The Passive Spring

Storing and utilizing elastic energy is not only an intrinsic neuromuscular quality, but a skill. It requires the proper tensioning and timing of strong structural and contractile properties, which in turn allows them to store and realize the kinetic forces acting upon the body during the amortization phase of the jump. In other words, proper skill and strength allows you to act more like a bouncy ball when you hit the ground and less like a sack of potatoes.

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Again, being able to properly tension is a skill and like all skills, it needs to be trained. Often, we see it being trained through methods that involve “stick and holds”. This is where an athlete may jump in the air and then stick the landing with minimal movement occurring between the landing time and the stopping of the athlete’s momentum. Here, the emphasis is on absorbing loads and learning how to stop with a small amount of vertical displacement. This is a great exercise, but in my opinion, its only a small piece of the puzzle.

The issue with only teaching the jump stick is that we never actually teach the athlete how to utilize the stored energy. The skill of stopping compared storing is similar, but not quite the same.

This is where the idea of the “passive spring” movements come into play. I was watching a video of a high-level jumper and he was performing these “passive” spring movements between his jumps (video below)

 

What you can see here is that in between the hurdle jumps, the athlete is acting as a “passive spring”. He is allowing the kinetic energies to be stored and utilized by his structures without actively “driving” into the ground to produce the upward propulsive movement. Thus, the jumps are occurring somewhat “passively”.

 

Skill and Development

The importance of training the passive spring:

1) The athlete will be getting a stimulus directed towards their SSC and the specific target tissues.

2) The athlete will be learning the skill of proper total body tensioning, which in turn will allow for them to better utilize the SSC.

One of the most underrated aspects of these types of elastic movements is the fact that energy leaks throughout the kinetic chain have to remain at a minimum. Not only do the lower limbs needs to be properly tense, but the core of the athlete has to be completely engaged. Any reduction in core stability will manifest itself through poor spring like mechanics. The body will fall forward, the knees will translate too far over the athlete’s feet and the kinetic energy will quickly dissipate.

How To Train The Passive Spring?

Training the passive spring can be done in a multitude of ways. It is more of a concept than an actual movement. However, if you want to specifically target in complete isolation, I would suggest some sort of low level depth jump.

Below is a video of me performing the passive spring off of a box that is probably too high for my own abilities. I would suggest about a 12-20 inch box to start off with and move up from there. On a side note, notice how I typically jump off the box. I found this to be a useful way of insuring my feet were hitting the ground at the same time. When performing a traditional depth jump, especially from a small box, the trail leg that does not step off the box has to catch up with the lead leg. By adding a small hop, you can synchronize your feet a little better (IMO).

 

 

Conclusion

Training the passive spring is critical. However, like all high velocity movements, progression should not be rushed. If the athlete is unable to properly tense, the risk for injury increases  The passive spring can be added to nearly all jumping exercises and can be integrated into the middle of a set (as seen in the first video). It is a great way to teach total body stiffness.

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Hobara, H., Hashizume, S., & Kobayashi, Y. (2017). Effects of prophylactic ankle and knee braces on leg stiffness during hopping. Open Access Journal of Sports Medicine8, 107–112. http://doi.org/10.2147/OAJSM.S132275

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