What assessments do you find useful in training for young athletes?
It depends on a lot of factors as the primary objectives of training young athletes varies as they progress in training age:
In the earliest stages you are primarily concerned with mobility, stability and motor control, in addition to performing fundamental movement patterns. For that reason I like the FMS. People have criticised the FMS in general and in particular for it’s use in assessing young athletes, but I like it. It puts movement into a standardised language that coaches easily understand, it is useful for organising one’s thoughts for programming and corrective exercise, and it is highly reliable from one coach to another.
At its most simplistic I find the FMS will always tell you who your best movers are. The guys who score highly on the FMS are the guys who tend to suffer fewer injuries, are easier to coach movement to, and are generally more efficient on the pitch. These are important qualities that I feel a lot of players overlook: coaches want players who aren’t going to be a drain on the medical department and who are easy to coach!
Right at the other end of youth training, you are primarily concerned with their ability to play the adult game, so strength, power, speed and repeat-ability tests become more important. As ever, the importance of these tests will vary by position, how your team plays the game and what you as a coach value, but certainly they are the important things at this time. Nobody gives a crap about a 20 year old kid who scores 21 on the FMS but is weaker than a vegan yoga instructor- a harsh reality.
From a developmental perspective you may also want to use peak height velocity to try and gauge when your athletes are undergoing growth spurts. Remember that growth is a huge energy drain, as is training, so both cannot be emphasised at once. If you are heavily stressing your guys when they are growing, that is when they will start to break. Temporary weaknesses in connective tissue combined with new found strength and size, but with the motor control of a fish out of water is a recipe for disaster!