Plyometric training is a commonly used practice across many sports. This is because it has been shown to enhance the rate of force development within muscle (i.e. power), muscle strength, co-ordination, and athletic performance (Adams et al. 1992).
A plyometric exercise is characterised by a stretch-shortening cycle (SSC) action, whereby the muscle undergoes an eccentric phase (stretch of the muscle) followed by a concentric phase (shortening of the muscle) (Bobbert. 1990). During the eccentric phase elastic energy is stored and then released during the concentric phase to enhance the force development during the action. The transition between the two phases is known as the amortization phase, keeping this phase to a minimum (< 250 milliseconds) is essential to not allow for the energy stored during the eccentric phase to be dissipated.
Sticking to this logic there is only one “true” plyometric exercise, which is the drop jump because it is the only exercise which you can keep the amortization phase below 250 milliseconds, however like with any training modality there has to be a progressive ladder building up to the main high level exercise. The drop jump being at the top of the plyometric spectrum, with more low level exercises that still involve the SSC action (the countermovement jump (CMJ), alternate-leg bounding, hopping, rebound double leg jumps, etc..) building up to it.
The effects of plyometric training can differ depending upon the individuals characteristics, such as training level (Brown et al. 1986), gender (Bosco C & Komi PV. 1980), age (Paasuke et al. 2001), and their familiarity with plyometric training (Verhoshanski. 1979). Thus it is essential to take these factors into account when planning a session. The most basic principle when planning a plyometric session with a beginner during the offseason is to implement 60 foot contacts in a session and increase that by 10 a week (Chu, 1992). Following a plyometric session the muscle damage will be extensive due to the eccentric load placed on the muscle, thus greater than 48 hours rest is required before undertaking another plyometric session is recommended to guard against possible injury.
Below is an example plyometric session I would undertake with younger and more novice trainees. This will help build the basic foundations for plyometric work. Technique is essential; the whole session should be on the balls of the feet.
- Balls of the feet bounce walk x 2
- Pilar march x 4 (double and single leg) – progressing intensity to make more forceful contacts
- Double contact pilar march x 4 (double and single leg) – not a skip, driving down to bounce back up to make double contact
- Bunny Hops 3 x 4 – quick contacts in a short distance
- Pogos 3 x 4 – emphasis more on vertical height of jump not going forward
- Bounds 3 x 4
A video example of this session will be posted on our YouTube channel later in the week.