For sports that have a very large endurance component, like soccer, would you recommend using higher reps for assistance exercises and keep the dynamic work, or do the repetition day instead of the dynamic days?
I use the weight room to build STRENGTH, regardless of what kind of endurance component is involved in the sport. Since there is definately more of an aerobic component to soccer than baseball, for example, I would make the biggest changes in my soccer players conditioning and GPP workouts.
As far as the weight room is concerned, it's up to you to figure out what you or your players need with regards to repetition work, dynamic work, etc. I feel soccer players can greatly benefit from repetion work, dynamic work and max-effort work. The key lies in WHEN, HOW and with WHO to implement these techniques.
Hope this clears things up a bit.