Plyometrics

Plyometric training is a method of training that aims to enhance high rates of force production and power which allows the player to become more explosive (Jeffreys and Moody, 2016; Popovic, 2016). Plyometric training can be thought of as exercises that require players to receive and control a high load at high speed and then explosively contract the muscles to produce a movement. An example would be if a player is asked to jump and as soon as they land jump again. The big landing force on the player from the jump must be received and controlled before the explosive movement of another jump. This type of training takes advantage of a physiological response call the stretch shortening cycle.

The stretch shortening cycle occurs when a rapid stretching of a muscle (landing from a jump) is followed by a shortening or contraction of the muscle (the second jump) (Jeffreys and Moody, 2016). This rapid stretch results in storing of elastic energy like stretching a spring and this energy is released in the following contraction resulting in a more explosive action. This is a very good training method for enhancing speed, as sprinting is basically a plyometric exercise - this fits well with the principle of training specificity. When the player’s foot hits the ground during sprinting there is a rapid stretch on the muscles to control the landing forces and then this is followed by an explosive push-off with the foot.

Plyometric training can be done for both the upper and lower body but the lower body has many more exercise variations and the enhanced explosiveness of the lower body transfers very well to most team sports. Upper body plyometric training may have relevance to rugby in action such as fending or handing-off but generally the player will benefit more from lower body plyometric training. A recent review on plyometric training in team sports athletes concluded that plyometric training was suitable to improve vertical jump performance and sprint performance which are key performance attributes in the game of rugby (Slimani et al, 2016). Plyometric training should be done when the player is fresh and not fatigued. The number of repetitions of an exercise is usually between 3-10 foot/hand contacts depending on the intensity of the exercise and work rest ratio of 1:10 is suggested to keep the quality of the movements high (Jeffreys and Moody, 2016). With plyometric exercise the coach is looking for quality of movement rather than quantity - so sufficient rest to get rid of fatigue is needed. Some examples of plyometric training exercises are detailed below:

Ankle hops (Beginner) – the player jumps as high as possible using mainly the drive from flexing their ankles, they then rebound in the same manner using the drive from the ankles, the hops are repeated in a row without rest, forefoot weight distribution with heel aiming to be off the ground, stiff ankle and knee on landing to quickly absorb the landing force, minimal ground contact time.

Drop jump (Advanced) – the player steps off a box, lands and immediately jumps up into the air, forefoot weight distribution with heel aiming to be off the ground, stiff ankle and knee on landing to quickly absorb the landing force, minimal ground contact time.

Tuck Jumps (Advanced) - stand in one spot the player jumps as high as they can, they bring their knees into their chest during the jump, as soon as they land they jump again, forefoot weight distribution with heel aiming to be off the ground, stiff ankle and knee on landing to quickly absorb the landing force, minimal ground contact time

Bounding (intermediate) – the player strides forward covering as much distance per ground contact as possible, arm action mimics sprinting with opposite arm to opposite leg, forefoot weight distribution with heel aiming to be off the ground, stiff ankle and knee on landing to quickly absorb the landing force, minimal ground contact time.

Plyometric push-up (Advanced) – they player starts in a push-up position with hands elevated on weights or a ledge, they drop the hands down to the ground, as soon as the hands make contact with the ground the player pushes up exploding back up to the original hand position, stiff elbow and shoulder to absorb the force quickly, minimal hand ground contact time.

Skipping for height