really I don't see fast pops as before though I am training 18 ylds, so I thought may be the trainer is the problem.
What are you training? Your pops might be slowing down because your players skill levels are higher. Either that or you need to buy a higher level trainer....
From BBMark, "We do give taller player bumps in rebounding, and shorter players bumps in handling in terms of how fast they train for example"