At the beginning of every off season or start to a junior development program you will see many tests being performed. Some are for strength or power in the gym, others are to asses "fitness" levels on the field. I have a few problems with this for a couple of reasons.
The tests are poorly chosen and don't correlate to increased sports performance
The tests chosen are too advanced for the athlete the majority of the time
The standards for how the tests are performed aren't strict enough or monitored correctly
The data collected isn't used appropriately to design programs or dictate the direction of training
Poorly chosen tests
If you decide to test something you want to make sure that by improving your performance in that test it increases performance on the field. If not it is a complete waste of time. I have done many tests over the years and can say that I have not done one that can correlate to levels of conditioning on the rugby league field effectively.
The closest in my opinion was a phosphate test done where you sprint for 7 seconds, your distance is measured while you jog to the end of the field in the remaining 23 seconds before repeating your 7 second sprint. You do 8 of these and it is one of the toughest tests out of them all. I like it because it can give you information on which athlete might need to work on anaerobic power and which one might need to work on anaerobic capacity for example.
The other tests such as 2km time trials, beep tests, yo-yo tests etc. don't give me this type of information. They have algorithms for training sessions that go with the results but I can tell you that if you score high on the initial test by week 3 or 4 of that program designed from the algorithm you will not make the target times. I have personally experienced this and so has Beau Ryan who was the fittest at the Wests Tigers for many years. He had to try and cover a ridiculous distance due to his high initial test score. It is impossible and disheartening to the athlete. Not only that he was already the fittest in the club at the time and plenty fit enough to play 80 minutes on the wing, so to me it makes no sense to get him to run more and more. For an athlete like that in my team, he would be in the gym twice a day working on his strength as that would have served him much better. You only need to be so fit.
The tests chosen are too advanced
This one relates to the gym. You may have a strength coach who tests the power clean, squat, bench, chin, and dip. All good lifts in most people's opinion. That is if the lifter is advanced enough and knows how to perform the lifts correctly. If you do these lifts with athletes of a young training age you can bet they are terrible tests. I don't see any young 15 year old that can squat efficiently on day one let alone power clean, so the chance for injury is high and the test results will be unreliable and irrelevant due to the poor technique. In fact, I see kids who are 20 years of age struggle to perform these lifts properly. They have not been shown the correct technique so are still like beginners, they should be treated that way.
A postural assessment and some length tension tests often give you enough information to design an effective program for a beginner. Throw in a Klatt test and you will have plenty of data to guide your initial program.
If you want or need so performance based tests then use a vertical jump, a med ball chest pass, a chin up, and maybe some type of bounding. They are all easy tests to perform technically, have a low risk of injury, can be tested easily and quickly, and are repeatable.
Standards for how the test are performed
The biggest problem for this is poor organisation and at times just laziness. When you perform any test you need strict guidelines on how the test is to be performed others your data will mean nothing. Not to the individual and not to the group. An example is the chin up. When I test the chin up, it is from arms fully stretched, to upper chest to the bar. You lower yourself in 4 seconds. That is a rep. if you don't lock out in the bottom, the rep doesn't count. If your chin doesn't clear the bar or you have to try and chuck your neck over it, doesn't count. if you "kip", doesn't count. That is the standard. If you go and watch a team get tested in the lower grades in rugby league you will see some guys doing half reps, others kipping, others not clearing the bar, but all the reps are still counted. Often the results are printed out and you are ranked accordingly. You can't compare when there is no standard. I might do 6 full range chins and another player gets 20, but he has only done little half rep pumps. You can't even compare an individual to his previous result if he doesn't stick to the standard of the test. If the half repper got 20 on day 1 and then 30 on the next testing day, how do you know if he is stronger? Did he just cut his range of motion even shorter?
You need a coach at each test monitoring the technique and keeping the standards in place. This doesn't happen because a lot of the time its one strength coach and 20 athletes floating around the gym. The other thing because of this is that the tests aren't performed in any specific order. So again how can you know if your results are accurate. Someone may test dips for max reps and then move over to the bench and perform a 3rm for example. Next test what happens if he does bench first and then dips second? I'm sure his bench will be way up. Again is it due to effective programming or is it because he was fresh this time around?
There is no exercise order, no set rest period, no standard for the technique to be used, no tempo, it is really a waste of time. Plan it properly or don't bother.
The data collected isn't used appropriately
The data collected is a waste of time because of all the above reasons. It should be used to dictate the direction of training but when your tests are useless then you can't do this effectively anyway. When done correctly you can use the data gained to individualise the athletes program much more effectively. For example you may have a great bench but terrible rotator cuff strength. In that case you would program more rotator cuff work in at the beginning of the program to bring them up to par, reduce injury, and increase performance. You can have an athlete with great anaerobic capacity but need to focus more on anaerobic power. You could find this out from an effective test, make their training more beneficial and avoid overtraining and injury.
Fortunately I learned how to effectively test and use the information from Charles Poliquin many years ago and is why my athletes tend to have far less injuries and improve there strength, speed, and conditioning at a really good rate.