Blog 1: Plyometrics: The Hidden Engine Behind Explosive Athleticism

Plyometrics: The Hidden Engine Behind Explosive Athleticism

Plyometrics is a term derived from the Greek words Plio, meaning greater, and metric, meaning measure. [1][2]

While strength is a factor in advanced training, the concept that you must have a certain strength level is often overstated when you consider the fundamental nature of plyometrics. In reality, many, if not all of us, have performed plyometrics at some point in our lives. Whether it is running in a play park or dancing to your favourite song, heck even celebrating your favourite team scoring a goal. Plyos are a form of expressing force produced from the body into the ground. The movement is characterised by a system called the stretch-shortening cycle (SSC). This cycle typically involves three movement mechanisms: Eccentric, Amortisation, and Concentric.

Beyond the Legs: The Full-Body Power of Plyometrics

Plyometrics can be things like the examples given like producing explosive ground contacts in running; jumping or hopping movements where you are using your muscles and tendons to propel you into the air either once or repetitively. The upper body and core are often overlooked when discussing plyometrics, yet they play significant roles across a spectrum of movements, especially in running, jumping, and throwing events. Events that require throwing—like field event throwers, basketball players, goalkeepers, baseball players, and many more sports—involves forceful use of the midsection, which involves upper body core muscles like the internal and external obliques, erector spinae (lower back), tranverse abdominis, and the well-known rectus abdominis, also known as the ‘six pack’. The core muscles provide explosiveness in various movement patterns: rotation, flexion, extension, lateral flexion, anti flexion, anti extension, anti rotation, and anti lateral rotation. Core Plyometrics focus on using the SSC in the trunk to generate rotational and anti-rotational power quickly— for example, in a soccer goalie's explosive dive or a baseball pitcher's wind-up. This rapid, forceful use of the core is essential for maximising power.

The Three Phases of SSC

Eccentric movement involves the lengthening of muscle fibres and absorption of vertical forces. Think of when you are lowering the bar after completing a deadlift or when you are landing after jumping off a box during depth jumps. In both examples, the lower leg complex (plantar flexor muscles like calves and ankles) absorb force upon landing, and that force gets transferred back into the femoral muscles (quads, glutes, hamstrings, and hip flexors). The agonist muscles experience a pre-stretch phase, elastic energy gets stored, and the muscle spindles become stimulated. Without muscles and tendons having the ability to work eccentrically, sprinting and jumping would be difficult because every time your leg makes contact with the ground, energy bleeds away and all the force that you were using to strike the ground with gets dissipated, slowing you down significantly.

Amortisation is where the elastic energy stored from the eccentric portion is maintained to prepare for concentric movement. The phase involves the usage of Type 1a afferent nerve fibres which act as stretch receptors to detect the muscle stretch caused by the eccentric loading. They are highly myelinated to send quick and efficient signals to the spinal cord to trigger rapid contraction of the stretched muscle and promote relaxation of antagonist muscles, preparing the muscles for transitioning from isometric to concentric movements. The amortisation phase is known for being extremely quick, with the phase occurring within tens of milliseconds depending on the speed of the plyometric movement.

Think of the amortisation phase as the momentary 'hold' at the bottom of a pogo stick bounce. It must be rapid—a mere tens of milliseconds—because any delay (a long amortisation phase) is like holding the spring down: the stored elastic energy bleeds away as heat, slowing you down significantly. This underpins the importance of being quick to ensure that energy produced in the eccentric acts as an elastic recoil and does not go to waste for the next stage.

This leads me to the next movement which many would associate with plyometrics, and that is concentric movement. This is the muscle shortening movement that your body experiences when you are preparing to jump, get out of the bottom part of a squat, or getting out of the blocks in sprinting. After loading force at the beginning of the movement, the concentric is the flight phase where force produced becomes unloaded, which results in the body pushing away from the ground and into the air. For running, the non-supporting leg will be lifted upwards, and for jumping the legs will elevate upwards into the air.

My Personal Plyometric Journey (So Far)

Being an athlete with flat feet, I learned of the importance of plyometric movements the hard way. When I was 15 I ran one of my first ever 200m races, and being the inexperienced athlete that I was, I never fully understood the importance of striking the ground in the right way. I had a tendency to strike the ground with my heels first instead of my forefoot.

This meant that my Ground Contact Time (GCT)—the overall time for my foot to be on and off the ground—was significantly longer than my competitors. This longer contact time allowed the stored elastic energy to dissipate, slowing me down and increasing the risk of lower body injury due to the highly explosive nature of sprinting.

Watching my race back, I realised how much time I was losing from forefoot striking, and I decided to watch how elite sprinters spend so little time on the ground—and then it clicked: they were efficiently utilising the stretch-shortening cycle (SSC).

As such, I did plenty of sprinting to drill in the forefoot striking technique and also incorporated full-body plyometrics like pogos and bounding to get a feel for how it is like to be explosive and bouncy in my strides. This plyometric work taught my lower leg complex to act like a stiff spring, maximising the elastic recoil of the SSC.

As a result, I was able to drop my 200m time from 27 seconds to 25 seconds just with that one change. Though I can attribute some of the improvement to growth as a teenager, two seconds is substantial in short events like sprinting where tenths and milliseconds make a massive difference between winning and losing.

The Secret is Out: Unlock Your Explosiveness

From the track to the court, plyometrics are unequivocally the hidden engine behind truly explosive athletic performance. By training your body to efficiently utilise the Stretch-Shortening Cycle—rapidly absorbing force in the eccentric phase and explosively releasing it in the concentric phase—you are not just getting stronger, you are getting faster, higher, and more powerful (Quite literally Citius, Altius, Fortius). Whether your goal is a faster sprint time, a higher vertical jump, a powerful kick, or a more forceful throw, the journey begins with mastering the quick, snappy contacts of plyometric training.

References:

[1] Flom, Cynthia K., "Plyometrics" (1993). Physical Therapy Scholarly Projects. 145. https://commons.und.edu/pt-grad/145  

[2] https://www.physio-pedia.com/Plyometrics