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Introduction
LTAD - a critique
Demands of the game
Profile of players
Functional screening
Resistance training
Speed and agility training
Integrated game conditioning
Periodisation
Content
Questions

Speed development - plyometrics

The stretch shortening cycle - a key concept

We have already introduced the concept of the stretch shortening cycle (SSC) action. It occurs when an eccentric muscle action moves rapidly to a concentric action after a very brief isometric contraction.The SSC action is the key neuromuscular action or mechanism operating in a plyometric exercise, drill or activity. There are three key factors or phases of a true plyometric action:

  1. A rapid eccentric contraction precedes an explosive concentric action – this is the ‘stretch’ and then the ‘shortening’.
  2. The amplitude or distance over which the SSC action occurs should be limited.
  3. The amortisation phase - that is the transition time between both contractions - must be short.

All three key factors must be evident for a true plyometric action to occur.

The first phase is the pre-stretch or eccentric muscle action. Here, it is theorised that elastic energy is generated and stored.

During the amortisation phase the muscle is literally stopping and changing from an eccentric action to a concentric one. The shorter this phase is, the more powerful the subsequent muscle contraction will be as a result of a return of stored energy in the previous eccentric action.

The third phase is the powerful and augmented muscle contraction leading to a jump, throw or propulsion of the leg or supported body mass upwards or forwards or backwards. This sequence of three phases is also known as the SSC. Plyometrics and stretch-shortening cycle actions are one of the same.