Strength and power needs to be assessed due to their importance with regard to speed (5, 6, 30, 40, 43, 45), change of direction (3), jumping (6, 34, 40, 45) kicking (6, 11, 13, 23, 30-32, 34, 41, 45, 48) and injury prevention (2, 8, 10, 12, 14, 20, 28, 29, 36, 37, 47). Differences in these components were also seen in level of play (7, 15, 16, 19) or age (21), with regard to positional specific characteristics (44) of players as well as their overall player development (6, 15, 22, 24, 26, 27, 45) - see references below.
As it seems evident strength and power plays a crucial role in football, however, there seems to be many questions with regard to strength and
power testing in football - what to test and how to test, the debate about strength and power testing with regard to football specific strength and power testing and finally the
targeted areas for testing in football specific strength/power training.
What to test?
Generally, testing the major muscle groups of the legs seemed to be appropriate. The major muscle groups can be divided into leg extensors and leg flexors.
Additionally, we believe it is appropriate to test the core and shoulder stability/performance.
Furthermore, it is also important what specific component of strength (i.e. maximum, reactive, and/or rate of force development (17, 18)) and power should be tested. However, we want to
(indirect) elaborate on this in the next section (how to test).
How to test?
Generally, strength and power is tested by lifting a certain amount of weight for a certain amount of times. Usually the procedures involve the 1-repetition maximum (1RM) test. However, if equipment is available, a more scientific and in depth analysis can be performed. In this case (and most of the times) an isokinetic dynamometer (41) will be used.
We believe that most environments will not have that relatively expensive type of equipment, and/or not the manpower and more importantly the time, therefore we would like to elaborate on
strength and power testing using free weights or machines.
First of all we would like to give some thoughts about the mentioned “issue” about strength and power tests vs. football specific strength and power tests. In order to do so, we would like to consider the speed of execution (during a football movement).
Usually any movement in football is quite fast compared to the speed in strength and power testing (and training).
The scientific name for that phenomena is called “force-velocity relationship” and basically saying that the faster a movement, the less force and power produced due to the less cross bridges in
the muscle, as it is more likely to activate (more) fast twitch fibers. Therefore, does a normal 1RM-strength and power test replicate the football specific strength and power?
With those information in mind the question arise how to test for football specific strength and power. Well, kinematic analysis of kicking (42) revealed how to test (scientifically) for a
particular movement, and therefore video and or accelerometers might present a possibility to test for football specific strength and power.
However, having said that and with the limitation in mind it seems that this setup is really impractical and we have not heard/read of any reliable test. As a result, testing for a classical
1-repetition maximum (1RM) in relation to body mass (44) seems to be a reliable way to test football players.
Leg strength/power should be measured as presented in the literature with a (half) back squat (1, 25, 34, 39, 40, 46), leg extension (34), isometric (30) leg press (6, 34), leg curl (25, 34), step up (25) for lower body and bench press (6, 38, 46) for upper body in a practical set-up.
Strength and power assessments utilizing a isokinetic dynamometer (41) (- just in case you have access to one, the time and knowledge to use it) should incorporate (35):
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