Stanislav Kasampalis | Laboratory evaluation
Laboratory evaluation »
In football it is well known that the ability to have explosiveness and power at the lower extremities in a football player are very important factors in performance, as the nature of the sport requires many explosive actions during a match (1,3). Also, the jumping ability, as an expression of power, is a basic factor for a good performance in the specific sport (2,7,9). The reason for this is that the football player requires to perform fast and jump high for a successful header and in order to achieve that, it also requires high and explosive jumping ability. One way to evaluate jumping ability, lower body power and neuromuscular coordination, is the use of vertical jump test. It’s a simple, practical, valid and very reliable measure which can provide us with very useful information and work on any weakness might present. The test has been measured using force platforms or led bar systems connected to a laptop. The most widely used techniques by researchers are Squat Jump (SJ) and Counter – Movement Jump (CMJ). Both are useful for assessing athletic performance and each of the test provides us with different information due to their different techniques. The SJ (Picture 1) is used as a measure of lower body concentric strength / power and is performed in a semi squat position while CMJ (Picture 2) is used as a measure of lower body reactive strength / power (performed with counter movement), the ability of the neuromuscular coordination and the coordination among muscles (stretch and shortening cycle, (SCS) (1,5,7).
Laboratory evaluation »
Why is this test useful and what is the conclusion? Research has shown that these tests have relationship with sprint performances (3), acceleration in a sprint (4), greater flight time (6), and increased 1RM maximal strength in squat (9). The jumping ability in football players varies between 47.8 – 60.1 cm. Based on the literature the vertical jumping profile of a football player should be at least 45 cm in a competitive level (2).
Taking these information into consideration, the strength and conditioning coach may design or develop a training plan based on the athletes results as well as for the whole team in order to enhance performance. A large proportion of literature has conducted variety of studies in improving jumping ability and also what kind of exercise training is more efficient. The vertical jumps are explosive movements which require fast action and strength in the lower extremities (3,5). For this reason, plyometric exercises have been proposed and have attracted the attention of sport scientists for the reasons mentioned earlier above. Several research studies have shown that plyometric exercise develop the power and explosiveness in athletes (7,8,9). The table below illustrates various of training methods in enhancement of jumping ability alongside with other parameters. It is clear that plyometric exercise training positively contributing to improved performance after conducting numerous of tests.
Table 1. Values for each exercise training program and its effect on different parameters
Laboratory evaluation »
Lastly, the vertical jump assessment can provide us with useful information regarding athlete jumping ability as well as other variables, where strengths and weaknesses can be detected and an appropriate training plan can be designed in order to develop sport specific characteristics. Based on the research, it can be concluded that applying plyometric exercise training into a football training program can induce significant improvements in various parameters.
- Arabatzi, F., Kellis, E. & De Villareal, E. S. (2010). Vertical jump biomechanics after plyometric, weight lifting, and combined (weight lifting + plyometric) training. Journal of Strength and Conditioning Research, 24(9), 2440- 2448
- Cronin, B, J., & Hansen, K, T. (2005). Strength and Power Predictors of Sports Speed. Journal of Strength and Conditioning Research, 19 (2), 349-357.
- Gerodimos, V., Manou, V., Ioakimidis, P., Perkos, S., & Kellis, S. (2006). Vertical Jumping Ability in Elite Young Soccer Players. Journal of Human Movement Studies,
- Heishman, A., Brown, B., Daub, B., Miller, R., Freitas, e., & Bemben, M. (2019). The Influence of Countermovement Jump Protocol on Reactive Strength Index and Flight Time: Contraction Time in Collegiate Basketball Players. Sports. 7(2),
- Kellis, E., Arabatzi, F. & Papadopoulos, C. (2003). Muscle co-activation around the knee in drop jumping using the co-contraction index. Journal of Electromyography and Kinesiology, 13, 229-238.
- Martinez, D, B. (2016). The use of Reactive Strength Index, Reactive Strength Index Modified, and flight time: Contraction time as monitoring tools. Journal of Australian Strength and Conditioning, 24, 37-41
- Meylan, C. & Malatesta, D. (2009). Effects of in-season plyometric training withing soccer practice on explosive actions of young players. Journal of Strength and Conditioning Research, 23(9), 2605-2613.
- Michailidis, Y., Fatouros, I. G., Primpa, E., Michailidis, C., Avloniti, A., Chatzinikolaou, A., Barbero-Alvarez, J. C., Tsoukas, D., Douroudos, I. I., Draganidis, D., Leontsini, D., Margonis, K., Berberidou, F. & Kambas, A. (2013). Plyometrics’ trainability in preadolescent soccer athletes. Journal of Strength and Conditioning. 27(1), 38-49.
- Vaczi, M., Tollar, J., Meszler, B., Juhasz, I. & Karsai, I. (2013). Short-term high intensity plyometric training program improves strength, power and agility in male soccer players. Journal of Human Kinetics, 36, 17-26.