Introduction to Plyometric Training (PT)
Plyometric, aka jump training, is a popular concept among fitness enthusiasts, clinicians, and strength and conditioning coaches alike. It refers to exercises that involve rapid stretching and contracting (jumping and rebounding) of muscles to increase power output.
Plyometric work improves specific power associated with low resistance, such as using an individual's body weight or additional lightweight while performing the movement. There are various examples of plyometric exercises, including box jumps, sprinting, depth jumps, and lateral jumps.
In contrast, this is different from __ Olympic weightlifting movements using heavy loads to improve power.
Critical elements of Plyometric Training
Muscle Spindle and GTO are sensory receptors (proprioceptors) that act as an internal feedback system to control the stretch and contraction of muscles.
Muscle Spindles
Location: MS aligns with muscle fibers in the muscle belly
Role: Sense a stretch in the muscle and signal the Central Nervous system (CNS) to invoke a muscle contraction.
"MS plays an essential role during the concentric phase of Plyometric Training."
Golgi Tendon Organ (GTOs)
Location: GTO locates between the muscle and tendon junction.
Role: These GTO receptors sense the tension in muscles and signal the CNS to inhibit muscle contraction, which helps the muscle relax.
"If the amortization phase in Plyometric Training extends by a few seconds, the simultaneous GTO activation drops force output."
Next, the article discussed the different phases of Plyometric Training.
Phases in Plyometric Training
While performing plyometric exercises, an individual will experience three distinct phases responsible for the output of Plyometric Training. The phases include:
- An eccentric phase (pre-stretch).
- Amortization (transition).
- A concentric phase (explosive force).
These three phases make up what is known as the "stretch-shortening cycle."
Eccentric phase (pre-stretch)
The muscle undergoes a pre-stretch during the eccentric phase, storing potential elastic energy. This stage comprises movements such as deceleration, absorption, or loading.
For example, a player pulls back his hockey stick before aiming for a goal. And when a fielder pulls back the arm before throwing the ball towards the wicket-keeper in cricket are both examples of the eccentric component.
Amortization phase (transition)
The amortization phase is the brief delay between the pre-stretch and explosive force phase in a plyometric exercise. The AP is a critical component in the performance of Plyometric Training since shorter amortization phases lead to better force output in the following concentric phase.
However, suppose the amortization phase extends over a few seconds. In that case, the stored elastic energy is wasted and dissipated as heat energy. As a result, the stretch reflex elements do not activate, resulting in a weak force output of the concentric phase. Therefore, an individual practicing plyometric training should aim to reduce the time taken to rebound.
Concentric phase (explosive force)
The final output phase in a plyometric exercise refers to the concentric phase. And the blending of the three steps together defines the stretch-shortening cycle. The explosive force or high force shortening of the muscle fiber results from the fast recoiling of the muscle spindle due to the elastic energy stored during the eccentric phase. For example, individual redirects stored energy by slinging the ball for a six in cricket or jumping to a great height after the dip.
Conclusion
The principle of specificity should be kept in mind when deciding to add plyometric exercises to a training program since it may not be necessary for all the clients. The plyometric exercises occur at high speed, generate high forces, and are multidirectional. Therefore, only individuals who need explosive and powerful movements in recreational or professional activities should consider adding them to meet the desired objective.
References
- George Davies, R., 2022. CURRENT CONCEPTS OF PLYOMETRIC EXERCISE. [online] PubMed Central (PMC). Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4637913/ [Accessed 10 February 2022].
