (getting slower and slower), not speed (being slow or fast), that will interest us when landing. Deceleration is what happens between the moment the feet touch the ground at a given speed and the moment when the speed of the body equals 0 (stillness).

Different forces interact during landing: gravity, ground reaction, muscular force & ligament force. As you land on the floor, the ground reaction will initiate a shock wave in the body that is likely to create compressing forces and deformations. Now, bear with me a little more and reread this paragraph a few times if you have trouble processing it: the intensity of the ground reaction depends on gravity (which is constant), mass (weight of your body, which you can’t really change overnight either) and deceleration. Deceleration itself deepens on speed and the landing time.

In other words: the only way for you to mitigate the intensity of the ground reaction, and its resulting compressing forces, is to decelerate as much as possible.

One more brain wrecking distinction: decelerating does not me going slower. Again it’s not about landing slowly, it’s about decelerating each segment so that the shock wave is absorbed properly.

Wait, how jump can be damaging?

Consider this: the human body is comprised of multiple joint segments. When it lands, our body acts like a set of dominos, not a rock: the shock wave is propagated along the dominos. The first segment that touches the ground therefore undergoes a huge deceleration that will create a compressive force that will be transferred to the next segment and so on and so forth, up to the top of the spine. The shock wave therefore travel from your tiptoes to your skulls.

So what’s the difference between a good and a bad landing you say? Simply put, as we were saying before, we want to decelerate more to mitigate the ground reaction. And to do that, the more we can use all segments available to us to slow down the landing, the less the compressive force will be.

Some body parts are more prone to injury than others during landing:

  • Perineum: when the pelvis stops its motion when the body lands, the viscera smash against the pelvic floor.
  • Internal knee ligaments.
  • Intervertebral disks.
  • Cartilaginous joints, sensitive to compression due to the landing.

But wait, I would know if I could not jump properly!

Thank you for asking! Actually, chances are you wouldn’t. There is a consensus amongst experts today to say that the cartilage (if you don’t know what that is, I’ll post about it later, meanwhile you can ask Wikipedia) is not vascularized and innervated. In other words, we don’t feel any stress in the cartilage of our little knees even if we land as bricks on the floor. You sprained your ankle? Good. Unfortunately, they may only be the tip of the iceberg.

So again, how can we mitigate the force applied to the body when landing?

  • Changing the footwear. Cushioned footwear may increase the delay of landing (you decelerate more) and as such decrease the forces, but as they impair proprioception, they can create problems about technique.
  • Changing the floor: the softer the floor, the more time you land, the less force your body will take on
  • Changing the landing technique.

What is a good landing technique?

A perfectly executed jump is when each joint will flex to slow down the movement (increase the deceleration) before the shock wave gets to the next segment, until the body is still.  Each joint is therefore an opportunity to slow down the propagation of the shock wave and the associated trauma. As such, a correct landing implies:

  • A movement where all segments possible are used to decelerate
  • A movement where full ROM is used: if the joint is fully extended before touching the ground, it has more time and power to decelerate during the flexion
  • A good muscular control and strength in eccentric phases
  • good coordination (flexing at the right time)

If you jump in your own movement practice, it is time to record yourself, ask a spotter to watch you, and investigate with these few concepts.

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