By Paul Parker BSc(Hons) MSc
You may well have heard the term “plyometric” training banded around the gym, or the changing rooms every now and then. You may have even seen it referenced on social media, or hashtagged after a video of someone’s box jumps, but what exactly constitutes plyometric training? Should you be incorporating it within your programme? Are you already doing so? This article hopes to shine a light on one of the most high value, high return training modalities available to everyone – and also raise the question as to why some people don’t seem to find them as sexy as other conventional training methods. There is a large and consistent body of research that supports the use of plyometric training when it comes to positively impacting performance. Positive adaptations causing improvements in muscular performance and stiffness consequently improve lower body power, strength output, running economy, jump height, and sprint speed – lending themselves to a wide variety of sporting domains.
Unfortunately though, there is a lack of practical guidelines for plyometric training when it comes to measuring and manipulating plyometric load on a session to session basis, nor on an athlete to athlete basis. It’s important to bear in mind the vast variety between individuals carrying out the same exercise, purely due to kinetics, kinematics, loading patterns, and anthropometry (body shape/limb lengths etc).
So, what are they? Now although other definitions may vary (not to confuse you from the outset), plyometric exercises are technically defined as exercises that occur in >250ms-worth of ground contact time, so typically bounds, repeated jumps, pogo’s etc (and of course SPRINTING). These are exercises that aim to improve your ability to produce, and effectively transmit, as much force as possible, in as little time as possible. That said, I personally do not believe that a “plyometric exercise” must contain a rapid ground contact – and this is not an opinion that is universally shared.
PAUSE! Before this, let’s first look at what makes up a ground contact. We are looking at 3 different components of each single contact from the nano-second we touch down on the surface:
Eccentric – The eccentric component occurs as tissue lengthens and force is absorbed. In an example of repeat jumping, think of this as the downward phase after I have touched the ground, tissue lengthens and my centre of mass lowers toward the floor.
Amortisation – We then have a brief amortisation period, where the tissues neither lengthen, nor shorten, the small window between the down and the up portion of repeated jumping in this example.
Concentric – Yes, you guessed it, we then have the upward portion as agonist tissue shortens as muscles contract and result in us propelling ourselves up off of the ground.
In a plyometric context the rapid nature of the eccentric portion, utilises what is called the Stretch-Shorterning Cycle (SSC), and in turn, produces heightened concentric power outputs to what you would normally generate in a standing position. This is due to the rapid impulse required to effectively kill the eccentric momentum and produce force at a heightened rate to reverse the direction of travel (down to up!)
So, as I was saying – although we can agree that for an activity to be plyometric, it requires a rapid ground contact, hopefully we can also agree that I can train individual parts of the plyometric spectrum (the three phases outlined above) in isolation of each other, without actually having to have a “bounce”. For example, I can improve my ability to rapidly absorb force by doing altitude drops. I can improve my concentric output by intensive jumping.
Plyometric training in my opinion should be a fundamental part of pretty much every athletes training programme. It is often knocked to the wayside because it is more difficult to quantify progression without the appropriate technology, than something as simple as more weight on the bar. That said, there is much higher transfer and crossover to your sport (pretty much irrespective of your sport) to improving your relationship with each foot strike, than any other training modality.
Why do they matter?
Pick a sport, any sport. I can almost guarantee that you can find a game/match /fight defining moment where it would give you a significant advantage to be able to either, produce MORE FORCE, in the SAME TIME as your opponent; or the SAME FORCE, in LESS TIME than it takes your opponent (Or, in an ideal world, more force in less time). Think beating the defender to a ball flashed across the face of the goal to turn the ball home, or euro-stepping your defender on your way to a match winning lay-up, or slipping away from a punch by the finest of margins – creating an angle for you to throw a fight-stopping counter. In any sport, fine margins matter and these defining moments on the grass, the court, the track, or in the ring, can be what matters most when it comes to succeeding where others fail.
And it’s not just for power either… In most of the context used so far, it’s easy to think that plyometrics refer purely to explosive speed and power, and really high threshold movement. But there is also massive benefit for the endurance athlete in improving their plyometric profile. Take endurance running for an example, if the runner can become more effective, and more efficient, in each foot strike then the relative energy cost of said touch down leaves more gas in the tank for the sprint finish victory over the closest competitor (Click here for more information on Stronger Running).
So whether you sprint, run, jump, turn, or hit the floor at all within your sporting arena, there is definitely serious value in plyometric training and if you’re not doing it already, then you’re missing the opportunity to get ahead of your competitors.
How can we factor them in to the program?
Now we have a handle on what plyometric’s are, we need to think about how we can effectively incorporate them within the training programme. We can split our plyometrics into two broad categories before addressing smaller more detailed sub-categories; Extensive and Intensive. Extensive plyometrics can be included into the vast majority of warm-ups as well as any technical session and refer to the sub-maximal accumulation of high volume plyometrics. Varying from Pogo’s, to more coordinative challenging Boom-Boom’s (with an intent of crossing more directly to sprinting), we can increase the robustness of tissue stiffness over a period of time that not only lends itself to better performance, but also lessens the likelihood of injury if done so correctly. The intensive end of the spectrum however is where we build those game winning performance qualities, and as the name suggests, are performed in lower volumes but at higher intensities, and that is what we are going to primarily focus on from here on.
One consideration, is that high volumes of high intensity plyometrics induce high stress (due to the large eccentric load of repeated ground contacts from a height) and therefore, it may not be best advised to immediately start adding 10 daily sets of drop jumps, so instead, we can ride a wave of different plyometric sub-types in order to maximise adaptation, without ever tipping the scale into the danger zone. Below, outlines a spectrum that I have frequently used (taken from a Continuum I first saw outlined by John Noonan) to ensure that a holistic program addresses multiple parts of the spectrum at any one time, with a gradual and transient shift in focus from sub-category to sub-category depending on athlete needs and competence.
Force Attenuation – Before we start thinking about a high multitude of bounds and drop jumps, it’s important we make sure that the tissue is adequately prepared to attenuate force. Personally, I ensure that this element is threaded through an athlete’s programme year round, in a plyometric context. This simply refers to our ability to absorb and accept load, and so it makes sense to master this skill first, before starting to experiment with more high demand, repeated efforts. Examples include simple “Drop and Stick’s” from a standing position, or Altitude Drops to overload the eccentric demand.
Concentric Emphasis – Whilst building the foundation of force attenuation ability, we can also look at developing our concentric output. Although this can be done with standard vertical jumping and box jumping (coming next…), we can also isolate this part of the continuum in order to purely target concentric output. By performing exercises from a seated start (or with a barbell pre-racked on pins) we remove the rapid pre-stretch and instead create a need for the body to produce pre-tension in the relevant tissue. This in itself is a task that novice athletes in particular struggle with, but pre-tension prior to concentric action aids in removing muscle slack, and improves the rate in which force is generated once initiated.
Jump Integration – After emphasising the concentric element, we can start moving on to the integration of jumps within the program. Allowing the eccentric portion of movement to form as the loading mechanism for a jump. As aforementioned, intensive jumping is key when it comes to developing power properties and maximum effort jumping is something I tend to include with nearly all of the athletes I work with, due to it’s exposure to max intent, but also the translation of rate of force development properties that relate so closely to high intensity sporting scenario’s.
Repeated Bout – As we develop proficiency through all of the above, we can start to integrate repeated efforts; consecutive tuck jumps, bounds, hurdle jumps etc, where the height of the fall, is dictated by the height of the previous jump. This can be used not only from a perspective of improving the relevant energetics of repeated efforts, but also for increasing the tolerance, robustness and repeatability of previously isolated efforts.
Shock Method – Shock method training, previously popularised decades ago by Verkhoshansky, are methods in which the eccentric component (loading phase) is heightened in order to overload the force demands and the vertical momentum that then requires a greater use of the SSC in order to jump. Typical examples include drop jumps, and depth jumps. The intensity of the shock method can then be altered by adjusting the mass of the falling weight (adding an external load such as a weighted vest, medicine ball, or barbell) and/or the height in which it falls from (stepping from a higher box into a rapid ground contact/jump.
To programme effectively, we need to understand what we’re chasing (ADAPTATION) We want to improve the relationship between the contractile component and the elastic component of (in this context) the lower body. By exposing our body to a variety of the above task demands, we can create a more powerful and stiff musculotendinous unit (MTU). This means that both the muscle and tendon can produce and transmit force effectively without the need to excessively lengthen in order to create tension. This is incredibly important in running, sprinting and jumping and can be explained using what is known as the Spring Mass Model. Now, it doesn’t relate to a physical spring, however, the vertical stiffness is used to model the vertical drop motion of the center of mass during contact. When sprinting or jumping, we want as little downward displacement of the centre of mass as possible, and therefore stronger muscle, stiffer MTU and in particular greater eccentric dorsi-flexion strength is going to result in a resistance to these deformations.
What can we manipulate? So, with all of this considered, what else do we need to take into account when it comes to structuring our plyometric training? As well as using the continuum outlined above, you should also be thinking about manipulating the three phases outlined at the start, and how simple variations can add novel stress and stimulus to your training to enable progressive overload over time, and ultimately, favourable adaptation. We know that we can manipulate the eccentric portion simply by changing either the weight of the falling person or the height from which they fall. But we can also manipulate the amortisation phase by adjusting its complexity – are you landing on one leg or two legs? are you including the absorption and redirection of lateral or rotational force? and finally, we can add task constraints to the concentric requirements by simply adding a hurdle that I need to clear, or a box that I need to land on (this simply shifts focus from not only rapid ground contact time, but also having a minimum requirement for the concentric output in order to meet a given task.
Of course, with any training modality, it may be of particular interest to keep a relatively good handle on volume, to ensure both progressive overload over a period of time, and also to minimise the risk of overload – instead ensuring that the athlete has developed an appropriate robustness prior to delivering a new stressor. This however, has its difficulty when it comes to plyometrics. In traditional strength training (take the back squat as an example) it is much easier to keep a tabs on load, volume, relative intensity, and time under tension, over a sequenced training cycle, but with plyometrics, it isn’t quite as straight forward.
Some have previously suggested thresholds for “contacts per session” and that beginners should amount to a certain amount in comparison to larger quantities for those with higher training ages and more competence when it comes to the training modality. We’ve already discussed however the range of variety and complexity that can be manipulated in order to vary the demand of any plyometric exercise and so, it scuppers the merit in just counting contacts.
As a coach, or as an athlete, the most important aspect is that you actually understand what you are trying to develop from an adaptation perspective within your training environment. Have you appropriately prepared for the level of exercise complexity? Are you in an appropriate physical state to accept the given training demand? Are you attacking your training from the angle that will best support you and your training needs/goals?
Although I’ve covered quite a broad spectrum of information in this article, I am only really scratching the surface. There are some excellent resources out there from some of the world’s best practitioners, but if you’re interested in learning more – or better yet, you want to be led via a professional through a structured program then contact the clinic on 01732 666050 or email email@example.com
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