What is it?
Plyometric training is a set of exercises or drill which looks to increase an individual’s power by combining exercised based on speed and power. Usually involving bodyweight exercises, plyometric uses the stretch-shortening cycle muscle action to produce maximal force in the shortest amount of time (Markovic and Mikulic, 2010). This development of explosive movement has become very popular with the arrival of programmes such as crossfit and includes a variety of disciplines such as jumping, box jumps, counter-movement jumps, kettlebells, pull-up bars and resistance bars carried out usually at a high intensity.
Why is this training method used?
Speed and agility training can provide stimulus at the high velocity spectrum of the force-velocity curve (see below) and can be beneficial in a variety of sports including football (Hoffman, Cooper, Wendell and Kang, 2004). That ability to jump higher to win the ball or leap over an oncoming defender can be the difference between success and failure.
Variations and Adaptations
With footballers required to make a huge number of explosive actions during a game, it is advantageous to build explosive power in the leg muscles to aid in jumping, kicking, turning and changing pace (Ronnestad, Kvamme, Sunde and Raastad, 2008). There are a variety of plyometric exercises that specifically target the lower limbs as shown in the video below.
After plyometric training, athletes can expect to find an increase in the proportion of type II muscle fibres as well as an increase in force development, motor unit recruitment and inter-muscular c-ordination resulting in a more efficient movement (Gouvea et al, 2012).
Further to this, plyometric training has also been found to increase anaerobic performance during short term plyometric programmes (Luebbers et al, 2003).
Literature and future research
Plyometric training has been found to increase power, jump height and sprint performance (Ronnestad et al, 2008). In a study of sprint times over 10m and 40m, sprint-specific plyometric training reduced the time taken for both distances compared to traditional sprint training (Rimmer and Sleivert, 2000).
Jumping has been found to produce forces up to 7 times an individual’s body weight and is conducive to increasing bone mass, predominantly in young teenagers (Markovic and Mikulic, 2010). This force however can be reduced significantly (up to 80%) by adopting the correct landing technique as found by (Hewett et al, 1996). Plyometric training traditionally takes place on hard surfaces such as wood or concrete with matting but this can lead to induced muscle damage. In a study of muscle soreness following jumping and sprinting on various surfaces, Impellizzeri et al (2008) highlighted that landing on sand induced less muscle soreness and resulted in improved jumping and sprint times. Plyometrics on a grass surface however resulted in greater improvements in counter-movement jumps. This study highlighted that different surface areas can lead to different adaptations and is one of the many factors to be taken into consideration when planning a plyometric session.
Many of the studies conducted have been over a short period of time with little research carried out supporting the long term effects of plyometric training (Luebbers et al, 2003).
Plyometric training has been shown to be effective on its own however greater improvements have been found when combing with other methods of training. Weightlifting, aerobics training, and electro-stimulation have been found to aid plyometric training in enhancing a number of physical attributes such as jumping, sprinting, agility and endurance (Markovic and Mikulic, 2010).
Plyometric training is very inexpensive and is easy to learn. Plyometric training is advisable to increase performance and prevent injury and is best used in conjunction with some sort of resistance programme. Before planning a plyometric programme coaches are advised to consider their athletes injury records, coordination and bodyweight as these are factors that can affect expected performance.
Personally I am not a fan of some aspects of plyometric training due to the impact on my knees. However it’s hard not to recognise the benefits of this method of training and the proposed reduction of impact using the correct technique. Therefore, I will look to incorporate plyometric training into my own training plan in the near future.
GOUVÊA, A. L., FERNANDES, I. A., CÉSAR, E. P., SILVA, W. A. B., & GOMES, P. S. C. 2013. The effects of rest intervals on jumping performance: A meta-analysis on post-activation potentiation studies. Journal of sports sciences, 31(5), 459-467.
HEWETT, T. E., STROUPE, A. L., NANCE, T. A., & NOYES, F. R. 1996. Plyometric training in female athletes decreased impact forces and increased hamstring torques. The American Journal of Sports Medicine, 24(6), 765-773.
HOFFMAN, J. R., COOPER, J., WENDELL, M., & KANG, J. 2004. Comparison of Olympic vs. traditional power lifting training programs in football players. The Journal of Strength & Conditioning Research, 18(1), 129-135.
IMPELLIZZERI, F. M., RAMPININI, E., CASTAGNA, C., MARTINO, F., FIORINI, S., & WISLOFF, U. 2008. Effect of plyometric training on sand versus grass on muscle soreness and jumping and sprinting ability in soccer players. British journal of sports medicine, 42(1), 42-46.
LUEBBERS, P. E., POTTEIGER, J. A., HULVER, M. W., THYFAULT, J. P., CARPER, M. J., & LOCKWOOD, R. H. 2003. Effects of plyometric training and recovery on vertical jump performance and anaerobic power. The Journal of Strength & Conditioning Research, 17(4), 704-709.
MARKOVIC, G., & MIKULIC, P. 2010. Neuro-musculoskeletal and performance adaptations to lower-extremity plyometric training. Sports medicine, 40(10), 859-895.
RIMMER, E., & SLEIVERT, G. 2000. Effects of a Plyometrics Intervention Program on Sprint Performance. The Journal of Strength & Conditioning Research, 14(3), 295-301.
RONNESTAD, B. R., KVAMME, N. H., SUNDE, A., & RAASTAD, T. 2008. Short-term effects of strength and plyometric training on sprint and jump performance in professional soccer players. The Journal of Strength & Conditioning Research, 22(3), 773-780.