I am looking for some opinions on stretching for training and
jumping.

I have researched quite a bit and have come up with the theory that
it is best to warm-up and stretch for all training sessions. This
obviously increases flexibility and range of motion. I also think
that when a person trains hard after stretching, his or her muscles
strengthen more.

Research has shown that warming-up is required to prevent injury,
and that stretching does not help prevent injury. On jumping or
competition days, it is my belief that only warming-up is
necessary. While I believe stretching is excellent before training,
I also believe that it releases power from and decreases elasticity
of one's legs. Therefore, only warming-up (no stretching) before
jumping will yield higher jumps.

This is a research based theory.
I would greatly appreciate input from anybody who knows more about
this or who has an opinion about this.

Thanks,

Dave