The biggest mistake in training athletes to get faster.
Both speed and agility are critically important for athletes to be successful on the field. Unfortunately I see plenty of programs or services offered by coaches that are skewed in the wrong direction, they promise to "decrease your 40 time" or "drop your home to first time". While both of these things are important in the recruitment of athletes, they are not critically important to the performance of athletes. Training speed and agility in some cases, verges on running some sprints and breaking out the agility ladder.
Here is the third and final portion of ‘Young Athletes & Coordination’:
(3) Teenage Athletes Are ‘Too Old’
Now, while there is truth to the matter that many of the sensitive periods for coordination development lay during the preadolescent phase of life, it would be shortsighted to suggest that teenage athletes should not be exposed to this type of training.
Firstly, much of the training of coordination takes the form of injury preventative. Any sort of ‘balance’ exercise, for example, requires proprioceptive conditioning and increases in stabilizer recruitment. With ‘synchronization of movement’, large ROM and mobility work is necessary. ‘Kinesthetic differentiation’, by definition, involves sub-maximal efforts or ‘fine-touch’ capacity which is a drastically different stimulus than most young athletes are used to in training settings.